Search Results (144)

Therapeutic interventions within the urinary system are often limited by the complex and tortuous anatomy of the renal pelvis and ureters, restricting access to deep regions and increasing the risk of mucosal trauma. In this study, we present a multifunctional, magnetically controlled ferrofluid droplet robotic platform engineered for high deformability and precision navigation. A custom electromagnetic actuation system was developed and optimized via COMSOL Multiphysics (version 6.3, COMSOL Inc., Stockholm, Sweden) simulations to generate programmable magnetic fields. Experimental validation in both simplified environments and anatomically realistic 3D-printed urinary tract models demonstrated the droplets’ capacity for controlled locomotion, reversible deformation, and traversing constrictions significantly smaller than their resting diameter. The droplets’ locomotion and extreme deformability are governed by the dynamic balance between the applied magnetic gradient forces, the restoring interfacial tension of the ferrofluid, and the fluidic viscous drag. Quantitatively, the droplets achieved robust translational velocities up to 260 mm/s under single-coil actuation (51 mT, 20 Hz) and 108 mm/s under a more stable dual-coil configuration (51 mT, 8.3 Hz). Furthermore, two clinically relevant functionalities were successfully executed: rapid vibration-induced release of encapsulated dye for targeted drug delivery, and the precise mechanical capture and transport of artificial kidney stones. These results establish a highly versatile platform for minimally invasive urological procedures, highlighting the immense potential of soft magnetic microrobotics for integrated therapeutic applications. Full article

Vat polymerization-based 3D printing has emerged as a promising approach for the rapid, low-cost, and scalable fabrication of microfluidic devices; however, achieving high-resolution and fully clog-free microchannels using commercial resins remains challenging. In this study, we systematically investigate key printing parameters—including channel orientation, length, layer thickness, and exposure time—to elucidate their effects on channel openness, dimensional fidelity, and surface morphology using a commercially available low-cost masked stereolithography (MSLA) printer and printing resin, thereby establishing quantitative fabrication boundaries that define the transition from fully open to blocked microchannels in practice. Under optimized printing conditions, microchannels with characteristic dimensions exceeding 200 µm were fabricated in a reliable and clog-free manner using standard commercial resins. In addition, by implementing a size-compensated design strategy, we achieved the fabrication of complex droplet generator arrays with a minimum central channel width of 400 µm, while maintaining an internal dimensional deviation below 2.5%. These investigations significantly expand the practical applicability of low-cost MSLA 3D printing for microfluidic device fabrication, providing a scalable and accessible pathway for producing high-fidelity microchannels without reliance on custom resins or post-processing-intensive workflows. Full article

Three-dimensional (3D) culture systems that recapitulate the tumor microenvironment are essential for studying cancer cell behavior, drug response, and cell–matrix interactions. Here, we present a detailed protocol for generating 3D spheroid cultures from murine breast cancer cells using methacrylated gelatin (GelMA)-based bioink and a CELLINK BioX bioprinter. This method enables precise deposition of spheroid-laden GelMA droplets into low-attachment plates, facilitating high-throughput and reproducible 3D culture formation. The protocol includes steps for spheroid formation, GelMA preparation, bioprinting, and post-printing analysis using a customized CellProfiler pipeline. The analysis pipeline takes advantage of the functionality of CellProfiler and ImageJ software (version 2.14.0) packages to create a versatile and accessible analysis tool. This approach provides a robust and adaptable platform for in vitro cancer research, including studies of metastasis, drug resistance, cancer cell lipid metabolism, and TME-associated hypoxia. Full article

In vitro models of the human nasal cavity are crucial for understanding the deposition dynamics of nasally administered drugs. Three-dimensional (3D) printing offers a powerful method for creating patient-specific, anatomically precise models for such experimental purposes. Background/Objectives: This study details the complete workflow for the development, design, and fabrication of a sectioned nasal cavity model intended for droplet deposition analysis of nasal sprays. Methods: A digital nasal cavity model was derived from medical imaging data and optimized for computer-aided design (CAD) operations. It was segmented into five therapeutically relevant regions: nasal vestibule, olfactory area, middle and upper turbinates, lower turbinate, and nasopharynx. Sections were 3D-printed in polypropylene for chemical compatibility, and a carbon fiber-reinforced fixation frame ensured precise alignment and airtight assembly. Results: Functional validation confirmed the model’s functional relevance through comparative deposition studies using automated actuation and high-performance liquid chromatography (HPLC) based regional quantification. Two devices with distinct spray characteristics (characterized separately by laser diffraction, plume geometry, and spray pattern imaging) were tested under varied administration conditions. The study demonstrated the model’s ability to discriminate between products, establishing a solid foundation for future investigations incorporating additional variables. Conclusions: Overall, the developed methodology provides a cost-effective and replicable platform for producing anatomically accurate, sectioned nasal cavity models. The newly developed in vitro system is well suited for detailed, region-specific analysis of nasal spray deposition, offering a valuable tool for pharmaceutical research and development. Full article

Droplet microfluidics enables high-throughput, compartmentalized reactions using minimal reagent volumes, but most implementations rely on precision-fabricated chips and external pumping systems that limit portability and accessibility. Here, we present a handheld vibrational droplet generator that repurposes a consumer electric toothbrush and a modified disposable pipette tip to produce nearly monodisperse water-in-oil droplets without microfluidic channels or syringe pumps. The device is powered by the toothbrush’s built-in motor and controlled by a simple 3D-printed adapter and adjustable counterweight that tune the vibration amplitude transmitted to the pipette tip. By varying the aperture of the pipette tip, droplets with diameters from ~100–300 µm were generated at rates of ~100 droplets s⁻¹. Image analysis revealed narrow size distributions with coefficients of variation below 5% in typical operating conditions. We further demonstrate proof-of-concept applications in digital loop-mediated isothermal amplification (LAMP) and microbiological colony-forming unit (CFU) assays. A commercial feline parvovirus (FPV) kit manufactured by Beyotime Biotechnology Co., Ltd. (Shanghai, China), three template concentrations yielded emulsified reaction droplets that remained stable at 65 °C for 45 min and produced distinct fractions of fluorescent-positive droplets, allowing estimation of template concentration via a Poisson model. In a second set of experiments, the device was used as a droplet-based spreader to dispense diluted Escherichia coli suspensions onto LB agar plates, achieving uniform colony distributions across the plate at different dilution factors. The proposed handheld vibrational generator is inexpensive, easy to assemble from off-the-shelf components, and minimizes dead volume and cross-contamination because only the pipette tip contacts the sample. Although the current prototype still exhibits device-to-device variability and moving droplets in open containers complicate real-time imaging, these results indicate that toothbrush-based vibrational actuation can provide a practical and scalable route toward “lab-in-hand” droplet assays in resource-limited or educational settings. Full article

Hundred-micron-sized microdroplets are widely used in microbial culture, chemical investigations and industrial processes. The size, velocity and frequency of microdroplets significantly affect the cultivation and processing effects. The detections of droplets mainly rely on capacitance detection or imaging, but it requires expensive and complex systems for capacitance detection, and high-throughput imaging detections are challenging. In this study, four-way microfluid structure (FWMS) is proposed for microdroplets generation and detection. FWMS, fixed on a 3D-printed holder, is designed to generate microdroplets (100–500 µm), with optical fibers embedded to collect double photoresist method pulses of scattering light by fast-moving microdroplets. The size and volume of the microdroplets are retrieved by tracking the double pulse signal in the time sequence. In the experiments, 50 groups of microdroplets (a total of 10⁵ microdroplets) with size ranging from 100 to 450 µm were generated and detected. Compared with traditional imaging detection, this method has a better sampling rate and detection error of less than 1.42%, which can provide a simple and accurate integrated microfluid system for microdroplet generation and synchronous detection. Full article

Laser-induced forward transfer (LIFT) bioprinting enables precise deposition of biological materials for advanced biomedical applications. This study presents a parametric analysis of the donor–receiver distances (1.0, 1.5, 2.0, 2.5, and 3.0 mm) in LIFT bioprinting, investigated through high-speed video and image analysis of 4 × 4 spot arrays. Droplet velocity was quantified and jet trajectory characterized, revealing that increased distances reduced spatial resolution, with significant shape deterioration observed beyond 2.0 mm. Thus, a maximum 2.0 mm donor–receiver gap was determined as optimal for acceptable printing resolution. As an application, a microfluidic device was fabricated using LCD 3D printing with a biocompatible resin and glass-bottomed configuration. The chamber height was matched to the validated 2.0 mm distance, ensuring compatibility with LIFT printing. Computational fluid dynamics simulations were conducted to model fluid flow conditions within the device. Subsequently, LLC cells were successfully printed inside the microfluidic chamber, cultured under continuous flow for 24 h, and demonstrated normal proliferation. This work highlights LIFT bioprinting’s viability and precision for integrating cells within microfluidic platforms, presenting promising potential for organ-on-chip applications and future biomedical advancements. Full article

This paper introduces a novel Lateral Extraction Enhanced Desorption Electrospray Ionization (LEE-DESI) source. This source is specifically designed to tackle the crucial issue of electric field interference in dual-channel ambient ionization mass spectrometry (AIMS). By incorporating dual-channel spraying-based desorption and extraction into a 3D-printed chamber with optimized spatial parameters, the system effectively reduces cross-channel interference while boosting ionization efficiency. The desorption spray is responsible for desorbing analytes from untreated samples, and the extraction spray further ionizes more neutral droplets through charge transfer, which substantially enhances sensitivity. Compared with traditional DESI, the LEE-DESI source demonstrates improved detection limits, reproducibility, and operational simplicity, as validated using Rhodamine B, L-arginine, and Angiotensin I, as well as drug standards including methadone, ketamine, and fentanyl. This highlights its potential for high-throughput analysis of complex matrices in proteomics, metabolomics, and biomedical applications. Full article

Advancements in bioinks and three-dimensional (3D) printing and bioprinting have significantly advanced cardiovascular tissue engineering by enabling the fabrication of biomimetic cardiac and vascular constructs. Traditional 3D printing has contributed to the development of acellular scaffolds, vascular grafts, and patient-specific cardiovascular models that support surgical planning and biomedical applications. In contrast, 3D bioprinting has emerged as a transformative biofabrication technology that allows for the spatially controlled deposition of living cells and biomaterials to construct functional tissues in vitro. Bioinks—derived from natural biomaterials such as collagen and decellularized matrix, synthetic polymers such as polyethylene glycol (PEG) and polycaprolactone (PCL), or hybrid combinations—have been engineered to replicate extracellular environments while offering tunable mechanical properties. These formulations ensure biocompatibility, appropriate mechanical strength, and high printing fidelity, thereby maintaining cell viability, structural integrity, and precise architectural resolution in the printed constructs. Advanced bioprinting modalities, including extrusion-based bioprinting (such as the FRESH technique), droplet/inkjet bioprinting, digital light processing (DLP), two-photon polymerization (TPP), and melt electrowriting (MEW), enable the fabrication of complex cardiovascular structures such as vascular patches, ventricle-like heart pumps, and perfusable vascular networks, demonstrating the feasibility of constructing functional cardiac tissues in vitro. This review highlights the respective strengths of these technologies—for example, extrusion’s ability to print high-cell-density bioinks and MEW’s ultrafine fiber resolution—as well as their limitations, including shear-induced cell stress in extrusion and limited throughput in TPP. The integration of optimized bioink formulations with appropriate printing and bioprinting platforms has significantly enhanced the replication of native cardiac and vascular architectures, thereby advancing the functional maturation of engineered cardiovascular constructs. Full article

Plant-based foods have emerged as a major focus of the modern food industry as it tries to create more sustainable, environmentally friendly, and healthy products. Plant-based emulsion gels (PBEGs) can be used to provide valuable structures, textures, and functions in many plant-based food applications. For instance, they can be used as a matrix to form semi-solid plant-based meat, fish, egg, or dairy analogs, delivery systems for bioactive compounds in functional foods, and edible inks in 3D food printing. The most common PBEGs used in the food industry consist of oil droplets embedded within an aqueous phase containing a biopolymer network. However, PBEGs may also be formed from high-internal-phase emulsions (HIPEs) or aggregated emulsions. PBEGs combine the benefits of emulsions and gels, such as the ability to encapsulate both polar and non-polar functional ingredients, as well as to create desirable textural attributes. This review summarizes recent advances (2017–2025) in the development and application of PBEGs in the food sector, with a focus on their preparation methods, characterization techniques, and potential applications. The future perspectives and challenges associated with PBEGs are also discussed. Overall, this review provides a useful platform for directing future research efforts and for the practical implementation of PBEGs in plant-based food systems. Full article

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

This study investigates the capillary performance and wetting behavior of SLA (Stereolithography) 3D-printed porous structures, focusing on TPMS (triply periodic minimal surfaces)-Gyroid, Octet, Diamond, and Isotruss lattice designs. High-speed imaging was used to analyze droplet interactions, including penetration, spreading, and contact angles, with 16 μL water droplets dropping from 30 mm at 0.77 m/s. Results showed variable contact angles, with Isotruss and Octet having higher angles, while Diamond faced measurement challenges due to surface roughness. Numerical simulations of TPMS-Gyroid of 2 mm³ unit cells validated the experimental results, and Diamond, Octet, and Isotruss structures were simulated. Capillary performance was assessed through deionized (DI) water weight–time (w-t) measurements, identifying that the TPMS-Gyroid structure performed adequately. Structures with 4 mm³ unit cells had low capillary performance, excluding them from permeability testing, whereas smaller 2 mm³ structures demonstrated capillary effects but had printability and cleaning issues. Permeability results indicated that Octet performed best, followed by Isotruss, Diamond, and TPMS-Gyroid. Findings emphasize unit cell size, beam thickness, and droplet positioning as key factors in optimizing fluid dynamics for cooling, filtration, and fluid management. Full article

Due to the health-driven demand for fat replacers in meat products, Lycopene (Lyc)-loaded yeast protein (YP) high internal phase Pickering emulsions (HIPPEs) were explored as fat replacers for 3D-printed meat products. HIPPEs with varying Lyc concentrations were formulated, and their encapsulation efficiency and antioxidant activity (DPPH and ABTS assays) were evaluated. The encapsulation efficiency of Lyc exceeded 90% for all samples. Microscopic analysis revealed significant droplet enlargement in emulsions containing Lyc concentrations of 1.25 mg/mL and 1.50 mg/mL. Antioxidant activity peaked at a Lyc concentration of 1.00 mg/mL. Three-dimensional-printed meat products with different fat replacement ratios (0%, 25%, 50%, 75% and 100%) were prepared using both Lyc-loaded and non-loaded emulsions, and their printing precision, cooking loss, color, pH, texture, and lipid oxidation were assessed. The replacement ratio had no significant impact on printing precision, while cooking yield improved with higher fat replacement levels. Lyc emulsions notably influenced meat color, resulting in lower lightness and higher redness and yellowness. pH values remained stable across formulations. Lipid oxidation decreased with increasing fat replacement levels. The results indicate that Lyc-loaded YP Pickering emulsions have great potential as effective fat replacers for 3D-printed meat products, enhancing antioxidant performance while preserving product quality. Full article

This study explores the potential of lysine (Lys) and tilapia myofibrillar protein (MP) composite particles in the formulation of highly inwardly directed emulsions (HIPEs). Infrared spectroscopy, potentiometric analysis, and molecular docking studies revealed that the interaction between Lys and MP is primarily governed by hydrogen bonding and electrostatic forces. The incorporation of Lys significantly influenced the particle size, secondary and tertiary structures, solubility, and turbidity of MP. Lys-MP-stabilized HIPEs can form highly stable denser self-supporting gel network structures. Rheological analysis of HIPEs stabilized by MP showed a low energy storage modulus (G’ 110.66 Pa) and water–oil separation, therefore preventing 3D printing. However, HIPEs stabilized by Lys (especially 1.5 wt%) significantly improved the energy storage modulus (G’ 1002.10 Pa), increased viscoelasticity and thixotropic recovery, and reduced droplet size (10.84 μm), facilitating the use of HIPE inks for 3D printing. Furthermore, HIPEs stabilized with 1.5 wt% Lys-MP demonstrated superior print accuracy (91.36%), resolution, and clarity in 3D printing applications. Overall, these findings offer a promising strategy for developing Lys-MP composite particle-stabilized HIPEs tailored for advanced 3D printing technologies. Full article

To address the challenge of imprecise micro-droplet formation control in piezoelectric jetting devices used in sand mold 3D printing and apply on-demand inkjet printing technology to sand mold manufacturing, this study first explains the working principle of a piezoelectric shear-mode printhead. A mathematical model of the droplet ejection process is then established based on Computational Fluid Dynamics (CFD). Building upon this model, numerical simulations of droplet generation, breakup, and flight are conducted by using the Volume of Fluid (VOF) model within the Fluent module of the Workbench 2020 R2 platform. Finally, under consistent driving conditions, the effects of key parameters—viscosity, surface tension, and inlet velocity—on the ejection process are investigated through simulation. Based on the results, appropriate ranges and recommended values for ink properties are determined. This study provides significant engineering value for improving the stability and precision of droplet formation in industrial sand mold 3D printing. Full article