{"title":"A Compact Hydraulic Head Auto-Regulating Module (CHARM) for long-term constant gravity-driven flow microfluidics.","authors":"Fan Xue, Ulri N Lee, Joel Voldman","doi":"10.1038/s41378-025-00968-6","DOIUrl":"https://doi.org/10.1038/s41378-025-00968-6","url":null,"abstract":"<p><p>Fluid flow is a ubiquitous aspect of microfluidic systems. Gravity-driven flow is one microfluidic flow initiation and maintenance mechanism that is appealing because it is simple, requires no external power source, and is easy to use. However, the driving forces created by hydraulic head differences gradually decrease during operation, resulting in decreasing flow rates that are undesirable in many microfluidic applications such as perfusion culture, droplet microfluidics, etc. Existing methods to maintain a constant gravity-driven flow either require additional control equipment, involve complex fabrication or operation, are incompatible with miniaturization, or introduce interfaces that lack robustness. Here we tackled those problems by introducing a 3D-printed compact hydraulic head auto-regulating module that automatically maintains a constant fluid level at the microfluidic inlet port without human intervention. Our module successfully maintained a constant hydraulic head for more than 24 h, with the operation time solely limited by the reservoir capacity. A comparison with the conventional gravity-driven flow demonstrated our device's capability to produce a more stable flow over the perfusion period. Overall, our module creates a simple, robust solution to produce a stable flow rate in gravity-driven flow systems. The compactness of the design allows easy parallelization and compatibility with high-throughput applications, and the biocompatibility of the materials enables the device's use with life science applications.</p>","PeriodicalId":18560,"journal":{"name":"Microsystems & Nanoengineering","volume":"11 1","pages":"113"},"PeriodicalIF":7.3,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144182858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Onboard visual micro-servoing on robotic surgery tools.","authors":"Xu Chen, Michail E Kiziroglou, Eric M Yeatman","doi":"10.1038/s41378-025-00955-x","DOIUrl":"https://doi.org/10.1038/s41378-025-00955-x","url":null,"abstract":"<p><p>Precision motion actuation is a key technology for miniature medical robotics in a variety of applications, such as optical fibre-based diagnosis and intervention tools. Conventional inductive actuation mechanisms are challenging to scale down. Piezoelectric materials offer a scalable, precise, fast and high-force method but at a limited displacement range. In previous work, the combination of piezoelectric beams (benders) with compliant motion translation structures has been shown to be promising for robotic micro-actuation. In this paper, this approach is employed to implement a three degrees of freedom delta robot, suitable for catheter, diagnostic optical fibre and microsurgery tool manipulation. The fabrication process combines additive manufacturing, origami structuring and piezoelectric beam assembly. Closed-loop control is implemented using a new, on-board visual feedback concept. In contrast to typical optical motion systems, the fully internal visual feedback offers system compactness with precise and reliable camera-to-marker geometry definition. By employment of this method, a delta robot with motion accuracy of 7.5 μm, resolution of 10 μm and 8.1 μm precision is demonstrated. The robot is shown to follow a range of programmable trajectories under these specifications, and to compensate for externally applied forces typically expected during microsurgery manipulations. This is the first, to our knowledge, demonstration of micromotion control using internal visual feedback, and it opens up the way for high-resolution compact microrobots.</p>","PeriodicalId":18560,"journal":{"name":"Microsystems & Nanoengineering","volume":"11 1","pages":"112"},"PeriodicalIF":7.3,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144181115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jie Ding, Chang He, Hongliang Ma, Wendong Zhang, Xuge Fan
{"title":"Suspended graphene-based NEMS accelerometers with direct electrical readout.","authors":"Jie Ding, Chang He, Hongliang Ma, Wendong Zhang, Xuge Fan","doi":"10.1038/s41378-025-00969-5","DOIUrl":"https://doi.org/10.1038/s41378-025-00969-5","url":null,"abstract":"<p><p>Atomically thin suspended graphene can be used as NEMS transducers for ultra-small and high-performance sensors due to its excellent mechanical and electrical properties. Most applications of suspended graphene in NEMS devices are limited to pressure sensors, resonators, switches, etc. Graphene-based NEMS accelerometers have rarely been reported, with limitations such as mechanical robustness, life span and device yield, thereby limiting their practical applications. Here, we reported piezoresistive graphene-based NEMS accelerometers with high manufacturing yield, excellent mechanical robustness and stability, and long life span, in which the width of trenches for suspending graphene membranes was only 1 µm and fully-clamped suspended double-layer graphene membranes with an attached SiO<sub>2</sub>/Si proof mass was used as acceleration transducer. The impact of geometrical sizes of the proof mass attached to the suspended graphene membranes on the output signal of devices has been studied. These findings would contribute to rapid developments and practical applications of ultra-small and high-performance graphene-based NEMS accelerometers and related devices.</p>","PeriodicalId":18560,"journal":{"name":"Microsystems & Nanoengineering","volume":"11 1","pages":"111"},"PeriodicalIF":7.3,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144174220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jenny Ka-Hei Wat, Miao Xu, Lang Nan, Haisong Lin, Kelvin Kai-Wang To, Ho Cheung Shum, Sammer Uɩ Hassan
{"title":"Rapid antimicrobial susceptibility tests performed by self-diluting microfluidic chips for drug resistance studies and point-of-care diagnostics.","authors":"Jenny Ka-Hei Wat, Miao Xu, Lang Nan, Haisong Lin, Kelvin Kai-Wang To, Ho Cheung Shum, Sammer Uɩ Hassan","doi":"10.1038/s41378-025-00938-y","DOIUrl":"10.1038/s41378-025-00938-y","url":null,"abstract":"<p><p>Antimicrobial resistance (AMR) is a global public health issue. Rapid and accurate antimicrobial susceptibility tests (AST) on bacteria isolates would facilitate appropriate choice of antibiotics, in which patients receive appropriate treatment and the emergence of multidrug-resistant organisms could be prevented simultaneously. In this study, we have developed a microfluidic device named Self Dilution for Faster Antimicrobial Susceptibility Testing (SDFAST). This SlipChip-based device consists of two layers of microchips, allowing injection of bacterial suspension and antibiotics by simply connecting the two chips. By slipping one microchip against another in a single press of the microchip, the antibiotics can be diluted within seconds and be well mixed with bacterial samples. By combining SDFAST with a water-soluble tetrazolium salt-8 (WST-8) assay, a range of clinically prevalent bacteria, including Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, and Staphylococci species, were tested under various antibiotics. Color analysis after 4-6 h of incubation showed an abrupt change in the WST-8 color of certain wells with diluted antibiotics, proving that instrument-free and immediate identification of minimum inhibitory concentration (MIC) could be achieved. The testing on 51 clinical isolates had an agreement of 92%, proving the accuracy of our method. These results validated its advantages of simple operation, rapid testing, and low sample consumption comparing to conventional methods, which require 16-24 h of incubation. Therefore, our method shows great potential to be further developed into a medical instrument for automated medical testing and point-of-care diagnosis.</p>","PeriodicalId":18560,"journal":{"name":"Microsystems & Nanoengineering","volume":"11 1","pages":"110"},"PeriodicalIF":7.3,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144160247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Study on polishing mechanisms of BEOL metal interconnects based on chemical and mechanical synergy.","authors":"Zhiqiang Tian, Shizhao Wang, Rui Li, Xiang Sun, Wei Shen, Sheng Liu","doi":"10.1038/s41378-025-00883-w","DOIUrl":"10.1038/s41378-025-00883-w","url":null,"abstract":"<p><p>Chemical mechanical polishing (CMP) is the sole process capable of achieving the required flatness and surface roughness for photolithography without any obvious distortion in the multilevel metal interconnects. As semiconductor manufacturing advances to the next process node, the introduction of new materials and structures has proposed higher performance standards for polishing slurries, resulting in the slurry composition becoming increasingly critical to the overall polishing process. In this work, ReaxFF-based molecular dynamics (MD) is employed to investigate the copper (Cu) CMP process in various slurries, aiming to uncover the chemical interactions of different components and the atomistic mechanisms involved in Cu atom removal. The results demonstrate that the presence of H<sub>2</sub>O<sub>2</sub> cannot only directly oxidize the Cu atoms on the substrate surface, but also inhibit the adsorption of H<sub>2</sub>O on the Cu surface and promote the dissociation of the adsorbed H<sub>2</sub>O to indirectly oxidize the Cu atoms. The Cu complexes Cu-C<sub>2</sub>H<sub>5</sub>O<sub>2</sub>N and Cu-H<sub>2</sub>C<sub>2</sub>O<sub>4</sub> are generated during the reaction due to the addition of glycine and oxalic acid, respectively. The oxidation of H<sub>2</sub>O<sub>2</sub> and the complexation of glycine and oxalic acid significantly enhance the Cu removal. Furthermore, Cu atoms tend to be removed in the form of clusters, and the removal rate is the highest in the mixed solution of H<sub>2</sub>O<sub>2</sub> and glycine. The surface roughness after polishing is 0.082 nm, which closely aligns with the atomic force microscopy (AFM) experimental data of 0.104 nm. This work sheds light on the role of different components in the polishing slurry, which is of great significance to the design of the CMP slurry components for more advanced process nodes.</p>","PeriodicalId":18560,"journal":{"name":"Microsystems & Nanoengineering","volume":"11 1","pages":"109"},"PeriodicalIF":7.3,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144160249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Tetrahedral-modified magnetic nanorobotic probe for enhanced imaging of cancer-related miRNA.","authors":"Xue Wu, Huijie Bai, Lingfeng Jiang, Cuiping Mao, Yi Li, Diangeng Li, Yong Wang, Shan Liu, Jinhong Guo","doi":"10.1038/s41378-025-00927-1","DOIUrl":"10.1038/s41378-025-00927-1","url":null,"abstract":"<p><p>Sensitive and rapid imaging of intracellular cancer-related miRNA holds great potential for early diagnosis and treatment monitoring of cancer. However, most imaging probes are constructed on nanoparticles that rely on passive diffusion to interact and bind with the target substance, resulting a long response time and a low target recognition capability due to the solution viscous resistance. Herein, we reported a DNA tetrahedral-modified magnetic nanorobotic probe (MNP) that performed framework nucleic acid-located catalytic hairpin assembly (CHA) reaction on the surface of magnetically driven nanorobot. The tetrahedral structure not only endowed the MNP with extremely high structural stability and perfect cell-uptake performance, but its spatial confinement effect made the signal amplification of the hairpin cascade more rapid and efficient. Additionally, the active movement of MNPs enhanced the micro-mixing of fluids and accelerated target capture, significantly reducing reaction time and improving reaction kinetics. This strategy exhibited the enhanced fluorescence signal and can accurately distinguish between miR-21 and various other miRNA sequences. Moreover, the feasibility and versatility of MNPs were also successfully verified in normal and various cancer cells imaging. Therefore, the proposed MNPs are promising candidates for the detection of intracellular biomarkers and extend the design space of self-propelled micro/nanorobots in the field of cancer diagnosis and therapy.</p>","PeriodicalId":18560,"journal":{"name":"Microsystems & Nanoengineering","volume":"11 1","pages":"108"},"PeriodicalIF":7.3,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144160251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiashuai Xu, Zijun Ren, Fangsheng Qian, Junyan Zheng, Yansong Yang
{"title":"A wafer-level sealed silicon cavity microacoustic platform for radio frequency integration.","authors":"Jiashuai Xu, Zijun Ren, Fangsheng Qian, Junyan Zheng, Yansong Yang","doi":"10.1038/s41378-025-00958-8","DOIUrl":"10.1038/s41378-025-00958-8","url":null,"abstract":"<p><p>This study presents a wafer-level sealed silicon cavity (SSC) microacoustic integration platform to address the limitations in the cavity Silicon-on-Insulator (C-SOI) wafers for the 5G/6G wireless communication system. The proposed SSC platform features an extremely smooth suspended membrane with adjustable thickness, flexible cavity shapes with high density, self-formed acoustic wave confinement steps, stable temperature coefficient of frequency (TCF), and highly integrated compatibility with complementary metal-oxide semiconductor (CMOS). A surface smoothing method based on wet oxidation for SSC wafers is presented, which achieves a root mean square (RMS) roughness on the cavity surface of 1.5 nm for the first time. Based on the presented SSC platform, an Al<sub>0.75</sub>Sc<sub>0.25</sub>N sealed cavity bulk acoustic wave resonator (S-BAR) is designed, fabricated, and characterized. The experimental results show that the asymmetric second-order (A2) Lamb mode of S-BAR is enhanced for higher frequency with a maximum piezoelectric coupling coefficient ( <math> <msubsup><mrow><mi>k</mi></mrow> <mrow><mi>t</mi></mrow> <mrow><mn>2</mn></mrow> </msubsup> </math> ) of 9.53%, a maximum quality factor (Q) of 439, and a TCF of -11.44 ppm/K. Different designs' piezoelectric coupling coefficient distribution is consistent with the theoretical prediction. The proposed smoothing process increases the S-BARs' quality factor by ~400%. The frequency shift caused by the temperature (absolute value of TCF) is reduced by 62% compared with the traditional Al<sub>0.75</sub>Sc<sub>0.25</sub>N thin film bulk acoustic wave resonator (without temperature compensation). The enhanced performances demonstrated the potential of SSC in the next-generation highly integrated RF communication systems.</p>","PeriodicalId":18560,"journal":{"name":"Microsystems & Nanoengineering","volume":"11 1","pages":"107"},"PeriodicalIF":7.3,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12106694/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144151096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Special Issue 2025: Micro and nano technologies in the UK.","authors":"Ian H White, Tianhong Cui","doi":"10.1038/s41378-025-00965-9","DOIUrl":"10.1038/s41378-025-00965-9","url":null,"abstract":"","PeriodicalId":18560,"journal":{"name":"Microsystems & Nanoengineering","volume":"11 1","pages":"104"},"PeriodicalIF":7.3,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12106690/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144151115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 local de-insulation method and its application in neural microneedle array.","authors":"Xin Zhao, Chunrong Wei, Deguang Zhu, Xiaowei Yang, Guowei Han, Jin Ning, Qiang Gui, Rongyu Tang, Yijun Wang, Jingfeng Zhou, Zhaoxin Geng, Weihua Pei","doi":"10.1038/s41378-025-00922-6","DOIUrl":"10.1038/s41378-025-00922-6","url":null,"abstract":"<p><p>Silicon-based neural microneedle arrays, such as the Utah Array, have demonstrated excellent performance in chronic recordings from the cerebral cortex. Unlike planar thin-film electrodes with recording sites arranged on the surface of a silicon film, the recording sites of microneedle arrays are located at the tips of three-dimensional needles, which significantly complicates the fabrication process required for single-neuron recordings. To address this challenge, we develop a local de-insulation method for microneedle recording electrodes that eliminates the need for etching: the microneedle tips are encapsulated in a controllable-thickness protective layer, followed by deposition of a Parylene-C insulation layer. By optimizing the elasticity of the protection material, as well as its adhesion and shape on both the protective layer and the electrode shaft, we were able to precisely control the area of the removed insulated layers, resulting in consistent tip exposure. Experimental results show that the non-uniformity of the exposed microneedle recording sites in the silicon-based neural microelectrode arrays (each has 10 × 10 array) fabricated using this method is 3.32 ± 1.02%. Furthermore, the arrays exhibited high stability and reliability in both mechanical performance and electrical characteristics. They achieved an average spike signal-to-noise ratio of 12.63 ± 6.64 during in vivo testing. This fabrication technique provides a valuable method for the development of high-performance neural microelectrode array.</p>","PeriodicalId":18560,"journal":{"name":"Microsystems & Nanoengineering","volume":"11 1","pages":"103"},"PeriodicalIF":7.3,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12106818/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144151083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dongyang Wang, Hailing Xue, Long Xia, Zongqi Li, Yubo Zhao, Xinan Fan, Kai Sun, Huanan Wang, Timo Hamalainen, Chi Zhang, Fengyu Cong, Yanhua Li, Fei Song, Jiaqi Lin
{"title":"A tough semi-dry hydrogel electrode with anti-bacterial properties for long-term repeatable non-invasive EEG acquisition.","authors":"Dongyang Wang, Hailing Xue, Long Xia, Zongqi Li, Yubo Zhao, Xinan Fan, Kai Sun, Huanan Wang, Timo Hamalainen, Chi Zhang, Fengyu Cong, Yanhua Li, Fei Song, Jiaqi Lin","doi":"10.1038/s41378-025-00908-4","DOIUrl":"10.1038/s41378-025-00908-4","url":null,"abstract":"<p><p>Non-invasive brain-computer interfaces (NI-BCIs) have garnered significant attention due to their safety and wide range of applications. However, developing non-invasive electroencephalogram (EEG) electrodes that are highly sensitive, comfortable to wear, and reusable has been challenging due to the limitations of conventional electrodes. Here, we introduce a simple method for fabricating semi-dry hydrogel EEG electrodes with antibacterial properties, enabling long-term, repeatable acquisition of EEG. By utilizing N-acryloyl glycinamide and hydroxypropyltrimethyl ammonium chloride chitosan, we have prepared electrodes that not only possess good mechanical properties (compression modulus 65 kPa) and anti-fatigue properties but also exhibit superior antibacterial properties. These electrodes effectively inhibit the growth of both Gram-negative (E. coli) and Gram-positive (S. epidermidis) bacteria. Furthermore, the hydrogel maintains stable water retention properties, resulting in an average contact impedance of <400 Ω measured over 12 h, and an ionic conductivity of 0.39 mS cm<sup>-1</sup>. Cytotoxicity and skin irritation tests have confirmed the high biocompatibility of the hydrogel electrodes. In an N170 event-related potential (ERP) test on human volunteers, we successfully captured the expected ERP signal waveform and a high signal-to-noise ratio (20.02 dB), comparable to that of conventional wet electrodes. Moreover, contact impedance on the scalps remained below 100 kΩ for 12 h, while wet electrodes became unable to detect signals after 7-8 h due to dehydration. In summary, our hydrogel electrodes are capable of detecting ERPs over extended periods in an easy-to-use manner with antibacterial properties. This reduces the risk of bacterial infection associated with prolonged reuse and expands the potential of NI-BCIs in daily life.</p>","PeriodicalId":18560,"journal":{"name":"Microsystems & Nanoengineering","volume":"11 1","pages":"105"},"PeriodicalIF":7.3,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12106760/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144151088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}