Micromachines

14 pages, 3445 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Hybrid Actuation MEMS Micromirror with Decoupled Piezoelectric Fast Axis and Electromagnetic Slow Axis for Crosstalk Suppression

by Haoxiang Li, Jiapeng Hou, Zheng Gong, Huijun Yu, Yue Liu and Wenjiang Shen

Micromachines 2025, 16(9), 1072; https://doi.org/10.3390/mi16091072 - 22 Sep 2025

Viewed by 124

Abstract

Electromagnetic micro-electro-mechanical system (MEMS) micromirrors are widely used in optical scanning systems but often encounter mechanical crosstalk due to the use of shared drive coils. This phenomenon leads to parasitic motion along the slow axis during fast-axis operation, resulting in undesirable elliptical scanning [...] Read more.

Electromagnetic micro-electro-mechanical system (MEMS) micromirrors are widely used in optical scanning systems but often encounter mechanical crosstalk due to the use of shared drive coils. This phenomenon leads to parasitic motion along the slow axis during fast-axis operation, resulting in undesirable elliptical scanning patterns that degrade image quality. To tackle this issue, a hybrid actuation scheme is proposed in which a piezoelectric actuator drives the fast axis through an S-shaped spring structure, achieving a resonance frequency of 792 Hz, while the slow axis is independently driven by an electromagnetic actuator operating in quasi-static mode. Finite element simulations and experimental measurements validate that the proposed decoupled design significantly suppresses mechanical crosstalk. When the fast axis is driven to a 40° optical scan angle, the hybrid system reduces the parasitic slow-axis deflection (typically around 1.43°) to a negligible level, thereby producing a clean single-line scan. The piezoelectric fast axis exhibits a quality factor of Q = 110, while the electromagnetic slow axis achieves a linear 20° deflection at 20 Hz. This hybrid design facilitates a distortion-free field of view measuring 40° × 20° with uniform line spacing, presenting a straightforward and effective solution for high-precision scanning applications such as LiDAR (Light Detection and Ranging) and structured light projection. Full article

(This article belongs to the Special Issue Piezoelectric MEMS/NEMS—Materials, Devices, and Applications, Third Edition)

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23 pages, 8269 KB

Open AccessFeature PaperEditor’s ChoiceArticle

A Novel Double-Diamond Microreactor Design for Enhanced Mixing and Nanomaterial Synthesis

by Qian Peng, Guangzu Wang, Chao Sheng, Haonan Wang, Yao Fu and Shenghong Huang

Micromachines 2025, 16(9), 1058; https://doi.org/10.3390/mi16091058 - 18 Sep 2025

Viewed by 311

Abstract

This study introduces the Double-Diamond Reactor (DDR), a novel planar passive microreactor designed to overcome the following conventional limitations: inefficient mass transfer, high flow resistance, and clogging. The DDR integrates splitting–turning–impinging (STI) hydrodynamic principles via CFD-guided optimization, generating chaotic advection to enhance mixing. [...] Read more.

This study introduces the Double-Diamond Reactor (DDR), a novel planar passive microreactor designed to overcome the following conventional limitations: inefficient mass transfer, high flow resistance, and clogging. The DDR integrates splitting–turning–impinging (STI) hydrodynamic principles via CFD-guided optimization, generating chaotic advection to enhance mixing. Experimental evaluations using Villermaux–Dushman tests showed a segregation index (

X_{s}

) as low as 0.027 at 100 mL·min⁻¹, indicating near-perfect mixing. In BaSO₄ nanoparticle synthesis, the DDR achieved a 46% smaller average particle size (95 nm) and narrower distribution (

σ_{g} = 1.27

) compared to reference designs (AFR-1), while maintaining low pressure drops (<20 kPa at 60 mL·min⁻¹). The DDR’s superior performance stems from its hierarchical flow division and concave-induced vortices, which eliminate stagnant zones. This work demonstrates the DDR’s potential for high-throughput nanomaterial synthesis with precise control over particle characteristics, offering a scalable and energy-efficient solution for advanced chemical processes. Full article

(This article belongs to the Section E：Engineering and Technology)

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16 pages, 1847 KB

Open AccessFeature PaperEditor’s ChoiceArticle

The Fluidic Shear Stress Loading Method Enables Mechanobiological Stimulation in an On-Chip Pump-Integrated Microphysiological System

by Jin Hong Yap, Satoshi Ishizaki, Hiroko Nakamura, Kenta Shinha and Hiroshi Kimura

Micromachines 2025, 16(9), 1051; https://doi.org/10.3390/mi16091051 - 15 Sep 2025

Viewed by 437

Abstract

Microphysiological systems (MPSs), such as organ-on-a-chip platforms, are promising alternatives to animal testing for drug development and physiological research. The BioStellar™ Plate is a commercial MPS platform featuring an open-top culture chamber design with on-chip stirrer pumps that circulate culture medium through six [...] Read more.

Microphysiological systems (MPSs), such as organ-on-a-chip platforms, are promising alternatives to animal testing for drug development and physiological research. The BioStellar™ Plate is a commercial MPS platform featuring an open-top culture chamber design with on-chip stirrer pumps that circulate culture medium through six independent, dual microchannel-connected chamber multiorgan units. Although this design enables a circular flow, the open-top culture chamber format prevents the application of fluidic shear stress, a force that cells experience in vivo, which affects their behavior and function. To address this, we developed two fluidic shear stress attachments for the BioStellar™ Plate. These attachment channel fluids provide controlled mechanical stimulation to cultured cells. The flow dynamics were simulated using COMSOL Multiphysics to estimate shear stress levels. The attachments were fabricated and validated through fluorescent bead tracking and biological assays. The FSSA-D is designed for flat-bottom standard cell cultures, while the FSSA-I is designed for epithelial monolayers, enabling the application of fluidic shear stress across the basal membrane. Experiments with intestinal epithelial cells (Caco-2) demonstrated that both attachments enhanced cell barrier function under a fluidic environment, as indicated by higher transepithelial electrical resistance (TEER). These findings demonstrate that the attachments are practical tools for mechanobiology research with MPS platforms. Full article

(This article belongs to the Special Issue Micro-/Nanofluidic and Lab-on-a-Chip Devices for Biomedical Applications, 3rd Edition)

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53 pages, 2691 KB

Open AccessFeature PaperEditor’s ChoiceReview

Heterogeneous Integration Technology Drives the Evolution of Co-Packaged Optics

by Han Gao, Wanyi Yan, Dan Zhang and Daquan Yu

Micromachines 2025, 16(9), 1037; https://doi.org/10.3390/mi16091037 - 10 Sep 2025

Viewed by 989

Abstract

The rapid growth of artificial intelligence (AI), data centers, and high-performance computing (HPC) has increased the demand for large bandwidth, high energy efficiency, and high-density optical interconnects. Co-packaged optics (CPO) technology offers a promising solution by integrating photonic integrated circuits (PICs) directly within [...] Read more.

The rapid growth of artificial intelligence (AI), data centers, and high-performance computing (HPC) has increased the demand for large bandwidth, high energy efficiency, and high-density optical interconnects. Co-packaged optics (CPO) technology offers a promising solution by integrating photonic integrated circuits (PICs) directly within or close to electronic integrated circuit (EIC) packages. This paper explores the evolution of CPO performance from various perspectives, including fan-out wafer level packaging (FOWLP), through-silicon via (TSV)-based packaging, through-glass via (TGV)-based packaging, femtosecond laser direct writing waveguides, ion-exchange glass waveguides, and optical coupling. Micro ring resonators (MRRs) are a high-density integration solution due to their compact size, excellent energy efficiency, and compatibility with CMOS processes. However, traditional thermal tuning methods face limitations such as high static power consumption and severe thermal crosstalk. To address these issues, non-volatile neuromorphic photonics has made breakthroughs using phase-change materials (PCMs). By combining the integrated storage and computing capabilities of photonic memory with the efficient optoelectronic interconnects of CPO, this deep integration is expected to work synergistically to overcome material, integration, and architectural challenges, driving the development of a new generation of computing hardware with high energy efficiency, low latency, and large bandwidth. Full article

(This article belongs to the Special Issue Emerging Packaging and Interconnection Technology, Second Edition)

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22 pages, 4991 KB

Open AccessFeature PaperEditor’s ChoiceReview

Meta-Optics for Optical Engineering of Next-Generation AR/VR Near-Eye Displays

by Junoh Lee and Sun-Je Kim

Micromachines 2025, 16(9), 1026; https://doi.org/10.3390/mi16091026 - 7 Sep 2025

Viewed by 900

Abstract

Meta-optics, enabled by metasurfaces consisting of two-dimensional arrays of meta-atoms, offers ultrathin and multi-functional control over the vectorial wavefront of light at subwavelength scales. The unprecedented optical element technology is a promising candidate to overcome key limitations in augmented reality (AR) and virtual [...] Read more.

Meta-optics, enabled by metasurfaces consisting of two-dimensional arrays of meta-atoms, offers ultrathin and multi-functional control over the vectorial wavefront of light at subwavelength scales. The unprecedented optical element technology is a promising candidate to overcome key limitations in augmented reality (AR) and virtual reality (VR) near-eye displays particularly in achieving compact, eyeglass-type form factors with a wide field-of-view, a large eyebox, high resolution, high brightness, and reduced optical aberrations, at the same time. This review highlights key performance bottlenecks of AR/VR displays in the perspective of optical design, with an emphasis on their practical significance for advancing current technologies. We then examine how meta-optical elements are applied to VR and AR systems by introducing and analyzing the major milestone studies. In case of AR systems, particularly, two different categories, free-space and waveguide-based architectures, are introduced. For each category, we summarize studies using metasurfaces as lenses, combiners, or waveguide couplers. While meta-optics enables unprecedented miniaturization and functionality, it also faces several remaining challenges. The authors suggest potential technological directions to address such issues. By surveying recent progress and design strategies, this review provides a comprehensive perspective on the role of meta-optics in advancing the optical engineering of next-generation AR/VR near-eye displays. Full article

(This article belongs to the Special Issue Advances in Nanophotonics: Physics, Materials, and Applications)

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19 pages, 5988 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Design of Hydrogel Microneedle Arrays for Physiology Monitoring of Farm Animals

by Laurabelle Gautier, Sandra Wiart-Letort, Alexandra Massé, Caroline Xavier, Lorraine Novais-Gameiro, Antoine Hoang, Marie Escudé, Ilaria Sorrentino, Muriel Bonnet, Florence Gondret, Claire Verplanck and Isabelle Texier

Micromachines 2025, 16(9), 1015; https://doi.org/10.3390/mi16091015 - 31 Aug 2025

Viewed by 650

Abstract

For monitoring animal adaptation when facing environmental challenges, and more specifically when addressing the impacts of global warming—particularly responses to heat stress and short-term fluctuations in osmotic regulations in the different organs influencing animal physiology—there is an increasing demand for digital tools to [...] Read more.

For monitoring animal adaptation when facing environmental challenges, and more specifically when addressing the impacts of global warming—particularly responses to heat stress and short-term fluctuations in osmotic regulations in the different organs influencing animal physiology—there is an increasing demand for digital tools to understand and monitor a range of biomarkers. Microneedle arrays (MNAs) have recently emerged as promising devices minimally invasively penetrating human skin to access dermal interstitial fluid (ISF) to monitor deviations in physiology and consequences on health. The ISF is a blood filtrate where the concentrations of ions, low molecular weight metabolites (<70 kDa), hormones, and drugs, often closely correlate with those in blood. However, anatomical skin differences between human and farm animals, especially large animals, as well as divergent tolerances of such devices among species with behavior specificities, motivate new MNA designs. We addressed technological challenges to design higher microneedles for farm animal (pigs and cattle) measurements. We designed microneedle arrays composed of 37 microneedles, each 2.8 mm in height, using dextran-methacrylate, a photo-crosslinked biocompatible biopolymer-based hydrogel. The arrays were characterized geometrically and mechanically. Their abilities to perforate pig and cow skin were demonstrated through histological analysis. The MNAs successfully absorbed approximately 10 µL of fluid within 3 h of application. Full article

(This article belongs to the Special Issue Biosensors for Biomedical, Agricultural and Environmental Applications)

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46 pages, 3495 KB

Open AccessFeature PaperEditor’s ChoiceReview

Assembly and Interconnection Technologies for 3D Plastic Circuit Carriers: An Overview of Technologies, Materials, and Applications

by Kai Werum, Wolfgang Eberhardt, Dieter Reenaers, Thomas Mager, Mika Endl, André Zimmermann and Wim Deferme

Micromachines 2025, 16(9), 980; https://doi.org/10.3390/mi16090980 - 26 Aug 2025

Viewed by 857

Abstract

This paper aims to present an overview of the state-of-the-art materials and technologies that can be used to create electronic circuits on 3D plastic carriers also known as 3D electronics. Strategies for print-based and laser-based 3D electronics will be discussed as well as [...] Read more.

This paper aims to present an overview of the state-of-the-art materials and technologies that can be used to create electronic circuits on 3D plastic carriers also known as 3D electronics. Strategies for print-based and laser-based 3D electronics will be discussed as well as the techniques to apply the circuit carrier and the way interconnection technology can be used to combine electronic components on top of the circuit carrier. A basic explanation of the functional principles, materials, and applications is given for different substrate and interconnection technologies. The aim is to make it easier to compare different technologies and its required materials to make the right decisions on what technology is best suited for the job. For this purpose, comparison tables for 3D plastic circuit carrier technologies and substrate materials considering their temperature stability were created. It can be concluded that there are a lot of influencing factors that determine which technologies are best suited for application. The most important factors are the 3D complexity and the field of application, the required structure size of the circuit, and the required production quantity. Full article

(This article belongs to the Section D：Materials and Processing)

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23 pages, 3673 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Backpropagation Neural Network-Based Prediction Model of Marble Surface Quality Cut by Diamond Wire Saw

by Hui Dong, Fan Cui, Zhipu Huo and Yufei Gao

Micromachines 2025, 16(9), 971; https://doi.org/10.3390/mi16090971 - 23 Aug 2025

Viewed by 611

Abstract

Marble is widely used in the field of construction and home decoration because of its high strength, high hardness and good wear resistance. Diamond wire sawing has been applied in marble cutting in industry due to its features such as low material loss, [...] Read more.

Marble is widely used in the field of construction and home decoration because of its high strength, high hardness and good wear resistance. Diamond wire sawing has been applied in marble cutting in industry due to its features such as low material loss, high cutting accuracy and low noise. The sawing surface quality directly affects the subsequent processing efficiency and economic benefit of marble products. The surface quality is affected by multiple parameters such as process parameters and workpiece sizes, making it difficult to accurately predict through traditional empirical equations or linear models. To improve prediction accuracy, this paper proposes a prediction model based on backpropagation (BP) neural network. Firstly, through the experiments of sawing marbles with the diamond wire saw, the datasets of surface roughness and waviness under different process parameters were obtained. Secondly, a BP neural network model was established, and the mixed-strategy-improved whale optimization algorithm (IWOA) was used to optimize the initial weight and threshold of the network, and established the IWOA-BP neural network model. Finally, the performance of the model was verified by comparison with the traditional models. The results showed that the IWOA-BP neural network model demonstrated the optimal prediction performance in both the surface roughness Ra and waviness Wa. The minimum predicted values of the root mean square error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE) were 0.0342%, 0.0284% and 1.5614%, respectively, which proved that the model had higher prediction accuracy. This study provides experimental basis and technical support for the prediction of the surface quality of marble material cut by diamond wire saw. Full article

(This article belongs to the Section D：Materials and Processing)

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14 pages, 2054 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Paperclip-Type Flexible Inductive Sensor Based on Liquid Metal Coils for Simple Fabrication and Multifunctional Applications

by Xun Sun, Kaixin Li, Zifeng Zhang, Linling Xiang, Yihao Zhou and Bin Sheng

Micromachines 2025, 16(8), 965; https://doi.org/10.3390/mi16080965 - 21 Aug 2025

Viewed by 702

Abstract

At present, high-resolution and reliable inductive sensors have increasingly emerged as a pivotal component in the advancement of flexible electronic devices. The integration of liquid metal with flexible substrates presents a promising approach for the fabrication of inductive sensors. This paper introduces a [...] Read more.

At present, high-resolution and reliable inductive sensors have increasingly emerged as a pivotal component in the advancement of flexible electronic devices. The integration of liquid metal with flexible substrates presents a promising approach for the fabrication of inductive sensors. This paper introduces a novel paperclip-type helical coil inductive sensor, characterized by advancements in both structural design and a simplified manufacturing process. The sensor comprises a fine silicone tube filled with liquid metal, encapsulated within polydimethylsiloxane (PDMS) glue. A significant innovation of this design is its complete elimination of the need for high-precision sacrificial metal molds. This approach bypasses complex processes such as precision mold machining, demolding, and post-mold residue cleaning, thereby significantly streamlining the production work-flow. We optimized the parameters of the paperclip-type helical coil, the aspect ratio, and the number of turns, achieving the maximum sensitivity under limited conditions. Experimental results demonstrate that this sensor is capable of tensile, pressure, and non-contact distance sensing. The linearity of the tensile sensing is exceptional (

R^{2} = 0.999

), with consistent performance observed after 800 tensile cycles. The pressure sensing range extends from 0 to 230 kPa, and the non-contact distance sensing is effective within a range of 10 mm. Furthermore, the sensor exhibits strong performance in monitoring human physiological activities and metal distance detection, demonstrating significant application potential in flexible electronics and wearable devices. Full article

(This article belongs to the Special Issue Structural Analyses and Designs for Flexible/Stretchable Electronics, 3rd Edition)

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23 pages, 7663 KB

Open AccessFeature PaperEditor’s ChoiceReview

Advances in 3D Printing: Microfabrication Techniques and Forming Applications

by Di Pan, Fanghui Jia, Muyuan Zhou, Hao Liu, Jingru Yan, Lisong Zhu, Ming Yang and Zhengyi Jiang

Micromachines 2025, 16(8), 940; https://doi.org/10.3390/mi16080940 - 15 Aug 2025

Viewed by 828

Abstract

Stainless steel is essential in high-performance industries due to its strength, corrosion resistance, and biocompatibility. However, conventional manufacturing methods limit material efficiency, design complexity, and customization. Additive manufacturing (AM) has emerged as a powerful alternative, enabling the production of stainless-steel components with complex [...] Read more.

Stainless steel is essential in high-performance industries due to its strength, corrosion resistance, and biocompatibility. However, conventional manufacturing methods limit material efficiency, design complexity, and customization. Additive manufacturing (AM) has emerged as a powerful alternative, enabling the production of stainless-steel components with complex geometries, tailored microstructures, and integrated functionalities. Key AM methodologies, including laser powder bed fusion (L-PBF), binder jetting, and directed energy deposition (DED), are evaluated for their effectiveness in producing stainless-steel components with optimal performance characteristics. This review highlights innovations in stainless-steel AM, focusing on microfabrication, multi-material approaches, and post-processing strategies such as heat treatment, hot isostatic pressing (HIP), and surface finishing. It also examines the impact of process parameters on microstructure, mechanical anisotropy, and defects. Emerging trends include AM-specific alloy design, functionally graded structures, and AI-based control. Applications span biomedical implants, micro-tooling, energy systems, and automotive parts, with emphasis on microfabrication for biomedical micromachines and precision microforming. Full article

(This article belongs to the Special Issue Innovations in 3D Printing Technologies: From Microfabrication to Functional Applications)

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23 pages, 4352 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Nondestructive Mechanical and Electrical Characterization of Piezoelectric Zinc Oxide Nanowires for Energy Harvesting

by Frank Eric Boye Anang, Markys Cain, Min Xu, Zhi Li, Uwe Brand, Darshit Jangid, Sebastian Seibert, Chris Schwalb and Erwin Peiner

Micromachines 2025, 16(8), 927; https://doi.org/10.3390/mi16080927 - 12 Aug 2025

Viewed by 719

Abstract

In this study we report on the structural, mechanical, and electrical characterization of different structures of vertically aligned zinc oxide (ZnO) nanowires (NWs) synthesized using hydrothermal methods. By optimizing the growth conditions, scanning electron microscopy (SEM) micrographs show that the ZnO NWs could [...] Read more.

In this study we report on the structural, mechanical, and electrical characterization of different structures of vertically aligned zinc oxide (ZnO) nanowires (NWs) synthesized using hydrothermal methods. By optimizing the growth conditions, scanning electron microscopy (SEM) micrographs show that the ZnO NWs could reach an astounding 51.9 ± 0.82 µm in length, 0.7 ± 0.08 µm in diameter, and 3.3 ± 2.1 µm⁻² density of the number of NWs per area within 24 h of growth time, compared with a reported value of ~26.8 µm in length for the same period. The indentation modulus of the as-grown ZnO NWs was determined using contact resonance (CR) measurements using atomic force microscopy (AFM). An indentation modulus of 122.2 ± 2.3 GPa for the NW array sample with an average diameter of ~690 nm was found to be close to the reference bulk ZnO value of 125 GPa. Furthermore, the measurement of the piezoelectric coefficient (d₃₃) using the traceable ESPY33 tool under cyclic compressive stress gave a value of 1.6 ± 0.4 pC/N at 0.02 N with ZnO NWs of 100 ± 10 nm and 2.69 ± 0.05 µm in diameter and length, respectively, which were embedded in an S1818 polymer. Current–voltage (I-V) measurements of the ZnO NWs fabricated on an n-type silicon (Si) substrate utilizing a micromanipulator integrated with a tungsten (W) probe exhibits Ohmic behavior, revealing an important phenomenon which can be attributed to the generated electric field by the tungsten probe, dielectric residue, or conductive material. Full article

(This article belongs to the Special Issue Research Progress on Advanced Piezoelectric Energy Harvesters)

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15 pages, 6688 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Integrated Additive Manufacturing of TGV Interconnects and High-Frequency Circuits via Bipolar-Controlled EHD Jetting

by Dongqiao Bai, Jin Huang, Hongxiao Gong, Jianjun Wang, Yunna Pu, Jiaying Zhang, Peng Sun, Zihan Zhu, Pan Li, Huagui Wang, Pengbing Zhao and Chaoyu Liang

Micromachines 2025, 16(8), 907; https://doi.org/10.3390/mi16080907 - 2 Aug 2025

Viewed by 625

Abstract

Electrohydrodynamic (EHD) printing offers mask-free, high-resolution deposition across a broad range of ink viscosities, yet combining void-free filling of high-aspect-ratio through-glass vias (TGVs) with ultrafine drop-on-demand (DOD) line printing on the same platform requires balancing conflicting requirements: for example, high field strengths to [...] Read more.

Electrohydrodynamic (EHD) printing offers mask-free, high-resolution deposition across a broad range of ink viscosities, yet combining void-free filling of high-aspect-ratio through-glass vias (TGVs) with ultrafine drop-on-demand (DOD) line printing on the same platform requires balancing conflicting requirements: for example, high field strengths to drive ink into deep and narrow vias; sufficiently high ink viscosity to prevent gravity-induced leakage; and stable meniscus dynamics to avoid satellite droplets and charge accumulation on the glass surface. By coupling electrostatic field analysis with transient level-set simulations, we establish a dimensionless regime map that delineates stable cone-jetting regime; these predictions are validated by high-speed imaging and surface profilometry. Operating within this window, the platform achieves complete, void-free filling of 200 µm × 1.52 mm TGVs and continuous 10 µm-wide traces in a single print pass. Demonstrating its capabilities, we fabricate transparent Ku-band substrate-integrated waveguide antennas on borosilicate glass: the printed vias and arc feed elements exhibit a reflection coefficient minimum of −18 dB at 14.2 GHz, a −10 dB bandwidth of 12.8–16.2 GHz, and an 8 dBi peak gain with 37° beam tilt, closely matching full-wave predictions. This physics-driven, all-in-one EHD approach provides a scalable route to high-performance, glass-integrated RF devices and transparent electronics. Full article

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16 pages, 2715 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Composite Behavior of Nanopore Array Large Memristors

by Ian Reistroffer, Jaden Tolbert, Jeffrey Osterberg and Pingshan Wang

Micromachines 2025, 16(8), 882; https://doi.org/10.3390/mi16080882 - 29 Jul 2025

Viewed by 557

Abstract

Synthetic nanopores were recently demonstrated with memristive and nonlinear voltage-current behaviors, akin to ion channels in a cell membrane. Such ionic devices are considered a promising candidate for the development of brain-inspired neuromorphic computing techniques. In this work, we show the composite behavior [...] Read more.

Synthetic nanopores were recently demonstrated with memristive and nonlinear voltage-current behaviors, akin to ion channels in a cell membrane. Such ionic devices are considered a promising candidate for the development of brain-inspired neuromorphic computing techniques. In this work, we show the composite behavior of nanopore-array large memristors, formed with different membrane materials, pore sizes, electrolytes, and device arrangements. Anodic aluminum oxide (AAO) membranes with 5 nm and 20 nm diameter pores and track-etched polycarbonate (PCTE) membranes with 10 nm diameter pores are tested and shown to demonstrate memristive and nonlinear behaviors with approximately 10⁷–10¹⁰ pores in parallel when electrolyte concentration across the membranes is asymmetric. Ion diffusion through the large number of channels induces time-dependent electrolyte asymmetry that drives the system through different memristive states. The behaviors of series composite memristors with different configurations are also presented. In addition to helping understand fluidic devices and circuits for neuromorphic computing, the results also shed light on the development of field-assisted ion-selection-membrane filtration techniques as well as the investigations of large neurons and giant synapses. Further work is needed to de-embed parasitic components of the measurement setup to obtain intrinsic large memristor properties. Full article

(This article belongs to the Section D4: Glassy Materials and Micro/Nano Devices)

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31 pages, 11019 KB

Open AccessFeature PaperEditor’s ChoiceReview

A Review of Tunnel Field-Effect Transistors: Materials, Structures, and Applications

by Shupeng Chen, Yourui An, Shulong Wang and Hongxia Liu

Micromachines 2025, 16(8), 881; https://doi.org/10.3390/mi16080881 - 29 Jul 2025

Viewed by 1772

Abstract

The development of an integrated circuit faces the challenge of the physical limit of Moore’s Law. One of the most important “Beyond Moore” challenges is the scaling down of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) versus their increasing static power consumption. This is because, at [...] Read more.

The development of an integrated circuit faces the challenge of the physical limit of Moore’s Law. One of the most important “Beyond Moore” challenges is the scaling down of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) versus their increasing static power consumption. This is because, at room temperature, the thermal emission transportation mechanism will cause a physical limitation on subthreshold swing (SS), which is fundamentally limited to a minimum value of 60 mV/decade for MOSFETs, and accompanied by an increase in off-state leakage current with the process of scaling down. Moreover, the impacts of short-channel effects on device performance also become an increasingly severe problem with channel length scaling down. Due to the band-to-band tunneling mechanism, Tunnel Field-Effect Transistors (TFETs) can reach a far lower SS than MOSFETs. Recent research works indicated that TFETs are already becoming some of the promising candidates of conventional MOSFETs for ultra-low-power applications. This paper provides a review of some advances in materials and structures along the evolutionary process of TFETs. An in-depth discussion of both experimental works and simulation works is conducted. Furthermore, the performance of TFETs with different structures and materials is explored in detail as well, covering Si, Ge, III-V compounds and 2D materials, alongside different innovative device structures. Additionally, this work provides an outlook on the prospects of TFETs in future ultra-low-power electronics and biosensor applications. Full article

(This article belongs to the Special Issue MEMS/NEMS Devices and Applications, 3rd Edition)

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29 pages, 14906 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Hydrothermal Engineering of Ferroelectric PZT Thin Films Tailoring Electrical and Ferroelectric Properties via TiO₂ and SrTiO₃ Interlayers for Advanced MEMS

by Chun-Lin Li and Guo-Hua Feng

Micromachines 2025, 16(8), 879; https://doi.org/10.3390/mi16080879 - 29 Jul 2025

Viewed by 634

Abstract

This work presents an innovative hydrothermal approach for fabricating flexible piezoelectric PZT thin films on 20 μm titanium foil substrates using TiO₂ and SrTiO₃ (STO) interlayers. Three heterostructures (Ti/PZT, Ti/TiO₂/PZT, and Ti/TiO₂/STO/PZT) were synthesized to enable low-temperature [...] Read more.

This work presents an innovative hydrothermal approach for fabricating flexible piezoelectric PZT thin films on 20 μm titanium foil substrates using TiO₂ and SrTiO₃ (STO) interlayers. Three heterostructures (Ti/PZT, Ti/TiO₂/PZT, and Ti/TiO₂/STO/PZT) were synthesized to enable low-temperature growth and improve ferroelectric performance for advanced flexible MEMS. Characterizations including XRD, PFM, and P–E loop analysis evaluated crystallinity, piezoelectric coefficient d₃₃, and polarization behavior. The results demonstrate that the multilayered Ti/TiO₂/STO/PZT structure significantly enhances performance. XRD confirmed the STO buffer layer effectively reduces lattice mismatch with PZT to ~0.76%, promoting stable morphotropic phase boundary (MPB) composition formation. This optimized film exhibited superior piezoelectric and ferroelectric properties, with a high d₃₃ of 113.42 pm/V, representing an ~8.65% increase over unbuffered Ti/PZT samples, and displayed more uniform domain behavior in PFM imaging. Impedance spectroscopy showed the lowest minimum impedance of 8.96 Ω at 10.19 MHz, indicating strong electromechanical coupling. Furthermore, I–V measurements demonstrated significantly suppressed leakage currents in the STO-buffered samples, with current levels ranging from 10⁻¹² A to 10⁻⁹ A over ±3 V. This structure also showed excellent fatigue endurance through one million electrical cycles, confirming its mechanical and electrical stability. These findings highlight the potential of this hydrothermally engineered flexible heterostructure for high-performance actuators and sensors in advanced MEMS applications. Full article

(This article belongs to the Special Issue Manufacturing and Application of Advanced Thin-Film-Based Device)

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38 pages, 21156 KB

Open AccessFeature PaperEditor’s ChoiceReview

A Review of the Application of Seal Whiskers in Vortex-Induced Vibration Suppression and Bionic Sensor Research

by Jinying Zhang, Zhongwei Gao, Jiacheng Wang, Yexiaotong Zhang, Jialin Chen, Ruiheng Zhang and Jiaxing Yang

Micromachines 2025, 16(8), 870; https://doi.org/10.3390/mi16080870 - 28 Jul 2025

Viewed by 762

Abstract

Harbor seals (Phoca vitulina) have excellent perception of water disturbances and can still sense targets as far as 180 m away, even when they lose their vision and hearing. This exceptional capability is attributed to the undulating structure of its vibrissae. [...] Read more.

Harbor seals (Phoca vitulina) have excellent perception of water disturbances and can still sense targets as far as 180 m away, even when they lose their vision and hearing. This exceptional capability is attributed to the undulating structure of its vibrissae. These specialized whiskers not only effectively suppress vortex-induced vibrations (VIVs) during locomotion but also amplify the vortex street signals generated by the wake of a target, thereby enhancing the signal-to-noise ratio (SNR). In recent years, researchers in fluid mechanics, bionics, and sensory biology have focused on analyzing the hydrodynamic characteristics of seal vibrissae. Based on bionic principles, various underwater biomimetic seal whisker sensors have been developed that mimic this unique geometry. This review comprehensively discusses research on the hydrodynamic properties of seal whiskers, the construction of three-dimensional geometric models, the theoretical foundations of fluid–structure interactions, the advantages and engineering applications of seal whisker structures in suppressing VIVs, and the design of sensors inspired by bionic principles. Full article

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18 pages, 3371 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Insight into the Propagation of Interface Acoustic Waves in Rotated YX-LiNbO₃/SU-8/Si Structures

by Cinzia Caliendo, Massimiliano Benetti, Domenico Cannatà and Farouk Laidoudi

Micromachines 2025, 16(8), 861; https://doi.org/10.3390/mi16080861 - 26 Jul 2025

Viewed by 2560

Abstract

The propagation of interface acoustic waves (IAWs) along rotated YX-LiNbO₃/SU-8/ZX-Si structures is theoretically investigated to identify the Y-rotation angles that support the efficient propagation of low-loss modes guided along the structure’s interface. A three-dimensional finite element analysis was performed to simulate [...] Read more.

The propagation of interface acoustic waves (IAWs) along rotated YX-LiNbO₃/SU-8/ZX-Si structures is theoretically investigated to identify the Y-rotation angles that support the efficient propagation of low-loss modes guided along the structure’s interface. A three-dimensional finite element analysis was performed to simulate IAW propagation in the layered structure and to optimize design parameters, specifically the thicknesses of the platinum (Pt) interdigital transducers (IDTs) and the SU-8 adhesive layer. The simulations revealed the existence of two types of IAWs travelling at different velocities under specific Y-rotated cuts of the LiNbO₃ half-space. These IAWs are faster than the surface acoustic wave (SAW) and slower than the leaky SAW (LSAW) propagating on the surface of the bare LiNbO₃ half-space. The mechanical displacement fields of both IAWs exhibit a rapid decay to zero within a few wavelengths from the LiNbO₃ surface. The piezoelectric coupling coefficients of the IAWs were found to be as high as approximately 7% and 31%, depending on the Y-rotation angle. The theoretical results were experimentally validated by measuring the velocities of the SAW and LSAW on a bare 90° YX-LiNbO₃ substrate, and the velocities of the IAWs in a 90° YX-LiNbO₃/SU-8/Si structure featuring 330 nm thick Pt IDTs, a 200 µm wavelength, and a 15 µm thick SU-8 layer. The experimental data showed good agreement with the theoretical predictions. These combined theoretical and experimental findings establish design principles for exciting two interface waves with elliptical and quasi-shear polarization, offering enhanced flexibility for fluidic manipulation and the integration of sensing functionalities. Full article

(This article belongs to the Special Issue Novel Surface and Bulk Acoustic Wave Devices, Second Edition)

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15 pages, 4646 KB

Open AccessFeature PaperEditor’s ChoiceArticle

A Wideband Magneto-Electric (ME) Dipole Antenna Enabled by ME Resonance and Aperture-Coupled Excitation

by Hyojin Jang, Seyeon Park, Junghyeon Kim, Kyounghwan Kim and Sungjoon Lim

Micromachines 2025, 16(8), 853; https://doi.org/10.3390/mi16080853 - 24 Jul 2025

Viewed by 802

Abstract

In this study, we propose a novel wideband aperture-coupled magneto-electric (ME) dipole antenna that achieves enhanced bandwidth by simultaneously leveraging ME resonance and aperture-coupled excitation. Building upon the conventional ME dipole architecture, the antenna integrates a pair of horizontal metal patches forming the [...] Read more.

In this study, we propose a novel wideband aperture-coupled magneto-electric (ME) dipole antenna that achieves enhanced bandwidth by simultaneously leveraging ME resonance and aperture-coupled excitation. Building upon the conventional ME dipole architecture, the antenna integrates a pair of horizontal metal patches forming the electric dipole and a pair of vertical metal patches forming the magnetic dipole. A key innovation is the aperture-coupled feeding mechanism, where electromagnetic energy is transferred from a tapered microstrip line to the dipole structure through a slot etched in the ground plane. This design not only excites the characteristic ME resonances effectively but also significantly improves impedance matching, delivering a markedly broader impedance bandwidth. To validate the proposed concept, a prototype antenna was fabricated and experimentally characterized. Measurements show an impedance bandwidth of 84.48% (3.61–8.89 GHz) for

S_{11}

≤ −10 dB and a maximum in-band gain of 7.88 dBi. The antenna also maintains a stable, unidirectional radiation pattern across the operating band, confirming its potential for wideband applications such as 5G wireless communications. Full article

(This article belongs to the Special Issue RF Devices: Technology and Progress)

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16 pages, 6885 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Research on Optimized Design of In Situ Dynamic Variable-Aperture Device for Variable-Spot Ion Beam Figuring

by Hongyu Zou, Hao Hu, Xiaoqiang Peng, Meng Liu, Pengxiang Wang and Chaoliang Guan

Micromachines 2025, 16(8), 849; https://doi.org/10.3390/mi16080849 - 24 Jul 2025

Viewed by 442

Abstract

Ion beam figuring (IBF) is an ultra-high-precision surface finishing technology characterized by a distinct trade-off between the spot size of the removal function and its corresponding figuring capabilities. A larger spot size for the removal function leads to higher processing efficiency but lower [...] Read more.

Ion beam figuring (IBF) is an ultra-high-precision surface finishing technology characterized by a distinct trade-off between the spot size of the removal function and its corresponding figuring capabilities. A larger spot size for the removal function leads to higher processing efficiency but lower figuring ability. Conversely, a smaller spot size results in higher figuring ability but lower efficiency. Adjusting the spot size of the removal function using tools with an aperture is a possible approach. However, existing variable-aperture tools have certain limitations in IBF processing. To leverage the advantages of both large and small spot sizes for the removal function during IBF processing, an in situ dynamic beam variable-aperture device has been designed. This device optimizes the parameters of diaphragm sheets and employs FOC for dynamic aperture adjustment. Simulations show that 12 numbers of 0.1 mm-thick sheets minimize removal function distortion, with the thermal strain-induced area variation being <5%. FOC enables rapid (≤0.45 s full range) and precise aperture control. Experiments confirm adjustable spot sizes (FWHM 0.7–17.2 mm) with Gaussian distribution (correlation >96.7%), operational parameter stability (relative change rate ≤5%), and high repeatable positioning precision (relative change rate ≤3.2% in repeated adjustments). The design enhances IBF efficiency, flexibility, and accuracy by enabling in situ spot size optimization, overcoming conventional limitations. Full article

(This article belongs to the Special Issue Recent Advances in Micro/Nanofabrication, 2nd Edition)

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23 pages, 3253 KB

Open AccessFeature PaperEditor’s ChoiceReview

Overcoming Challenges in Silicon Anodes: The Role of Electrolyte Additives and Solid-State Electrolytes

by Jinsik Nam, Hanbyeol Lee and Oh B. Chae

Micromachines 2025, 16(7), 800; https://doi.org/10.3390/mi16070800 - 9 Jul 2025

Cited by 1 | Viewed by 2883

Abstract

Silicon-based anodes have emerged as promising candidates for advanced lithium-ion batteries (LIBs) owing to their outstanding lithium storage capacity; however, the commercial implementation of silicon-based anodes is hindered primarily by their significant volumetric changes and the resulting solid electrolyte interphase (SEI) instability during [...] Read more.

Silicon-based anodes have emerged as promising candidates for advanced lithium-ion batteries (LIBs) owing to their outstanding lithium storage capacity; however, the commercial implementation of silicon-based anodes is hindered primarily by their significant volumetric changes and the resulting solid electrolyte interphase (SEI) instability during the lithiation/delithiation process. To overcome these issues, electrolyte optimization, particularly through the use of functional additives and solid-state electrolytes, has attracted significant research attention. In this paper, we review the recent developments in electrolyte additives, such as vinylene carbonate, fluoroethylene carbonate, and silane-based additives, and new additives, such as dimethylacetamide, that improve the SEI stability and overall electrochemical performance of silicon-based anodes. We also discuss the role of solid electrolytes, including oxides, sulfides, and polymer-based systems, in mitigating the volume changes in Si and improving safety. Such approaches can effectively enhance both the longevity and capacity retention of silicon-based anodes. Despite significant progress, further studies are essential to optimize electrolyte formulation and solve interfacial problems. Integrating these advances with improved electrode designs and anode materials is critical for realizing the full potential of silicon-based anodes in high-performance LIBs, particularly in electric vehicles and portable electronics. Full article

(This article belongs to the Special Issue Nanomaterials for Micro/Nano Devices, 2nd Edition)

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39 pages, 7348 KB

Open AccessFeature PaperEditor’s ChoiceReview

Artificial Intelligence Control Methodologies for Shape Memory Alloy Actuators: A Systematic Review and Performance Analysis

by Stefano Rodinò, Giuseppe Rota, Matteo Chiodo, Antonio Corigliano and Carmine Maletta

Micromachines 2025, 16(7), 780; https://doi.org/10.3390/mi16070780 - 30 Jun 2025

Cited by 1 | Viewed by 964

Abstract

Shape Memory Alloy (SMA) actuators are pivotal in modern engineering due to their unique thermomechanical properties, but their inherent non-linearities, hysteresis, and temperature sensitivity pose significant control challenges. This systematic review evaluates artificial intelligence (AI)-based control methodologies to address these limitations, analyzing their [...] Read more.

Shape Memory Alloy (SMA) actuators are pivotal in modern engineering due to their unique thermomechanical properties, but their inherent non-linearities, hysteresis, and temperature sensitivity pose significant control challenges. This systematic review evaluates artificial intelligence (AI)-based control methodologies to address these limitations, analyzing their efficacy in enhancing precision, adaptability, and reliability for SMA and Magnetic SMA (MSMA) systems. A PRISMA-guided literature review (2003–2025) identified 24 studies, which were categorized by control architectures (hybrid AI-linear, pure AI, adaptive, and model predictive control) and evaluated through quantitative metrics, including Root Mean Square Error (RMSE%) and a weighted scoring system for experimental rigor. Results revealed hybrid AI-linear controllers as the dominant approach (36%), with online-trained neural networks achieving superior accuracy (+2.4%) over offline methods. Feedforward neural networks outperformed recurrent architectures (+3.1%), while Model Predictive Control (MPC) excelled for SMA actuators (+5.8% accuracy) but underperformed for MSMAs (−7.7%). Sensorless strategies proved advantageous for MSMAs (+5.0%), leveraging intrinsic material properties like electrical resistance for state estimation. The analysis underscores AI’s capacity to mitigate hysteresis and non-linear dynamics, though material-specific optimization is critical: SMA systems favor dynamic control and MPC, whereas MSMAs benefit from sensorless AI and pure neural networks. Challenges persist in computational demands for online training and reinforcement learning’s exploration–exploitation trade-offs. Future research should prioritize adaptive algorithms for fatigue compensation, lightweight AI models for embedded deployment, and standardized benchmarking to bridge material-specific performance gaps. This synthesis establishes AI as a transformative paradigm for SMA actuation, enabling precise control in aerospace, biomedical, and soft robotics applications. Full article

(This article belongs to the Special Issue Design and Real Time Implementation of Intelligent Control Schemes for Actuators)

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20 pages, 23523 KB

Open AccessFeature PaperEditor’s ChoiceArticle

A Wrist Brace with Integrated Piezoelectric Sensors for Real-Time Biomechanical Monitoring in Weightlifting

by Sofia Garcia, Ethan Ortega, Mohammad Alghamaz, Alwathiqbellah Ibrahim and En-Tze Chong

Micromachines 2025, 16(7), 775; https://doi.org/10.3390/mi16070775 - 30 Jun 2025

Viewed by 710

Abstract

This study presents a self-powered smart wrist brace integrated with a piezoelectric sensor for real-time biomechanical monitoring during weightlifting activities. The system was designed to quantify wrist flexion across multiple loading conditions (0 kg, 0.5 kg, and 1.0 kg), leveraging mechanical strain-induced voltage [...] Read more.

This study presents a self-powered smart wrist brace integrated with a piezoelectric sensor for real-time biomechanical monitoring during weightlifting activities. The system was designed to quantify wrist flexion across multiple loading conditions (0 kg, 0.5 kg, and 1.0 kg), leveraging mechanical strain-induced voltage generation to capture angular displacement. A flexible PVDF film was embedded within a custom-fitted wrist brace and tested on male and female participants performing controlled wrist flexion. The resulting voltage signals were analyzed to extract root-mean-square (RMS) outputs, calibration curves, and sensitivity metrics. To interpret the experimental results analytically, a lumped-parameter cantilever beam model was developed, linking wrist flexion angles to piezoelectric voltage output based on mechanical deformation theory. The model assumed a linear relationship between wrist angle and induced strain, enabling theoretical voltage prediction through simplified material and geometric parameters. Model-predicted voltage responses were compared with experimental measurements, demonstrating a good agreement and validating the mechanical-electrical coupling approach. Experimental results revealed consistent voltage increases with both wrist angle and applied load, and regression analysis demonstrated strong linear or mildly nonlinear fits with high

R^{2}

values (up to 0.994) across all conditions. Furthermore, surface plots and strain sensitivity analyses highlighted the system’s responsiveness to simultaneous angular and loading changes. These findings validate the smart wrist brace as a reliable, low-power biomechanical monitoring tool, with promising applications in injury prevention, rehabilitation, and real-time athletic performance feedback. Full article

(This article belongs to the Special Issue Next-Generation Wearable Technologies: Integrating Smart Sensing, Biomedical Innovation, and Sustainable Energy Solutions)

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24 pages, 11574 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Using Adaptive Surrogate Models to Accelerate Multi-Objective Design Optimization of MEMS

by Ali Nazari, Armin Aghajani, Phiona Buhr, Byoungyoul Park, Yunli Wang and Cyrus Shafai

Micromachines 2025, 16(7), 753; https://doi.org/10.3390/mi16070753 - 26 Jun 2025

Cited by 1 | Viewed by 3396

Abstract

This study presents a comprehensive multi-objective optimization framework specifically designed for micro-electromechanical systems (MEMS). The framework integrates both traditional and adaptive optimization techniques, named Surrogate-Assisted Multi-Objective Optimization (SAMOO) and Adaptive-SAMOO (A-SAMOO), respectively. By addressing key limitations of traditional approaches, such as the consideration [...] Read more.

This study presents a comprehensive multi-objective optimization framework specifically designed for micro-electromechanical systems (MEMS). The framework integrates both traditional and adaptive optimization techniques, named Surrogate-Assisted Multi-Objective Optimization (SAMOO) and Adaptive-SAMOO (A-SAMOO), respectively. By addressing key limitations of traditional approaches, such as the consideration of objective constraints and the provision of multiple design options, the proposed framework enhances both flexibility and practical applicability. Results show that adaptive optimization outperforms traditional offline methods by delivering a greater number and higher quality of optimal solutions while requiring fewer finite element method simulations. The adaptive approach showed a significant advantage by attaining high-quality solutions while requiring only 2.8% of the finite element method (FEM) evaluations compared to traditional methods that do not incorporate surrogate models. This performance boost highlights the advantages of online learning in enhancing the accuracy, speed, and diversity of solutions in MEMS optimization. These optimization schemes were tested on multiple MEMS devices with varying physics and complexities, specifically the U-shaped Lorentz force actuator, serpentine Lorentz force actuator, and thermal actuator. The results highlight the robustness and versatility of the proposed methods, particularly in addressing cases involving discrete design variables and strict objective constraints. This comprehensive, step-by-step framework serves as a valuable resource for researchers and practitioners aiming to optimize MEMS designs from the ground up, providing a reliable and effective approach to multi-objective optimization in MEMS applications. Full article

(This article belongs to the Special Issue MEMS Actuators and Their Applications)

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23 pages, 4929 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Low Phase Noise, Dual-Frequency Pierce MEMS Oscillators with Direct Print Additively Manufactured Amplifier Circuits

by Liguan Li, Di Lan, Xu Han, Tinghung Liu, Julio Dewdney, Adnan Zaman, Ugur Guneroglu, Carlos Molina Martinez and Jing Wang

Micromachines 2025, 16(7), 755; https://doi.org/10.3390/mi16070755 - 26 Jun 2025

Cited by 1 | Viewed by 923

Abstract

This paper presents the first demonstration and comparison of two identical oscillator circuits employing piezoelectric zinc oxide (ZnO) microelectromechanical systems (MEMS) resonators, implemented on conventional printed-circuit-board (PCB) and three-dimensional (3D)-printed acrylonitrile butadiene styrene (ABS) substrates. Both oscillators operate simultaneously at dual frequencies (260 [...] Read more.

This paper presents the first demonstration and comparison of two identical oscillator circuits employing piezoelectric zinc oxide (ZnO) microelectromechanical systems (MEMS) resonators, implemented on conventional printed-circuit-board (PCB) and three-dimensional (3D)-printed acrylonitrile butadiene styrene (ABS) substrates. Both oscillators operate simultaneously at dual frequencies (260 MHz and 437 MHz) without the need for additional circuitry. The MEMS resonators, fabricated on silicon-on-insulator (SOI) wafers, exhibit high-quality factors (Q), ensuring superior phase noise performance. Experimental results indicate that the oscillator packaged using 3D-printed chip-carrier assembly achieves a 2–3 dB improvement in phase noise compared to the PCB-based oscillator, attributed to the ABS substrate’s lower dielectric loss and reduced parasitic effects at radio frequency (RF). Specifically, phase noise values between −84 and −77 dBc/Hz at 1 kHz offset and a noise floor of −163 dBc/Hz at far-from-carrier offset were achieved. Additionally, the 3D-printed ABS-based oscillator delivers notably higher output power (4.575 dBm at 260 MHz and 0.147 dBm at 437 MHz). To facilitate modular characterization, advanced packaging techniques leveraging precise 3D-printed encapsulation with sub-100 μm lateral interconnects were employed. These ensured robust packaging integrity without compromising oscillator performance. Furthermore, a comparison between two transistor technologies—a silicon germanium (SiGe) heterojunction bipolar transistor (HBT) and an enhancement-mode pseudomorphic high-electron-mobility transistor (E-pHEMT)—demonstrated that SiGe HBT transistors provide superior phase noise characteristics at close-to-carrier offset frequencies, with a significant 11 dB improvement observed at 1 kHz offset. These results highlight the promising potential of 3D-printed chip-carrier packaging techniques in high-performance MEMS oscillator applications. Full article

(This article belongs to the Section E：Engineering and Technology)

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14 pages, 2324 KB

Open AccessFeature PaperEditor’s ChoiceArticle

An Organ-on-a-Chip Modular Platform with Integrated Immunobiosensors for Monitoring the Extracellular Environment

by Anastasia Kanioura, Myrto Kyriaki Filippidou, Dimitra Tsounidi, Panagiota S. Petrou, Stavros Chatzandroulis and Angeliki Tserepi

Micromachines 2025, 16(7), 740; https://doi.org/10.3390/mi16070740 - 25 Jun 2025

Viewed by 1252

Abstract

OoC systems employing human cells mirror the functionality of human organs and faithfully simulate their physiological microfluidic environment. Despite the potential of OoC technology in emulating tissue complexity, a significant gap persists in the continuous real-time monitoring of cellular behaviors and their responses [...] Read more.

OoC systems employing human cells mirror the functionality of human organs and faithfully simulate their physiological microfluidic environment. Despite the potential of OoC technology in emulating tissue complexity, a significant gap persists in the continuous real-time monitoring of cellular behaviors and their responses to external stimuli, arising from the lack of biosensors integrated onto OoC microfluidic platforms. Addressing this limitation constitutes the primary objective of this study. By developing and incorporating biosensors onto a modular integrated OoC platform, we aim to enable the monitoring of changes taking place in the cellular environment under various stimuli in real time. An in-series modular integration of a biosensor array into an OoC platform is demonstrated herein, along with its potential to sustain human cell proliferation and accommodate the detection of IL-6, as an example of a mediator protein secreted as part of the immune response to inflammation. The implementation of commercially fabricated PCB components also addresses the issue of cost efficiency and manufacturing scaling-up of sensor-integrated OoCs. This advancement will not only enhance the accuracy and reliability of preclinical studies, but also pave the way for improved drug development and disease treatment. Full article

(This article belongs to the Special Issue Microfluidic Chips for Biomedical Applications)

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13 pages, 4027 KB

Open AccessFeature PaperEditor’s ChoiceArticle

A Dialysis Membrane-Integrated Microfluidic Device for Controlled Drug Retention and Nutrient Supply

by Hajime Miyashita, Yuya Ito, Kenta Shinha, Hiroko Nakamura and Hiroshi Kimura

Micromachines 2025, 16(7), 745; https://doi.org/10.3390/mi16070745 - 25 Jun 2025

Viewed by 744

Abstract

Traditional pre-clinical drug evaluation methods, including animal experiments and static cell cultures using human-derived cells, face critical limitations such as interspecies differences, ethical concerns, and poor physiological relevance. More recently, microphysiological systems (MPSs) that use microfluidic devices to mimic in vivo conditions have [...] Read more.

Traditional pre-clinical drug evaluation methods, including animal experiments and static cell cultures using human-derived cells, face critical limitations such as interspecies differences, ethical concerns, and poor physiological relevance. More recently, microphysiological systems (MPSs) that use microfluidic devices to mimic in vivo conditions have emerged as promising platforms. By enabling perfusion cell culture and incorporating human-derived cells, MPSs can evaluate drug efficacy and toxicity in a more human-relevant manner. However, standard MPS protocols rely on discrete medium changes, causing abrupt changes in drug concentrations that do not reflect the continuous pharmacokinetics seen in vivo. To overcome this limitation, we developed a Dialysis Membrane-integrated Microfluidic Device (DMiMD) which maintains continuous drug concentrations through selective medium change via a dialysis membrane. The membrane’s molecular weight cut-off (MWCO) enables the retention of high-molecular-weight drugs while facilitating the passage of essential low-molecular-weight nutrients such as glucose. We validated the membrane’s molecular selectivity and confirmed effective nutrient supply using cells. Additionally, anticancer drug efficacy was evaluated under continuously changing drug concentrations, demonstrating that the DMiMD successfully mimics in vivo drug exposure dynamics. These results indicate that the DMiMD offers a robust in vitro platform for accurate assessment of drug efficacy and toxicity, bridging the gap between conventional static assays and the physiological complexities of the human body. Full article

(This article belongs to the Special Issue Microfluidic Chips for Biomedical Applications)

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32 pages, 5584 KB

Open AccessFeature PaperEditor’s ChoiceReview

Recent Advancements in Metal–Organic Framework-Based Microfluidic Chips for Biomedical Applications

by Alemayehu Kidanemariam and Sungbo Cho

Micromachines 2025, 16(7), 736; https://doi.org/10.3390/mi16070736 - 24 Jun 2025

Cited by 1 | Viewed by 1928

Abstract

The integration of metal–organic frameworks (MOFs) with microfluidic technologies has opened new frontiers in biomedical diagnostics and therapeutics. Microfluidic chips offer precise fluid control, low reagent use, and high-throughput capabilities features further enhanced by MOFs’ ample surface area, adjustable porosity, and catalytic activity. [...] Read more.

The integration of metal–organic frameworks (MOFs) with microfluidic technologies has opened new frontiers in biomedical diagnostics and therapeutics. Microfluidic chips offer precise fluid control, low reagent use, and high-throughput capabilities features further enhanced by MOFs’ ample surface area, adjustable porosity, and catalytic activity. Together, they form powerful lab-on-a-chip platforms for sensitive biosensing, drug delivery, tissue engineering, and microbial detection. This review highlights recent advances in MOF-based microfluidic systems, focusing on material innovations, fabrication methods, and diagnostic applications. Particular emphasis is placed on MOF nanozymes, which enhance biochemical reactions for multiplexed testing and rapid pathogen identification. Challenges such as stability, biocompatibility, and manufacturing scalability are addressed, along with emerging trends like responsive MOFs, AI-assisted design, and clinical translation strategies. By bridging MOF chemistry and microfluidic engineering, these systems hold great promise for next-generation biomedical technologies. Full article

(This article belongs to the Special Issue Microfluidic Chips for Biomedical Applications)

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16 pages, 3111 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Parametric Rule-Based Intelligent System (PRISM) for Design and Analysis of High-Strength Separable Microneedles

by Sanghwi Ju, Seung-hyun Im, Kyungsun Seo, Junhyeok Lee, Seokjae Kim, Tongil Park, Taeksu Lee, Byungjeon Kang, Jayoung Kim, Ryong Sung, Jong-Oh Park and Doyeon Bang

Micromachines 2025, 16(7), 726; https://doi.org/10.3390/mi16070726 - 21 Jun 2025

Viewed by 800

Abstract

Transdermal microneedle systems have received great attention due to their minimally invasive way of delivering biomolecules through the skin with reduced pain. However, designing high-strength separable microneedles, which enable easy skin penetration and easy patch detachment, is challenging. Here, we present a Parametric [...] Read more.

Transdermal microneedle systems have received great attention due to their minimally invasive way of delivering biomolecules through the skin with reduced pain. However, designing high-strength separable microneedles, which enable easy skin penetration and easy patch detachment, is challenging. Here, we present a Parametric Rule-based Intelligent System (PRISM), which generates the design of and analyzes high-strength separable microneedles. The PRISM platform integrates parametric 3D modeling, geometry-based structural analysis, and high-resolution micro-3D printing for the creation of high-strength separable microneedles. We fabricated prototype microneedle arrays via microscale stereolithographic printing (pµSL) and demonstrated separation of microneedle tips in a skin-mimicking phantom sample. Mechanical testing showed that the suggested design achieved 2.13 ± 0.51 N axial resistance and 73.92 ± 34.77 mN shear fracture force; this surpasses that of conventional designs. Finally, an experiment using a skin-mimicking artificial phantom sample confirmed that only the PRISM-designed separable microneedles could have been inserted and separated at the target depth, whereas conventional designs failed to detach. This approach addresses the development of microneedle systems, which achieve both robust skin phantom penetration and reliable separable delivery, presenting an efficient development tool in transdermal drug delivery technology. Full article

(This article belongs to the Section D3: 3D Printing and Additive Manufacturing)

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15 pages, 2341 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Roll-to-Roll (R2R) High-Throughput Manufacturing of Foil-Based Microfluidic Chips for Neurite Outgrowth Studies

by Nihan Atak, Martin Smolka, Anja Haase, Alexandra Lorenz, Silvia Schobesberger, Stephan Ruttloff, Christian Wolf, Ana Ayerdi-Izquierdo, Peter Ertl, Nerea Briz Iceta, Jan Hesse and Martin Frauenlob

Micromachines 2025, 16(6), 713; https://doi.org/10.3390/mi16060713 - 16 Jun 2025

Cited by 1 | Viewed by 3304

Abstract

Microfluidic devices have emerged as a pivotal in vitro technology for axon outgrowth studies, facilitating the separation of the cell body from the neurites by geometric constraints. However, traditional microfabrication techniques fall short in terms of scalability for large-scale production, hindering widespread application. [...] Read more.

Microfluidic devices have emerged as a pivotal in vitro technology for axon outgrowth studies, facilitating the separation of the cell body from the neurites by geometric constraints. However, traditional microfabrication techniques fall short in terms of scalability for large-scale production, hindering widespread application. This study presents the development of foil-based cell culture chips, made of polyethylene terephthalate and in-house formulated ultraviolet curable liquid resin by high-throughput roll-to-roll (R2R) manufacturing. Here, two microchannel designs were tested to optimize manufacturing quality and assess the neurite outgrowth behavior. The fabricated neuron-foil chips demonstrated biocompatibility and supported neurite outgrowth within microchannels under static cell culture conditions. Furthermore, fluidic flow, oriented either perpendicular or parallel to the microchannel direction, was applied to enhance the biological reproducibility within the neuron-foil chips. These findings suggest that R2R manufacturing offers a promising approach for the high-throughput production of biocompatible microfluidic devices, advancing their potential application in modeling neurological diseases within the biomedical industry. Full article

(This article belongs to the Section B2: Biofabrication and Tissue Engineering)

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23 pages, 2579 KB

Open AccessFeature PaperEditor’s ChoiceReview

From Micro to Marvel: Unleashing the Full Potential of Click Chemistry with Micromachine Integration

by Zihan Chen, Zimo Ren, Carmine Coluccini and Paolo Coghi

Micromachines 2025, 16(6), 712; https://doi.org/10.3390/mi16060712 - 15 Jun 2025

Viewed by 3629

Abstract

Micromachines, small-scale engineered devices prepared to carry out exact tasks at the micro level, have garnered great interest across different fields such as drug delivery, chemical synthesis, and biomedical applications. In emerging applications, micromachines have indicated great potential in advancing click chemistry, a [...] Read more.

Micromachines, small-scale engineered devices prepared to carry out exact tasks at the micro level, have garnered great interest across different fields such as drug delivery, chemical synthesis, and biomedical applications. In emerging applications, micromachines have indicated great potential in advancing click chemistry, a highly selective and efficient chemical technique widely applied in materials science, bioconjugation, and pharmaceutical development. Click chemistry, distinguished by its rapid reaction rates, high efficiency, and bioorthogonality, serves as a robust method for molecular assembly and functionalization. Incorporating micromachines into click chemistry processes paves the way for precise, automated, and scalable chemical synthesis. These tiny devices can effectively transport reactants, boost reaction efficiency through localized mixing, and enable highly exact site-specific modifications. Moreover, micromachines driven by external forces such as magnetic fields, ultrasound, or chemical fuels provide exceptional control over reaction conditions, significantly enhancing the selectivity and efficiency of click reactions. In this review, we explore the interaction between micromachines and click chemistry, showcasing recent advancements, potential uses, and future prospects in this cross-disciplinary domain. By leveraging micromachine-supported click chemistry, scientists can surpass conventional reaction constraints, opening doors to groundbreaking innovations in materials science, drug discovery, and beyond. Full article

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20 pages, 12065 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Design and Optimization of a Tapered Magnetic Soft Continuum Robot for Enhanced Navigation in Cerebral Vasculature

by Jiahang Wang, Yuhang Liu, Xiwen Lu, Yunlong Zhu and Chenyao Bai

Micromachines 2025, 16(6), 701; https://doi.org/10.3390/mi16060701 - 12 Jun 2025

Cited by 1 | Viewed by 1269

Abstract

Magnetic soft continuum robots (MSCRs) have broad application advantages in vascular intervention; however, current MSCRs still face challenges in navigating the narrower and tortuous structure of the cerebral vasculature. To address this challenge, we propose a tapered MSCR (T-MSCR), which is designed to [...] Read more.

Magnetic soft continuum robots (MSCRs) have broad application advantages in vascular intervention; however, current MSCRs still face challenges in navigating the narrower and tortuous structure of the cerebral vasculature. To address this challenge, we propose a tapered MSCR (T-MSCR), which is designed to facilitate smooth navigation through microvascular structures via its miniature tip. Specifically, to optimize its bending ability, we combine the Gray Wolf Optimizer (GWO) with the Euler–Bernoulli beam theory and introduce a Discrete GWO (DGWO) approach to optimize the distribution of magnetic particles within the T-MSCR. We then demonstrate the optimization process of the T-MSCR’s bending ability, comparing and analyzing its deflection angle and deformation characteristics, highlighting its capability to enter microvasculars. Furthermore, we demonstrate the magnetic steering and path selection capabilities of T-MSCR in a two-dimensional vascular model and its navigation performance in real-scale human vascular models. Finally, biocompatibility tests confirm that T-MSCR exhibits no toxicity to human cells, thereby laying a solid foundation for its clinical application. The proposed T-MSCR design and optimization are expected to provide a more efficient and feasible solution for future cerebrovascular interventions. Full article

(This article belongs to the Section B：Biology and Biomedicine)

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24 pages, 10324 KB

Open AccessFeature PaperEditor’s ChoiceArticle

A Versatile Platform for Designing and Fabricating Multi-Material Perfusable 3D Microvasculatures

by Nathaniel Harris, Charles Miller and Min Zou

Micromachines 2025, 16(6), 691; https://doi.org/10.3390/mi16060691 - 8 Jun 2025

Cited by 1 | Viewed by 1604

Abstract

Perfusable microvasculature is critical for advancing in vitro tissue models, particularly for neural applications where limited diffusion impairs organoid growth and fails to replicate neurovascular function. This study presents a versatile fabrication platform that integrates mesh-driven design, two-photon lithography (TPL), and modular interfacing [...] Read more.

Perfusable microvasculature is critical for advancing in vitro tissue models, particularly for neural applications where limited diffusion impairs organoid growth and fails to replicate neurovascular function. This study presents a versatile fabrication platform that integrates mesh-driven design, two-photon lithography (TPL), and modular interfacing to create multi-material, perfusable 3D microvasculatures. Various 2D and 3D capillary paths were test-printed using both polygonal and lattice support strategies. A double-layered capillary scaffold based on the Hilbert curve was used for comparative materials testing. Methods for printing rigid (OrmoComp), moderately stiff hydrogel (polyethylene glycol diacrylate, PEGDA 700), and soft elastomeric (photocurable polydimethylsiloxane, PDMS) materials were developed and evaluated. Cone support structures enabled high-fidelity printing of the softer materials. A compact heat-shrink tubing interface provided leak-free perfusion without bulky fittings. Physiologically relevant flow velocities and Dextran diffusion through the scaffold were successfully demonstrated. Cytocompatibility assays confirmed that all TPL-printed scaffold materials supported human neural stem cell viability. Among peripheral components, lids fabricated via fused deposition modeling designed to hold microfluidic needle adapters exhibited good biocompatibility, while those made using liquid crystal display-based photopolymerization showed significant cytotoxicity despite indirect exposure. Overall, this platform enables creation of multi-material microvascular systems facilitated by TPL technology for complex, 3D neurovascular modeling, blood–brain barrier studies, and integration into vascularized organ-on-chip applications. Full article

(This article belongs to the Special Issue Microfluidic Chips for Biomedical Applications)

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26 pages, 7002 KB

Open AccessFeature PaperEditor’s ChoiceReview

Recent Advances in Microfluidic Impedance Detection: Principle, Design and Applications

by Yigang Shen, Zhenxiao Wang, Tingyu Ren, Jianming Wen, Jianping Li and Tao Tang

Micromachines 2025, 16(6), 683; https://doi.org/10.3390/mi16060683 - 5 Jun 2025

Cited by 2 | Viewed by 1680

Abstract

Under the dual drivers of precision medicine development and health monitoring demands, the development of real-time biosensing technologies has emerged as a key breakthrough in the field of life science analytics. Microfluidic impedance detection technology, achieved through the integration of microscale fluid manipulation [...] Read more.

Under the dual drivers of precision medicine development and health monitoring demands, the development of real-time biosensing technologies has emerged as a key breakthrough in the field of life science analytics. Microfluidic impedance detection technology, achieved through the integration of microscale fluid manipulation and bioimpedance spectrum analysis, has enabled the real-time monitoring of biological samples ranging from single cells to organ-level systems, now standing at the forefront of biological real-time detection research. This review systematically summarizes the core principles of microfluidic impedance detection technology, modeling methods for cell equivalent circuits, system optimization strategies, and recent research advancements in biological detection applications. We first elucidate the fundamental principles of microfluidic impedance detection technologies, followed by a comprehensive analysis of cellular equivalent circuit model construction and microfluidic system design optimization strategies. Subsequently, we categorize applications based on biological sample types, elaborating on respective research progress and existing challenges. This review concludes with prospective insights into future developmental trajectories. We hope this work will provide novel research perspectives for advancing microfluidic impedance detection technology while stimulating interdisciplinary collaboration among researchers in biology, medicine, chemistry, and physics to propel technological innovation collectively. Full article

(This article belongs to the Special Issue Application of Microfluidic Technology in Bioengineering)

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20 pages, 8428 KB

Open AccessFeature PaperEditor’s ChoiceArticle

The Role of Pd-Pt Bimetallic Catalysts in Ethylene Detection by CMOS-MEMS Gas Sensor Dubbed GMOS

by Hanin Ashkar, Sara Stolyarova, Tanya Blank and Yael Nemirovsky

Micromachines 2025, 16(6), 672; https://doi.org/10.3390/mi16060672 - 31 May 2025

Cited by 2 | Viewed by 3241

Abstract

The importance and challenges of ethylene detection based on combustion-type low-cost commercial sensors for agricultural and industrial applications are well-established. This work summarizes the significant progress in ethylene detection based on an innovative Gas Metal Oxide Semiconductor (GMOS) sensor and a new catalytic [...] Read more.

The importance and challenges of ethylene detection based on combustion-type low-cost commercial sensors for agricultural and industrial applications are well-established. This work summarizes the significant progress in ethylene detection based on an innovative Gas Metal Oxide Semiconductor (GMOS) sensor and a new catalytic composition of metallic nanoparticles. The paper presents a study on ethylene and ethanol sensing using a miniature catalytic sensor fabricated by Complementary Metal Oxide Semiconductor–Silicon-on-Insulator–Micro-Electro-Mechanical System (CMOS-SOI-MEMS) technology. The GMOS performance with bimetallic palladium–platinum (Pd-Pt) and monometallic palladium (Pd) and platinum (Pt) catalysts is compared. The synergetic effect of the Pd-Pt catalyst is observed, which is expressed in the shift of combustion reaction ignition to lower catalyst temperatures as well as increased sensitivity compared to monometallic components. The optimal catalysts and their temperature regimes for low and high ethylene concentrations are chosen, resulting in lower power consumption by the sensor. Full article

(This article belongs to the Collection Women in Micromachines)

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16 pages, 13475 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Low Thermal Stress and Instant Efficient Atomization of Narrow Viscous Microfluid Film Using a Paper Strip Located at the Edge of a Surface Acoustic Wave Atomizer

by Yulin Lei, Yusong Li, Jia Ning, Yu Gu, Chenhui Gai, Qinghe Ma, Yizhan Ding, Benzheng Wang and Hong Hu

Micromachines 2025, 16(6), 628; https://doi.org/10.3390/mi16060628 - 27 May 2025

Viewed by 580

Abstract

A traditional SAW (surface acoustic wave) atomizer directly supplies liquid to the surface of the atomized chip through a paper strip located in the path of the acoustic beam, resulting in irregular distribution of the liquid film, which generates an aerosol with an [...] Read more.

A traditional SAW (surface acoustic wave) atomizer directly supplies liquid to the surface of the atomized chip through a paper strip located in the path of the acoustic beam, resulting in irregular distribution of the liquid film, which generates an aerosol with an uneven particle size distribution and poor directional controllability, and a high heating phenomenon that can easily break the chip in the atomization process. This paper presents a novel atomization method: a paper strip located at the edge of the atomizer (PSLEA), which forms a micron-sized narrow liquid film at the junction of the atomization chip edge and the paper strip under the effect of acoustic wetting. By using this method, physical separation of the atomized aerosol and jetting droplets can be achieved at the initial stage of atomizer startup, and an ideal aerosol plume with no jetting of large droplets, a uniform particle size distribution, a vertical and stable atomization direction, and good convergence of the aerosol beam can be quickly formed. Furthermore, the effects of the input power, and different paper strips and liquid supply methods on the atomization performance, as well as the heating generation capacity of the liquid in the atomization zone during the atomization process were explored through a large number of experiments, which highlighted the advantages of PSLEA atomization. The experiments demonstrated that the maximum atomization rate under the PSLEA atomization mode reached 2.6 mL/min initially, and the maximum thermal stress was 45% lower compared with that in the traditional mode. Additionally, a portable handheld atomizer with stable atomization performance and a median aerosol particle size of 3.95 μm was designed based on the proposed PSLEA atomization method, showing the great potential of SAW atomizers in treating respiratory diseases. Full article

(This article belongs to the Special Issue Novel Surface and Bulk Acoustic Wave Devices)

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14 pages, 17404 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Reconfigurable Orbital Electrowetting for Controllable Droplet Transport on Slippery Surfaces

by Jiayao Wu, Huafei Li, Yifan Zhou, Ge Gao, Teng Zhou, Ziyu Wang and Huai Zheng

Micromachines 2025, 16(6), 618; https://doi.org/10.3390/mi16060618 - 25 May 2025

Viewed by 954

Abstract

The controllable transport of droplets on solid surfaces is crucial for many applications, from water harvesting to bio-analysis. Herein, we propose a novel droplet transport controlling method, reconfigurable orbital electrowetting (ROEW) on inclined slippery liquid-infused porous surfaces (SLIPS), which enables controllable transport and [...] Read more.

The controllable transport of droplets on solid surfaces is crucial for many applications, from water harvesting to bio-analysis. Herein, we propose a novel droplet transport controlling method, reconfigurable orbital electrowetting (ROEW) on inclined slippery liquid-infused porous surfaces (SLIPS), which enables controllable transport and dynamic handling of droplets by non-contact reconfiguration of orbital electrodes. The flexible reconfigurability is attributed to the non-contact wettability modulation and reversibly deformable flexible electrodes. ROEW graphically customizes stable wettability pathways by real-time and non-contact printing of charge-orbit patterns on SLIPS to support the continuous transport of droplets. Benefiting from the fast erase-writability of charges and the movability of non-contact electrodes, ROEW enables reconfiguration of the wetting pathways by designing electrode shapes and dynamically switching electrode configurations, achieving controllable transport of various pathways and dynamic handling of droplet sorting and mixing. ROEW provides a new approach for reconfigurable, electrode-free arrays and reusable microfluidics. Full article

(This article belongs to the Topic Micro-Mechatronic Engineering, 2nd Edition)

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20 pages, 4542 KB

Open AccessFeature PaperEditor’s ChoiceArticle

A Multifunctional Capsule-like Puncture Biopsy Robot for the Gastrointestinal System

by Xinmiao Xu, Jinghan Gao, Dingwen Tong, Yiqun Zhao, Xinjian Fan and Wanning Ge

Micromachines 2025, 16(5), 589; https://doi.org/10.3390/mi16050589 - 18 May 2025

Viewed by 1066

Abstract

Gastrointestinal submucosal tumors (SMTs) are difficult to diagnose accurately due to their deep location and the limitations of traditional biopsy tools. To address these issues, we propose a multifunctional capsule-shaped puncture biopsy robot (PBR) with capabilities for tissue sampling, thermal hemostasis, and multi-stage [...] Read more.

Gastrointestinal submucosal tumors (SMTs) are difficult to diagnose accurately due to their deep location and the limitations of traditional biopsy tools. To address these issues, we propose a multifunctional capsule-shaped puncture biopsy robot (PBR) with capabilities for tissue sampling, thermal hemostasis, and multi-stage drug delivery. The PBR measures 27 mm in length and 13 mm in diameter, integrating a micro-scale electro-permanent magnetic system with a 60-turn dual-layer coil (wire diameter: 0.6 mm) to drive an 8 mm-depth puncture needle. A graphene–carbon nanotube composite heating film enables rapid and safe temperature elevation, achieving effective hemostasis and triggering sequential drug release using paraffin-based phase-change materials. Heating remains within the clinical safety range. Experiments demonstrated successful tissue penetration, precise magnetic control, and reliable staged pigment release simulating drug delivery. Tests on an ex vivo porcine stomach confirmed adaptability to irregular gastric surfaces. This compact PBR provides an integrated and minimally invasive approach to both the diagnosis and treatment of gastrointestinal lesions. Full article

(This article belongs to the Section A：Physics)

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13 pages, 2446 KB

Open AccessFeature PaperEditor’s ChoiceArticle

A Novel Pathogen Detection System Combining a Nucleic Acid Extraction Biochip with a Perovskite Photodetector

by Zhuo Gao, Pan Wang, Chang Chen, Jian Duan, Shilun Feng and Bo Liu

Micromachines 2025, 16(5), 581; https://doi.org/10.3390/mi16050581 - 15 May 2025

Viewed by 2804

Abstract

The increasing spread of infectious diseases caused by pathogenic microorganisms underscores the urgent need for highly sensitive, portable, and rapid nucleic acid detection technologies to facilitate early diagnosis and effective prevention. In this study, we developed a fluorescence-based nucleic acid detection platform that [...] Read more.

The increasing spread of infectious diseases caused by pathogenic microorganisms underscores the urgent need for highly sensitive, portable, and rapid nucleic acid detection technologies to facilitate early diagnosis and effective prevention. In this study, we developed a fluorescence-based nucleic acid detection platform that integrates a microfluidic chip with an all-inorganic perovskite photodetector. The system enables integrated operation of nucleic acid extraction, purification, and amplification on a microfluidic chip, combined with real-time electrical signal readout via a CsPbBr₃ perovskite photodetector. Experimental results indicate that the photodetector exhibits high responsivity at 530 nm, aligning well with the primary emission peak of FAM. The system demonstrates a strong linear correlation between photocurrent and FAM concentration over the range of 0.01–0.4 μM (R² = 0.928), with a low detection limit of 0.01 μM and excellent reproducibility across multiple measurements. Validation using FAM standard solutions and Escherichia coli samples confirmed the system’s reliable linearity and signal stability. This platform demonstrates strong potential for rapid pathogen screening and point-of-care diagnostic applications. Full article

(This article belongs to the Special Issue Recent Progress of Lab-on-a-Chip Assays)

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14 pages, 4835 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Development and Evaluation of Multi-Module Retinal Devices for Artificial Vision Applications

by Kuang-Chih Tso, Yoshinori Sunaga, Yuki Nakanishi, Yasuo Terasawa, Makito Haruta, Kiyotaka Sasagawa and Jun Ohta

Micromachines 2025, 16(5), 580; https://doi.org/10.3390/mi16050580 - 15 May 2025

Viewed by 810

Abstract

Artificial retinal devices require a high-density electrode array and mechanical flexibility to effectively stimulate retinal cells. However, designing such devices presents significant challenges, including the need to conform to the curvature of the eyeball and cover a large area using a single platform. [...] Read more.

Artificial retinal devices require a high-density electrode array and mechanical flexibility to effectively stimulate retinal cells. However, designing such devices presents significant challenges, including the need to conform to the curvature of the eyeball and cover a large area using a single platform. To address these issues, we developed a parylene-based multi-module retinal device (MMRD) integrating a complementary metal-oxide semiconductor (CMOS) system. The proposed device is designed for suprachoroidal transretinal stimulation, with each module comprising a parylene-C thin-film substrate, a CMOS chip, and a ceramic substrate housing seven platinum electrodes. The smart CMOS system significantly reduces wiring complexity, enhancing the device’s practicality. To improve fabrication reliability, we optimized the encapsulation process, introduced multiple silane coupling modifications, and utilized polyvinyl alcohol (PVA) for easier detachment in flip-chip bonding. This study demonstrates the fabrication and evaluation of the MMRD through in vitro and in vivo experiments. The device successfully generated the expected current stimulation waveforms in both settings, highlighting its potential as a promising candidate for future artificial vision applications. Full article

(This article belongs to the Section E：Engineering and Technology)

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20 pages, 2666 KB

Open AccessFeature PaperEditor’s ChoiceReview

Development of Energy-Selective Surface for Electromagnetic Protection

by Jinghao Lv, Caofei Luo, Jiwei Zhao, Haoran Han, Huan Lu and Bin Zheng

Micromachines 2025, 16(5), 555; https://doi.org/10.3390/mi16050555 - 1 May 2025

Cited by 2 | Viewed by 1034

Abstract

Energy-selective surfaces (ESSs) have gained attention as an advanced electromagnetic protection technology. This review discusses the evolution of ESSs, focusing on four key areas: frequency bandwidth expansion, material innovations, functional enhancements, and application diversification. ESSs have evolved from narrowband designs to providing ultra-wideband [...] Read more.

Energy-selective surfaces (ESSs) have gained attention as an advanced electromagnetic protection technology. This review discusses the evolution of ESSs, focusing on four key areas: frequency bandwidth expansion, material innovations, functional enhancements, and application diversification. ESSs have evolved from narrowband designs to providing ultra-wideband protection, covering L-band to K-band frequencies. New designs, including non-reciprocal mechanisms and cascaded filters, enhance the shielding efficiency. Material advancements like the use of vanadium dioxide (VO₂) and micro–nano fabrication techniques have reduced costs and improved performance, enabling higher-frequency applications. Future developments aim to overcome the current limitations, offering a broader bandwidth, higher power tolerance, and faster response times. ESSs play a key role in integrated electromagnetic protection systems. Full article

(This article belongs to the Special Issue Novel Electromagnetic and Acoustic Devices)

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46 pages, 6940 KB

Open AccessFeature PaperEditor’s ChoiceReview

High-Performance Carbon Nanotube Electronic Devices: Progress and Challenges

by Zirui Zhang, Nie Zhang and Zhiyong Zhang

Micromachines 2025, 16(5), 554; https://doi.org/10.3390/mi16050554 - 1 May 2025

Cited by 4 | Viewed by 4251

Abstract

As silicon-based complementary metal-oxide-semiconductor (CMOS) technology approaches its physical and scaling limits at sub-3-nanometer nodes, critical challenges including the short-channel effect (SCE), surging power consumption, and aggravated parasitic effects have severely constrained further improvements in device performance, integration density, and energy efficiency. Carbon [...] Read more.

As silicon-based complementary metal-oxide-semiconductor (CMOS) technology approaches its physical and scaling limits at sub-3-nanometer nodes, critical challenges including the short-channel effect (SCE), surging power consumption, and aggravated parasitic effects have severely constrained further improvements in device performance, integration density, and energy efficiency. Carbon nanotubes (CNTs), with their superior electrical properties, exceptional gate controllability enabled by one-dimensional nanostructure, and compatibility with existing semiconductor processes, have emerged as an ideal candidate material for post-silicon high-performance electronics. Since their discovery, CNT electronics have evolved from fundamental research to a comprehensive technological framework. This review first systematically elaborates the physical characteristics of CNTs and operation mechanisms of electronic devices. Subsequently, we comprehensively summarize recent research progress in high-performance CNT electronic devices with particular emphasis on their breakthrough achievements. Through critical analysis of current developments, we thoroughly discuss fundamental challenges in material synthesis, device fabrication, and circuit integration, while evaluating potential solutions. Finally, we concentrate on future development directions for high-performance CNT devices, aiming to call for collaborative efforts from both academia and industry to accelerate the transition of CNT electronics from laboratory research to industrial implementation. Full article

(This article belongs to the Special Issue Multifunctional Transistors: Outlooks and Challenges)

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9 pages, 13670 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Ultra-Short-Pulse Laser Welding of Glass to Metal with a Shear Strength Above 50 MPa

by Lukas Günther, Jens Ulrich Thomas, Jens Hermann, Axel Ohlinger and Dominique de Ligny

Micromachines 2025, 16(5), 538; https://doi.org/10.3390/mi16050538 - 30 Apr 2025

Cited by 1 | Viewed by 1081

Abstract

We report an ultra-short-pulse laser welding process that allows one to consistently weld Borofloat^® 33 glass to aluminum with a shear strength above 50 MPa. We explored the morphology of the welding seam and quantified the quality of the bonding by statistically [...] Read more.

We report an ultra-short-pulse laser welding process that allows one to consistently weld Borofloat^® 33 glass to aluminum with a shear strength above 50 MPa. We explored the morphology of the welding seam and quantified the quality of the bonding by statistically determining the shear strength with more than 30 samples. The results of the shear strength tests indicate that the intrinsic shear strength of the aluminum serves as the upper limit of the glass-to-metal bond. Full article

(This article belongs to the Special Issue Advancement of Laser Technology from Materials Processing to Nano/Micro Fabrications)

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19 pages, 1093 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Rheological Property Changes in Polyacrylamide Aqueous Solution Flowed Through Microchannel Under Low Reynolds Number and High Shear Rate Conditions

by Yishuai Li, Yukihiro Yonemoto, Yuki Yamahata and Akimaro Kawahara

Micromachines 2025, 16(5), 545; https://doi.org/10.3390/mi16050545 - 30 Apr 2025

Viewed by 654

Abstract

As an important structure of microfluidic devices, microchannels have the advantages of precise flow control and high reaction efficiency. This study investigates experimentally changing the rheological properties of a polyacrylamide (PAM) aqueous solution after flowing through a square microchannel with a hydraulic diameter [...] Read more.

As an important structure of microfluidic devices, microchannels have the advantages of precise flow control and high reaction efficiency. This study investigates experimentally changing the rheological properties of a polyacrylamide (PAM) aqueous solution after flowing through a square microchannel with a hydraulic diameter of 0.5 mm under low Reynolds number and high shear rate conditions. To know the effect of the channel length on the change in viscosity and relaxation time, the length is changed to 100 mm and 200 mm. From the experiment, it is found that both the viscosity and relaxation time of the solution decrease with increasing the shear rate and the microchannel length. Based on the present experimental data, an empirical model is proposed to predict the change ratio of the relaxation time before and after passing through the microchannel, and the calculation with the model has an agreement with the experiment with root-mean-square absolute error of 0.007. Full article

(This article belongs to the Special Issue Flows in Micro- and Nano-Systems)

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15 pages, 2084 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Characterization of the Coating Layers Deposited onto Curved Surfaces Using a Novel Multi-Nozzle Extrusion Printer

by Ramses Seferino Trigo Torres, Lawrence Kulinsky and Arash Kheradvar

Micromachines 2025, 16(5), 505; https://doi.org/10.3390/mi16050505 - 26 Apr 2025

Cited by 1 | Viewed by 686

Abstract

Over the past two decades, additive manufacturing has advanced significantly, enabling rapid fabrication of functional components across various applications. In medical devices, it has been used for prototyping, prosthetics, drug delivery platforms, and more recently, tissue scaffolding. However, current technologies face challenges, particularly [...] Read more.

Over the past two decades, additive manufacturing has advanced significantly, enabling rapid fabrication of functional components across various applications. In medical devices, it has been used for prototyping, prosthetics, drug delivery platforms, and more recently, tissue scaffolding. However, current technologies face challenges, particularly in depositing conformal layers over curved surfaces. This study introduces a novel multi-nozzle extrusion printer concept designed to deposit soft gel layers onto curved surfaces. A custom clearance locking mechanism enhances the printer’s ability to achieve conformal coatings on both flat and curved substrates. We investigate key deposition parameters, including displacement volume and nozzle configuration, while comparing two deposition sequences: “Press and Express” and “Express and Press”. Our results demonstrate that the “Express and Press” technique yields more uniform, merged conformal layers than the “Press and Express” method. This technology holds promise for further refinement and potential applications in tissue engineering. Full article

(This article belongs to the Section B2: Biofabrication and Tissue Engineering)

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15 pages, 2921 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Application of Inertial Microfluidics for Isolation and Removal of Round Spermatids from a Spermatogenic Cell Sample to Assist In-Vitro Human Spermatogenesis

by Sabin Nepal, Joey Casalini, Alex Jafek and Bruce Gale

Micromachines 2025, 16(5), 500; https://doi.org/10.3390/mi16050500 - 25 Apr 2025

Viewed by 751

Abstract

In-vitro spermatogenesis holds great potential in addressing male infertility, yet one of the main challenges is separating round spermatids from other germ cells in spermatogonial stem cell cultures. STA-PUT, a method based on velocity sedimentation, has been extensively tested for this application. Though [...] Read more.

In-vitro spermatogenesis holds great potential in addressing male infertility, yet one of the main challenges is separating round spermatids from other germ cells in spermatogonial stem cell cultures. STA-PUT, a method based on velocity sedimentation, has been extensively tested for this application. Though somewhat effective, it requires bulky, expensive equipment and significant time. In contrast, the method of inertial microfluidics offers a compact, cost-effective, and faster alternative. In this study, we designed, fabricated, and tested a microfluidic spiral channel for isolating round spermatids and purifying spermatogenic cells. A commercially available spiral device close to the calculated specifications was tested for rapid prototyping, achieving 79% purity for non-spermatid cells in a single pass, with ability to achieve higher purity through repeated passes. However, the commercial device’s narrow outlets caused clogging, prompting the fabrication of a custom polydimethylsiloxane device matching the calculated specifications. This custom device demonstrated significant improvements, achieving 86% purity in a single pass compared to STA-PUT’s 38%, and that without any clogging issues. Further purification could be attained by repeated passes, as shown in earlier studies. This work underscores the efficacy of inertial microfluidics for efficient, high-purity cell separation, with the potential to revolutionize workflows in in-vitro spermatogenesis research. Full article

(This article belongs to the Special Issue Application of Microfluidic Technology in Biology)

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15 pages, 13926 KB

Open AccessFeature PaperEditor’s ChoiceArticle

High-Temperature Properties of LP-DED Additive Manufactured Ferritic STS 430 Deposits on Martensitic STS 410 Base Metal

by Samsub Byun, Hyun-Ki Kang, Namhyun Kang and Seunghun Lee

Micromachines 2025, 16(5), 494; https://doi.org/10.3390/mi16050494 - 23 Apr 2025

Cited by 1 | Viewed by 798

Abstract

The aim of this work is to study the phase transformations, microstructures, and mechanical properties of ferritic stainless steel (FSS) 430 deposits on martensitic stainless steel (MSS) 410 base metal (BM) using laser powder-directed energy deposition (LP-DED) additive manufacturing. The LP-DED additive manufactured [...] Read more.

The aim of this work is to study the phase transformations, microstructures, and mechanical properties of ferritic stainless steel (FSS) 430 deposits on martensitic stainless steel (MSS) 410 base metal (BM) using laser powder-directed energy deposition (LP-DED) additive manufacturing. The LP-DED additive manufactured FSS 430 deposits on MSS 410 BM underwent post-heat treatment at 815 °C and 980 °C for 1 h, respectively. The analyses of phase transformations and microstructural evolutions of LP-DED FSS 430 on MSS 410 BM were carried out using X-ray diffraction, SEM, and EBSD. The highest strain was observed at the coarsened chromium carbide (Cr₂₃C₆) in the joint interface between AM FSS 430 and MSS 410 MB. This contributed to localized lattice distortion and mismatch in crystal structure between chromium carbide and the surrounding ferrite. Tensile strength properties at elevated temperatures were discussed to investigate the effects of the different post-heat treatments. The tensile properties of the as-built samples including tensile strength of about 550 MPa and elongation of about 20%, were the same as those of the commercial FSS 430 material. Tensile properties at 500 °C indicated a modest increase in tensile strength to 540–550 MPa. The specimens heat treated at 980 °C retained higher tensile strength than those heat treated at 815 °C. This would be attributed to the grain refinement from prior LP-DED microstructure and chromium carbide coarsening at higher heat treatment, which can increase dislocation density and yield harder mechanical behavior. Full article

(This article belongs to the Special Issue Laser Additive Manufacturing of Metallic Materials, 2nd Edition)

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17 pages, 9262 KB

Open AccessEditor’s ChoiceArticle

Infrared Absorption of Laser Patterned Sapphire Al₂O₃ for Radiative Cooling

by Nan Zheng, Daniel Smith, Soon Hock Ng, Hsin-Hui Huang, Dominyka Stonytė, Dominique Appadoo, Jitraporn Vongsvivut, Tomas Katkus, Nguyen Hoai An Le, Haoran Mu, Yoshiaki Nishijima, Lina Grineviciute and Saulius Juodkazis

Micromachines 2025, 16(4), 476; https://doi.org/10.3390/mi16040476 - 16 Apr 2025

Cited by 1 | Viewed by 1330

Abstract

The reflectance (R) of linear and circular micro-gratings on c-plane sapphire Al₂O₃ ablated by a femtosecond (fs) laser were spectrally characterised for thermal emission

\propto (1 - R)

in the mid-to-far infrared (IR) spectral range. An [...] Read more.

The reflectance (R) of linear and circular micro-gratings on c-plane sapphire Al₂O₃ ablated by a femtosecond (fs) laser were spectrally characterised for thermal emission

\propto (1 - R)

in the mid-to-far infrared (IR) spectral range. An IR camera was used to determine the blackbody radiation temperature from laser-patterned regions, which showed (3–6)% larger emissivity dependent on the grating pattern. The azimuthal emission curve closely followed the Lambertian angular profile

\propto cos θ_{a}

at the 7.5–13 μm emission band. The back-side ablation method on transparent substrates was employed to prevent debris formation during energy deposition as it applies a forward pressure of >0.3 GPa to the debris and molten skin layer. The back-side ablation maximises energy deposition at the exit interface where the transition occurs from the high-to-low refractive index. Phononic absorption in the Reststrahlen region 20–30 μm can be tailored with the fs laser inscription of sensor structures/gratings. Full article

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15 pages, 6112 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Study on the Mechanism of the Micro-Charge-Detonation-Driven Flyer

by Shuang Li, Jie Ren, Chang Leng, Zhenhao Shi, Yan Ma, Mingyu Li and Qingxuan Zeng

Micromachines 2025, 16(4), 441; https://doi.org/10.3390/mi16040441 - 9 Apr 2025

Viewed by 485

Abstract

To investigate the energy transfer mechanisms during the micro-explosive initiator-driven flyer process and to guide the performance evaluation of micro-sized charges and the structural design of micro-initiators, a combined approach of numerical simulations and experimental tests was employed to study the detonation process [...] Read more.

To investigate the energy transfer mechanisms during the micro-explosive initiator-driven flyer process and to guide the performance evaluation of micro-sized charges and the structural design of micro-initiators, a combined approach of numerical simulations and experimental tests was employed to study the detonation process of copper-based azide micro-charges driving a flyer. The output pressure and detonation velocity of the copper-based azide micro-charge were measured using the manganese–copper piezoresistive method and electrical probe technique, and the corresponding JWL equation of the state parameters was subsequently fitted. A simulation model for the micro-charge-driven flyer was established and validated using Photonic Doppler Velocimetry (PDV), and the influence of charge conditions, structural parameters, and other factors on the flyer velocity and morphology was investigated. The results indicate that the flyer velocity decreases as its thickness increases, whereas the specific kinetic energy of the flyer initially increases and then decreases with increasing thickness. The optimal flyer thickness was found to be in the range of 30 to 70 μm. The flyer velocity increases with the density and height of the micro-charge; however, when the micro-charge density exceeds a certain threshold, the flyer velocity decreases. The flyer velocity exhibits an exponential decline as the diameter of the acceleration chamber increases, whereas it shows a slight increase with the increase in the length of the acceleration chamber. The diameter of the acceleration chamber should not exceed the charge diameter and must be no smaller than the critical diameter required for detonation initiation of the underlying charge. The use of a multi-layer accelerating chamber structure leads to a slight reduction in flyer velocity and further increases in the transmission hole diameter while having no significant impact on the flyer velocity. Full article

(This article belongs to the Special Issue Micro/Nanostructures in Sensors and Actuators, 2nd Edition)

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18 pages, 3245 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Electrical Phenotyping of Aged Human Mesenchymal Stem Cells Using Dielectrophoresis

by Lexi L. C. Simpkins, Tunglin Tsai, Emmanuel Egun and Tayloria N. G. Adams

Micromachines 2025, 16(4), 435; https://doi.org/10.3390/mi16040435 - 3 Apr 2025

Cited by 1 | Viewed by 812

Abstract

Human mesenchymal stem cells (hMSCs) are widely used in regenerative medicine, but large-scale in vitro expansion alters their function, impacting proliferation and differentiation potential. Currently, a predictive marker to assess these changes is lacking. Here, we used dielectrophoresis (DEP) to characterize the electrical [...] Read more.

Human mesenchymal stem cells (hMSCs) are widely used in regenerative medicine, but large-scale in vitro expansion alters their function, impacting proliferation and differentiation potential. Currently, a predictive marker to assess these changes is lacking. Here, we used dielectrophoresis (DEP) to characterize the electrical phenotype of hMSCs derived from bone marrow (BM), adipose tissue (AT), and umbilical cord (UC) as they aged in vitro from passage 4 (P4) to passage 9 (P9). The electrical phenotype was defined by the DEP spectra, membrane capacitance, and cytoplasm conductivity. Cell morphology and size, growth characteristics, adipogenic differentiation potential, and osteogenic differentiation potential were assessed alongside label-free biomarker membrane capacitance and cytoplasm conductivity. Differentiation was confirmed by histological staining and RT-qPCR. All hMSCs exhibited typical morphology, though cell size varied, with UC-hMSCs displaying the largest variability across all size metrics. Growth analysis revealed that UC-hMSCs proliferated the fastest. The electrical phenotype varied with cell source and in vitro age, with high passage hMSCs showing noticeable shifts in DEP spectra, membrane capacitance, and cytoplasm conductivity. Correlation analysis revealed that population doubling level (PDL) correlated with membrane capacitance and cytoplasm conductivity, indicating PDL as a more precise marker of in vitro aging than passage number. Additionally, we demonstrate that membrane capacitance correlates with the osteogenic marker COL1A1 and that cytoplasm conductivity correlates with the adipogenic markers ADIPOQ and FABP4, suggesting that DEP-derived electrical properties serve as label-free biomarkers of differentiation potential. While DEP has previously been applied to BM-hMSCs and AT-hMSCs, and more recently to UC-hMSCs, few studies have provided a direct comparison across all three sources or tracked changes across continuous expansion. These findings underscore the utility of DEP as a label-free approach for assessing hMSC aging and function, offering practical applications for optimizing stem cell expansion and stem cell banking in clinical settings. Full article

(This article belongs to the Special Issue Micro/Nanotechnology for Cell Manipulation, Detection and Analysis)

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Open AccessFeature PaperEditor’s ChoiceArticle

Multi-Nozzles 3D Bioprinting Collagen/Thermoplastic Elasto-Mer Scaffold with Interconnect Pores

by Kuo Yao, Kai Guo, Heran Wang and Xiongfei Zheng

Micromachines 2025, 16(4), 429; https://doi.org/10.3390/mi16040429 - 2 Apr 2025

Cited by 1 | Viewed by 1312

Abstract

Scaffolds play a crucial role in tissue engineering as regenerative templates. Fabricating scaffolds with good biocompatibility and appropriate mechanical properties remains a major challenge in this field. This study proposes a method for preparing multi-material scaffolds, enabling the 3D printing of collagen and [...] Read more.

Scaffolds play a crucial role in tissue engineering as regenerative templates. Fabricating scaffolds with good biocompatibility and appropriate mechanical properties remains a major challenge in this field. This study proposes a method for preparing multi-material scaffolds, enabling the 3D printing of collagen and thermoplastic elastomers at room temperature. Addressing the previous challenges such as the poor printability of pure collagen and the difficulty of maintaining structural integrity during multilayer printing, this research improved the printability of collagen by optimizing its concentration and pH value and completed the large-span printing of thermoplastic elastomer using a precise temperature-control system. The developed hybrid scaffold has an interconnected porous structure, which can support the adhesion and proliferation of fibroblasts. The scaffolds were further treated with different post-treatment methods, and it was proven that the neutralized and cross-linked collagen scaffold, which has both nano-fibers and a certain rigidity, can better support the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). The research results show that the collagen thermoplastic elastomer hybrid scaffold has significant clinical application potential in soft tissue and hard tissue regeneration, providing a versatile solution to meet the diverse needs of tissue engineering. Full article

(This article belongs to the Section B2: Biofabrication and Tissue Engineering)

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