Journal of Micromechanics and Microengineering最新文献

{"title":"Microfluidic platform for nanoliter qPCR of several retinal pigment epithelial (RPE) cells.","authors":"Debdyuti Mandal, Akash Roy, Xuelian Chen, Jiang F Zhong, Eun Sok Kim","doi":"10.1088/1361-6439/ae9c4b","DOIUrl":"10.1088/1361-6439/ae9c4b","url":null,"abstract":"<p><p>The clinical implant of stem cell-derived retinal pigment epithelium (RPE) monolayer for age-related macular degeneration requires rigorous validation of the monolayer's cellular maturity. Conventional bulk molecular assays lack the sensitivity to resolve cellular heterogeneity and are prone to damaging the RPE monolayer. This study developed and validated an automated nanoliter-scale microfluidic platform for single-cell transcriptomic quality control of engineered RPE monolayers. A compact polydimethylsiloxane -based microfluidic platform was developed to generate monodisperse 10 nL RPE cell cDNA droplets and 90 nL quantitative PCR (qPCR) reagent droplets using dual-focused-flow geometries. Deterministic droplet fusion was achieved via direct current electrocoalescence, enabling ∼100% merging efficiency. An auxiliary co-flow spacing mechanism was implemented to prevent secondary coalescence during downstream transport. Automated droplet collection into oil-filled 96-well plates was achieved through a custom two-dimensional gantry system, and droplet volume consistency was verified using a Python-based computer vision algorithm. Biological validation was conducted using H14 human embryonic stem cell-derived RPE cells targeting <i>β</i>-actin and lineage-specific markers MITF1, MITF2, PEDF, and PMEL17. The platform demonstrated stable generation and deterministic merging of nanoliter droplets, yielding uniform 100 nL reaction volumes suitable for qPCR analysis. Automated volumetric verification confirmed high droplet uniformity and reliability. Gene expression analysis revealed robust detection of housekeeping and lineage-specific genes at nanoliter scales. These findings demonstrated the feasibility of performing nanoliter-scale qPCR using the proposed microfluidic workflow. The workflow enabled reliable detection of extremely low quantities of nucleic acid using a widely available commercial qPCR platform, providing a practical and accessible approach for routine laboratory and translational research applications. The system-maintained assay sensitivity while significantly reducing reagent consumption and sample input. This automated microfluidic platform enabled reproducible, sample-efficient, single-cell transcriptomic validation of stem cell-derived RPE monolayers. By integrating droplet generation, deterministic merging, automated collection, and computational verification, the system addressed key limitations of bulk molecular quality control of RPE monolayers. This work established a scalable and cost-effective nanoliter qPCR framework for high-resolution molecular quality assurance of regenerative cell therapies.</p>","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"36 9","pages":"095001"},"PeriodicalIF":2.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13531439/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148880392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A 3D-printed microdevice for dielectrophoretic torque-driven rotation of dielectric microspheres to support development of manipulation systems for zebrafish eggs.","authors":"Seyedmajid Hosseini, Mohsen Norouzi, Jose Cibelli, Jack C Koch, W Todd Monroe, Georgios Veronis, Terrence R Tiersch, Jian Xu, Yue Liu","doi":"10.1088/1361-6439/ae2518","DOIUrl":"10.1088/1361-6439/ae2518","url":null,"abstract":"<p><p>Precise control of microscale object rotation is essential for numerous biomedical and microelectromechanical applications. For example, somatic cell nuclear transfer for aquatic biomedical models such as zebrafish faces significant technical challenges, particularly in egg trapping and alignment of an injection needle with the micropyle. In this study, we developed a 3D resin-printed microdevice to achieve frequency-selective electrorotation of dielectric microspheres using a quadrupole electrode configuration driven by phase-shifted alternating current (AC). Theoretical analysis based on the Clausius-Mossotti factor, which governs the polarization of a particle concerning its surrounding environment, highlights the critical role of its imaginary component in the induced dipole moment from the AC field that generates torque. Simulations conducted in COMSOL Multiphysics confirmed the formation of symmetric torque-driven rotation without significant micro-scale object translation. The frequency response of angular velocity exhibited a unimodal profile, with a peak near 4 MHz corresponding to maximum torque efficiency. Experimental validation using 700 <i>μ</i>m polystyrene microspheres in Dulbecco's Phosphate Buffered Saline demonstrated consistent clockwise rotation, with a peak angular velocity of 8.1° s^-1 observed at 900 kHz and 16 Vp-p. Although the experimental peak angular velocity occurred at a lower frequency than the theoretical maximum, the rotational trend followed the polarization relaxation behavior captured by <math><mi>I</mi> <mi>m</mi> <mfenced> <mrow> <msub><mrow><mi>K</mi></mrow> <mrow><mi>c</mi> <mi>m</mi></mrow> </msub> </mrow> </mfenced> </math> . Parameter studies further revealed that increasing microscale object permittivity amplified torque generation, while higher medium permittivity reduced it, underscoring the tunability of electrorotation via dielectric properties. This work demonstrates a robust and scalable platform for manipulating large microscale objects. It lays the foundation for future applications involving biologically relevant objects, such as eggs of biomedical research models.</p>","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"35 12","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13155384/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147868573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fabrication and morphological optimization of TPU/PDMS blend nanofibers via one-step blending electrospinning","authors":"Xuanjie Zong, Chengpeng Zhang, Xue Shang, Nianqiang Zhang, Jilai Wang","doi":"10.1088/1361-6439/adf3c1","DOIUrl":"https://doi.org/10.1088/1361-6439/adf3c1","url":null,"abstract":"Abstract Blend nanofibers have attracted significant interest in biomedical, energy storage, and flexible electronics due to their outstanding synergistic properties. However, the coaxial electrospinning of thermoplastic polyurethane/polydimethylsiloxane (TPU/PDMS) nanofibers remains challenging due to complex processing procedures and high associated costs, which impede further material optimization. To address these limitations, a one-step blending electrospinning strategy was developed by formulating a TPU/PDMS blend system, achieving homogeneous nanoscale dispersion and integration. Using nanofiber diameter and morphology as metrics, we systematically explored the effects of solution concentration, feed rate, and voltage via single-factor experiments and response surface methodology. Results revealed that concentration and feed rate critically influenced nanofiber morphology. The constructed regression model exhibited strong predictive capability (coefficient of determination R 2 = 0.9865, adjusted R 2 = 0.9693). Scanning electron microscopy characterization confirmed the formation of uniform, adhesive overlapped structures, validating the effective co-forming behavior. Furthermore, energy dispersion spectroscopy mapping and x-ray photoelectron spectroscopy results confirm the nanoscale uniform distribution and physical blending of TPU and PDMS. This study presents an efficient strategy for producing uniform TPU/PDMS blend nanofibers and contributes to the rational design of multifunctional materials with tunable structure-property relationships. The findings enhance the practical potential of electrospinning in flexible electronics, biomedical and intelligent sensing.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"35 8","pages":"085002-085002"},"PeriodicalIF":0.0,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147890601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fabrication of Cu/SiC composite microgears by microelectroforming using PDMS-Cu conductive molds","authors":"Aoxiang Li, Bo Wen Zhou, Longfei Xie, Li Ren, Tingli Wang, Bowei Pan, Haixia Jiang, Bo Su, Yuntao Xi","doi":"10.1088/1361-6439/ade0c9","DOIUrl":"https://doi.org/10.1088/1361-6439/ade0c9","url":null,"abstract":"Abstract Cu/SiC composite microgears exhibit significant potential in microelectromechanical systems due to their enhanced mechanical strength and retained electrical conductivity. However, conventional fabrication methods relying on photoresist-based molds face challenges of high cost and complex demolding processes. This study proposes a cost-effective approach combining soft lithography and microelectroforming to fabricate Cu/SiC composite microgears using reusable polydimethylsiloxane -Cu conductive molds. The influence of current density (2–10 A dm −2 ) on dimensional accuracy, SiC co-deposition behavior, and mechanical performance was systematically investigated. Results demonstrated that the composite microgears achieved a dimensional deviation as low as 0.07% compared to the Ni master. The SiC content in the Cu matrix peaked at 6.42 wt% under 8 A dm −2 , accompanied by a maximum microhardness of 240.56 HV, representing a 22.2% hardness improvement over pure Cu. Microstructural analysis indicated grain refinement and reduced residual stress due to SiC particle incorporation. This work provides a scalable strategy for manufacturing high-performance metal matrix composite microcomponents with precise geometries.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"35 6","pages":"065007-065007"},"PeriodicalIF":0.0,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147907735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"3D-printed microneedle arrays for real-time interstitial fluid glucose monitoring","authors":"Qingdi Zhou, Yangjun Wang, Mingqiang Pan, Chunju Wang, Liguo Chen","doi":"10.1088/1361-6439/adb75e","DOIUrl":"https://doi.org/10.1088/1361-6439/adb75e","url":null,"abstract":"Abstract Efficient, accurate, and real-time blood glucose monitoring is crucial for diabetes management. Using interstitial fluid (ISF) instead of blood for monitoring is a key focus. However, microneedle-based in-situ methods face challenges in comfort and miniaturization. This study presents a novel wearable patch for ISF glucose monitoring. The patch features a miniature square microneedle array (MNA) connected to the substrate via microstructure, ensuring strong fixation and easy replacement. The MNA is 3D-printed, offering personalization, efficiency, low cost and biocompatibility. Through the design of the microneedle arrangement on the array, an innovative circular array microneedle configuration is utilized to reduce insertion difficulty and enhance long-term wear comfort by reducing issues related to skin elasticity. Its surface is modified with a bonding, conductive, and functionalized layer for accurate glucose monitoring after insertion. Experimental results show the sensor’s high sensitivity and selectivity for real-time ISF glucose monitoring, suitable for both healthy individuals and diabetics. The device is painless, compact, flexible, low-cost, and comfortable, with replaceable electrodes, making it promising for practical diabetes management.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"35 3","pages":"035010-035010"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147887665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alignment-free solvent-enabled automatic packaging for thermoplastic microfluidics","authors":"Xiang Pan, Zecong Fang, Pin Lv, Pan tingrui","doi":"10.1088/1361-6439/ada61b","DOIUrl":"https://doi.org/10.1088/1361-6439/ada61b","url":null,"abstract":"Abstract As the demands in function versatility, integration density and mass manufacturability grow, multilayer thermoplastic microfluidic devices with sophisticated structures have rapidly gained interests. Yet, great challenges persist in packaging process, namely alignment and sealing of the multiple layers, since the current schemes are typically labour-intensive and lack of automation. Herein, we introduce alignment-free solvent-enabled automatic packaging (ASAP), a novel packaging methodology that combines alignment and bonding in a single automated step. The ASAP technology applies a specialized solvent to form a liquid bridge and induce capillary action for self-alignment while promoting bonding through polymer entanglement. For the first time, the use of the solvent-based liquid bridge has combined the previously independent alignment and bonding processes into one step for thermoplastic microfluidics, as demonstrated by theoretical modelling and proof-of-concept experimentation with PMMA (the substrate) and toluene (the matching solvent). Alignment accuracy better than 1.0 μ m and bonding strength greater than 7.87 MPa have been achieved in a fully automated manner. Leveraging ASAP, a 3D-structured digital flowmeter has been successfully assembled, which eliminates the otherwise tedious alignment and bonding processes. The proposed ASAP technology simplifies the packaging of multilayer thermoplastic microfluidic devices, showing great potential in numerous emerging thermoplastic microfluidics-based applications.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"35 2","pages":"025007-025007"},"PeriodicalIF":0.0,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147881750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"3D simulation estimation and experimental validation of droplet generation in CFD-based flow-focusing microfluidic chips","authors":"Jianming Shu, Chen Wei, Yongfang Zhao, Minghai Li, Zhenye Ma","doi":"10.1088/1361-6439/ad8206","DOIUrl":"https://doi.org/10.1088/1361-6439/ad8206","url":null,"abstract":"Abstract Microdroplets generated using microfluidic techniques offer significant advantages over those generated using conventional methods, including high accuracy and excellent monodispersity. However, there remains a paucity of literature regarding the influence of fluid operating conditions and physical properties on droplet generation, specifically in relation to size and frequency, using computational fluid dynamics (CFD) techniques. In this study, we present a simplified microfluidic chip capable of flexibly adjusting the structure and size of the microchannels based on specific requirements. Subsequently, three-dimensional numerical simulations of this chip were conducted using CFD techniques and fitted a dimensionless model to estimate the droplet generation size and frequency through multivariate nonlinear regression methods. The experimental validation results demonstrated a strong correlation between the fitted data and the experimental observations, with size differences not exceeding 8% and good monodispersity, indicated by a coefficient of variation of less than 2.4%. This study provides valuable insights and a reference for future research.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"34 11","pages":"115006-115006"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147906848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and performance analysis of an embedded amplified piezoelectric jetting dispensing valve","authors":"Jingwei Yang, Lintong Han, Hongxin Wang, Hongnan Zhou, Limin Zhang and Lipeng He","doi":"10.1088/1361-6439/ad76b5","DOIUrl":"https://doi.org/10.1088/1361-6439/ad76b5","url":null,"abstract":"In order to satisfy the market’s demand for high-consistency, micro-dispensing of colloids, an embedded lever-amplified piezoelectric dispensing valve based on flexure hinge is designed. This structure has stable jetting performance, strong reliability, and can achieve micro-dispensing of medium and low viscosity glue. Theoretical analysis shows that the output displacement of the piezoelectric stack can meet the displacement requirement of dispensing after being amplified by this amplification mechanism. And the output displacement and mode of the amplification mechanism are calculated and analyzed by simulation. The rationality of the simulation model is verified by experiments, and the effect law of driving voltage, signal duty cycle and working frequency on the mass of glue droplets is obtained. The results show that under the conditions of driving voltage 100 V, duty cycle 50%, glue supply pressure 0.6 MPa, working frequency 100 Hz, the consistency deviation of single dispensing amount is ±2.01%, as a whole, 0.34–0.38 mg of uniform tiny glue dots can be obtained. The experimental results have verified the stability and micro-dispensing performance of the embedded lever amplification piezoelectric dispensing valve, providing reference for the subsequent application and research of jet dispensing.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"60 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142188714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fabrication of ultra-low expansion glass based double paddle oscillator","authors":"Sabitha Ann Jose, Yahya Atwa, Faisal Iqbal, David McNeill and Hamza Shakeel","doi":"10.1088/1361-6439/ad750f","DOIUrl":"https://doi.org/10.1088/1361-6439/ad750f","url":null,"abstract":"Ultra-low expansion (ULE) glasses, with their excellent material properties like low thermal expansion coefficient (0.5 ppm K−1), are highly suitable for manufacturing micromechanical resonators. However, the lack of suitable microfabrication processes primarily limits the use of ULE glasses to macroscopic applications. This paper describes a detailed micro fabrication technique for producing double paddle oscillators (DPOs) using ULE glass substrates. We used a combination of low-pressure chemical vapor deposition (LPCVD), lithography, and wet etching techniques to manufacture millimeter sized mechanical oscillator with a thickness of 500 μm. We utilized a thick layer of LPCVD polysilicon (∼2.5 μm) as a hard mask for double side etching of thick ULE substrate. We were able to successfully identify different resonant modes of the DPOs using both electrostatic and optical detection methods. A laser Doppler vibrometer system was utilized to confirm different simulated resonant modes. Additionally, quality factor was extracted for different modes from ring down measurements for the first time in ULE based DPO.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"3 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heterogeneous micro-architectonic integration of SU-8 and highly entangled polyacrylamide hydrogel to realize cut-resistant soft superhydrophobic surfaces","authors":"Junce Cheng and Tingyi ‘Leo’ Liu","doi":"10.1088/1361-6439/ad76b6","DOIUrl":"https://doi.org/10.1088/1361-6439/ad76b6","url":null,"abstract":"This paper presents a novel idea to create cut-resistant superhydrophobic (SHPo) surfaces by integrating an array of SU-8 micropillars on a highly entangled polyacrylamide (PAAm) hydrogel substrate. We begin by demonstrating that this highly entangled PAAm hydrogel exhibits superior resistance to cutting while being as transparent, flexible, and stretchable as other polymeric substrates like polydimethylsiloxane (PDMS). Currently, there are no well-known methods or chemicals to directly integrate SU-8 and PAAm with a covalent bond. To overcome this challenge, we introduce a thin layer of chemically modified PDMS between the SU-8 and PAAm so that covalent bonds can be formed between both the SU-8/PDMS interface and the PDMS/PAAm interface. After validating the reliability of the bonding in our experiments, we develop a heterogeneous integration process to fabricate the desired SHPo surface. To demonstrate the critical role of PAAm hydrogel in achieving the cut-resistant SHPo surface, we contrast this new SHPo surface with a reference version that uses a PDMS substrate instead. We conduct microscopic inspections using scanning electron microscopy and a contact angle goniometer before and after cutting the two surfaces. These evaluations show significant differences in their structural integrity and behavior in water interaction.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"23 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142188718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}