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Micromachines
Volume 17
Issue 5
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Micromachines, Volume 17, Issue 5 (May 2026) – 131 articles

Cover Story (view full-size image): Soft magnetic droplet robots offer a promising strategy for minimally invasive urological procedures, where narrow and tortuous anatomy limits conventional rigid tools. In this work, we developed a programmable electromagnetic actuation system to guide ferrofluid droplets through confined urinary tract environments. These liquid-phase robots can deform, split, merge, and navigate curved pathways while maintaining controllable motion. Using COMSOL-guided magnetic field design and anatomically realistic 3D-printed urinary models, we demonstrated targeted dye release as a model for localized drug delivery and mechanical capture of artificial kidney stones. This platform highlights the potential of highly deformable magnetic droplet robots for precision therapy and atraumatic stone retrieval in complex urological spaces. View this paper
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15 pages, 12002 KB  
Article
Miniaturized Flexible Corrosion-Resistant Tag Antenna with Folding Arm Based on Graphene Film
by Meng Zeng, Xin Zhao, Hongyu Zhou, Jinling Li, Rongguo Song, Haoran Zu and Daping He
Micromachines 2026, 17(5), 634; https://doi.org/10.3390/mi17050634 - 21 May 2026
Viewed by 227
Abstract
Radio frequency identification (RFID) technology has been widely adopted in a variety of practical applications. Usually, the size of a passive tag antenna largely determines the read performance of tag. However, excessively large tag antennas can hinder their practical application and a tag [...] Read more.
Radio frequency identification (RFID) technology has been widely adopted in a variety of practical applications. Usually, the size of a passive tag antenna largely determines the read performance of tag. However, excessively large tag antennas can hinder their practical application and a tag that is too small has poor performance. In this paper, a compact, flexible and corrosion-resistant folding dipole tag antenna is proposed, which has a geometrical dimension of 24 mm × 13 mm (0.074λ0×0.040λ0). It is designed on only one surface of a flexible polyethylene terephthalate (PET) substrate, which can be folded. The paper proposes a single-sided laser-patterned GAF/PET flexible RFID tag that is mechanically folded to form a backside dipole arm without vias, targeting compact and corrosion-resistant UHF RFID operation. Changing the size of the folding arm can effectively adjust the resonant frequency and impedance of the tag antenna. A stepped radiation arm is used to extend the current path and lower the resonance frequency. The capacitance and inductance effects introduced by loading a T match for reducing the resonant frequency of the tag to the useful UHF RFID band. Finally, it can achieve a power transfer coefficient of 99.9% and exhibit high impedance matching between the tag antenna and the chip. The proposed tag antenna uses graphene-assembled film (GAF) as its conductor material. Thanks to the physicochemical properties of GAF, the proposed tag antenna maintains stable radiation performance even after prolonged exposure to acidic (5 wt%), alkaline (5 wt%), and salt (5 wt%) corrosion, as well as more than 1000 mechanical bending cycles. When the EIRP of the reader is 2.2 W, the maximum read range of the tag in the 800–1000 MHz is 1.38 m. Full article
(This article belongs to the Section E：Engineering and Technology)
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13 pages, 2026 KB  
Article
Sustainable Approach for Improving Tool Life and Surface Quality During Diamond Cutting of Ultra-Low-Expansion Glass Using Laser Assistance
by Han Zhang, Shizhen Zhu, Xiao Chen and Chuangting Lin
Micromachines 2026, 17(5), 633; https://doi.org/10.3390/mi17050633 - 21 May 2026
Viewed by 170
Abstract
Ultra-low-expansion (ULE) glass serves as a critical material in high-precision optical devices and semiconductor manufacturing; however, its inherent hardness and brittleness pose significant challenges for machining processes. During the diamond cutting of ULE glass, severe tool wear emerges as the primary factor limiting [...] Read more.
Ultra-low-expansion (ULE) glass serves as a critical material in high-precision optical devices and semiconductor manufacturing; however, its inherent hardness and brittleness pose significant challenges for machining processes. During the diamond cutting of ULE glass, severe tool wear emerges as the primary factor limiting machined quality, which not only shortens tool life but also prolongs subsequent polishing time, thereby increasing processing costs and hindering sustainable manufacturing. To address this challenge, in situ laser assisted diamond cutting (LADC) has emerged as a promising technique for the sustainable machining of difficult-to-machine materials. In this study, for achieving sustainable machining of ULE glass, the effects of cutting speed on surface roughness and tool wear were systematically investigated. To determine the optimal parameter combination for minimizing surface roughness and tool wear simultaneously, an integrated optimization approach combining artificial neural network (ANN) and non-dominated sorting genetic algorithm II (NSGA-II) was employed. The experimental results indicated that a spindle speed of 2900 rpm and a feed speed of 1.1 mm/min was ascertained as the optimum combination to attain the desired outcomes for in situ LADC of ULE glass. Under the optimum machining parameters, in situ LADC resulted in a 70.08% reduction in surface roughness and 61.24% reduction in tool wear compared to conventional diamond cutting (CDC). This study demonstrates that in situ LADC can be recognized as a promising sustainable machining technique for machining of ULE glass. Full article
(This article belongs to the Special Issue Future Trends in Ultra-Precision Machining, Second Edition)
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25 pages, 3533 KB  
Article
Ultrasensitive Hydrogen Detection Using GNRFET Sensor: Multimetric Optimization via Geometry, Temperature, and Oxygen Environment
by Mohammad K. Anvarifard and Zeinab Ramezani
Micromachines 2026, 17(5), 632; https://doi.org/10.3390/mi17050632 - 21 May 2026
Viewed by 218
Abstract
This work presents a comprehensive analysis of a Palladium (Pd)-gated graphene nanoribbon field-effect transistor (GNRFET) as a high-sensitivity potential hydrogen sensor under idealized conditions, focusing on the structural and environmental control of multimetric sensitivity. Hydrogen adsorption is modeled through pressure-dependent work-function modulation and [...] Read more.
This work presents a comprehensive analysis of a Palladium (Pd)-gated graphene nanoribbon field-effect transistor (GNRFET) as a high-sensitivity potential hydrogen sensor under idealized conditions, focusing on the structural and environmental control of multimetric sensitivity. Hydrogen adsorption is modeled through pressure-dependent work-function modulation and interface coverage, including competition with oxygen. For hydrogen gas at a pressure of PH2=10−6 Torr without O2, the sensor exhibits a maximum threshold voltage sensitivity of about 300 mV, which is reduced to roughly 40 mV under an oxygen partial pressure of 152 Torr, quantifying the impact of background gas on response. Band diagrams, transmission spectra, local density of states, and transfer characteristics are examined over wide ranges of H2 pressure, temperature, gate length, and nanoribbon width. Sensitivity is evaluated using drain current change, threshold voltage shift, and average subthreshold swing variation. Results showed that the sensitivity based on current is high for ultralow hydrogen pressures, whereas it is low in higher levels of pressure compared to the sensitivity based on subthreshold. Also, uncertainty analysis revealed that the threshold voltage metric remains largely geometry-independent and thus tolerant to fabrication variations. Full article
(This article belongs to the Special Issue Electrochemical Microdevices and Microsystems: Design, Fabrication, and Applications)
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15 pages, 15745 KB  
Article
Thermal Recovery of Damaged Hydrophobic Coatings in EWOD Devices Using an Integrated Mesh-Patterned Heater
by Youngdoo Son, Woochan Kim, Youngkwang Kim, Daeyoung Lee and Sangkug Chung
Micromachines 2026, 17(5), 631; https://doi.org/10.3390/mi17050631 - 21 May 2026
Viewed by 268
Abstract
We propose an integrated electrowetting-on-dielectric (EWOD) device incorporating a mesh-patterned heater to restore damaged hydrophobic coatings and evaluate its recovery performance. Hydrophobic degradation was induced under submersion and falling droplet conditions, and the damage and recovery mechanisms of the coating were examined. A [...] Read more.
We propose an integrated electrowetting-on-dielectric (EWOD) device incorporating a mesh-patterned heater to restore damaged hydrophobic coatings and evaluate its recovery performance. Hydrophobic degradation was induced under submersion and falling droplet conditions, and the damage and recovery mechanisms of the coating were examined. A damaged Cytop (CTL-809M) coating was thermally treated using the embedded heater at 200 °C for 24 h, successfully restoring its hydrophobicity. Coating properties before and after recovery were characterized by contact angle (CA) and contact angle hysteresis (CAH) measurements, evaluating EWOD performance and surface analyses using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). After treatment, the reduced CA and increased CAH were recovered, and wetting/dewetting performance in EWOD operation also recovered to pre-damage levels. AFM and XPS analyses confirmed the simultaneous restoration of the surface morphology and chemical composition. These results demonstrate a practical approach for restoring hydrophobic coatings within EWOD devices and offering a promising solution for improving device reliability and lifetime in applications related to EWOD. Full article
(This article belongs to the Special Issue Microfluidic Systems for Sustainable Energy)
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17 pages, 16470 KB  
Article
The Effect of Material Microstructures on Tool Edge Preparation of PCBN Cutting Tools
by Zhiping Huang, Xian Wu, Chao Zhang and Yanxin Zhai
Micromachines 2026, 17(5), 630; https://doi.org/10.3390/mi17050630 - 21 May 2026
Viewed by 248
Abstract
PCBN tools are widely used in the machining of ferrous metals. Tool edge preparation is a crucial procedure in the tool preparation process that directly affects tool performance. In this paper, tool chamfer grinding and edge blunting were conducted on the PCBN tool [...] Read more.
PCBN tools are widely used in the machining of ferrous metals. Tool edge preparation is a crucial procedure in the tool preparation process that directly affects tool performance. In this paper, tool chamfer grinding and edge blunting were conducted on the PCBN tool to investigate the effect of material microstructures. In tool chamfer grinding, the PCBN tool with larger particles exhibits a larger chamfer width error and roughness than that of smaller particles, and the PCBN tool with higher Al content exhibits a larger chamfer width error and roughness than that with lower Al content. The optimal tool chamfer grinding speed is 24 m/s for the PCBN tool with larger particles, and 27 m/s for smaller particles. The optimal feed rate is 70 mm/min for both PCBN materials. In edge blunting, PCBN tools with larger particles or lower Al content are more difficult to passivate, and the optimal blunting time is about 30 s for an edge radius of 30 μm. The PCBN tools were prepared using the obtained machining parameters and used in the turning of brake pads. It is found that the PCBN tool with smaller particles exhibits longer life than that of larger particles. Although it exhibits the same wear characteristics, the tool life of the PCBN tool with lower Al content is longer than that of the tool with higher Al content. Full article
(This article belongs to the Special Issue Micro/Nanomanufacturing and Cross-Scale Fabrication: Methods, Systems, and Applications)
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27 pages, 12440 KB  
Review
Research Progress of La1-xSrxMnO3-Based Flexible Wearable Sensors
by Xiaoqing Xing, Xinjie Fan, Ruoshi Li, Boxin Lu, Yin Ma, Chun Jia, Dong Gao, Jie Wu, Guogang Ren and Mian Zhong
Micromachines 2026, 17(5), 629; https://doi.org/10.3390/mi17050629 - 21 May 2026
Viewed by 356
Abstract
With the rapid development of flexible electronics technology, flexible wearable sensors based on Lanthanum Strontium Manganese Oxide (La1-xSrxMnO3) have garnered extensive attention in recent years due to their excellent multi-functional integration, environmental stability and biocompatibility. This review [...] Read more.
With the rapid development of flexible electronics technology, flexible wearable sensors based on Lanthanum Strontium Manganese Oxide (La1-xSrxMnO3) have garnered extensive attention in recent years due to their excellent multi-functional integration, environmental stability and biocompatibility. This review systematically analyzes the preparation methods, process optimization strategies, multi-performance integration technologies, and the expansion of the application field of La1-xSrxMnO3-based flexible sensors. Firstly, the basic characteristics and sensing mechanism of the La1-xSrxMnO3 material were presented, including its temperature sensitivity, strain response characteristics, and magnetoresistance effect. Secondly, the fabrication process of flexible sensors was elaborately discussed, with a focus on analyzing crucial technologies, such as laser induction and transfer printing technology. Subsequently, the strategies for regulating the electrical, thermal, and mechanical properties of materials through element doping, along with the multimodal sensing integration and signal decoupling methods, were expounded. Furthermore, the actual performance of this type of sensor in fields such as health monitoring, human–computer interaction, and extreme environment applications was summarized. Finally, the challenges and future development directions of La1-xSrxMnO3-based flexible sensors are outlined, providing theoretical references for the design and optimization of next-generation flexible electronic devices. Full article
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13 pages, 2259 KB  
Article
Halide Site Engineering of Organic–Inorganic Hybrid Perovskites: A Facile Strategy for Frequency-Controllable Microwave Absorption
by Jinhuai Zhou, Zhi Zhang, Yao Yao, Fei Wang, Hanmin Wu, Mengjie Shi and Wenke Zhou
Micromachines 2026, 17(5), 628; https://doi.org/10.3390/mi17050628 - 20 May 2026
Viewed by 339
Abstract
High-performance electromagnetic wave absorption materials are desperately needed due to the growing serious electromagnetic interference and pollution issues brought on by the quick growth of modern electronic technology and wireless communication. This work uses the organic–inorganic hybrid perovskite MAPbBrxI3−x as [...] Read more.
High-performance electromagnetic wave absorption materials are desperately needed due to the growing serious electromagnetic interference and pollution issues brought on by the quick growth of modern electronic technology and wireless communication. This work uses the organic–inorganic hybrid perovskite MAPbBrxI3−x as a model system to address the problem of restricted loss mechanisms and the challenges in changing the absorption bandwidth of single-component wave-absorbing materials. It achieves systematic tuning of electromagnetic wave absorption performance, especially within the effective working frequency spectrum, through accurate halogen site engineering. According to the study, MAPbI3 (MPI), MAPbBr1.5I1.5 (MPIB), and MAPbBr3 (MPB), which were synthesized using the anti-solvent approach, all demonstrated exceptional microwave absorption capability, with maximum reflection loss values exceeding −37 dB, among which MPB achieves a remarkable value of −42.41 dB at 16.60 GHz. More significantly, this work shows a distinct structure-property relationship between the effective absorption peak frequency range of this series of materials and their band structure: the strongest absorption peak shows a regular blue shift as the material bandgap widens and the bromine content rises. This finding suggests that focused tailoring of the operating frequency band in wave-absorbing materials can be achieved by manipulating the band structure of perovskites by varying the halogen concentration. In addition to confirming the significant application potential of organic–inorganic hybrid perovskites in the field of microwave absorption, this study offers a novel research perspective and material template for precisely and programmably controlling the absorption frequency band of wave-absorbing materials based on their basic electronic structures. Full article
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23 pages, 5955 KB  
Article
Simulations of Novel Semi-Spherical Electrode Detectors Formed by Simultaneously Deep-Etched Trenches
by Hongfei Wang and Zheng Li
Micromachines 2026, 17(5), 627; https://doi.org/10.3390/mi17050627 - 20 May 2026
Viewed by 216
Abstract
A novel 3D detector with a semi-spherical electrode detector structure is proposed in this study. The semi-spherical electrode is formed by concentric deep circular-type trenches of varying depths. These concentric trenches can be simultaneously deep-etched using DRIE (Deep Reactive-Ion Etching) depths obtained from [...] Read more.
A novel 3D detector with a semi-spherical electrode detector structure is proposed in this study. The semi-spherical electrode is formed by concentric deep circular-type trenches of varying depths. These concentric trenches can be simultaneously deep-etched using DRIE (Deep Reactive-Ion Etching) depths obtained from our calculations for a certain time at a given aspect ratio. The focus of this work is the conceptualization, design considerations, 3D modeling, and electrical simulation of the proposed 3D detector. The detector’s electrical properties, including electric potential distribution, electric field distribution, electron concentration distribution, full depletion voltage, leakage current, and capacitance, were simulated using a technology computer-aided design (TCAD) tool. Simulation and analysis of the detector’s performance post-irradiation were also conducted. The small capacitance of our semi-spherical electrode detector renders it highly suitable for applications in photon sciences (e.g., X-ray). Full article
(This article belongs to the Special Issue Advanced Nano-Semiconductor Devices: Design, Modeling and Next-Generation AI Applications)
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20 pages, 4281 KB  
Article
High-Precision Localization Algorithm for Target Symmetry Center in Image-Based Overlay Metrology
by Wuhao Liu, Maoxin Song, Shuming Shi, Mingchun Ling, Hengwei Qin, Hengrui Guan, Jun Wang and Jin Hong
Micromachines 2026, 17(5), 626; https://doi.org/10.3390/mi17050626 - 20 May 2026
Viewed by 172
Abstract
Achieving high-precision overlay target center localization is critical for image-based overlay (IBO) metrology in advanced semiconductor manufacturing. This paper proposes a novel IBO target localization algorithm based on symmetry center matching. Leveraging the symmetry design of the IBO optical system as a physical [...] Read more.
Achieving high-precision overlay target center localization is critical for image-based overlay (IBO) metrology in advanced semiconductor manufacturing. This paper proposes a novel IBO target localization algorithm based on symmetry center matching. Leveraging the symmetry design of the IBO optical system as a physical prior, the algorithm reformulates center localization as a global correlation optimization problem. The grayscale projection profile of a single-sided edge is extracted, spatially mirrored, and used as a reference template for sliding correlation matching against the opposite edge. The symmetry center is then determined from the peak of the Pearson correlation coefficient curve. Simulation results demonstrate a center localization accuracy better than 0.00013 pixels (3σ), with repeatability precision remaining within 0.012 pixels (3σ) under stringent noise and blur conditions. Experimental validation yields object-space repeatability precision of 0.129 nm (3σ) and 0.144 nm (3σ) in the X and Y directions, respectively, surpassing the 0.32 nm measurement uncertainty requirement for advanced process nodes. The average single-frame processing time is approximately 0.07 s, demonstrating that the proposed algorithm simultaneously satisfies the demands of high precision and high throughput. Full article
(This article belongs to the Special Issue Emerging Technologies and Applications for Semiconductor Industry)
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19 pages, 5323 KB  
Article
A Comprehensive Experimental and Finite Element Analysis Study on the Bonding Strength Evaluation of Wafer-to-Wafer Hybrid Bonding with Polyimide Film Dielectrics
by Cong Mei, Tianze Zheng, Ziyang Ding, Dan Zhang, Yuan Xu, Huiyao Zhao, Liu Chang, Qiuhan Hu, Chenhui Xia, Shuli Liu and Liyi Li
Micromachines 2026, 17(5), 625; https://doi.org/10.3390/mi17050625 - 19 May 2026
Viewed by 298
Abstract
Polymer insulation layers such as polyimide (PI) have gradually replaced inorganic dielectric layers (SiO2, SiCN) in the integrated packaging process of hybrid bonding (HB). PI can fill the gaps in the thermal compression bonding process and help to obtain a good [...] Read more.
Polymer insulation layers such as polyimide (PI) have gradually replaced inorganic dielectric layers (SiO2, SiCN) in the integrated packaging process of hybrid bonding (HB). PI can fill the gaps in the thermal compression bonding process and help to obtain a good Cu/Polymer bonding interface. At present, the existing post-crack double cantilever beam tensile test (PBC-DCB) has been successfully applied to the quantitative measurement of bonding strength of hybrid bonding with inorganic materials, but this method only considers elastic behavior. Since PI exhibits viscidity, elasticity and plasticity, knowing how to correlate these properties to the bonding process is challenging. Whether PBC-DCB is suitable for the characterization of PI bonding is unclear. This paper presents a comprehensive experimental and finite element analysis (FEA) study on the PI–PI bonding interface. Firstly, nanoindentation experiments and simulations are performed on the prepared PI interface to obtain key elasticity and plasticity parameters. Then, the bonding strength is characterized by the PBC-DCB test. Theoretical and experimental results show that the plasticity of PI causes energy dissipation during stretching, resulting in a deviation of approximately 2.51% compared with pure elasticity. Based on experimental data, the Cohesive Zone Model (CZM) FEA method is used to simulate the crack propagation. The results indicate that the Embedded Process Zone (EPZ) model can accurately describe crack initiation and delamination behavior, with a margin of error of about 3.61%. Finally, based on the EPZ CZM, defects such as bonding void and wafer warpage are further discussed in relation to bonding strength measurement. Full article
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16 pages, 19283 KB  
Communication
Single-Band-Notched Ultra-Wideband Low-Sidelobe Planar Array Antenna for Millimeter-Wave Applications
by Yuanjun Shen and Tianling Zhang
Micromachines 2026, 17(5), 624; https://doi.org/10.3390/mi17050624 - 19 May 2026
Viewed by 311
Abstract
A single-band-notched ultra-wideband (UWB) low-sidelobe planar array antenna for millimeter-wave (mmWave) applications is presented. The antenna element employs a planar dipole excited through an H-shaped coupling slot to achieve broadband impedance matching, while a centrally loaded parasitic patch acts as a half-wavelength resonator [...] Read more.
A single-band-notched ultra-wideband (UWB) low-sidelobe planar array antenna for millimeter-wave (mmWave) applications is presented. The antenna element employs a planar dipole excited through an H-shaped coupling slot to achieve broadband impedance matching, while a centrally loaded parasitic patch acts as a half-wavelength resonator to generate a controllable notch band. Additional parasitic patches are introduced to recover the high-frequency matching without degrading the notch response. An 8×8 array is then developed using a Taylor-weighted feed network implemented with three classes of 1-to-4 microstrip power dividers. Measured results show that the array operates from 19.0 to 45.0 GHz with VSWR<2, while providing a rejection band from 35.0 to 38.5 GHz. The notch suppresses the realized gain by about 5 dB around 37.0 GHz, the peak gain reaches 20.5 dBi in the passband, and average sidelobe levels better than −17 dB are obtained. The proposed design provides a practical approach for combining ultra-wide bandwidth, in-band interference rejection, and low-sidelobe radiation in a compact mmWave planar array. Full article
(This article belongs to the Special Issue Microwave Passive Components, 3rd Edition)
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31 pages, 9328 KB  
Review
Emerging Trends in Artificial Intelligence-Integrated Biochip Technologies for Biomedical Applications
by Muniyandi Maruthupandi and Nae Yoon Lee
Micromachines 2026, 17(5), 623; https://doi.org/10.3390/mi17050623 - 19 May 2026
Viewed by 213
Abstract
Neurological disorders, diabetes, cancer, and infectious diseases remain major global health concerns, particularly in low- and middle-income countries with insufficient access to accurate and rapid diagnostics. Conventional biochip sensing platforms, while effective, are often constrained by complex instrumentation and have limited capability for [...] Read more.
Neurological disorders, diabetes, cancer, and infectious diseases remain major global health concerns, particularly in low- and middle-income countries with insufficient access to accurate and rapid diagnostics. Conventional biochip sensing platforms, while effective, are often constrained by complex instrumentation and have limited capability for handling complex and large datasets. This review aims to address these limitations by evaluating the integration of artificial intelligence (AI) with biochip technology improve biomedical diagnostics. We systematically analyze recent advances in AI-integrated biochips, such as spectroscopic, paper-based, lab-on-chip, and microfluidic platforms integrated with reinforcement learning, machine learning, and deep learning models. These pre-trained AI models simplify pattern recognition, feature extraction, and automated data processing from a variety of biosensor outputs, such as electrochemical, fluorescence, and colorimetric signals. The reviewed studies indicate improved real-time diagnostic sensitivity and accuracy across biomedical applications. Overall, we discuss ongoing challenges and future perspectives toward explainable, robust, and smartphone-assisted AI-integrated biochips for rapid and accurate diagnostics. The review offers a comprehensive overview of AI-integrated biochips to support effective disease detection and clinical decision-making. 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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19 pages, 3709 KB  
Article
An Energy-Efficient LiDAR Receiver Using Time-to-Voltage Converter and SAR ADC in 180 nm CMOS
by Bobin Seo and Sung-Min Park
Micromachines 2026, 17(5), 622; https://doi.org/10.3390/mi17050622 - 19 May 2026
Viewed by 192
Abstract
This paper proposes an energy-efficient LiDAR receiver topology based on a time-to-voltage converter (TVC) followed by a 5-bit SAR ADC. By converting the time-interval between START and STOP signals into the voltage domain, the proposed topology avoids the complexity of conventional TDC-based designs [...] Read more.
This paper proposes an energy-efficient LiDAR receiver topology based on a time-to-voltage converter (TVC) followed by a 5-bit SAR ADC. By converting the time-interval between START and STOP signals into the voltage domain, the proposed topology avoids the complexity of conventional TDC-based designs and enables the use of a moderate-speed, energy-efficient SAR ADC. The proposed TVC in the proposed LiDAR receiver consists of an on-chip avalanche photodiode (APD), a CMOS transimpedance-limiting amplifier (CTLA), a time-gating circuit, a ramp generator, and a peak-and-hold (PDH) block. Thereafter, the converted voltages are digitized by a VCM-based single-ended SAR ADC with a binary-weighted CDAC, a strong-arm latch comparator, and custom digital logic. A reset generator is also incorporated to coordinate the sampling, comparison, and settling phases. The proposed LiDAR receiver is implemented in a 180 nm CMOS process, where the TVC occupies an area of 171 μm × 98.8 μm, while the TVC-SAR receiver occupies 417 μm × 356 μm, respectively. The proposed LiDAR receiver consumes 13 mW from a single 1.8 V supply, in which the SAR ADC consumes 3.68 mW only. The TVC-SAR receiver resolves the time-intervals ranging from 7 ns to 32.1 ns with a resolution of 0.81 ns. Hence, the proposed topology provides an energy-efficient solution along with its reduced circuit complexity and chip implementation for short-range LiDAR applications. Full article
(This article belongs to the Special Issue Photonic and Optoelectronic Devices and Systems, 4th Edition)
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17 pages, 15272 KB  
Article
Interlayer Engineering of Layered VOPO4 Through Organic Intercalation for Enhanced Potassium Storage Kinetics
by Xuyun Peng, Shuang Fan, Jingfeng Tai, Jinqiu Zhang, Xinhua Qiu, Suliang Chen, Weihua Li and Yingmeng Zhang
Micromachines 2026, 17(5), 621; https://doi.org/10.3390/mi17050621 - 19 May 2026
Viewed by 234
Abstract
Nonaqueous potassium-ion batteries (KIBs) are emerging as promising next-generation energy storage systems owing to their abundant resources and high energy density. However, their large-scale application is hindered by structural degradation and sluggish kinetics resulting from the large ionic radius of K ions. Engineering [...] Read more.
Nonaqueous potassium-ion batteries (KIBs) are emerging as promising next-generation energy storage systems owing to their abundant resources and high energy density. However, their large-scale application is hindered by structural degradation and sluggish kinetics resulting from the large ionic radius of K ions. Engineering electrode materials with open frameworks, such as two-dimensional (2D) layered structures, present an effective strategy to address these challenges by providing rapid ion diffusion pathways and robust host structures. Herein, a rational interlayer engineering strategy is developed by intercalating phenylamine derivatives with varying molecular sizes (P-butylaniline: PTA, P-Methylaniline: PMA, and phenylamine: PA) into layered 2D VOPO4 nanosheets. The intercalation of PANI derivatives progressively expands the interlayer spacing from 0.76 nm (pristine VOPO4) to 1.58, 1.85, and 2.09 nm, while maintaining the structural integrity of the layered framework. Notably, the regulated interlayer expansion (from 0.76 to 2.09 nm) not only provides enlarged diffusion pathways for rapid K+ ion intercalation/deintercalation kinetics, but also facilitates the formation of oxygen vacancies that may serve as additional active sites for potassium storage. By correlating the electrochemical performance with the modulated interlayer distances, it is established that a preferred spacing of 1.85 nm achieves the best synergy between fast kinetics, high capacity, and structural stability. As expected, the electrode with the optimal interlayer spacing (1.85 nm) exhibits superior potassium-ion storage performance, delivering a high reversible capacity of 333.2 mAh g−1 at 0.1 A g−1 over 100 cycles and exceptional rate capability with 205.7 mAh g−1 retained at 1 A g−1, as well as maintaining remarkable stability up to 600 cycles even at high rates. This work innovatively proposes phenylamine derivative-enabled interlayer regulation as a promising approach for designing high-performance VOPO4-based electrode materials. Full article
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13 pages, 7369 KB  
Article
Characterization of a Metasurface Integrated 8-Plate Reconfigurable Coding Unit-Cell Coupler for Rotational Misalignment Resilience in UAV Wireless Power Transfer
by Jaewoo Jeong and Sangwook Park
Micromachines 2026, 17(5), 620; https://doi.org/10.3390/mi17050620 - 18 May 2026
Viewed by 223
Abstract
This study proposes a metasurface integrated reconfigurable unit-cell coupler designed for wireless power transfer (WPT) applications in unmanned aerial vehicles (UAVs). In near-field capacitive WPT systems, flexible UAV charging is restricted by rotational misalignment, which causes null power points (NPP) where energy transfer [...] Read more.
This study proposes a metasurface integrated reconfigurable unit-cell coupler designed for wireless power transfer (WPT) applications in unmanned aerial vehicles (UAVs). In near-field capacitive WPT systems, flexible UAV charging is restricted by rotational misalignment, which causes null power points (NPP) where energy transfer is suppressed. To address this, the proposed model emulates 1-bit digital coding states through Symmetric Excitation (SE) and Cross-Excitation (CE) states. Since precise unit-cell characterization is a prerequisite for array expansion, this research focuses on meta-atom-level analysis at 6.78 MHz with a deep sub-wavelength profile (0.002λ). Characterized through 3D full-wave analysis, the unit-cell achieves peak transmission coefficients of 0.945 for SE State and 0.903 for CE State. Crucially, these states exhibit complementary extinction angles at 90° and 45°, respectively, ensuring that the NPP of one state is effectively bypassed by the high transmissivity of the other. This dynamic switching between coding states maintains stable power transfer across a full 360° rotation, providing a technical foundation for scalable, intelligent metasurface-based wireless charging platforms. Full article
(This article belongs to the Special Issue Electromagnetic Metamaterials and Metasurfaces: From Design to Applications)
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23 pages, 8071 KB  
Article
Intelligent Optimization of Gas-Assisted Electrospinning via LLM-Guided Bayesian Inference
by Jun Zeng, Rongguang Zhang, Weicheng Ou, Xuanzhi Zhang, Shize Huang, Xun Chen and Guojie Xu
Micromachines 2026, 17(5), 619; https://doi.org/10.3390/mi17050619 - 18 May 2026
Viewed by 195
Abstract
Nanofiber-based structures have shown considerable potential in semiconductor-related applications, including ultra-thin dielectric layers and flexible electronic devices, owing to their tunable micro-/nanoscale morphology. However, the manufacturing of these structures is often hindered by the complex multiparameter coupling and poor reproducibility inherent in conventional [...] Read more.
Nanofiber-based structures have shown considerable potential in semiconductor-related applications, including ultra-thin dielectric layers and flexible electronic devices, owing to their tunable micro-/nanoscale morphology. However, the manufacturing of these structures is often hindered by the complex multiparameter coupling and poor reproducibility inherent in conventional electrospinning processes. To address these challenges, this study develops an intelligent optimization framework for gas-assisted electrospinning by integrating Large Language Models (LLMs) with Bayesian Optimization (BO). A Gaussian Process Regression (GPR) surrogate model was established to navigate the high-dimensional parameter space efficiently. Comparative studies demonstrate that the proposed BO+LLM strategy not only outperforms pure data-driven BO and pure knowledge-driven LLM approaches but also surpasses the conventional Response Surface Methodology (RSM) baseline, successfully locating a verified minimum fiber diameter of 239 nm. Furthermore, through response-surface analysis, this work identifies a specific multiphysics collaborative window where electrostatic stretching and aerodynamic assistance are balanced. These findings provide a robust pathway for the reproducible fabrication of nanofiber-based electronic devices. Full article
(This article belongs to the Special Issue Emerging Technologies and Applications for Semiconductor Industry)
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18 pages, 8493 KB  
Article
Chemical Modification Mechanism of SiC Substrates in Electrical Discharge Machining
by Qiufa Luo, Gu Li, Ningchang Wang, Sirong Wang, Jing Lu and Congming Ke
Micromachines 2026, 17(5), 618; https://doi.org/10.3390/mi17050618 - 18 May 2026
Viewed by 240
Abstract
Electrical discharge machining (EDM) is an efficient method for processing silicon carbide (SiC) substrates. However, the chemical modification mechanism of SiC substrates in the EDM process remains not fully elucidated. To clarify the material removal mechanism of SiC substrates in EDM, this study [...] Read more.
Electrical discharge machining (EDM) is an efficient method for processing silicon carbide (SiC) substrates. However, the chemical modification mechanism of SiC substrates in the EDM process remains not fully elucidated. To clarify the material removal mechanism of SiC substrates in EDM, this study investigated the behaviors of SiC substrates under different discharge conditions through experimental analysis and interface temperature field simulation. Results indicate that the SiC substrates sequentially exhibit characteristic morphologies of surface oxidation, thermal decomposition, and fracture as discharge energy increases. A discolored layer composed of amorphous SiO2 is formed on the SiC surface in low-discharge energy. Crystalline silicon and graphitic carbon are generated from the thermal decomposition of SiC substrates in high-discharge energy. Excessively high discharge energy induces the breakdown of SiC substrates. A critical temperature threshold is identified that delineates the initiation of prominent thermal oxidation on the SiC surface. Temperature field simulations further reveal the correlation between EDM parameters and interfacial temperature variations, along with the mechanisms of material removal driven by thermal diffusion. This study deepens the fundamental understanding of the EDM removal mechanism of SiC substrates and is expected to provide a scientific basis for the efficient material removal of SiC substrates. Full article
(This article belongs to the Section A2: Surfaces and Interfaces)
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18 pages, 30264 KB  
Article
Microstructural Evolution and Enhanced Macroscopic Properties of La-Doped TiO2-SiO2 Composite Films Under Gradient Annealing
by Yanbo Yuan, Li Zhang, Lei Li, Mengyang Wang, Wenjun Wang and Lin Wang
Micromachines 2026, 17(5), 617; https://doi.org/10.3390/mi17050617 - 17 May 2026
Viewed by 197
Abstract
In this study, La-doped TiO2-SiO2 composite films were deposited on glass substrates by radio-frequency magnetron sputtering. The evolution of microstructure and macroscopic properties was systematically investigated across an annealing temperature range of 350–650 °C. The results show that the La-doped [...] Read more.
In this study, La-doped TiO2-SiO2 composite films were deposited on glass substrates by radio-frequency magnetron sputtering. The evolution of microstructure and macroscopic properties was systematically investigated across an annealing temperature range of 350–650 °C. The results show that the La-doped TiO2-SiO2 composite structure effectively suppresses abnormal grain growth and delays the anatase-to-rutile phase transition, thereby improving the films’ high-temperature structural stability. Notably, the composite film annealed at 550 °C (LS-550) exhibits the highest anatase crystallinity and forms a dense, smooth (RMS = 1.37 nm), crack-free nanocrystalline network. In terms of wettability, the improved hydrophilicity is attributed to the combined effects of La incorporation and hydrophilic silanol (Si-OH) groups in the amorphous SiO2 phase. As a result, the water contact angle of the LS-550 film decreases dramatically to 28.0°, indicating excellent hydrophilicity. Moreover, the LS-550 film demonstrates an optimal photocatalytic degradation efficiency of approximately 76% for methylene blue, significantly outperforming the pure TiO2 film. Furthermore, the enhanced mechanical performance is associated with the combined effects of the SiO2-containing amorphous phase and the finer microstructure induced by La incorporation. Consequently, the critical load (Lc) of the LS-550 film reaches 75.64 mN, significantly exceeding that of the pure TiO2 film annealed at the same temperature (61.25 mN). In summary, the composite film annealed at 550 °C concurrently achieves high crystallographic thermal stability, robust interfacial mechanical durability, excellent surface hydrophilicity, and enhanced photocatalytic activity, thereby offering practical guidance for developing TiO2-based coatings with self-cleaning potential for high-rise building curtain walls. Full article
(This article belongs to the Section E：Engineering and Technology)
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16 pages, 3396 KB  
Article
Parametric Optimization of a Star-Shaped Bluff Body for Enhanced VIV-Galloping Coupled Energy Harvesting
by Li Zhang, Hai Wang, Chunlai Yang, Weiwei Duan and Jingjing Peng
Micromachines 2026, 17(5), 616; https://doi.org/10.3390/mi17050616 - 17 May 2026
Viewed by 250
Abstract
Under low wind speed conditions, conventional bluff body energy harvesters suffer from a single vibration mechanism and a narrow effective wind speed range, making it difficult to meet the continuous power supply demands of miniature electronic devices. In this paper, by systematically optimizing [...] Read more.
Under low wind speed conditions, conventional bluff body energy harvesters suffer from a single vibration mechanism and a narrow effective wind speed range, making it difficult to meet the continuous power supply demands of miniature electronic devices. In this paper, by systematically optimizing the number of triangular prisms N and the circumferential installation angle α, a parametrically adjustable star-shaped energy harvester (SEH) is proposed. The proposed structure consists of a cylindrical base with a tunable number of triangular prisms uniformly distributed along its circumference, aiming to reveal the regulation mechanism of the VIV-galloping coupling response and energy harvesting performance. Conceptual design and theoretical modeling of the SEH are first carried out. Then, three-dimensional fluid–structure interaction simulations are performed by varying N and α, and a prototype is fabricated for wind tunnel experimental validation. The results show that under the optimal parameter combination of N = 7 and α = 51.4°, the SEH achieves a maximum output voltage of 12.2 V at a wind speed of 3.41 m/s, with a maximum output power of 1.488 mW, and the effective wind speed range is broadened to 2.5~12.44 m/s. Compared with the conventional cylindrical energy harvester (CEH), the SEH (N = 7) increases the maximum output voltage by 44.38%, the maximum output power by 108.4%, and expands the effective wind speed range by 198.50%. Through systematic optimization of key geometric parameters, this study achieves synergistic regulation of flow-induced vibration modes and performance enhancement, providing a parametric design basis for efficient low-speed wind energy harvesting, which can promote the development of self-powered technologies for micro-sensors and IoT devices. Full article
(This article belongs to the Topic Advanced Energy Harvesting Technology, 2nd Edition)
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17 pages, 2003 KB  
Article
Thermoelectric Transport Properties of Cu4Bi4Se9 Prepared by Mechanical Alloying and Hot Pressing
by Gyuseong Chu and Il-Ho Kim
Micromachines 2026, 17(5), 615; https://doi.org/10.3390/mi17050615 - 17 May 2026
Viewed by 193
Abstract
Single-phase Cu4Bi4Se9 was successfully synthesized through a simple and rapid process combining mechanical alloying (MA) and hot pressing (HP). The phase formation behavior, microstructural evolution, charge transport characteristics, and thermoelectric properties were systematically investigated. X-ray diffraction analysis as [...] Read more.
Single-phase Cu4Bi4Se9 was successfully synthesized through a simple and rapid process combining mechanical alloying (MA) and hot pressing (HP). The phase formation behavior, microstructural evolution, charge transport characteristics, and thermoelectric properties were systematically investigated. X-ray diffraction analysis as a function of MA time confirmed that all powders crystallized into a single orthorhombic phase with space group Pnma. No decompositions or secondary phases were observed after HP sintering, indicating high phase stability. Thermogravimetric and differential scanning calorimetric analyses revealed distinct endothermic peaks at 714–717 K for all samples, corresponding to the onset of the decomposition of Cu4Bi4Se9. Microstructural observations showed that the relative density decreased with increasing HP temperature (>573 K), accompanied by grain growth and pore formation, reflecting the competition between Cu–Se interdiffusion and pore coarsening during high-temperature sintering. Hall effect measurements indicated p-type conduction for all samples, with carrier concentrations on the order of 1017 cm−3 and carrier mobilities of approximately 102 cm2 V−1 s−1. With increasing temperature, the electrical conductivity increased monotonically, while the Seebeck coefficient gradually decreased, resulting in a maximum power factor of 0.12 mW m−1 K−2 at 573 K. The total thermal conductivity remained extremely low, ranging from 0.33 to 0.48 W m−1 K−1, with the electronic contribution accounting for less than 10%, indicating that lattice thermal transport is dominant. The suppressed lattice thermal conductivity is attributed to the combined effects of Cu atomic rattling, asymmetric bonding induced by Bi 6s2 lone-pair electrons, and strong anharmonic phonon scattering arising from the complex crystal structure. Consequently, Cu4Bi4Se9 achieved a peak dimensionless figure of merit ZT of 0.19 in the temperature range of 573–623 K, demonstrating that the MA–HP process enables stable phase formation and competitive thermoelectric performance without post-annealing. Full article
(This article belongs to the Special Issue Materials and Devices for Advanced Thermal Energy Harvesting and Management)
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24 pages, 1613 KB  
Article
Preparation and Optimization of Silver Nanoparticle-Loaded Dendritic Fibrous Membranes for High-Efficiency Antibacterial Activity and Air Filtration
by Yang Huang, Bofeng Li, Zhongyi Yu, Xianruo Du, Ruixin Chen, Xiang Wang, Jiaxin Jiang, Gaofeng Zheng and Huatan Chen
Micromachines 2026, 17(5), 614; https://doi.org/10.3390/mi17050614 - 16 May 2026
Viewed by 214
Abstract
Metal nanoparticles are widely used in fibrous membrane materials due to their excellent antibacterial properties. However, metal nanoparticle-loaded fibrous membranes often face the trade-off between antibacterial performance and filtration efficiency. To address this issue, silver nanoparticle-loaded dendritic fibrous membranes were prepared via electrospinning [...] Read more.
Metal nanoparticles are widely used in fibrous membrane materials due to their excellent antibacterial properties. However, metal nanoparticle-loaded fibrous membranes often face the trade-off between antibacterial performance and filtration efficiency. To address this issue, silver nanoparticle-loaded dendritic fibrous membranes were prepared via electrospinning technology in this study, and the dual optimization of antibacterial and filtration performance was achieved by adjusting the silver loading amount and fiber morphology. The results showed that the prepared silver nanoparticle-loaded PVDF dendritic fibrous membrane exhibited an outstanding air filtration performance with a filtration efficiency of 99.87% for 0.3 µm particulate matter, a pressure drop of 87.4 Pa, and a quality factor (QF) of 0.076 Pa−1. In addition, the membrane presented excellent antibacterial activity with inhibition rates of 99.9% and 99.8% against Escherichia coli and Staphylococcus aureus, respectively. This study provides a new insight into resolving the trade-off between air filtration and antibacterial performance of metal nanoparticle-loaded fibrous membranes and offers an important reference for applications in related fields. Full article
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22 pages, 14296 KB  
Article
Electroosmosis and Solute Diffusion Transport of Maxwell Fluid Through a Polyelectrolyte-Grafted Microchannel with Modulated Charged Surfaces
by Yin Shang, Fengqin Li and Chunhong Yang
Micromachines 2026, 17(5), 613; https://doi.org/10.3390/mi17050613 - 16 May 2026
Viewed by 186
Abstract
This study investigates the time-periodic electroosmotic flow and solute transport of Maxwell fluid in a parallel microchannel with modulated surface charges. The Poisson–Boltzmann equation and the linearized momentum equations are solved using a superposition-based analytical approach. The influences of oscillation intensity, fluid elasticity, [...] Read more.
This study investigates the time-periodic electroosmotic flow and solute transport of Maxwell fluid in a parallel microchannel with modulated surface charges. The Poisson–Boltzmann equation and the linearized momentum equations are solved using a superposition-based analytical approach. The influences of oscillation intensity, fluid elasticity, and electrokinetic parameters on the velocity and concentration distributions are examined. The results show that wall-potential modulation combined with a time-periodic electric field generates recirculating motion and oscillatory velocity patterns. Moderate oscillation strengthens both flow and solute transport, whereas stronger oscillation weakens transport efficiency. This work provides a quantitative analysis the interplay between oscillatory electroosmotic flow and solute transport in Maxwell fluid and clarifies the role of oscillation strength in controlling solute dispersion. Full article
(This article belongs to the Collection Micro/Nanoscale Electrokinetics)
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28 pages, 31934 KB  
Review
The Application of Micro/Nanorobots in Cancer Therapy
by Yinglei Zhang, Bo Yang and Xiang Zou
Micromachines 2026, 17(5), 612; https://doi.org/10.3390/mi17050612 - 15 May 2026
Viewed by 224
Abstract
Cancer continues to present a profound challenge due to high mortality and the inherent limitations of conventional treatments, including suboptimal targeting, systemic toxicity, and difficulty in overcoming physiological barriers. Micro/nanorobots (MNRs) offer a promising enhanced precision and efficacy in cancer therapy. This review [...] Read more.
Cancer continues to present a profound challenge due to high mortality and the inherent limitations of conventional treatments, including suboptimal targeting, systemic toxicity, and difficulty in overcoming physiological barriers. Micro/nanorobots (MNRs) offer a promising enhanced precision and efficacy in cancer therapy. This review systematically analyzes recent advancements in MNR applications, establishing a consistent framework that interlinks their diverse material compositions, propulsion strategies, and therapeutic functions. We critically compare various materials (inorganic, organic/polymeric, and biological/hybrid materials), elucidating their respective trade-offs in biocompatibility, biodegradability, and stimulus responsiveness. This paper further examines both internal (chemical and biological) and external (magnetic, light, and ultrasound) propulsion mechanisms, highlighting their strengths in overcoming biological barriers and enabling complex in vivo navigation, while also discussing their inherent limitations in control, fuel dependency, and tissue penetration. We then synthesize the therapeutic capabilities of MNRs across targeted drug delivery, phototherapy, radiotherapy, and immunotherapy, emphasizing common advantages like enhanced tumor specificity and reduced systemic side effects. A forward-looking perspective was also provided on the remaining challenges, particularly focusing on in vivo controllability, long-term biosafety, manufacturing scalability, and the significant hurdles in clinical translation. By offering a more critical and integrated analysis, this review underscores the immense potential of MNRs to revolutionize personalized precision cancer treatment, while candidly addressing the complex obstacles that must be surmounted for their successful clinical adoption. Full article
(This article belongs to the Special Issue Biomedical Micro/Nanorobots: Design, Fabrication and Applications)
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31 pages, 4370 KB  
Review
Bridging the Gap: Integrated High-Density Microelectrode Arrays for Cellular, Organoid, and Clinical Electrophysiology
by Qinghua Wu, Yan Gong and Xiang Liu
Micromachines 2026, 17(5), 611; https://doi.org/10.3390/mi17050611 - 15 May 2026
Viewed by 374
Abstract
High-density microelectrode arrays (HDMEAs) have become increasingly important tools in neuroscience and biomedical engineering because of their high spatial and temporal resolution for recording and modulating electrical activity across diverse biological systems. Initially developed for in vitro studies of cultured cells, HDMEAs are [...] Read more.
High-density microelectrode arrays (HDMEAs) have become increasingly important tools in neuroscience and biomedical engineering because of their high spatial and temporal resolution for recording and modulating electrical activity across diverse biological systems. Initially developed for in vitro studies of cultured cells, HDMEAs are now being applied to increasingly complex models, including organoids, animal systems, and even human neural systems. These advancements enable a deeper investigation of cellular interactions, network dynamics, and disease mechanisms, as well as providing novel therapeutic and diagnostic tools for neurological disorders. This review explores the evolution of HDMEAs, emphasizing recent innovations in their design, fabrication, and functionalization. We discuss their applications across cellular models, organoid systems, animal studies, and human electrophysiology, and highlight current challenges such as biocompatibility, long-term stability, scalability, and translational deployment. Finally, we outline future directions for advancing HDMEA technologies in both research and clinical settings. Full article
(This article belongs to the Special Issue Neural Microelectrodes: Design, Integration, and Applications)
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21 pages, 4051 KB  
Article
Development of pH-Dependent Magnetically Actuated Millirobot for Colon-Targeted Delivery of Diverse Drug Types
by Xiaoyu Li, Weibin Rong, Lefeng Wang, Hongda Jia, Xianghe Meng and Hui Xie
Micromachines 2026, 17(5), 610; https://doi.org/10.3390/mi17050610 - 15 May 2026
Viewed by 328
Abstract
Oral administration is an ideal route for colon-targeted drug delivery; however, precise delivery to the colon remains a challenge. This work presents a magnetically actuated millirobot combined with a traditional pH-dependent strategy. It aims to combine the advantages of the two methods: under [...] Read more.
Oral administration is an ideal route for colon-targeted drug delivery; however, precise delivery to the colon remains a challenge. This work presents a magnetically actuated millirobot combined with a traditional pH-dependent strategy. It aims to combine the advantages of the two methods: under normal physiological conditions, it enables autonomous targeted drug delivery, effectively reducing manipulation costs; in abnormal physiological environments, precise targeted delivery can be achieved via external magnetic intervention. The millirobot uses a magnetic composite shell and a pH-dependent film to encapsulate drug carriers. The pH-dependent film ensures an appropriate delay in drug release under different simulated pH conditions. The magnetic composite shell exhibits satisfactory magnetic responsiveness and can perform stable tumbling motion on the surface of the ex vivo intestinal tract, demonstrating good controllability and motility. Furthermore, the millirobot can carry different types of drug carriers to achieve tunable drug-release rates, thereby improving its versatility. These experimental results demonstrate that this pH-dependent magnetically actuated millirobot is a promising platform for reducing manipulation costs and enhancing the reliability of colon-targeted drug delivery. Full article
(This article belongs to the Section B5: Drug Delivery System)
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19 pages, 4740 KB  
Article
Rapid Prototyping of Compartmentalized 3D Microfluidic Devices for Organotypic Cell Culture
by Qasem Ramadan, Rana Hazaymeh and Mohamed Zourob
Micromachines 2026, 17(5), 609; https://doi.org/10.3390/mi17050609 - 15 May 2026
Viewed by 195
Abstract
We present a modular microfluidic platform for constructing miniaturized, compartmentalized cell culture systems that support monoculture, co-culture, and organ-on-a-chip models of human tissues. The devices provide architecturally defined three-dimensional microenvironments in which heterogeneous cell populations can be cultured in close proximity while maintaining [...] Read more.
We present a modular microfluidic platform for constructing miniaturized, compartmentalized cell culture systems that support monoculture, co-culture, and organ-on-a-chip models of human tissues. The devices provide architecturally defined three-dimensional microenvironments in which heterogeneous cell populations can be cultured in close proximity while maintaining precise spatial organization and independent access to each compartment. In vivo-like perfusion into, from, and between adjacent chambers is achieved via micro-engineered porous barriers that act as perfusion microchannels, enabling controlled convective and diffusive transport and recapitulating paracrine signaling between tissue units. As a proof of concept, we implement an adipose–immune co-culture model that reproduces key features of inflamed, insulin-resistant adipose tissue, including altered cytokine secretion and glucose uptake. Together, these features establish a versatile platform for the biofabrication of customizable single-organ and multi-organ in vitro models that more faithfully recapitulate human tissue structure and function for applications in disease modeling, immunometabolic studies, and preclinical drug testing. Full article
(This article belongs to the Special Issue Current and Emerging Microfabrication Techniques for Lab-on-a-Chip and Biomedical Microdevices: From Photolithography to 3D Printing)
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25 pages, 3691 KB  
Review
Toward the Advancement of Soft Pneumatic Rotary Actuators: A Comprehensive Design Review
by Ehsan Kiani Harchegani and Joško Valentinčič
Micromachines 2026, 17(5), 608; https://doi.org/10.3390/mi17050608 - 15 May 2026
Viewed by 397
Abstract
The development of robotic systems that can operate safely and adaptively alongside humans requires actuators that combine compliance with reliable performance. Soft pneumatic rotary actuators (SPRAs) have emerged as promising candidates due to their inherent compliance, lightweight design, and capability to generate smooth [...] Read more.
The development of robotic systems that can operate safely and adaptively alongside humans requires actuators that combine compliance with reliable performance. Soft pneumatic rotary actuators (SPRAs) have emerged as promising candidates due to their inherent compliance, lightweight design, and capability to generate smooth rotational motion through elastic deformation. However, the diverse designs and performance characteristics of SPRAs make it challenging to identify optimal configurations for specific applications. This review comprehensively surveys current SPRAs, focusing on structural designs, materials, and fabrication methods. While SPRAs offer advantages such as reduced risk of injury and enhanced adaptability, significant challenges remain in optimizing torque output, rotational range, and durability. By comparing existing designs and highlighting open research challenges, this paper aims to guide the advancement of SPRAs, facilitating their integration into safe, effective robotic systems for industrial, medical, and wearable applications. Full article
(This article belongs to the Special Issue Micro/Nano Sensors and Actuators for Biomedical Applications: Novel Materials, Innovative Designs, and Emerging Functions)
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15 pages, 1732 KB  
Article
Wafer-Level Transfer of GaN-on-Si Light-Emitting Devices via SiO2–SiO2 Direct Bonding: Strain Evolution and Optoelectronic Performance
by Siyi Zhang, Shuhan Zhang, Qian Fan, Xianfeng Ni and Xing Gu
Micromachines 2026, 17(5), 607; https://doi.org/10.3390/mi17050607 - 15 May 2026
Viewed by 474
Abstract
GaN-on-Si light-emitting devices have been widely studied in the field of opto-electronics, while their optical performance and characterization accessibility are severely limited by the strong visible light absorption of the native silicon substrate. Conventional substrate transfer technologies often suffer from inherent thermal, optical, [...] Read more.
GaN-on-Si light-emitting devices have been widely studied in the field of opto-electronics, while their optical performance and characterization accessibility are severely limited by the strong visible light absorption of the native silicon substrate. Conventional substrate transfer technologies often suffer from inherent thermal, optical, or mechanical bottlenecks. In this study, we developed a robust wafer-level substrate transfer strategy for 8-inch green GaN-on-Si light-emitting device wafers, utilizing a hybrid planarization process combined with SiO2–SiO2 direct bonding. The hybrid planarization precisely eliminated the 900 nm macroscopic steps, achieving sub-nanometer surface roughness for high-yield wafer bonding. We systematically investigated the physical evolution during substrate removal. Results indicate that the removal of the thick native silicon and high-stress buffer layers effectively released the additional in-plane biaxial compressive stress within the multiple quantum wells (MQWs), thereby mitigating the quantum-confined Stark effect (QCSE). Benefiting from the elimination of the light-absorbing silicon substrate and the incorporation of a built-in back-surface reflector (BSR), the transferred devices achieved a remarkable 1.9-fold enhancement in relative optical performance, albeit with an inherent trade-off of increased reverse leakage current while preserving basic diode functionality. Furthermore, optothermal dynamic analysis at high injection levels suggests a potential localized thermal bottleneck at the thick SiO2 bonding interface, where a hypothesized heat-induced spectral red shift may counteract the carrier-screening blue shift. This work provides a feasible wafer-level substrate transfer process for GaN-on-Si devices and offers systematic experimental insights into stress relaxation and optothermal behaviors during the substrate transfer process. Full article
(This article belongs to the Special Issue Photonic and Optoelectronic Devices and Systems, 4th Edition)
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19 pages, 6565 KB  
Article
Simulation and Response Surface Methodology for Predicting Mass Transfer in Coaxial Electrospun Core-Shell Fibers
by Xun Chen, Weiming Shu, Rongguang Zhang, Shize Huang and Xuanzhi Zhang
Micromachines 2026, 17(5), 606; https://doi.org/10.3390/mi17050606 - 15 May 2026
Viewed by 246
Abstract
Coaxial electrospinning technology enables the fabrication of nanofibers with a core-shell structure, thereby facilitating the encapsulation of functional materials. Its efficacy lies in the precise regulation of mass transfer behavior at the sensing interface. However, achieving the controllable preparation of core-shell fiber structures [...] Read more.
Coaxial electrospinning technology enables the fabrication of nanofibers with a core-shell structure, thereby facilitating the encapsulation of functional materials. Its efficacy lies in the precise regulation of mass transfer behavior at the sensing interface. However, achieving the controllable preparation of core-shell fiber structures in complex environments and quantitatively predicting their mass transfer kinetics remain challenging. This study aims to establish a predictive framework combining simulation and experiment. Firstly, finite element simulations using COMSOL clarified that increasing the shell thickness or decreasing its effective diffusion coefficient can significantly delay analyte transport. A model incorporating time-varying parameters further revealed the influence of polymer swelling on the initial release kinetics. Using the diffusion of an aqueous KCl solution as a model system, experiments confirmed that increasing the shell solution concentration is an effective processing strategy for enhancing the mass transfer barrier. Based on the Box-Behnken design and response surface methodology (RSM), a quantitative model linking key process parameters to release kinetic parameters was established. Model diagnostics indicated that the regression equation is significant and reliable. Validation experiments demonstrated that the model possesses good predictive capability for the key release kinetic parameters, with prediction errors within an acceptable range. The framework established in this study indicates that active design of the mass transfer behavior of core-shell fibers can be achieved through process control, providing a quantitative predictive tool and methodological reference for the preparation of controllable mass transfer interfaces for sensing applications. Full article
(This article belongs to the Special Issue Emerging Technologies and Applications for Semiconductor Industry)
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13 pages, 29558 KB  
Article
Wideband Linearly Polarized Over-2-Bit Transmitarray Antenna for Millimeter-Wave Applications
by Yuanjun Shen, Xuli Feng and Tianling Zhang
Micromachines 2026, 17(5), 605; https://doi.org/10.3390/mi17050605 - 14 May 2026
Viewed by 177
Abstract
A wideband linearly polarized over-2-bit transmitarray antenna (TA) using the receiving-transmitting (R-T) scheme in the millimeter-wave band is presented in this work. The TA unit consists of two rectangular patches with a pair of bent branches, and the patches are connected by a [...] Read more.
A wideband linearly polarized over-2-bit transmitarray antenna (TA) using the receiving-transmitting (R-T) scheme in the millimeter-wave band is presented in this work. The TA unit consists of two rectangular patches with a pair of bent branches, and the patches are connected by a metalized via. Two methods are used in this TA to obtain an over-2-bit phase shift of 0–90° and 180–270° from 18 GHz to 30 GHz. Firstly, 180° phase resolution is obtained by rotating the receiving patch around via by 180°. Secondly, by tuning the connection position between the branches and rectangular patch of the TA unit cell, a continuous 90° phase shift is further achieved. A TA prototype with 20×20 units is designed, fabricated, and measured. The measured 1 dB and 3 dB gain bandwidth is 24.9% (24.47–31.43 GHz) and 46.96% (20.45–33 GHz) respectively, with a peak gain of 25.17 dBi and a peak aperture efficiency of 55.2%. The measured results agree well with the simulated ones. Full article
(This article belongs to the Special Issue Microwave Passive Components, 3rd Edition)
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