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Volume 16
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Micromachines, Volume 16, Issue 5 (May 2025) – 99 articles

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26 pages, 2454 KiB  
Review
Mechanical Properties of Medical Microbubbles and Echogenic Liposomes—A Review
by Hussain Alsadiq and Zahra Alhay
Micromachines 2025, 16(5), 588; https://doi.org/10.3390/mi16050588 (registering DOI) - 17 May 2025
Abstract
Lipid-shelled microbubbles (MBs) and echogenic liposomes (ELIPs) have been proposed as acoustofluidic theranostic agents after having been proven to be efficient in diagnostics as ultrasonic contrast agents. Their mechanical properties—such as shell stiffness, friction, and resonance frequency—are critical to their performance, stability, oscillatory [...] Read more.
Lipid-shelled microbubbles (MBs) and echogenic liposomes (ELIPs) have been proposed as acoustofluidic theranostic agents after having been proven to be efficient in diagnostics as ultrasonic contrast agents. Their mechanical properties—such as shell stiffness, friction, and resonance frequency—are critical to their performance, stability, oscillatory dynamics, and response to sonication. A precise characterization of these properties is essential for optimizing their biomedical applications, however the current methods vary significantly in their sensitivity and accuracy. This review examines the experimental and theoretical methodologies used to quantify the mechanical properties of MBs and ELIPs, discusses how each approach estimates shell stiffness and friction, and outlines the strengths and limitations inherent to each technique. Additionally, the effects of parameters such as temperature and lipid composition on MB and ELIP mechanical behavior are examined. Four characterization methods are analyzed, including frequency-dependent attenuation, optical observation, atomic force microscopy (AFM), and laser scattering, their advantages and limitations are critically assessed. Additionally, the factors that influence the mechanical properties of the MBs and ELIPs, such as temperature and lipid composition, are examined. Frequency-dependent attenuation was shown to provide reliable shell elasticity estimates but is influenced by nonlinear oscillations, AFM confirms that microbubble stiffness is size-dependent with smaller bubbles exhibiting higher shell stiffness, and theoretical models such as modified Rayleigh–Plesset equations increasingly incorporate viscoelastic shell properties to improve prediction accuracy. However, many of these models still assume radial symmetry and neglect inter-bubble interactions, which can lead to inaccurate elasticity values when applied to dense suspensions. In such cases, using modified frameworks like the Sarkar model, which incorporates damping and surface tension explicitly, may provide more reliable estimates under nonlinear conditions. Additionally, lipid composition and temperature significantly affect shell mechanics, with higher temperatures generally reducing stiffness. On the other hand, inconsistencies in experimental protocols hinder direct comparison across studies, highlighting the need for standardized characterization methods and improved computational modeling. Full article
(This article belongs to the Section B：Biology and Biomedicine)
16 pages, 28515 KiB  
Article
CMOS Low-Power Optical Transceiver for Short Reach
by Ruixuan Yang, Yiming Dang, Jinhao Chen, Dan Li and Francesco Svelto
Micromachines 2025, 16(5), 587; https://doi.org/10.3390/mi16050587 (registering DOI) - 17 May 2025
Abstract
The emergence of the AI era driven by Large Language Models (LLMs) and the next-generation high-definition multimedia interface for immersive technologies (AR/VR/metaverse) have created an unprecedented demand for high-bandwidth interconnects. While optical communication systems provide a broad bandwidth, their relatively low power efficiency [...] Read more.
The emergence of the AI era driven by Large Language Models (LLMs) and the next-generation high-definition multimedia interface for immersive technologies (AR/VR/metaverse) have created an unprecedented demand for high-bandwidth interconnects. While optical communication systems provide a broad bandwidth, their relatively low power efficiency continues to limit their deployment in new applications. This work addresses the power efficiency challenges in CMOS optical transceiver design, leveraging the inherent cost and integration advantages of CMOS technology. After outlining the design principles for low-power optical transmitter (Tx) and receiver (Rx) design, we present a comprehensive design of a low-power optical transceiver chipset implemented in 28 nm CMOS. The Tx features a high-impedance asymmetric current-steering output stage with a stacked architecture that facilitates unipolar power supply operation for the efficient anode driving of a common-cathode VCSEL array and achieved a power efficiency of 1.59 pJ/bit. The Rx incorporates a tail-current-controlled Cherry–Hooper-based variable gain amplifier (VGA), which achieved a transimpedance gain that ranged from 68.4 to 78.5 dBΩ and a power efficiency of 1.06 pJ/bit. The Rx–Tx back-to-back measurements confirmed successful data transmission at 4 × 20 Gbps, which demonstrated an overall power efficiency of 2.65 pJ/bit. Full article
(This article belongs to the Special Issue Microelectronics and Optoelectronic Devices: From Fundamental Research to Advanced Applications, 2nd Edition)
21 pages, 5064 KiB  
Article
Experimental and Numerical Study of Slug-Flow Velocity Inside Microchannels Through In Situ Optical Monitoring
by Samuele Moscato, Emanuela Cutuli, Massimo Camarda and Maide Bucolo
Micromachines 2025, 16(5), 586; https://doi.org/10.3390/mi16050586 (registering DOI) - 17 May 2025
Abstract
Miniaturization and reliable, real-time, non-invasive monitoring are essential for investigating microfluidic processes in Lab-on-a-Chip (LoC) systems. Progress in this field is driven by three complementary approaches: analytical modeling, computational fluid dynamics (CFD) simulations, and experimental validation techniques. In this study, we present an [...] Read more.
Miniaturization and reliable, real-time, non-invasive monitoring are essential for investigating microfluidic processes in Lab-on-a-Chip (LoC) systems. Progress in this field is driven by three complementary approaches: analytical modeling, computational fluid dynamics (CFD) simulations, and experimental validation techniques. In this study, we present an on-chip experimental method for estimating the slug-flow velocity in microchannels through in situ optical monitoring. Slug flow involving two immiscible fluids was investigated under both liquid–liquid and gas–liquid conditions via an extensive experimental campaign. The measured velocities were used to determine the slug length and key dimensionless parameters, including the Reynolds number and Capillary number. A comparison with analytical models and CFD simulations revealed significant discrepancies, particularly in gas–liquid flows. These differences are mainly attributed to factors such as gas compressibility, pressure fluctuations, the presence of a liquid film, and leakage flows, all of which substantially affect flow dynamics. Notably, the percentage error in liquid–liquid flows was lower than that in gas–liquid flows, largely due to the incompressibility assumption inherent in the model. The high-frequency monitoring capability of the proposed method enables in situ mapping of evolving multiphase structures, offering valuable insights into slug-flow dynamics and transient phenomena that are often difficult to capture using conventional measurement techniques. Full article
(This article belongs to the Special Issue Complex Fluid Flows in Microfluidics)
10 pages, 2567 KiB  
Article
A TM01-TE11 Circular Waveguide Mode Converter on the Basis of Dielectric Filling
by Zibin Weng, Ziming Lv, Liupeng Zan, Sihan Xiao and Chen Liang
Micromachines 2025, 16(5), 585; https://doi.org/10.3390/mi16050585 (registering DOI) - 16 May 2025
Abstract
In this paper, a dielectric-filled circular waveguide TM01-TE11 mode converter is proposed, which has high conversion efficiency and a wide operating bandwidth. Filling the circular waveguide with dielectric material changes the local propagation characteristics, thus achieving a [...] Read more.
In this paper, a dielectric-filled circular waveguide TM01-TE11 mode converter is proposed, which has high conversion efficiency and a wide operating bandwidth. Filling the circular waveguide with dielectric material changes the local propagation characteristics, thus achieving a phase difference between the TE11 modes in the two halves of the circular waveguide during propagation. This, in turn, facilitates the completion of mode conversion with high efficiency. Compared with the conventional radial dielectric plate, this paper improves the method of filling the dielectric inside the circular waveguide by transforming it into a coaxial structure. This is followed by the incorporation of a radial dielectric plate, a modification that has been proven to enhance the conversion efficiency and extend the operational bandwidth. The mode converter operates at 9.7 GHz, and when the dielectric filler material is polytetrafluoroethylene (PTFE), both simulation and practical studies are carried out. The simulation results demonstrate that the maximum conversion efficiency of this mode converter is 99.2%, and the bandwidth with conversion efficiency greater than 90% is nearly 21.1%. The maximum conversion efficiency in the actual test is essentially consistent with the simulation results. The validity of the design scheme of this converter and the accuracy of the simulation study are demonstrated. Full article
(This article belongs to the Section E：Engineering and Technology)
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21 pages, 4471 KiB  
Article
Precision Molding Simulation Study of 3D Ultra-Thin Glass Components for Smartwatches
by Xinfeng Zhao, Shunchang Hu, Peiyan Sun and Wuyi Ming
Micromachines 2025, 16(5), 584; https://doi.org/10.3390/mi16050584 - 16 May 2025
Abstract
High stress and shape deviation during the glass forming process often led to low yield rates, posing a challenge in the production of high-precision smartwatch components. To address this issue, a numerical model was developed to simulate and analyze the forming behavior of [...] Read more.
High stress and shape deviation during the glass forming process often led to low yield rates, posing a challenge in the production of high-precision smartwatch components. To address this issue, a numerical model was developed to simulate and analyze the forming behavior of 3D curved glass. The study focused on achieving a balance between energy consumption and key quality attributes, such as residual stress and shape accuracy. Results showed that forming pressure primarily affects shape deviation, while forming temperature plays a dominant role in energy usage and residual stress. Through orthogonal experiments, optimal parameters were identified: a forming temperature of 630 °C, pressure of 0.25 MPa, and cooling rate of 0.25 °C/s effectively minimize residual stress. Meanwhile, shape deviation is minimized at 630 °C, 0.30 MPa, and a cooling rate of 0.75 °C/s. Energy efficiency analysis indicated that low efficiency occurs at 610 °C with a 3 °C/s heating rate. Furthermore, NSGA-II multi-objective optimization validated the model’s accuracy, with prediction errors under 20%, offering valuable guidance for the precise fabrication of smartwatch glass. Full article
(This article belongs to the Collection Microdevices and Applications Based on Advanced Glassy Materials)
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11 pages, 4845 KiB  
Article
Deep Learning Method for Breakdown Voltage and Forward I-V Characteristic Prediction of Silicon Carbide Schottky Barrier Diodes
by Hao Zhou, Xiang Wang, Shulong Wang, Chenyu Liu, Dongliang Chen, Jiarui Li, Lan Ma and Guohao Zhang
Micromachines 2025, 16(5), 583; https://doi.org/10.3390/mi16050583 - 15 May 2025
Abstract
This work employs a deep learning method to develop a high-precision model for predicting the breakdown voltage (Vbr) and forward I-V characteristics of silicon carbide Schottky barrier diodes (SiC SBDs). The model significantly reduces the testing costs associated with destructive [...] Read more.
This work employs a deep learning method to develop a high-precision model for predicting the breakdown voltage (Vbr) and forward I-V characteristics of silicon carbide Schottky barrier diodes (SiC SBDs). The model significantly reduces the testing costs associated with destructive experiments, such as breakdown voltage testing. Although the model requires a certain amount of time to establish itself, it supports linear variations in related variables once developed. A predicted model for Vbr with an accuracy of up to 99% was successfully developed using 600 sets of input data after 200 epochs of training. After training for 1000 epochs, the deep learning-based model could predict not only point values like Vbr but also curves, such as forward I-V characteristics, with a mean squared error (MSE) of less than 10−3. Our research shows the applicability and high efficiency of introducing deep learning into device characteristic prediction. Full article
(This article belongs to the Special Issue Advanced Wide Bandgap Semiconductor Materials and Devices)
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21 pages, 13910 KiB  
Article
Modeling and Simulation for Predicting Thermo-Mechanical Behavior of Wafer-Level Cu-PI RDLs During Manufacturing
by Xianglong Chu, Shitao Wang, Chunlei Li, Zhizhen Wang, Shenglin Ma, Daowei Wu, Hai Yuan and Bin You
Micromachines 2025, 16(5), 582; https://doi.org/10.3390/mi16050582 - 15 May 2025
Abstract
The development of chip manufacturing and advanced packaging technologies has significantly changed redistribution layers (RDLs), leading to shrinking line width/spacing, increasing the number of build-up layers and package size, and introducing organic materials such as polyimide (PI) for dielectrics. The fineness and complexity [...] Read more.
The development of chip manufacturing and advanced packaging technologies has significantly changed redistribution layers (RDLs), leading to shrinking line width/spacing, increasing the number of build-up layers and package size, and introducing organic materials such as polyimide (PI) for dielectrics. The fineness and complexity of structures, combined with the temperature-dependent and viscoelastic properties of organic materials, make it increasingly difficult to predict the thermo-mechanical behavior of wafer-level Cu-PI RDL structures, posing a severe challenge in warpage prediction. This study models and simulates the thermo-mechanical response during the manufacturing process of Cu-PI RDL at the wafer level. A cross-scale wafer-level equivalent model was constructed using a two-level partitioning method, while the PI material properties were extracted via inverse fitting based on thermal warpage measurements. The warpage prediction results were compared against experimental data using the maximum warpage as the indicator to validate the extracted PI properties, yielding errors under less than 10% at typical process temperatures. The contribution of RDL build-up, wafer backgrinding, chemical mechanical polishing (CMP), and through-silicon via (TSV)/through-glass via (TGV) interposers to the warpage was also analyzed through simulation, providing insight for process risk evaluation. Finally, an artificial neural network was developed to correlate the copper ratios of four RDLs with the wafer warpages for a specific process scenario, demonstrating the potential for wafer-level warpage control through copper ratio regulation in RDLs. Full article
(This article belongs to the Special Issue 3D Integration: Trends, Challenges and Opportunities)
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13 pages, 2446 KiB  
Article
A Novel Pathogen Detection System Combining a Nucleic Acid Extraction Biochip with a Perovskite Photodetector
by Zhuo Gao, Pan Wang, Chang Chen, Jian Duan, Shilun Feng and Bo Liu
Micromachines 2025, 16(5), 581; https://doi.org/10.3390/mi16050581 - 15 May 2025
Abstract
The increasing spread of infectious diseases caused by pathogenic microorganisms underscores the urgent need for highly sensitive, portable, and rapid nucleic acid detection technologies to facilitate early diagnosis and effective prevention. In this study, we developed a fluorescence-based nucleic acid detection platform that [...] Read more.
The increasing spread of infectious diseases caused by pathogenic microorganisms underscores the urgent need for highly sensitive, portable, and rapid nucleic acid detection technologies to facilitate early diagnosis and effective prevention. In this study, we developed a fluorescence-based nucleic acid detection platform that integrates a microfluidic chip with an all-inorganic perovskite photodetector. The system enables integrated operation of nucleic acid extraction, purification, and amplification on a microfluidic chip, combined with real-time electrical signal readout via a CsPbBr3 perovskite photodetector. Experimental results indicate that the photodetector exhibits high responsivity at 530 nm, aligning well with the primary emission peak of FAM. The system demonstrates a strong linear correlation between photocurrent and FAM concentration over the range of 0.01–0.4 μM (R2 = 0.928), with a low detection limit of 0.01 μM and excellent reproducibility across multiple measurements. Validation using FAM standard solutions and Escherichia coli samples confirmed the system’s reliable linearity and signal stability. This platform demonstrates strong potential for rapid pathogen screening and point-of-care diagnostic applications. Full article
(This article belongs to the Special Issue Recent Progress of Lab-on-a-Chip Assays)
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14 pages, 4835 KiB  
Article
Development and Evaluation of Multi-Module Retinal Devices for Artificial Vision Applications
by Kuang-Chih Tso, Yoshinori Sunaga, Yuki Nakanishi, Yasuo Terasawa, Makito Haruta, Kiyotaka Sasagawa and Jun Ohta
Micromachines 2025, 16(5), 580; https://doi.org/10.3390/mi16050580 - 15 May 2025
Abstract
Artificial retinal devices require a high-density electrode array and mechanical flexibility to effectively stimulate retinal cells. However, designing such devices presents significant challenges, including the need to conform to the curvature of the eyeball and cover a large area using a single platform. [...] Read more.
Artificial retinal devices require a high-density electrode array and mechanical flexibility to effectively stimulate retinal cells. However, designing such devices presents significant challenges, including the need to conform to the curvature of the eyeball and cover a large area using a single platform. To address these issues, we developed a parylene-based multi-module retinal device (MMRD) integrating a complementary metal-oxide semiconductor (CMOS) system. The proposed device is designed for suprachoroidal transretinal stimulation, with each module comprising a parylene-C thin-film substrate, a CMOS chip, and a ceramic substrate housing seven platinum electrodes. The smart CMOS system significantly reduces wiring complexity, enhancing the device’s practicality. To improve fabrication reliability, we optimized the encapsulation process, introduced multiple silane coupling modifications, and utilized polyvinyl alcohol (PVA) for easier detachment in flip-chip bonding. This study demonstrates the fabrication and evaluation of the MMRD through in vitro and in vivo experiments. The device successfully generated the expected current stimulation waveforms in both settings, highlighting its potential as a promising candidate for future artificial vision applications. Full article
(This article belongs to the Section E：Engineering and Technology)
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12 pages, 2357 KiB  
Article
MXene-Based High-Performance Soft Pressure Sensor Using Gel–Deep Eutectic Solvent Composite
by Riku Sasaki, Kaiin Tou, Shoma Kamanoi, Junya Yoshida, Yoshihito Takabe, Yasuyuki Miura, Eri Kamiya, Ayana Hirayama and Tomohito Sekine
Micromachines 2025, 16(5), 579; https://doi.org/10.3390/mi16050579 - 15 May 2025
Abstract
MXene, a layered nanocarbon material, exhibits excellent conductivity and solubility. Its high sensitivity also makes it useful for soft pressure sensors. However, the compatibility between sensitivity and fast responses in resistance-change sensors remains a major issue. This study developed an MXene-based high-performance soft [...] Read more.
MXene, a layered nanocarbon material, exhibits excellent conductivity and solubility. Its high sensitivity also makes it useful for soft pressure sensors. However, the compatibility between sensitivity and fast responses in resistance-change sensors remains a major issue. This study developed an MXene-based high-performance soft pressure sensor using a gel–deep eutectic solvent composite. The composite conductive material exhibited excellent solubility and printability in soft device fabrication. The aim of this work was to produce a high-quality soft pressure sensor that exhibited quick responses over a wide sensitivity range for detecting applied pressure. The sensors achieved high performance in terms of a high-speed response (40 ms) and good sensitivity (−0.0109 kPa−1). These results represent an advance in intelligent wearable sensing systems by combining materials science and electronic devices. Full article
(This article belongs to the Special Issue Soft Sensors and Soft Circuits: Design, Implementation and Applications)
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18 pages, 14476 KiB  
Article
Modulating Reaction Kinetics Using an Electrolytic Method to Achieve Efficient Vehicle Identification Number Reappearance
by Jintao Wang, Xiaoshun Zhang, Mengfan Chen, Xihao Zhang, Zhongliang Zhang and Jianguo Liu
Micromachines 2025, 16(5), 578; https://doi.org/10.3390/mi16050578 - 15 May 2025
Abstract
Vehicle identification number (VIN) reappearance technology is an important means of vehicle traceability in various criminal cases. However, with the advancement of metallurgical techniques, the corrosion resistance of metal becomes stronger, and the traditional chemical etching reappearance method gradually fails. In order to [...] Read more.
Vehicle identification number (VIN) reappearance technology is an important means of vehicle traceability in various criminal cases. However, with the advancement of metallurgical techniques, the corrosion resistance of metal becomes stronger, and the traditional chemical etching reappearance method gradually fails. In order to break through the dilemma of traditional methods, this study establishes an electrochemical corrosion system by introducing the corrosion inhibitor hexamethylenetetramine (HMTA) to precisely regulate the electrochemical dissolution kinetics. Material characterization and electrochemical measurements demonstrated that the selective adsorption of HMTA significantly enhances the potential difference between plastically deformed regions and the normal metal substrate (ΔEmax = 6 mV). By effectively suppressing the corrosion rate in non-target areas, HMTA promotes selective anodic oxidation reactions in the vehicle identification number character regions due to their distinct microstructural characteristics, thereby substantially improving the contrast of the reappeared VIN markings. Density functional theory calculations and molecular dynamics simulations further reveal the formation of a dense adsorption layer, which is a key factor in improving the reproducibility of the results. The experimental results demonstrate that under conditions of 6 V applied voltage, with 0.5 M hydrochloric acid and 0.02–0.03 M HMTA in the electrolyte, efficient VIN reappearance could be achieved within 3–4 min on filed-down surfaces. Full article
(This article belongs to the Section E：Engineering and Technology)
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17 pages, 985 KiB  
Article
SlimPort: Port-Driven High-Level Synthesis for Continuous-Flow Microfluidic Biochips
by Youlin Pan, Yanbo Xu, Ziyang Chen, Xing Huang and Genggeng Liu
Micromachines 2025, 16(5), 577; https://doi.org/10.3390/mi16050577 - 14 May 2025
Viewed by 59
Abstract
Continuous-flow microfluidic biochips (CFMBs) automatically execute various bioassays by precisely controlling the transport of fluid samples, which is driven by pressure delivered through fluidic ports. High-level synthesis, as an important stage in the design flow of CFMBs, generates binding and scheduling solutions whose [...] Read more.
Continuous-flow microfluidic biochips (CFMBs) automatically execute various bioassays by precisely controlling the transport of fluid samples, which is driven by pressure delivered through fluidic ports. High-level synthesis, as an important stage in the design flow of CFMBs, generates binding and scheduling solutions whose quality directly affects the efficiency of the execution of bioassays. Existing high-level synthesis methods perform numerous transport tasks concurrently to increase efficiency. However, fluidic ports cannot be shared between concurrently executing transport tasks, resulting in a large number of fluidic ports introduced by existing methods. Increasing the number of fluidic ports undermines the integration, reduces the reliability, and increases the manufacturing cost. In this paper, we propose a port-driven high-level synthesis method based on integer linear programming (ILP) called SlimPort, integrating the optimization of fluidic port number into high-level synthesis, which has never been considered in prior work. Meanwhile, to ensure bioassay correctness, volume management between devices with a non-fixed input/output ratio is realized. Additionally, two acceleration strategies for ILP, scheduling constraint reduction and upper boundary estimation of fluidic port number, are proposed to improve the efficiency of SlimPort. Experimental results from multiple benchmarks demonstrate that SlimPort leads to high assay execution efficiency and a low number of fluidic ports. Full article
(This article belongs to the Special Issue Electronic Design Automation (EDA) for Microfluidic Biochips)
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18 pages, 4707 KiB  
Article
Development of Wearable Wireless Multichannel f-NIRS System to Evaluate Activities
by Xiaojie Ma, Tianchao Miao, Fawen Xie, Jieyu Zhang, Lulu Zheng, Xiang Liu and Hangrui Hai
Micromachines 2025, 16(5), 576; https://doi.org/10.3390/mi16050576 - 14 May 2025
Viewed by 57
Abstract
Functional near-infrared spectroscopy is a noninvasive neuroimaging technique that uses optical signals to monitor subtle changes in hemoglobin concentrations within the superficial tissue of the human body. This technology has widespread applications in long-term brain–computer interface monitoring within both traditional medical domains and, [...] Read more.
Functional near-infrared spectroscopy is a noninvasive neuroimaging technique that uses optical signals to monitor subtle changes in hemoglobin concentrations within the superficial tissue of the human body. This technology has widespread applications in long-term brain–computer interface monitoring within both traditional medical domains and, increasingly, domestic settings. The popularity of this approach lies in the fact that new single-channel brain oxygen sensors can be used in a variety of scenarios. Given the diverse sensor structure requirements across applications and numerous approaches to data acquisition, the accurate extraction of comprehensive brain activity information requires a multichannel near-infrared system. This study proposes a novel distributed multichannel near-infrared system that integrates two near-infrared light emissions at differing wavelengths (660 nm, 850 nm) with a photoelectric receiver. This substantially improves the accuracy of regional signal sampling. Through a basic long-time mental arithmetic paradigm, we demonstrate that the accompanying algorithm supports offline analysis and is sufficiently versatile for diverse scenarios relevant to the system’s functionality. Full article
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10 pages, 3266 KiB  
Article
Extended Shortwave Infrared T2SL Detector Based on AlAsSb/GaSb Barrier Optimization
by Jing Yu, Yuegang Fu, Lidan Lu, Weiqiang Chen, Jianzhen Ou and Lianqing Zhu
Micromachines 2025, 16(5), 575; https://doi.org/10.3390/mi16050575 - 14 May 2025
Viewed by 107
Abstract
Extended shortwave infrared (eSWIR) detectors operating at high temperatures are widely utilized in planetary science. A high-performance eSWIR based on pBin InAs/GaSb/AlSb type-II superlattice (T2SL) grown on a GaSb substrate is demonstrated. It achieves the optimization of the device’s optoelectronic performance by adjusting [...] Read more.
Extended shortwave infrared (eSWIR) detectors operating at high temperatures are widely utilized in planetary science. A high-performance eSWIR based on pBin InAs/GaSb/AlSb type-II superlattice (T2SL) grown on a GaSb substrate is demonstrated. It achieves the optimization of the device’s optoelectronic performance by adjusting the p-type doping concentration in the AlAs0.1Sb0.9/GaSb barrier. Experimental and TCAD simulation results demonstrate that both the device’s dark current and responsivity grow as the doping concentration rises. Here, the bulk dark current density and bulk differential resistance area are extracted to calculate the bulk detectivity for evaluating the photoelectric performance of the device. When the barrier concentration is 5 × 1016 cm−3, the bulk detectivity is 2.1 × 1011 cm·Hz1/2/W, which is 256% higher than the concentration of 1.5 × 1018 cm−3. Moreover, at 300 K (−10 mV), the 100% cutoff wavelength of the device is 1.9 μm, the dark current density is 9.48 × 10−6 A/cm2, and the peak specific detectivity is 7.59 × 1010 cm·Hz1/2/W (at 1.6 μm). An eSWIR focal plane array (FPA) detector with a 320 × 256 array scale was fabricated for this purpose. It demonstrates a remarkably low blind pixel rate of 0.02% and exhibits an excellent imaging quality at room temperature, indicating its vast potential for applications in infrared imaging. Full article
(This article belongs to the Special Issue Integrated Photonics and Optoelectronics, 2nd Edition)
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19 pages, 7121 KiB  
Article
UV–Vis Detection of Thioacetamide: Balancing the Performances of a Mn(III)-Porphyrin, Gold Colloid, and Their Complex for Selecting the Most Sensitive Material
by Camelia Epuran, Ion Fratilescu, Ionela Fringu, Anca Lascu, Liliana Halip, Mihaela Gherban and Eugenia Fagadar-Cosma
Micromachines 2025, 16(5), 574; https://doi.org/10.3390/mi16050574 - 14 May 2025
Viewed by 148
Abstract
The optical detection of thioacetamide was investigated using a metalated porphyrin, Mn(III)-5,10,15,20-tetrakis-(3,4-dimethoxyphenyl)-21H,23H-porphyrin chloride (Mn-3,4-diMeOPP), a gold colloid solution (AuNPs), and a complex formed between them (Mn-3,4-diMeOPP–AuNPs) in order to select the most sensitive material and to achieve complementarity between methods. Mn-3,4-diMeOPP, AuNPs, and [...] Read more.
The optical detection of thioacetamide was investigated using a metalated porphyrin, Mn(III)-5,10,15,20-tetrakis-(3,4-dimethoxyphenyl)-21H,23H-porphyrin chloride (Mn-3,4-diMeOPP), a gold colloid solution (AuNPs), and a complex formed between them (Mn-3,4-diMeOPP–AuNPs) in order to select the most sensitive material and to achieve complementarity between methods. Mn-3,4-diMeOPP, AuNPs, and their complex were synthesized and characterized by means of UV–Vis, FT-IR spectrometry, and AFM investigations. It could be concluded that Mn-3,4-diMeOPP could detect/quantify thioacetamide (TAA) in the range 3.13 × 10−8 M–7.67 × 10−7 M in a linear fashion, with a 99.85% confidence coefficient. The gold colloidal particles alone could detect TAA in an extremely narrow concentration domain of 2–9.8 × 10−7 M, slightly complementary with that of Mn-3,4-diMeOPP. The complex between Mn-3,4-diMeOPP and gold colloid proved to be able to quantify TAA in the trace domain with concentrations of 1.99 × 10−8 M–1.76 × 10−7 M in a polynomial fashion, with the method being more difficult. A potential mechanism for TAA detection based on Mn-3,4-diMeOPP is discussed based on computational modeling. The distorted porphyrin conformation and its electronic configuration favor the generation of a grid of electrostatic interactions between porphyrin and TAA. Full article
(This article belongs to the Special Issue Nanoparticle-Based (Bio)Sensors for Biomedical and Environmental Monitoring)
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38 pages, 9782 KiB  
Review
Laser-Fabricated Micro/Nanostructures: Mechanisms, Fabrication Techniques, and Applications
by Andrei Teodor Matei, Anita Ioana Visan and Irina Negut
Micromachines 2025, 16(5), 573; https://doi.org/10.3390/mi16050573 - 13 May 2025
Viewed by 128
Abstract
The rapid evolution of optoelectronic devices necessitates innovative fabrication techniques to improve their performance and functionality. This review explores the advancements in laser processing as a versatile method for creating micro- and nanostructured surfaces, tailored to enhance the efficiency of optoelectronic applications. We [...] Read more.
The rapid evolution of optoelectronic devices necessitates innovative fabrication techniques to improve their performance and functionality. This review explores the advancements in laser processing as a versatile method for creating micro- and nanostructured surfaces, tailored to enhance the efficiency of optoelectronic applications. We begin by elucidating the fundamental mechanisms underlying laser interactions with materials, which facilitate the precise engineering of surface topographies. Following this, we systematically review various micro/nanostructures fabricated by laser techniques, such as laser ablation, laser-induced periodic surface structures (LIPSS), and two-photon polymerization, highlighting their unique properties and fabrication parameters. The review also delves into the significant applications of these laser-fabricated surfaces in optoelectronic devices, including photovoltaics, photodetectors, and sensors, emphasizing how tailored surface structures can lead to improved light absorption, enhanced charge carrier dynamics, and optimized device performance. By synthesizing current knowledge and identifying emerging trends, this work aims to inspire future research directions in the design and application of laser-fabricated micro/nanostructures within the field of optoelectronics. Our findings underscore the critical role of laser technology in advancing the capabilities of next-generation optoelectronic devices, aligning with the scope of emerging trends in device engineering. Full article
(This article belongs to the Special Issue Emerging Trends in Optoelectronic Device Engineering)
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21 pages, 9705 KiB  
Article
Modeling and Validation of Material Removal Based on Rheological Behavior Under Dynamic-Viscosity Nonlinear Coupling Effects
by Tianchen Zhao, Luguang Guo, Qilong Gao, Xu Wang, Binghai Lyu and Chen Li
Micromachines 2025, 16(5), 572; https://doi.org/10.3390/mi16050572 - 13 May 2025
Viewed by 158
Abstract
Compliant rheological polishing advanced in facilitating the generation of smooth curved surfaces. However, the inherent energy dissipation of the medium during flow results in an uncontrollable material removal distribution. This study proposes utilizing the motion of the tool to regulate the distribution of [...] Read more.
Compliant rheological polishing advanced in facilitating the generation of smooth curved surfaces. However, the inherent energy dissipation of the medium during flow results in an uncontrollable material removal distribution. This study proposes utilizing the motion of the tool to regulate the distribution of physical fields within the computational domain, thereby controlling material removal. A film thickness model is developed based on fluid dynamics and tribology principles to examine the pressure and velocity distributions within the film. In conjunction with contact mechanics and metallography, a material removal model is formulated and then validated and refined by valid experiment, demonstrating a positive correlation between material removal rate and surface quality. Optimization experiments produced a curved surface with an Ra of 17.59 nm. Full article
(This article belongs to the Special Issue Ultra-Precision Machining of Difficult-to-Machine Materials)
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13 pages, 4920 KiB  
Article
Thermal Performance of T-Shaped Ultra-Thin Vapor Chamber with Double-Sided Heating for LED Automotive Headlamp Cooling
by Yaokang Zhang, Tengqing Liu, Yu Bai, Shuangfeng Wang, Qianxi Zhang and Huifeng Kang
Micromachines 2025, 16(5), 571; https://doi.org/10.3390/mi16050571 - 12 May 2025
Viewed by 177
Abstract
High heat flux brings about severe thermal problems for light-emitting diode (LED) automotive headlamps in narrow heat removal spaces, which will degrade their performance and lifespan. This study proposes an easily fabricated and feasible 1.3 mm thick 2D T-shaped in-plane ultra-thin vapor chamber [...] Read more.
High heat flux brings about severe thermal problems for light-emitting diode (LED) automotive headlamps in narrow heat removal spaces, which will degrade their performance and lifespan. This study proposes an easily fabricated and feasible 1.3 mm thick 2D T-shaped in-plane ultra-thin vapor chamber (UTVC) for cooling the high heat flux of LED automotive headlamps. The effects of heating modes, unequal input heat load, and orientations on the thermal performance of the T-shaped UTVC are investigated. The results show that double-sided heating can improve the temperature uniformity of the T-shaped UTVC and reduce the thermal resistance compared to the single-sided heating. The lowest thermal resistances under single-sided and double-sided heating are 1.127 K/W at 12 W and 0.898 K/W at 16 W, respectively. When the total power is identical, the proposed 2D T-shaped UTVC can work effectively at unequal input power. The orientations have a significant impact on the thermal performance of the 2D T-shaped UTVC, and the thermal performance under different orientations changes with anti-gravity state < horizontal state < gravity-assisted state. The proposed T-shaped UTVC can work effectively under diverse operating ranges. Full article
(This article belongs to the Special Issue Functional Materials and Microdevices, 2nd Edition)
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16 pages, 6462 KiB  
Article
Nanoindentation Response of Monocrystalline Copper via Molecular Dynamics: Anisotropic Edge Effects
by Desong Du, Peng Wu, Huan Liu, Zhengkun Li and Jiubin Tan
Micromachines 2025, 16(5), 570; https://doi.org/10.3390/mi16050570 - 12 May 2025
Viewed by 195
Abstract
In the nanoindentation testing of metallic materials, mechanical properties often decrease significantly when the indentation position shifts from the central region to the edge due to edge effects, leading to premature edge failure and potential device malfunctions. In this work, molecular dynamic (MD) [...] Read more.
In the nanoindentation testing of metallic materials, mechanical properties often decrease significantly when the indentation position shifts from the central region to the edge due to edge effects, leading to premature edge failure and potential device malfunctions. In this work, molecular dynamic (MD) simulations were conducted to investigate the anisotropic edge effects of nanoindentation on monocrystalline copper with a specific crystal orientation. The results reveal that changes in indentation position strongly influence surface collapse and lateral pile-up behaviors. Notably, edge positions resulted in significant reductions in indentation force and hardness, accompanied by pronounced anisotropy in nanoindentation hardness. Additionally, distinct von Mises stress distributions were observed at different indentation positions, highlighting the crystallographic orientation’s role in modulating edge effects. This study provides new insights into the atomic-scale mechanisms underlying edge effects in metallic materials and their anisotropic characteristics. Full article
(This article belongs to the Special Issue Recent Advances in Nanoindentation Techniques)
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22 pages, 5620 KiB  
Article
Zinc Oxide Nanorod-Based Sensor for Precision Detection and Estimation of Residual Pesticides on Tea Leaves
by Baharul Islam, Rakesh A. Afre, Sunandan Baruah and Diego Pugliese
Micromachines 2025, 16(5), 569; https://doi.org/10.3390/mi16050569 - 10 May 2025
Viewed by 271
Abstract
This study presents the development of a zinc oxide (ZnO) nanorod-based sensor for the detection and quantification of residual pesticides commonly found in tea plantations, with a focus on quinalphos and thiamethoxam. Exploiting the unique electrical characteristics of ZnO nanorods, the sensor exhibits [...] Read more.
This study presents the development of a zinc oxide (ZnO) nanorod-based sensor for the detection and quantification of residual pesticides commonly found in tea plantations, with a focus on quinalphos and thiamethoxam. Exploiting the unique electrical characteristics of ZnO nanorods, the sensor exhibits high sensitivity and selectivity in monitoring trace levels of pesticide residues. The detection mechanism relies on measurable changes in electrical resistance when the ZnO nanorod-coated electrodes interact with varying concentrations of the target pesticides. A performance evaluation was carried out using water samples spiked with different pesticide concentrations. The sensor displayed distinct response profiles for each compound: a linear resistance–concentration relationship for quinalphos and a non-linear, saturating trend for thiamethoxam, reflecting their differential interactions with the ZnO surface. Statistical analysis confirmed the sensor’s reliability, reproducibility, and consistency across repeated measurements. The rapid response time and ease of fabrication underscore its potential for real-time, on-site pesticide monitoring. This method offers a promising alternative to traditional analytical techniques, enhancing food safety assurance and supporting sustainable agricultural practices through effective environmental surveillance. Full article
(This article belongs to the Special Issue Nanomaterials for Micro/Nano Devices, 2nd Edition)
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15 pages, 2615 KiB  
Article
An Improved YOLOv5 Model for Lithographic Hotspot Detection
by Mu Lin, Wenjing He, Jiale Liu, Fencheng Li, Jun Luo and Yijiang Shen
Micromachines 2025, 16(5), 568; https://doi.org/10.3390/mi16050568 - 9 May 2025
Viewed by 193
Abstract
The gap between the ever-shrinking feature size of integrated circuits and lithographic manufacturing ability is causing unwanted shape deformations of printed layout patterns. The deformation region with problematic imaging, known as a hotspot (HS), should be detected and corrected before mask manufacturing. In [...] Read more.
The gap between the ever-shrinking feature size of integrated circuits and lithographic manufacturing ability is causing unwanted shape deformations of printed layout patterns. The deformation region with problematic imaging, known as a hotspot (HS), should be detected and corrected before mask manufacturing. In this paper, we propose a hotspot detection method to improve the precision and recall rate of the fatal pinching and bridging error due to the poor printability of certain layout patterns by embedding a spatial attention mechanism into the YOLOv5 model. Additionally, transfer learning and pre-trained techniques are used to expedite training convergence. Simulation results outperform the depth-based or representative machine learning-based methods on the ICCAD 2012 dataset with an average recall rate of 1, a precision rate of 0.8277 and an F1-score of 0.9057. Full article
(This article belongs to the Special Issue Recent Advances in Lithography)
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28 pages, 10258 KiB  
Article
Microfluidic Chip for Quantitatively Assessing Hemorheological Parameters
by Yang Jun Kang
Micromachines 2025, 16(5), 567; https://doi.org/10.3390/mi16050567 - 8 May 2025
Viewed by 259
Abstract
The biomechanical properties of blood are regarded as promising biomarkers for monitoring early-stage abnormalities and disease progression. To detect any changes in blood, it is necessary to measure as many rheological properties as possible. Herein, a novel method is proposed for measuring multiple [...] Read more.
The biomechanical properties of blood are regarded as promising biomarkers for monitoring early-stage abnormalities and disease progression. To detect any changes in blood, it is necessary to measure as many rheological properties as possible. Herein, a novel method is proposed for measuring multiple rheological properties of blood using a microfluidic chip. The syringe pump turns off for 5 min to induce RBC (red blood cell) sedimentation in the driving syringe. RBC aggregation is determined by analyzing the time-lapse blood image intensity at stasis: I(t) = I1 exp (−k1t) + I2 exp (−k2t). RBC-rich blood and RBC-depleted blood are sequentially infused into the microfluidic chip. Based on blood pressure estimated with time-lapse blood velocity, blood viscosity is acquired with the Hagen–Poiseuille law. RBC sedimentation is quantified as RBC sedimentation distance (Xesr) and erythrocyte sedimentation rate (ESR). The proposed method provides a consistent viscosity compared with previous methods. Two of the four variables (I1, I2) exhibited a strong correlation with the conventional RBC aggregation index (AI). The indices Xesr and ESR showed consistent trends with respect to the blood medium and hematocrit. In conclusion, the proposed method is then regarded as effective for monitoring multiple rheological properties. Full article
(This article belongs to the Special Issue Microfluidic Chips for Biomedical Applications)
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25 pages, 9693 KiB  
Article
Research on Pneumatic Proportional Pressure Valve Based on Silicon Microfluidic Chip with V-Shaped Electrothermal Microactuator
by Jun Zhang, Chengjie Zhou and Yangfang Wu
Micromachines 2025, 16(5), 566; https://doi.org/10.3390/mi16050566 - 8 May 2025
Viewed by 172
Abstract
This study presents a pneumatic proportional pressure valve employing a silicon microfluidic chip (SMC) integrated with a V-shaped electrothermal microactuator, aiming to address the limitations of traditional solenoid-based valves in miniaturization and high-precision control. The SMC, fabricated via MEMS technology, leverages the thermal [...] Read more.
This study presents a pneumatic proportional pressure valve employing a silicon microfluidic chip (SMC) integrated with a V-shaped electrothermal microactuator, aiming to address the limitations of traditional solenoid-based valves in miniaturization and high-precision control. The SMC, fabricated via MEMS technology, leverages the thermal expansion of microactuator ribs to regulate pressure through adjustable orifices. A first-order transfer function between input voltage and displacement of the microactuator was derived through theoretical modeling and validated via COMSOL Multiphysics 5.2a simulations. Key geometric parameters of the actuator ribs—cross-section, number, inclination angle, width, span length and thickness—were analyzed for their influence on lever mechanism displacement, actuator displacement, static gain and time constant. AMESim 16.0-based simulations of single- and dual-chip valve structures revealed that increasing ζ shortens step-response rise time, while reducing τ improves hysteresis. Experimental validation confirmed the valve’s static and dynamic performance, achieving a step-response rise time of <40 ms, linearity within the 30–60% input voltage range, and effective tracking of sinusoidal control signals up to 8 Hz with a maximum pressure deviation of 0.015 MPa. The work underscores the potential of MEMS-based actuators in advancing compact pneumatic systems, offering a viable alternative to conventional solenoids. Key innovations include geometry-driven actuator optimization and dual-chip integration, providing insights into high-precision, low-cost pneumatic control solutions. Full article
(This article belongs to the Special Issue MEMS Actuators and Their Applications)
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17 pages, 10965 KiB  
Article
Evaluation of Surface Integrity of Multi-Energy Field Coupling-Assisted Micro-Grinding Hastelloy Alloy
by Peng Bian, Zhenjing Duan, Yishuai Jia, Ziheng Wang, Shuaishuai Wang, Ji Tan, Yuyang Zhou, Jinlong Song and Xin Liu
Micromachines 2025, 16(5), 565; https://doi.org/10.3390/mi16050565 - 8 May 2025
Viewed by 291
Abstract
Hastelloy is widely used in the manufacturing of high-temperature components in the aerospace industry because of its high strength and corrosion-resistant physical properties, as well as its ability to maintain excellent mechanical properties at high temperatures. However, with developments in science and technology, [...] Read more.
Hastelloy is widely used in the manufacturing of high-temperature components in the aerospace industry because of its high strength and corrosion-resistant physical properties, as well as its ability to maintain excellent mechanical properties at high temperatures. However, with developments in science and technology, the amount of available components for use in high-temperature and corrosive environments is increasing, their structures are becoming more complex and varied, and requirements with regard to the surface quality of the components has also become more stringent. The integration of cold plasma (CP) and nano-lubricant minimum quantity lubrication (NMQL), within a multi-physics coupling-assisted micro-grinding process (CPNMQL), presents a promising strategy to overcome this bottleneck. In this paper, micro-grinding of Hastelloy C-276 was performed under dry, CP, NMQL, and CPNMQL conditions, respectively. Contact angle testing, X-ray photoelectron spectroscopy (XPS) analysis, and nano-scratch experiments were used to investigate the mechanism of CPNMQL and to compare the micro-milling performance under different cooling and lubrication conditions employing various characteristics such as grinding temperature, surface roughness, and 3D surface profile. The results showed that at different micro-grinding depths, the micro-grinding temperature and surface roughness were significantly reduced under CP, NMQL, and CPNMQL conditions compared to dry friction. Among them, CPNMQL showed the best performance, with 53.4% and 54.7% reductions in temperature and surface roughness, respectively, compared to the dry condition. Full article
(This article belongs to the Special Issue Recent Advances in Micro/Nanofabrication, 2nd Edition)
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21 pages, 595 KiB  
Review
Optical Detection Techniques for Biomedical Sensing: A Review of Printed Circuit Board (PCB)-Based Lab-on-Chip Systems
by Francisco Perdigones, Pablo Giménez-Gómez, Xavier Muñoz-Berbel and Carmen Aracil
Micromachines 2025, 16(5), 564; https://doi.org/10.3390/mi16050564 - 8 May 2025
Viewed by 299
Abstract
Lab on Printed Circuit Boards (Lab-on-PCB) technology has emerged as a promising platform, offering miniaturization, integration, and cost-effective fabrication for a wide range of sensing applications. This review explores the most common optical detection techniques implemented on printed circuit boards (PCBs), including absorbance, [...] Read more.
Lab on Printed Circuit Boards (Lab-on-PCB) technology has emerged as a promising platform, offering miniaturization, integration, and cost-effective fabrication for a wide range of sensing applications. This review explores the most common optical detection techniques implemented on printed circuit boards (PCBs), including absorbance, fluorescence, and chemiluminescence, discussing their working principles, advantages, and limitations in the context of PCB-based sensing. Additionally, evanescent wave generation is considered as an alternative optical approach with benefits for specific applications. Elements such as excitation sources, photodetectors, and the distinguishing characteristics of each method are analyzed to provide a comprehensive, but concise, overview of the field. Emphasis is placed on how the PCB platform influences the performance, sensitivity, and feasibility of these detection methods, highlighting relevant design considerations. This work aims to provide a solid foundation for researchers interested in optical sensing within this technology, serving as a reference for future developments and applications in PCB-based optical detection. Full article
(This article belongs to the Special Issue Lab on Chips and Optical Detection Methods)
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22 pages, 10376 KiB  
Article
Thermal Error Prediction in High-Power Grinding Motorized Spindles for Computer Numerical Control Machining Based on Data-Driven Methods
by Quanhui Wu, Yafeng Li, Zhengfu Lin, Baisong Pan, Dawei Gu and Hailin Luo
Micromachines 2025, 16(5), 563; https://doi.org/10.3390/mi16050563 - 7 May 2025
Viewed by 146
Abstract
The thermal error of the high-power grinding motorized spindle, caused by heating, seriously affects machining accuracy. In this paper, an ensemble learning algorithm is used to predict the thermal error of a high-precision motorized spindle. The subsequent problem of thermal error compensation can [...] Read more.
The thermal error of the high-power grinding motorized spindle, caused by heating, seriously affects machining accuracy. In this paper, an ensemble learning algorithm is used to predict the thermal error of a high-precision motorized spindle. The subsequent problem of thermal error compensation can be effectively solved by a suitable thermal error model, which is crucial for improving the machining accuracy of the actual machining process. Firstly, the steady-state temperature field of the grinding motorized spindle is analyzed and used to determine the position of the sensors. Then, a signal acquisition instrument is used to monitor real-time temperature data. After that, experimental results are obtained, followed by verification. Finally, based on experimental data and the optimization results of temperature measurement points, temperature data are used as the input variable, and thermal deformation data are used as the output variable. The ensemble learning model is composed of different weak learners, which include multiple linear regression, back-propagation, and radial basis function neural networks. Different weak learners are trained using datasets separately, and the output of the weak learners is used as input to the model. Through integrating strategies, an ensemble learning model is established and compared with a weak learner. The error residual set of the ensemble learning model remains within [−0.2, 0.2], and the prediction performance shows that the ensemble learning model has a better predictive effect and strong robustness. Full article
(This article belongs to the Section E：Engineering and Technology)
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13 pages, 2011 KiB  
Article
High-Efficiency Drug Loading in Lipid Vesicles by MEMS-Driven Gigahertz Acoustic Streaming
by Bingxuan Li, Haopu Wang, Zhen Wang, Huikai Xie and Yao Lu
Micromachines 2025, 16(5), 562; https://doi.org/10.3390/mi16050562 - 7 May 2025
Viewed by 172
Abstract
Drug carriers hold significant promise for precision medicine but face persistent challenges in balancing high encapsulation efficiency with structural preservation during active loading. In this study, we present a microelectromechanical system (MEMS)-driven platform that can generate gigahertz (GHz)-frequency acoustic streaming (1.55 GHz) to [...] Read more.
Drug carriers hold significant promise for precision medicine but face persistent challenges in balancing high encapsulation efficiency with structural preservation during active loading. In this study, we present a microelectromechanical system (MEMS)-driven platform that can generate gigahertz (GHz)-frequency acoustic streaming (1.55 GHz) to enable nondestructive, power-tunable drug encapsulation in lipid vesicles. Utilizing DSPE-PEG-modified bilayers with hydrodynamic shear forces, our method achieves transient membrane permeability that preserves membrane integrity while permitting controlled doxorubicin (DOX) influx. We developed the GHz acoustic MEMS platform and applied it to systematically investigate two drug loading strategies: (1) loading DOX into giant unilamellar vesicles (GUVs, >10 μm in diameter) prior to extrusion into small unilamellar vesicles (SUVs, 100 nm) versus (2) direct acoustic loading into pre-formed SUVs. The GUV-first approach demonstrated better performance, achieving 60.04% ± 1.55% encapsulation efficiency (EE%) at 250 mW acoustic power—a 5.93% enhancement over direct SUV loading (54.11% ± 0.72%). Structural analysis via TEM confirmed intact SUV morphology post-loading, while power-dependent EE% analysis showed a linear trend. This work bridges gaps in nanocarrier engineering by optimizing drug loading strategies, aiming to offer a potential drug carrier platform for drug delivery in biomedical treatment in future. Full article
(This article belongs to the Special Issue Advances in Microfluidic Chips for Chemical and Biomedical Applications)
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27 pages, 27489 KiB  
Review
Advances in Magnetically Controlled Medical Robotics: A Review of Actuation Systems, Continuum Designs, and Clinical Prospects for Minimally Invasive Therapies
by Tiantian Kong, Qitong Zheng, Jiarong Sun, Chunxiao Wang, Huibin Liu, Zhizheng Gao, Zezheng Qiao and Wenguang Yang
Micromachines 2025, 16(5), 561; https://doi.org/10.3390/mi16050561 - 6 May 2025
Viewed by 248
Abstract
Magnetically controlled micro-robots hold immense potential for revolutionizing advanced medical applications, garnering significant research interest. This potential is underscored by the dual focus on magnetic control systems—both as driving forces and manipulation field sources—and magnetic continuums that have demonstrated clinical therapeutic efficacy. This [...] Read more.
Magnetically controlled micro-robots hold immense potential for revolutionizing advanced medical applications, garnering significant research interest. This potential is underscored by the dual focus on magnetic control systems—both as driving forces and manipulation field sources—and magnetic continuums that have demonstrated clinical therapeutic efficacy. This comprehensive review delves into the actuation characteristics of permanent magnet systems, electromagnetic systems, and commercially available magnetic control systems. It also explores innovative designs of magnetic wires and tubes serving as continuum structures and investigates the variable stiffness properties of magnetic continua, informed by material and structural attributes. Furthermore, the discussion extends to their prospective roles and future applications within the medical realm. The objective is to elucidate emerging trends in the study of magnetic control systems and magnetic continua, marked by an expanding operational scope and enhanced precision in manipulation. By aligning these trends with clinical challenges and requirements, this review seeks to refine research trajectories, expedite practical implementations, and ultimately advocate for minimally invasive therapies. These therapies, leveraging magnetic control systems and magnetic continuums as cutting-edge treatment modalities, promise transformative impacts on the future of healthcare. Full article
(This article belongs to the Special Issue Functional Materials and Microdevices, 2nd Edition)
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22 pages, 2007 KiB  
Article
Design and Contact Performance Analysis of 3D-Printed Alloy Metal Inertial Micro Switch
by Jinghao Li, Zhipeng Li and Hejuan Chen
Micromachines 2025, 16(5), 560; https://doi.org/10.3390/mi16050560 - 5 May 2025
Viewed by 181
Abstract
In order to reduce space occupation and improve reliability, the modularization and integration of micro switches and their components are a necessary path for development. In this paper, a scheme for an alloy metal inertial micro switch using 3D printing technology is proposed [...] Read more.
In order to reduce space occupation and improve reliability, the modularization and integration of micro switches and their components are a necessary path for development. In this paper, a scheme for an alloy metal inertial micro switch using 3D printing technology is proposed for an integrated design. The switch realizes the turn-on function by causing the deformable electrodes to undergo plastic deformation and make close contact with the outer sleeve under the columnar block extrusion. The influence of electrode structure parameters on electrode contact performance was studied by the orthogonal experimental method. And the best parameter combination scheme for the electrode was determined. The aluminum alloy switch and titanium alloy switch were processed by SLM (selective laser melting) technology. The plastic deformation of the 3D-printed titanium alloy electrode occurred later than that of the 3D-printed aluminum alloy electrode under the same impact. The aluminum alloy electrode underwent plastic deformation and realized stable contact with a response time of 5 µs when the impact load was applied with an amplitude of 627 N and a pulse width of 2.7 ms (simulating high acceleration), which meets the application requirement of the response time being no more than 20 µs. The feasibility of 3D printing technology in high-precision and complex-structure micro switch manufacturing was verified. The research in this paper will provide guidance and reference for engineering applications. Full article
(This article belongs to the Section E：Engineering and Technology)
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18 pages, 5700 KiB  
Article
A Highly Sensitive Giant Magnetoresistive (GMR) Biosensor Based on the Magnetic Flux Concentrator Effect
by Hao Sun, Jiao Li, Changhui Zhao, Chunming Ren, Tian Tian, Chong Lei and Xuecheng Sun
Micromachines 2025, 16(5), 559; https://doi.org/10.3390/mi16050559 - 3 May 2025
Viewed by 311
Abstract
Magnetic biosensors have wide applications in biological target detection due to their advantages such as low background noise, convenient detection, and low requirements for sample pretreatment. However, existing magnetic biosensors still have the drawback of low sensitivity compared to optical and electrochemical biosensors. [...] Read more.
Magnetic biosensors have wide applications in biological target detection due to their advantages such as low background noise, convenient detection, and low requirements for sample pretreatment. However, existing magnetic biosensors still have the drawback of low sensitivity compared to optical and electrochemical biosensors. This paper presents the novel design of a high-sensitivity magnetic biosensor by utilizing the magnetic field line convergence effect, which was applied to bacterial detection. The results indicate that it can achieve a detection limitation of 10 CFU/mL, demonstrating that it can be implemented in high-sensitivity biological target detection. Full article
(This article belongs to the Section B1: Biosensors)
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