Journal Description
Micro
Micro
is an international, peer-reviewed, open access journal on microscale and nanoscale research and applications in physics, chemistry, materials, biology, medicine, food, environment technology, engineering, etc., published quarterly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 22.5 days after submission; acceptance to publication is undertaken in 2.8 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: APC discount vouchers, optional signed peer review, and reviewer names published annually in the journal.
Latest Articles
A Microfluidic Paper-Based Lateral Flow Device for Quantitative ELISA
Micro 2024, 4(2), 348-367; https://doi.org/10.3390/micro4020022 - 16 May 2024
Abstract
This study presents an innovative lateral flow microfluidic paper-based analytical device (μPAD) designed for conducting quantitative paper-based enzyme-linked immunosorbent assays (p-ELISA), seamlessly executing conventional ELISA steps in a paper-based format. The p-ELISA device utilizes a passive fluidic circuit with functional elements such as
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This study presents an innovative lateral flow microfluidic paper-based analytical device (μPAD) designed for conducting quantitative paper-based enzyme-linked immunosorbent assays (p-ELISA), seamlessly executing conventional ELISA steps in a paper-based format. The p-ELISA device utilizes a passive fluidic circuit with functional elements such as a multi-bi-material cantilever (B-MaC) assembly, delay channels, and a buffer zone, all enclosed within housing for autonomous, sequential loading of critical reagents onto the detection zone. This novel approach not only demonstrates a rapid assay completion time of under 30 min, but also boasts reduced reagent requirements, minimal equipment needs, and broad applicability across clinical diagnostics and environmental surveillance. Through detailed descriptions of the design, materials, and fabrication methods for the multi-directional flow assay (MDFA), this manuscript highlights the device’s potential for complex biochemical analyses in a user-friendly and versatile format. Analytical performance evaluation, including a limit of detection (LOD) of 8.4 pM for Rabbit IgG, benchmarks the device’s efficacy compared to existing p-ELISA methodologies. This pioneering work lays the groundwork for future advancements in autonomous diagnostics, aiming to enhance global health outcomes through accessible and reliable testing solutions.
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(This article belongs to the Collection Advances in Microtechnology for Cell/Tissue Engineering and Biosensing)
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Coupled Mode Design of Low-Loss Electromechanical Phase Shifters
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Nathnael S. Abebe, Sunil Pai, Rebecca L. Hwang, Payton Broaddus, Yu Miao and Olav Solgaard
Micro 2024, 4(2), 334-347; https://doi.org/10.3390/micro4020021 - 6 May 2024
Abstract
Micro-electromechanical systems (MEMS) have the potential to provide low-power phase shifting in silicon photonics, but techniques for designing low-loss devices are necessary for adoption of the technology. Based on coupled mode theory (CMT), we derive analytical expressions relating the loss and, in particular,
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Micro-electromechanical systems (MEMS) have the potential to provide low-power phase shifting in silicon photonics, but techniques for designing low-loss devices are necessary for adoption of the technology. Based on coupled mode theory (CMT), we derive analytical expressions relating the loss and, in particular, the phase-dependent loss, to the geometry of the MEMS phase shifters. The analytical model explains the loss mechanisms of MEMS phase shifters and enables simple optimization procedures. Based on that insight, we propose phase shifter geometries that minimize coupling power out of the waveguide. Minimization of the loss is based on mode orthogonality of a waveguide and phase shifter modes. We numerically model such geometries for a silicon nitride MEMS phase shifter over a silicon nitride waveguide, predicting less than −1.08 dB loss over a range and −0.026 dB loss when optimized for a range. We demonstrate this design framework with a custom silicon nitride process and achieve −0.48 dB insertion loss and less than 0.05 dB transmission variation over a phase shift. Our work demonstrates the strength of the coupled mode approach for the design and optimization of MEMS phase shifters.
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(This article belongs to the Special Issue Microsystem and Nanosystem Researches for Sensors, Actuators and Energy Conversion Devices)
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Silver Nanoparticles’ Localized Surface Plasmon Resonances Emerged in Polymeric Environments: Theory and Experiment
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Maria Tsarmpopoulou, Dimitrios Ntemogiannis, Alkeos Stamatelatos, Dimitrios Geralis, Vagelis Karoutsos, Mihail Sigalas, Panagiotis Poulopoulos and Spyridon Grammatikopoulos
Micro 2024, 4(2), 318-333; https://doi.org/10.3390/micro4020020 - 2 May 2024
Abstract
Considering that the plasmonic properties of metallic nanoparticles (NPs) are strongly influenced by their dielectric environment, comprehension and manipulation of this interplay are crucial for the design and optimization of functional plasmonic systems. In this study, the plasmonic behavior of silver nanoparticles encapsulated
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Considering that the plasmonic properties of metallic nanoparticles (NPs) are strongly influenced by their dielectric environment, comprehension and manipulation of this interplay are crucial for the design and optimization of functional plasmonic systems. In this study, the plasmonic behavior of silver nanoparticles encapsulated in diverse copolymer dielectric environments was investigated, focusing on the analysis of the emerging localized surface plasmon resonances (LSPRs) through both experimental and theoretical approaches. Specifically, two series of nanostructured silver ultrathin films were deposited via magnetron sputtering on heated Corning Glass substrates at 330 °C and 420 °C, respectively, resulting in the formation of self-assembled NPs of various sizes and distributions. Subsequently, three different polymeric layers were spin-coated on top of the silver NPs. Optical and structural characterization were carried out by means of UV–Vis spectroscopy and atomic force microscopy, respectively. Rigorous Coupled Wave Analysis (RCWA) was employed to study the LSPRs theoretically. The polymeric environment consistently induced a red shift as well as various alterations in the LSPR amplitude, suggesting the potential tunability of the system.
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(This article belongs to the Section Microscale Materials Science)
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Micro-Spectrometer-Based Interferometric Spectroscopy and Environmental Sensing with Zinc Oxide Thin Film
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Ciao-Ming Tsai, Yu-Chen Hsu, Chang-Ting Yang, Wei-Yi Kong, Chitsung Hong and Cheng-Hao Ko
Micro 2024, 4(2), 305-317; https://doi.org/10.3390/micro4020019 - 1 May 2024
Abstract
This study introduces a novel approach for analyzing thin film interference spectra by employing a micro-spectrometer equipped with a spectral chip. Focusing on zinc oxide (ZnO) thin films prepared via the sol–gel method, this research aims to explore the films’ physical properties through
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This study introduces a novel approach for analyzing thin film interference spectra by employing a micro-spectrometer equipped with a spectral chip. Focusing on zinc oxide (ZnO) thin films prepared via the sol–gel method, this research aims to explore the films’ physical properties through spectral analysis. After obtaining the interference spectrum of the ZnO thin films, the peak positions within the spectrum were cataloged. Mathematical simulation was used to adjust the refractive index and thickness of the films to match the simulated interference peak positions with the observed peak positions. The thickness of the prepared ZnO film was estimated to be 4.9 μm and its refractive index at 80 °C was estimated to be 1.96. In addition, the measurement system was used to detect environmental changes, including temperature changes and gas exposure. It was observed that the optical characteristics of ZnO films exhibit marked variations with temperature shifts, enabling the establishment of a temperature calibration curve based on spectral feature displacement. In addition, experiments using a variety of gases showed that NO2 and gaseous isopropanol significantly affect the interference spectrum of ZnO, with the peak of the interference spectrum shifted by 2.3 nm and 5.2 nm, respectively, after injection of the two gases. This indicates that interferometric spectroscopy can serve as an effective tool for ZnO monitoring, capable of selectively detecting specific gases.
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(This article belongs to the Section Analysis Methods and Instruments)
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Open AccessArticle
Single-Cell Screening through Cell Encapsulation in Photopolymerized Gelatin Methacryloyl
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Venkatesh Kumar Panneer Selvam, Takeru Fukunaga, Yuya Suzuki, Shunya Okamoto, Takayuki Shibata, Tuhin Subhra Santra and Moeto Nagai
Micro 2024, 4(2), 295-304; https://doi.org/10.3390/micro4020018 - 27 Apr 2024
Abstract
This study evaluated the potential of gelatin methacryloyl (GelMA) for single-cell screening compared to polyethylene glycol diacrylate (PEGDA). GelMA photopolymerized at 1000–2000 mJ/cm2 produced consistent patterns and supported HeLa cell viability. GelMA (5%w/v) facilitated better cell collection within 2 days due
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This study evaluated the potential of gelatin methacryloyl (GelMA) for single-cell screening compared to polyethylene glycol diacrylate (PEGDA). GelMA photopolymerized at 1000–2000 mJ/cm2 produced consistent patterns and supported HeLa cell viability. GelMA (5%w/v) facilitated better cell collection within 2 days due to its shape retention. GelMA demonstrated biocompatibility with HeLa cells exhibiting exponential proliferation and biodegradation over 5 days. The average cell displacement over 2 days was 16 µm. Two targeted cell recovery strategies using trypsin were developed: one for adherent cells encapsulated at 800 mJ/cm2, and another for floating cells encapsulated at 800 mJ/cm2, enabling the selective removal of unwanted cells. These findings suggest GelMA as a promising biomaterial for single-cell screening applications, offering advantages over PEGDA in cell encapsulation and targeted recovery.
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(This article belongs to the Collection Advances in Microtechnology for Cell/Tissue Engineering and Biosensing)
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Water Diffusion in Additively Manufactured Polymers: Analysis of the Capillary Effect
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Boyu Li, Konstantinos P. Baxevanakis and Vadim V. Silberschmidt
Micro 2024, 4(2), 281-294; https://doi.org/10.3390/micro4020017 - 25 Apr 2024
Abstract
Additive manufacturing (AM) is an advanced manufacturing method that produces objects by sequential layering. Material extrusion AM (MEAM) with continuous-fibre reinforcement is becoming more widely used in naval structures, which are exposed to the marine environment. However, the water diffusion process and the
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Additive manufacturing (AM) is an advanced manufacturing method that produces objects by sequential layering. Material extrusion AM (MEAM) with continuous-fibre reinforcement is becoming more widely used in naval structures, which are exposed to the marine environment. However, the water diffusion process and the effect of water ageing on the mechanical performance of AM materials are not yet well understood because of their complex internal structure, caused by defects generated during manufacturing. Current research on diffusion is mostly based on experimental methods for conventionally manufactured materials without considering AM-induced defects. The objective of this study is to explore how the defects inherent to MEAM affect water diffusion in a composite material by the capillary effect. Results from a numerical study of capillary flow in MEAM polymer are applied as a boundary condition in the subsequent finite-element analysis. The study illustrates that flow in the capillary reaches the steady state quicker compared to the saturation time in the matrix, predicted by Fick’s diffusion equation. It is demonstrated that the capillary effect can significantly affect the water diffusion in MEAM parts and reduce the saturation time to one-third compared to the case without accounting for this effect.
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(This article belongs to the Special Issue Functional Micro Structures and Textures: Manufacturing and Applications)
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Open AccessReview
Porous Inorganic Nanomaterials: Their Evolution towards Hierarchical Porous Nanostructures
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Anitta Jose, Tom Mathew, Nora Fernández-Navas and Christine Joy Querebillo
Micro 2024, 4(2), 229-280; https://doi.org/10.3390/micro4020016 - 18 Apr 2024
Abstract
The advancement of both porous materials and nanomaterials has brought about porous nanomaterials. These new materials present advantages both due to their porosity and nano-size: small size apt for micro/nano device integration or in vivo transport, large surface area for guest/target molecule adsorption
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The advancement of both porous materials and nanomaterials has brought about porous nanomaterials. These new materials present advantages both due to their porosity and nano-size: small size apt for micro/nano device integration or in vivo transport, large surface area for guest/target molecule adsorption and interaction, porous channels providing accessibility to active/surface sites, and exposed reactive surface/active sites induced by uncoordinated bonds. These properties prove useful for the development of different porous composition types (metal oxides, silica, zeolites, amorphous oxides, nanoarrays, precious metals, non-precious metals, MOFs, carbon nanostructures, MXenes, and others) through different synthetic procedures—templating, colloidal synthesis, hydrothermal approach, sol-gel route, self-assembly, dealloying, galvanostatic replacement, and so—for different applications, such as catalysis (water-splitting, etc.), biosensing, energy storage (batteries, supercapacitors), actuators, SERS, and bio applications. Here, these are presented according to different material types showing the evolution of the structure design and development towards the formation of hierarchical porous structures, emphasizing that the formation of porous nanostructures came about out of the desire and need to form hierarchical porous nanostructures. Common trends observed across these different composition types include similar (aforementioned) applications and the use of porous nanomaterials as templates/precursors to create novel ones. Towards the end, a discussion on the link between technological advancements and the development of porous nanomaterials paves the way to present future perspectives on these nanomaterials and their hierarchical porous architectures. Together with a summary, these are given in the conclusion.
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(This article belongs to the Special Issue Advances in Micro- and Nanomaterials: Synthesis and Applications)
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Magnetic Micro and Nano Sensors for Continuous Health Monitoring
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Tomasz Blachowicz, Ilda Kola, Andrea Ehrmann, Karoline Guenther and Guido Ehrmann
Micro 2024, 4(2), 206-228; https://doi.org/10.3390/micro4020015 - 6 Apr 2024
Abstract
Magnetic micro and nano sensors can be used in a broad variety of applications, e.g., for navigation, automotives, smartphones and also for health monitoring. Based on physical effects such as the well-known magnetic induction, the Hall effect, tunnel magnetoresistance and giant magnetoresistance, they
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Magnetic micro and nano sensors can be used in a broad variety of applications, e.g., for navigation, automotives, smartphones and also for health monitoring. Based on physical effects such as the well-known magnetic induction, the Hall effect, tunnel magnetoresistance and giant magnetoresistance, they can be used to measure positions, flow, pressure and other physical properties. In biomedicine and healthcare, these miniaturized sensors can be either integrated into garments and other wearables, be directed through the body by passive capsules or active micro-robots or be implanted, which usually necessitates bio-functionalization and avoiding cell-toxic materials. This review describes the physical effects that can be applied in these sensors and discusses the most recent micro and nano sensors developed for healthcare applications.
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(This article belongs to the Section Microscale Physics)
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Piezoelectric and Pyroelectric Properties of Organic MDABCO-NH4Cl3 Perovskite for Flexible Energy Harvesting
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Rosa M. F. Baptista, Bruna Silva, João Oliveira, Bernardo Almeida, Cidália Castro, Pedro V. Rodrigues, Ana Machado, Etelvina de Matos Gomes and Michael Belsley
Micro 2024, 4(2), 196-205; https://doi.org/10.3390/micro4020014 - 27 Mar 2024
Abstract
This study describes the synthesis and characterization of the lead-free organic ferroelectric perovskite N-methyl-N’-diazabicyclo [2.2.2]octonium)-ammonium trichloride (MDABCO-NH4Cl3). The electrospinning technique was employed to obtain nanofibers embedded with this perovskite in a PVC polymer for hybrid fiber
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This study describes the synthesis and characterization of the lead-free organic ferroelectric perovskite N-methyl-N’-diazabicyclo [2.2.2]octonium)-ammonium trichloride (MDABCO-NH4Cl3). The electrospinning technique was employed to obtain nanofibers embedded with this perovskite in a PVC polymer for hybrid fiber production. The dielectric, piezoelectric, and pyroelectric properties of these fibers were carefully examined. Based on measurements of the dielectric permittivity temperature and frequency dependence, together with the pyroelectric results, a transition from a high temperature paraelectric to a ferroelectric phase that persisted at room temperature was found to occur at 438 K. The measured pyroelectric coefficient yielded values as high as 290 μC K−1 m−2, which is in between the values reported for MDABCO-NH4I3 and the semiorganic ferroelectric triglycine sulfate (TGS). The hybrid nanofibers exhibited good morphological characteristics and demonstrated very good piezoelectric properties. Specifically, a piezoelectric coefficient of 42 pC/N was obtained when applying a periodical force of 3 N and a piezoelectric voltage coefficient of geff = 0.65 V mN−1. The performance of these fibers is on par with that of materials discussed in the existing literature for the fabrication of nano energy-harvesting generators. Importantly, the perovskite nanocrystals within the fibers are protected from degradation by the surrounding polymer, making them a promising environmentally friendly platform for flexible mechanical energy harvesting.
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(This article belongs to the Section Microscale Physics)
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Janus Particles in Acoustofluidic Setup: The Interplay between Self-Propulsion and Acoustic Trapping
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Lisa Marie Benko, Vyacheslav R. Misko, Larysa Baraban, Denys Makarov, Antonio Maisto and Wim De Malsche
Micro 2024, 4(1), 185-195; https://doi.org/10.3390/micro4010013 - 16 Mar 2024
Abstract
Acoustic focusing of particle flow in microfluidics has been shown to be an efficient tool for particle separation for various chemical and biomedical applications. The mechanism behind the method is the selective effect of the acoustic radiation force on distinct particles. In this
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Acoustic focusing of particle flow in microfluidics has been shown to be an efficient tool for particle separation for various chemical and biomedical applications. The mechanism behind the method is the selective effect of the acoustic radiation force on distinct particles. In this way, they can be selectively focused and separated. The technique can also be applied under stationary conditions, i.e., in the absence of fluid flows. In this study, the manipulation of self-propelled particles, such as Janus particles, in an acoustofluidic setup was investigated. In experiments with self-propelled Janus particles and passive beads, we explored the interplay between self-propulsion and the acoustic radiation force. Our results demonstrated unusual and potentially useful effects such as selective trapping, escape, and assisted escape in binary mixtures of active and passive particles. We also analyzed various aspects related to the behavior of Janus particles in acoustic traps in the presence and absence of flows.
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(This article belongs to the Collection Advances in Microtechnology for Cell/Tissue Engineering and Biosensing)
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An Investigation into the Effect of Length Scale of Reinforcement on the Cryogenic Response of a Mg/2wt.%CeO2 Composite
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Shwetabh Gupta, Michael Johanes, Gururaj Parande and Manoj Gupta
Micro 2024, 4(1), 170-184; https://doi.org/10.3390/micro4010012 - 14 Mar 2024
Abstract
The present study attempted for the first time an investigation on the effect of deep cryogenic treatment in liquid nitrogen (LN) on magnesium–cerium oxide (Mg/2wt.%CeO2) composites containing equal amounts of different length scales (micron and nanosize) cerium oxide (CeO2)
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The present study attempted for the first time an investigation on the effect of deep cryogenic treatment in liquid nitrogen (LN) on magnesium–cerium oxide (Mg/2wt.%CeO2) composites containing equal amounts of different length scales (micron and nanosize) cerium oxide (CeO2) particles. The disintegrated melt deposition method was used to synthesize Mg-2CeO2 micro- and nanocomposites, followed by hot extrusion as the secondary processing. Further liquid nitrogen treatment was performed at a cryogenic temperature of −196 °C. The combined effects of cryogenic treatment and reinforcement length scale on physical, mechanical, and thermal behaviors were studied. The results indicate that LN-treated micro- and nanocomposite samples exhibit, in common, a reduction in porosity, similar grain size, and a limited effect on the original texture of the matrix. However, microhardness, 0.2% Compressive Yield Strength (CYS), failure strain, and energy absorbed increased for both micro- and nanocomposite samples. Overall, results clearly indicate the capability of deep cryogenic treatment with LN to positively diversify the properties of both micro- and nanocomposite samples.
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(This article belongs to the Special Issue Advances in Micro- and Nanomaterials: Synthesis and Applications)
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Influence of Pt Ultrathin Interlayers on Magnetic Anisotropy in Ni/NiO Multilayers
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Dimitrios I. Anyfantis, Alexandros Barnasas, Nikolaos C. Diamantopoulos, Constantinos M. Tsakiris, Georg Schmidt, Evangelos Th. Papaioannou and Panagiotis Poulopoulos
Micro 2024, 4(1), 157-169; https://doi.org/10.3390/micro4010011 - 29 Feb 2024
Abstract
Perpendicular magnetic anisotropy at transition metal/oxide interfaces plays a significant role in technological applications such as magnetic storage and spintronics. In this study, we investigate the effects of thermal annealing and Pt ultrathin interlayers on the magnetic anisotropy in Ni/NiO multilayers. Ni/NiO/Pt multilayers
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Perpendicular magnetic anisotropy at transition metal/oxide interfaces plays a significant role in technological applications such as magnetic storage and spintronics. In this study, we investigate the effects of thermal annealing and Pt ultrathin interlayers on the magnetic anisotropy in Ni/NiO multilayers. Ni/NiO/Pt multilayers were fabricated via radiofrequency magnetron sputtering and natural oxidation. The static magnetic properties of the samples were studied using temperature-dependent SQUID magnetometry. We focus on a sample with a Nickel thickness of 6.7 nm in each multilayer period. This multilayer in Ni/NiO form showed the maximum enhancement of perpendicular magnetic anisotropy after mild thermal annealing in past work. In this work, we study the effects of ultrathin Pt interlayers on the magnetic properties of such a Ni/NiO multilayer before and after annealing. We have observed a further increase in perpendicular magnetic anisotropy, and we study the temperature-dependent magnetic properties of this system, which combines the favorable magnetic properties of Ni/Pt and Ni/NiO multilayers.
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(This article belongs to the Section Microscale Materials Science)
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Characterization of Thin AlN/Ag/AlN-Reflector Stacks on Glass Substrates for MEMS Applications
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Christian Behl, Regine Behlert, Jan Seiler, Christian Helke, Alexey Shaporin and Karla Hiller
Micro 2024, 4(1), 142-156; https://doi.org/10.3390/micro4010010 - 29 Feb 2024
Cited by 1
Abstract
Thin metal layers such as silver (Ag) are being utilized for various optical and plasmonic applications as well as for electrical purposes, e.g., as transparent electrodes in display devices or solar cells. This paper focuses on optical MEMS applications such as the Fabry–Pérot
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Thin metal layers such as silver (Ag) are being utilized for various optical and plasmonic applications as well as for electrical purposes, e.g., as transparent electrodes in display devices or solar cells. This paper focuses on optical MEMS applications such as the Fabry–Pérot interferometer (FPI). Within such filters, reflector materials such as distributed Bragg reflectors (DBRs) or subwavelength gratings (SWGs) have been widely used so far, whereas metallic thin films (MTFs) were limited in application due to their comparatively higher absorption. In this paper, thin sputtered Ag layers with thicknesses of 20, 40 and 60 nm on glass substrates have been investigated, and it is shown that the absorption is very low in the visible spectral range (VIS) and increases only in near-infrared (NIR) with increasing wavelength. Thus, we consider Ag-thin layers to be an interesting reflector material at least for the VIS range, which can be easily fabricated and integrated. However, Ag is not inert and stable when exposed to the atmosphere. Hence, it needs a passivation material. For this purpose, AlN has been chosen in this contribution, which can be deposited by sputtering as well. In this contribution, we have chosen thin AlN layers for this purpose, which can also be deposited by sputtering. Thus, various AlN/Ag/AlN-reflector stacks were created and patterned by lift-off technology preferably. The fabricated reflectors were characterized with respect to adhesion, stress, cohesion, homogeneity, and most importantly, their optical properties. It was found that the thickness of the AlN can be used to adjust the reflectance–transmittance ratio in the VIS range, and influences the adsorption in the NIR range as well. Based on the measured values of the reflectors with 40 nm Ag, an exemplary transmission filter characteristics has been predicted for a wavelength range from 400 to 800 nm. Both the maximum transmittance and the full width at half maximum (FWHM) can be tuned by variation of the AlN thickness from 20 to 60 nm.
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(This article belongs to the Special Issue Microsystem and Nanosystem Researches for Sensors, Actuators and Energy Conversion Devices)
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Open AccessReview
Nanomedicine-Based Drug Delivery Systems and the Treatment of Autism Spectrum Disorders: A Review
by
Zaria Jean-Baptiste, Yashwant Pathak and Kevin B. Sneed
Micro 2024, 4(1), 132-141; https://doi.org/10.3390/micro4010009 - 27 Feb 2024
Abstract
Nanotechnology has played a pioneering role in advancing medical applications, aiming to enhance healthcare through innovation and collaboration. Nanomedicine can be seen expanding into many fields from cancer therapies, cosmetics, tissue regeneration, biosensing, and infectious diseases, and now, it is seen venturing into
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Nanotechnology has played a pioneering role in advancing medical applications, aiming to enhance healthcare through innovation and collaboration. Nanomedicine can be seen expanding into many fields from cancer therapies, cosmetics, tissue regeneration, biosensing, and infectious diseases, and now, it is seen venturing into the realm of research geared toward autism spectrum disorder (ASD). ASD is a neurodevelopmental disorder characterized by restrictive, monotonous activities or fixed interests as well as difficulties with social communication. As of now, there are no validated quantitative metrics for diagnosing autism, nor is there a drug that is specifically designed to treat the condition. As identifiers of ASD have improved, the diagnosis of individuals who meet established criteria have dramatically increased over the years. Although there is still no recognized nanomedicine treatment specifically intended for ASD, research is looking into how nanotechnology might be used in a number of ASD-related areas. This comprehensive review examines prior research efforts aimed at preventing, treating, and diagnosing individuals with ASD. It particularly focuses on the significance of prenatal care and investigates advancements in drug delivery methods through the blood–brain barrier concerning ASD treatment and management.
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(This article belongs to the Section Microscale Biology and Medicines)
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The Decorated Garden Grotto of Condes de Basto Palace in Évora, Portugal: Microbial Community Characterization and Biocide Tests for Conservation
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Inês Silva, Cátia Salvador, Sílvia Arantes, Ana Z. Miller, António Candeias and Ana Teresa Caldeira
Micro 2024, 4(1), 117-131; https://doi.org/10.3390/micro4010008 - 17 Feb 2024
Abstract
The Eugénio de Almeida Foundation’s Casa de Fresco is a historical monument of valuable historic–artistic significance, which currently reveals an assortment of biofilms due to the proliferation of microorganisms in the stone and rocaille elements. The biodeterioration in this area was studied as
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The Eugénio de Almeida Foundation’s Casa de Fresco is a historical monument of valuable historic–artistic significance, which currently reveals an assortment of biofilms due to the proliferation of microorganisms in the stone and rocaille elements. The biodeterioration in this area was studied as part of the Conservation and Restoration Project. We effectively characterized the local microbial community using modern high-throughput DNA analysis. Our results suggested the existence of a variety of lichens or lichenized fungi, including genera such as Variospora, Verrucaria, Circinaria, and Caloplaca. Furthermore, we detected several prokaryote microorganisms related to the identification of these lichens. To properly deal with this microbiological issue and avoid fungal recolonization, we evaluated available commercial antimicrobial treatments.
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(This article belongs to the Section Microscale Biology and Medicines)
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Open AccessArticle
Electrodeposition of Zn and Cu Nanoparticles into TiO2 Nanotubes on Ti6Al4V: Antimicrobial Effect against S. Epidermidis and Cytotoxicity Assessment
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Bruno Ribeiro, Ruben Offoiach, Claudia Monteiro, Miguel R. G. Morais, M. Cristina L. Martins, Ana Paula Pêgo, Elisa Salatin, Lorenzo Fedrizzi and Maria Lekka
Micro 2024, 4(1), 97-116; https://doi.org/10.3390/micro4010007 - 8 Feb 2024
Abstract
Surface modification of the Ti6Al4V alloy (ASTM grade 5), with the fabrication of vertically oriented TiO2 nanotubes, has been receiving increasing attention both as a way to provide advanced bioactive features and the ability to act as reservoirs for a localized, controlled
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Surface modification of the Ti6Al4V alloy (ASTM grade 5), with the fabrication of vertically oriented TiO2 nanotubes, has been receiving increasing attention both as a way to provide advanced bioactive features and the ability to act as reservoirs for a localized, controlled drug release. In this work, TiO2 nanotubes were grown on the surface of a Ti6Al4V alloy through electrochemical anodization. An ethylene glycol-based electrolyte containing 0.5 wt.% NH4F and 2.5% (v/v) H2O was used. Post-anodizing heat treatments at 500 °C in air atmosphere were performed to achieve a crystalline oxide layer with a higher mechanical stability. Following these treatments, Zn or Cu nanoparticles were incorporated into the nanotubular structures through electrodeposition processes. Then, the antimicrobial performance of the obtained surfaces was assessed against Staphylococcus epidermidis, a Gram-positive bacterium common in implant-related infections. Lastly, the cytotoxicity of the produced surface was evaluated against MC3T3-E1 mouse pre-osteoblast cells. In general, Cu-doped TiO2 nanotubes presented an almost total antimicrobial action, while Zn doped samples had a lower, but still significant antibacterial effect. However, a highly cytotoxic effect against MC3T3-E1 cells was observed on all anodized samples due to the release of vanadium from the alloy. In spite of this, the surface modification reported in this work can be a valid solution for existing commercially available orthopedic implants, considering that similar solutions were already studied in in vivo assays.
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(This article belongs to the Section Microscale Materials Science)
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A Method for Directly Observing Mechanical Oscillations in Photonic Structures Based on Porous Silicon Nanostructures
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Miller Toledo Solano, Hector H. Cerecedo-Nuñez, Martha Alicia Palomino Ovando, Jocelyn Faubert, Khashayar Misaghian and J. Eduardo Lugo
Micro 2024, 4(1), 80-96; https://doi.org/10.3390/micro4010006 - 1 Feb 2024
Abstract
Due to their unique properties, porous silicon nanostructures have garnered much attention in photonics. For example, these structures can exhibit photoluminescence and are highly efficient in trapping light, making them ideal for applications such as biosensors, optical communication, and solar cells. The production
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Due to their unique properties, porous silicon nanostructures have garnered much attention in photonics. For example, these structures can exhibit photoluminescence and are highly efficient in trapping light, making them ideal for applications such as biosensors, optical communication, and solar cells. The production of electromagnetic forces by light is a well-established concept, and the mechanism behind it is well-understood. In the past, we have used these forces to induce mechanical oscillations in a photonic structure based on porous silicon. Usually, to detect the oscillations, a high-precision vibrometer is utilized. However, we report a novel approach to visualizing photonic structure oscillations here. The traditional method of using a vibrometer as an indirect measurement tool has been replaced by one that involves directly observing the changes using a camera, digital movement amplification, a theoretical approximation, and FDTE simulations. This original technique provides researchers with a less expensive means of studying photonic structure movements. This proposal could be extended to other microscopic movements or for dynamical interferometric fringe analysis.
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(This article belongs to the Section Microscale Physics)
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Enhanced Gypsum Boards with Activated Carbon Composites and Phase Change Materials for Advanced Thermal Energy Storage and Electromagnetic Interference Shielding Properties
by
Christina Gioti, Konstantinos C. Vasilopoulos, Maria Baikousi, Constantinos E. Salmas, Angelos Ntaflos, Alkiviadis S. Paipetis, Zacharias Viskadourakis, Rabia Ikram, Simeon Agathopoulos, George Kenanakis and Michael A. Karakassides
Micro 2024, 4(1), 61-79; https://doi.org/10.3390/micro4010005 - 24 Jan 2024
Abstract
This work presents the development of novel gypsum board composites for advanced thermal energy storage (TES) and electromagnetic interference (EMI) shielding applications. Activated carbon (AC) derived from spent coffee with a high surface area (SBET = 1372 m2/g) was used
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This work presents the development of novel gypsum board composites for advanced thermal energy storage (TES) and electromagnetic interference (EMI) shielding applications. Activated carbon (AC) derived from spent coffee with a high surface area (SBET = 1372 m2/g) was used as a shape stabilizer, while the commercial paraffin, RT18HC, was used as organic encapsulant phase change material (PCM). The AC showed a remarkable encapsulation efficiency as a shape stabilizer for PCM, with ~120.9 wt% (RT18HC), while the melting enthalpy (ΔHm) of the shape-stabilized PCM was 117.3 J/g. The performance of this PCM/carbon nanocomposite as a thermal energy storage material was examined by incorporating it into building components, such as gypsum wallboards. The microstructure of these advanced panels, their density, and their dispersion of additives were examined using X-ray microtomography. Their thermal-regulated performance was measured through a self-designed room model with a similar homemade environmental chamber that was able to create a uniform temperature environment, surrounding the test room during heating and cooling. The measurements showed that the advanced panels reduce temperature fluctuations and the indoor temperature of the room model, in comparison with normal gypsum panels, by a range of 2–5%. The investigated gypsum board composite samples showed efficient electromagnetic shielding performance in a frequency range of 3.5–7.0 GHz, reaching an EMI value of ~12.5 dB, which is adequate and required for commercial applications, when filled with PCMs.
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(This article belongs to the Section Microscale Materials Science)
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Open AccessArticle
Toward Remote Detection of Chemical Warfare Simulants Using a Miniature Potentiostat
by
Amer Dawoud, Rashid Mia, Jesy Alka Motchaalangaram, Wujian Miao and Karl Wallace
Micro 2024, 4(1), 49-60; https://doi.org/10.3390/micro4010004 - 22 Jan 2024
Cited by 1
Abstract
A miniaturized electrochemical sensor was developed for the remote detection of chemical warfare agent (CWA) simulants. To facilitate drone-based remote sensing, this present study focuses on advancing the miniaturized and compact electrochemical sensor for monitoring two CWA simulants, diisopropyl fluorophosphate (DFP) and O,S-diethylmethylphosphonothioate
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A miniaturized electrochemical sensor was developed for the remote detection of chemical warfare agent (CWA) simulants. To facilitate drone-based remote sensing, this present study focuses on advancing the miniaturized and compact electrochemical sensor for monitoring two CWA simulants, diisopropyl fluorophosphate (DFP) and O,S-diethylmethylphosphonothioate (O,S-DEMPT). The differential pulse voltammetry (DPV) signal was processed, and the DPV signature features were extracted on the basis of the redox properties associated with the absence and the presence of DFP and O,S-DEMPT. Upon the addition of 0.10 equivalence of DFP or O,S-DEMPT, a shift in potential (E) of ~0.13 V was recorded. The limit of detection (LOD) was calculated to be 0.25 µM (0.046 ppm) and 0.10 µM (0.017 ppm) for DFP and O,S-DEMPT, respectively. These results were validated using a portable Palmsens Emstat HR potentiostat, which corroborated the results obtained using a lab benchtop potentiostat. Additionally, Boolean logic (“AND” operation) was implemented for future drone technology deployment. This advancement enables the fabrication of a networked device capable of autonomously executing tasks without constant oversight.
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(This article belongs to the Special Issue Microsystem and Nanosystem Researches for Sensors, Actuators and Energy Conversion Devices)
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Open AccessArticle
Photochromic Responses and Stability of Functional Inks Applied on Sustainable Packaging Materials
by
Sanja Mahović Poljaček, Maja Strižić Jakovljević and Tamara Tomašegović
Micro 2024, 4(1), 33-48; https://doi.org/10.3390/micro4010003 - 15 Jan 2024
Abstract
Photochromism refers to a reversible colour change induced by the irradiation of photochromic materials with ultraviolet (UV) or visible light that reverts to the original colour after the light source is removed. This effect arises from chemical transformations between two isomers with different
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Photochromism refers to a reversible colour change induced by the irradiation of photochromic materials with ultraviolet (UV) or visible light that reverts to the original colour after the light source is removed. This effect arises from chemical transformations between two isomers with different absorption spectra, involving processes like proton transfer, chemical-bond formation, and isomerisation. These photochromic inks, appearing as crystalline powders with micro-sized particles, require dissolution in a suitable matrix to achieve the colour change. Photochromic inks are used in security, as functional coatings for paper and packaging, in the fabric industry, and in other ways. This study examines the influence of varying concentrations of micro-sized photochromic pigments and different ink-coating thicknesses on the photochromic effect on sustainable paperboard substrates. Artificial ageing was performed to assess the photochromic response and lightfastness in relation to pigment concentration, ink-coating thickness, and the influence of the paperboard substrates. The results of this research could contribute to enhancing knowledge on employing photochromic inks for diverse packaging applications.
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(This article belongs to the Section Microscale Materials Science)
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