Pub Date : 2024-08-23DOI: 10.1088/1361-6439/ad6e98
Tao Wang, Xue Shang, Hu Wang, Jilai Wang, Chengpeng Zhang
Porous nanofibers are widely used in the fields of water treatment, sensors, energy storage and biomedicine. In this paper, environmentally friendly polylactic acid material was used to achieve controlled fabrication of porous nanofibers using electrostatic spinning technology. Taking fiber diameter and fiber aperture as evaluation indexes, the effects of process parameters on the formation of porous nanofiber were investigated respectively through single-factor experiments, including solution concentration, solvent ratio and feed rate. The results showed that the solution concentration and feed rate were the most important parameters affecting fiber diameter, and the solvent ratio was the most important parameter affecting fiber aperture. The coupling effect of these three parameters was analyzed using response surface experiments and controlled fabrication of porous nanofibers was achieved with diameters ranging from 1.470 to 3.298 μm and apertures ranging from 0.062 to 0.22 μm.
{"title":"Experimental investigation of electrostatic spinning of polylactic acid porous nanofibers","authors":"Tao Wang, Xue Shang, Hu Wang, Jilai Wang, Chengpeng Zhang","doi":"10.1088/1361-6439/ad6e98","DOIUrl":"https://doi.org/10.1088/1361-6439/ad6e98","url":null,"abstract":"Porous nanofibers are widely used in the fields of water treatment, sensors, energy storage and biomedicine. In this paper, environmentally friendly polylactic acid material was used to achieve controlled fabrication of porous nanofibers using electrostatic spinning technology. Taking fiber diameter and fiber aperture as evaluation indexes, the effects of process parameters on the formation of porous nanofiber were investigated respectively through single-factor experiments, including solution concentration, solvent ratio and feed rate. The results showed that the solution concentration and feed rate were the most important parameters affecting fiber diameter, and the solvent ratio was the most important parameter affecting fiber aperture. The coupling effect of these three parameters was analyzed using response surface experiments and controlled fabrication of porous nanofibers was achieved with diameters ranging from 1.470 to 3.298 <italic toggle=\"yes\">μ</italic>m and apertures ranging from 0.062 to 0.22 <italic toggle=\"yes\">μ</italic>m.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"7 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224654","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}
Pub Date : 2024-08-22DOI: 10.1088/1361-6439/ad6f1d
P Ramya Priya, K S Deepak, Satish Kumar Dubey, Sanket Goel
Purified DNA and Polymerase Chain Reaction (PCR) are crucial parts of molecular biology techniques in various fields such as genomics, forensics, and diagnostics. The proposed microfluidic device is used to perform several steps like the adsorption of DNA present in processed PCR onto bare magnetic beads, cleaning of contaminants with ethanol-diluted buffer reagent, and eluting the adsorbed DNA in an elution buffer, which is further used for downstream application. The entire sample purification is accomplished in about 25 min. A comparative analysis is conducted using a commercially available DNA purification kit. By employing the suggested microfluidic chip alongside the commercial kit, a commercial spectrophotometer is utilized to measure the purity. This is done by obtaining the A260/A280 ratio, which allows for the assessment of both the quantity and purity of the extracted DNA. The A260/A280 ratios for the spin column-based, magnetic stand-based, and microfluidic chip- based tests were 1.86, 1.98, and 1.74, respectively. The analysis of the eluted DNA findings indicated that the quality was suitable for future PCR amplification. Additionally, this microchip-based device has the potential to be utilized as a bedside device for DNA purification in point of care applications, with a purification time of 25 min.
纯化 DNA 和聚合酶链式反应（PCR）是基因组学、法医学和诊断学等各个领域分子生物学技术的重要组成部分。拟议的微流体设备用于执行几个步骤，如将处理过的 PCR 中的 DNA 吸附到裸磁珠上，用乙醇稀释的缓冲试剂清除杂质，将吸附的 DNA 在洗脱缓冲液中洗脱，洗脱缓冲液将进一步用于下游应用。整个样品纯化过程大约需要 25 分钟。我们使用市售的 DNA 纯化试剂盒进行了对比分析。在使用建议的微流控芯片和商用试剂盒的同时，还使用了商用分光光度计来测量纯度。通过获得 A260/A280 比率，可以评估提取 DNA 的数量和纯度。旋柱式、磁力架式和微流控芯片式测试的 A260/A280 比率分别为 1.86、1.98 和 1.74。对洗脱 DNA 的分析结果表明，其质量适于今后的 PCR 扩增。此外，这种基于微芯片的设备还可用作床旁设备，在护理点应用中进行 DNA 纯化，纯化时间为 25 分钟。
{"title":"Nucleic acid purification through nanoarchitectonics: magnetic bead integration with microfluidic chip technology","authors":"P Ramya Priya, K S Deepak, Satish Kumar Dubey, Sanket Goel","doi":"10.1088/1361-6439/ad6f1d","DOIUrl":"https://doi.org/10.1088/1361-6439/ad6f1d","url":null,"abstract":"Purified DNA and Polymerase Chain Reaction (PCR) are crucial parts of molecular biology techniques in various fields such as genomics, forensics, and diagnostics. The proposed microfluidic device is used to perform several steps like the adsorption of DNA present in processed PCR onto bare magnetic beads, cleaning of contaminants with ethanol-diluted buffer reagent, and eluting the adsorbed DNA in an elution buffer, which is further used for downstream application. The entire sample purification is accomplished in about 25 min. A comparative analysis is conducted using a commercially available DNA purification kit. By employing the suggested microfluidic chip alongside the commercial kit, a commercial spectrophotometer is utilized to measure the purity. This is done by obtaining the A260/A280 ratio, which allows for the assessment of both the quantity and purity of the extracted DNA. The A260/A280 ratios for the spin column-based, magnetic stand-based, and microfluidic chip- based tests were 1.86, 1.98, and 1.74, respectively. The analysis of the eluted DNA findings indicated that the quality was suitable for future PCR amplification. Additionally, this microchip-based device has the potential to be utilized as a bedside device for DNA purification in point of care applications, with a purification time of 25 min.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"23 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142188747","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}
Pub Date : 2024-08-22DOI: 10.1088/1361-6439/ad6dfe
Kazim Haider, Thomas Lijnse, Wenting Shu, Eoin O’Cearbhaill, Colin Dalton
Microneedles are a promising technology for pain-free and efficient pharmaceutical delivery. However, their clinical translation is currently limited by the absence of standardized testing methods for critical quality attributes (CQAs), such as mechanical robustness, which are essential for demonstrating safety and efficacy during regulatory review. A key aspect of mechanical robustness is transverse load capacity, which is currently assessed using diverse, non-standardized methods, which have limited capability to measure transverse failure forces at different heights along a microneedle. This is critical for understanding mechanics of potential failure modes during insertion after skin penetration. In this work we utilize a wire bond shear tester, a piece of test equipment widely used in the semiconductor industry, to measure the transverse load capacities of various microneedle designs. This approach is compatible with diverse microneedle types, geometries, and materials, and offers high-throughput and automated testing capabilities with high precision. We measure transverse failure loads with micron-scale control over the test height and have established comprehensive profiles of mechanical robustness along the length of different microneedle designs, which is a capability not previously demonstrated in literature for polymeric and metal microneedles. Transverse failure forces were 10 ± 0.3 gf–128 ± 12 gf for wire bonded gold and silver microneedles, 11 ± 0.7 gf–480 ± 69 gf for conical and pyramidal polymeric microneedles, and 206 ± 80 gf–381 ± 1 gf for 3D printed conical stainless steel microneedles. Additionally, we present standardized definitions for microneedle structural failure modes resulting from transverse loads, which can facilitate root cause failure analysis and defect detection during design and manufacturing, and aid in risk assessment of microneedle products. This work establishes a standardized approach to evaluating a significant CQA of microneedle products, which is a critical step towards expediting their clinical adoption.
{"title":"From microchips to microneedles: semiconductor shear testers as a universal solution for transverse load analysis of microneedle mechanical performance","authors":"Kazim Haider, Thomas Lijnse, Wenting Shu, Eoin O’Cearbhaill, Colin Dalton","doi":"10.1088/1361-6439/ad6dfe","DOIUrl":"https://doi.org/10.1088/1361-6439/ad6dfe","url":null,"abstract":"Microneedles are a promising technology for pain-free and efficient pharmaceutical delivery. However, their clinical translation is currently limited by the absence of standardized testing methods for critical quality attributes (CQAs), such as mechanical robustness, which are essential for demonstrating safety and efficacy during regulatory review. A key aspect of mechanical robustness is transverse load capacity, which is currently assessed using diverse, non-standardized methods, which have limited capability to measure transverse failure forces at different heights along a microneedle. This is critical for understanding mechanics of potential failure modes during insertion after skin penetration. In this work we utilize a wire bond shear tester, a piece of test equipment widely used in the semiconductor industry, to measure the transverse load capacities of various microneedle designs. This approach is compatible with diverse microneedle types, geometries, and materials, and offers high-throughput and automated testing capabilities with high precision. We measure transverse failure loads with micron-scale control over the test height and have established comprehensive profiles of mechanical robustness along the length of different microneedle designs, which is a capability not previously demonstrated in literature for polymeric and metal microneedles. Transverse failure forces were 10 ± 0.3 gf–128 ± 12 gf for wire bonded gold and silver microneedles, 11 ± 0.7 gf–480 ± 69 gf for conical and pyramidal polymeric microneedles, and 206 ± 80 gf–381 ± 1 gf for 3D printed conical stainless steel microneedles. Additionally, we present standardized definitions for microneedle structural failure modes resulting from transverse loads, which can facilitate root cause failure analysis and defect detection during design and manufacturing, and aid in risk assessment of microneedle products. This work establishes a standardized approach to evaluating a significant CQA of microneedle products, which is a critical step towards expediting their clinical adoption.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"45 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142188723","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}
Pub Date : 2024-08-07DOI: 10.1088/1361-6439/ad690e
Faizan Tariq Beigh, Nadeem Tariq Beigh and Dhiman Mallick
This paper presents an optimized, lithographically patternable SU-8/Graphene nanocomposite based piezoresistive strain sensor for localized, high-precision assessment, which marks a significant advancement in the field of soft-MEMS based technologies. The fabrication process involves the photolithography of a SU-8/Graphene nanocomposite with a minimum resolution of 50 μm, resulting in a material with excellent electrical conductivity and mechanical properties. Specifically, a 3% SU-8/Graphene composition was chosen to exceed the percolation threshold, enabling substantial changes in the resistance and facilitating photopatternability. The sensor exhibited exceptional performance characteristics, including a rapid response time of 0.1 s and a wide bending range from 0° to 60°. Notably, it demonstrated a remarkable %ΔR/R of 19.21, indicating its superior sensing capability. Such high sensitivity is crucial for applications that require precise, localized measurements, such as biomedical engineering, sports science, and smart healthcare.
{"title":"Lithographically patternable SU-8/Graphene nanocomposite based strain sensors for soft-MEMS applications","authors":"Faizan Tariq Beigh, Nadeem Tariq Beigh and Dhiman Mallick","doi":"10.1088/1361-6439/ad690e","DOIUrl":"https://doi.org/10.1088/1361-6439/ad690e","url":null,"abstract":"This paper presents an optimized, lithographically patternable SU-8/Graphene nanocomposite based piezoresistive strain sensor for localized, high-precision assessment, which marks a significant advancement in the field of soft-MEMS based technologies. The fabrication process involves the photolithography of a SU-8/Graphene nanocomposite with a minimum resolution of 50 μm, resulting in a material with excellent electrical conductivity and mechanical properties. Specifically, a 3% SU-8/Graphene composition was chosen to exceed the percolation threshold, enabling substantial changes in the resistance and facilitating photopatternability. The sensor exhibited exceptional performance characteristics, including a rapid response time of 0.1 s and a wide bending range from 0° to 60°. Notably, it demonstrated a remarkable %ΔR/R of 19.21, indicating its superior sensing capability. Such high sensitivity is crucial for applications that require precise, localized measurements, such as biomedical engineering, sports science, and smart healthcare.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"12 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141948234","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}
This article proposes an efficient analytical model and strategy for designing curved piezoelectric micromachined ultrasonic transducers (curved PMUTs). The model is developed based on the Donnell–Mushtari–Vlasov theory and the equivalent single layer method, and validated through finite element analysis. Utilizing the model, we further analyze the diaphragm’s vibration modes and key design parameters. The proposed strategy is centered on 2 design equations, facilitating the rapid design of devices at any frequency through parametric sweeps. Furthermore, to minimize bandwidth loss, we employ the merging of adjacent vibration modes to broaden the bandwidth. Using the proposed method for modes merging, we have effortlessly designed devices with operating frequencies of 2.15 MHz, 6.3 MHz, 10.65 MHz, and 18.75 MHz in water. For comparison, we also designed planar PMUTs and general curved PMUTs operating around 6 MHz and 15 MHz. Compared to planar PMUTs, curved PMUTs show exceptional performance improvements in output pressure and sensitivity. Moreover, the proposed strategy for bandwidth extension results in 1.33× and 1.25× bandwidth improvements around 6 MHz and 15 MHz. The proposed design methodology is anticipated to assist engineers in designing high-performance PMUT arrays more efficiently and systematically.
{"title":"Efficient strategy for frequency design and bandwidth extension of curved piezoelectric ultrasonic micromachined transducers","authors":"Hao Li, Xiaofan Hu, Xingli Xu, Yongquan Ma, Chenyang Yu, Wei Wei and Pengfei Niu","doi":"10.1088/1361-6439/ad690d","DOIUrl":"https://doi.org/10.1088/1361-6439/ad690d","url":null,"abstract":"This article proposes an efficient analytical model and strategy for designing curved piezoelectric micromachined ultrasonic transducers (curved PMUTs). The model is developed based on the Donnell–Mushtari–Vlasov theory and the equivalent single layer method, and validated through finite element analysis. Utilizing the model, we further analyze the diaphragm’s vibration modes and key design parameters. The proposed strategy is centered on 2 design equations, facilitating the rapid design of devices at any frequency through parametric sweeps. Furthermore, to minimize bandwidth loss, we employ the merging of adjacent vibration modes to broaden the bandwidth. Using the proposed method for modes merging, we have effortlessly designed devices with operating frequencies of 2.15 MHz, 6.3 MHz, 10.65 MHz, and 18.75 MHz in water. For comparison, we also designed planar PMUTs and general curved PMUTs operating around 6 MHz and 15 MHz. Compared to planar PMUTs, curved PMUTs show exceptional performance improvements in output pressure and sensitivity. Moreover, the proposed strategy for bandwidth extension results in 1.33× and 1.25× bandwidth improvements around 6 MHz and 15 MHz. The proposed design methodology is anticipated to assist engineers in designing high-performance PMUT arrays more efficiently and systematically.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"13 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141948233","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}
Pub Date : 2024-07-17DOI: 10.1088/1361-6439/ad5c6d
Aaron J Yeiser, Emma F Wawrzynek, John Z Zhang, Lukas Graf, Christopher I McHugh, Ioannis Kymissis, Elizabeth S Olson, Jeffrey H Lang and Hideko Heidi Nakajima
Objective. We present the ‘UmboMic,’ a prototype piezoelectric cantilever microphone designed for future use with totally-implantable cochlear implants. Methods. The UmboMic sensor is made from polyvinylidene difluoride (PVDF) because of its low Young’s modulus and biocompatibility. The sensor is designed to fit in the middle ear and measure the motion of the underside of the eardrum at the umbo. To maximize its performance, we developed a low noise charge amplifier in tandem with the UmboMic sensor. This paper presents the performance of the UmboMic sensor and amplifier in fresh cadaveric human temporal bones. Results. When tested in human temporal bones, the UmboMic apparatus achieves an equivalent input noise of 32.3 dB SPL over the frequency range 100 Hz–7 kHz, good linearity, and a flat frequency response to within 10 dB from about 100 Hz–6 kHz. Conclusion. These results demonstrate the feasibility of a PVDF-based microphone when paired with a low-noise amplifier. The reported UmboMic apparatus is comparable in performance to a conventional hearing aid microphone. Significance. The proof-of-concept UmboMic apparatus is a promising step towards creating a totally-implantable cochlear implant. A completely internal system would enhance the quality of life of cochlear implant users.
{"title":"The UmboMic: a PVDF cantilever microphone *","authors":"Aaron J Yeiser, Emma F Wawrzynek, John Z Zhang, Lukas Graf, Christopher I McHugh, Ioannis Kymissis, Elizabeth S Olson, Jeffrey H Lang and Hideko Heidi Nakajima","doi":"10.1088/1361-6439/ad5c6d","DOIUrl":"https://doi.org/10.1088/1361-6439/ad5c6d","url":null,"abstract":"Objective. We present the ‘UmboMic,’ a prototype piezoelectric cantilever microphone designed for future use with totally-implantable cochlear implants. Methods. The UmboMic sensor is made from polyvinylidene difluoride (PVDF) because of its low Young’s modulus and biocompatibility. The sensor is designed to fit in the middle ear and measure the motion of the underside of the eardrum at the umbo. To maximize its performance, we developed a low noise charge amplifier in tandem with the UmboMic sensor. This paper presents the performance of the UmboMic sensor and amplifier in fresh cadaveric human temporal bones. Results. When tested in human temporal bones, the UmboMic apparatus achieves an equivalent input noise of 32.3 dB SPL over the frequency range 100 Hz–7 kHz, good linearity, and a flat frequency response to within 10 dB from about 100 Hz–6 kHz. Conclusion. These results demonstrate the feasibility of a PVDF-based microphone when paired with a low-noise amplifier. The reported UmboMic apparatus is comparable in performance to a conventional hearing aid microphone. Significance. The proof-of-concept UmboMic apparatus is a promising step towards creating a totally-implantable cochlear implant. A completely internal system would enhance the quality of life of cochlear implant users.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"47 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141741813","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}
Pub Date : 2024-07-17DOI: 10.1088/1361-6439/ad5b00
Ayaka Nakama and Takashi Yasuda
When a single neuron is cultured in isolation from other neurons, its axon connects with its own dendrites to form a simple, independent network with no synaptic inputs from other neurons. This culture system enables detailed analysis of synaptic function and morphology change in neurites at the single-neuron level, which is useful for elucidating the pathogenesis of neurological diseases and for evaluating the efficacy of therapeutic drugs for them. However, there was previously no device technology capable of simultaneously forming multiple single-neuron samples while allowing co-culture with astrocytes, which is essential for culture of a single neuron isolated from other neurons. In this study, we propose a novel microwell-array device for preparing single-neuron samples. The device consists of an upper layer for cell seeding and a lower layer for cell culture. Each layer has 16 × 16 microwells, and the bottom of each well is made of a 1 μm thick silicon nitride membrane. The membrane of the upper well has one microhole for seeding a single neuron, and the lower membrane has multiple microholes for interaction between a single neuron and astrocytes which are co-cultured back-to-back on both sides of the membrane. When neurons are seeded into the upper well, only one of them passes through the microhole in the upper membrane and falls onto the lower membrane. We evaluated a seeding efficiency of single neurons by changing seeding hole diameter and seeding density. The results showed that the yield of more than 20% was obtained regardless of the seeding density when the seeding hole diameter was 13 μm. We also confirmed that single neurons seeded in this manner and co-cultured with astrocytes developed neurites and formed synapses. These results demonstrated the usefulness of this device for the preparation of single-neuron culture samples.
{"title":"Two-layered microwell-array device for preparation of single-neuron culture samples","authors":"Ayaka Nakama and Takashi Yasuda","doi":"10.1088/1361-6439/ad5b00","DOIUrl":"https://doi.org/10.1088/1361-6439/ad5b00","url":null,"abstract":"When a single neuron is cultured in isolation from other neurons, its axon connects with its own dendrites to form a simple, independent network with no synaptic inputs from other neurons. This culture system enables detailed analysis of synaptic function and morphology change in neurites at the single-neuron level, which is useful for elucidating the pathogenesis of neurological diseases and for evaluating the efficacy of therapeutic drugs for them. However, there was previously no device technology capable of simultaneously forming multiple single-neuron samples while allowing co-culture with astrocytes, which is essential for culture of a single neuron isolated from other neurons. In this study, we propose a novel microwell-array device for preparing single-neuron samples. The device consists of an upper layer for cell seeding and a lower layer for cell culture. Each layer has 16 × 16 microwells, and the bottom of each well is made of a 1 μm thick silicon nitride membrane. The membrane of the upper well has one microhole for seeding a single neuron, and the lower membrane has multiple microholes for interaction between a single neuron and astrocytes which are co-cultured back-to-back on both sides of the membrane. When neurons are seeded into the upper well, only one of them passes through the microhole in the upper membrane and falls onto the lower membrane. We evaluated a seeding efficiency of single neurons by changing seeding hole diameter and seeding density. The results showed that the yield of more than 20% was obtained regardless of the seeding density when the seeding hole diameter was 13 μm. We also confirmed that single neurons seeded in this manner and co-cultured with astrocytes developed neurites and formed synapses. These results demonstrated the usefulness of this device for the preparation of single-neuron culture samples.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"6 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141741815","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}
Pub Date : 2024-07-11DOI: 10.1088/1361-6439/ad5dc7
Partha Sarkar and Ajay M Sidpara
Microneedle (MN) arrays have many applications in biomedical engineering to deliver drugs transdermally or extract biomarkers from the interstitial fluid from the human skin. Several methods have been developed to fabricate different sizes and shapes of MN using polymers, ceramics and metals. However, most of these methods require expensive sophisticated machines and clean room facilities. So, it is difficult to fabricate microneedle arrays in large quantities at a reasonable cost. This study reports the fabrication of a high-quality stainless steel master pattern for an MN array using a wire-cut electric discharge machining process followed by electrochemical polishing (ECP). Different densities of a 5 × 5 array of microneedles with pyramidal shapes were fabricated by machining channels onto the workpiece surface in a criss-cross pattern. A systematic experimental study was carried out with reference to the offset between the two consecutive channel faces and the depth of channels. The output parameters are MN height (MNH), MN base (MNBW) and tip width (MNTW). The average needle tip width, base width, and height of microneedles were found to be 55.3 ± 5 µm, 679.8 ± 10 µm, and 914.7 ± 19 µm. Finally, the sharpness of the MN tips and the overall surface finish of the MN array were improved with ECP. The reductions in MNH, MNBW, and MNTW were reported to be −18.3%, −9.7%, and −95.4%, respectively, with a final tip width of 2.55 ± 1.62 µm. The MNs’ tip angle was reported to be 32.52° ± 1.56.
{"title":"Fabrication of microneedles using wire electric discharge machining and improving surface quality by electrochemical polishing","authors":"Partha Sarkar and Ajay M Sidpara","doi":"10.1088/1361-6439/ad5dc7","DOIUrl":"https://doi.org/10.1088/1361-6439/ad5dc7","url":null,"abstract":"Microneedle (MN) arrays have many applications in biomedical engineering to deliver drugs transdermally or extract biomarkers from the interstitial fluid from the human skin. Several methods have been developed to fabricate different sizes and shapes of MN using polymers, ceramics and metals. However, most of these methods require expensive sophisticated machines and clean room facilities. So, it is difficult to fabricate microneedle arrays in large quantities at a reasonable cost. This study reports the fabrication of a high-quality stainless steel master pattern for an MN array using a wire-cut electric discharge machining process followed by electrochemical polishing (ECP). Different densities of a 5 × 5 array of microneedles with pyramidal shapes were fabricated by machining channels onto the workpiece surface in a criss-cross pattern. A systematic experimental study was carried out with reference to the offset between the two consecutive channel faces and the depth of channels. The output parameters are MN height (MNH), MN base (MNBW) and tip width (MNTW). The average needle tip width, base width, and height of microneedles were found to be 55.3 ± 5 µm, 679.8 ± 10 µm, and 914.7 ± 19 µm. Finally, the sharpness of the MN tips and the overall surface finish of the MN array were improved with ECP. The reductions in MNH, MNBW, and MNTW were reported to be −18.3%, −9.7%, and −95.4%, respectively, with a final tip width of 2.55 ± 1.62 µm. The MNs’ tip angle was reported to be 32.52° ± 1.56.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"78 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141608477","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}
Pub Date : 2024-07-10DOI: 10.1088/1361-6439/ad5dc6
Chao Xie, Leijie Lai, Yunzhuang Chen and Limin Zhu
In this paper, a novel large stroke six degrees-of-freedom (6-DOF) electromagnetic redundant actuated micropositioning stage is proposed. The 6-DOF stage adopts a configuration that is composed of eight parallel driving branch chains. Each branch chain is driven by a voice coil motor and incorporates a parallelogram flexure mechanism and a decoupling mechanism for guidance and decoupling. The positioning stage is symmetrically arranged and possesses the advantages of simple structure and easy assembly. As a result, assembly errors are significantly reduced and positioning accuracy is enhanced. The decoupling mechanism uses a large stroke flexible ball joint that increases the motion range of the positioning stage and decouples the coupled motion, thereby enhancing the stability and accuracy of the stage. To evaluate the performance of the stage, static and dynamic analytical models of the 6-DOF stage are derived based on the compliance matrix method and the Lagrangian dynamic modeling method. Additionally, the accuracy of the analytical models and the static and dynamic performances of the positioning stage are verified through finite element analysis (FEA) and experimental testing. The experimental results demonstrate that the stage realizes a workspace of 2.06 mm × 2.02 mm × 3.1 mm × 23.4 mrad × 23.1 mrad × 14.9 mrad. Finally, to verify the tracking performance trajectory of the 6-DOF positioning stage, tracking experiments are performed using a controller that combines a proportional-integral controller and a notch filter.
本文提出了一种新型大行程六自由度（6-DOF）电磁冗余致动微定位平台。6-DOF 平台采用由八条平行驱动支链组成的结构。每个支链由音圈电机驱动，并包含一个平行四边形挠性机构和一个用于导向和退耦的退耦机构。定位平台采用对称布置，具有结构简单、易于装配等优点。因此，装配误差大大降低，定位精度也得到了提高。解耦机构采用大行程柔性球形关节，既增加了定位平台的运动范围，又实现了耦合运动的解耦，从而提高了平台的稳定性和精度。为了评估平台的性能，基于顺应矩阵法和拉格朗日动态建模法，推导出了 6-DOF 平台的静态和动态分析模型。此外，还通过有限元分析（FEA）和实验测试验证了分析模型的准确性以及定位平台的静态和动态性能。实验结果表明，该平台可实现 2.06 mm × 2.02 mm × 3.1 mm × 23.4 mrad × 23.1 mrad × 14.9 mrad 的工作空间。最后，为了验证 6-DOF 定位平台的跟踪性能轨迹，使用比例积分控制器和陷波滤波器相结合的控制器进行了跟踪实验。
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Pub Date : 2024-07-09DOI: 10.1088/1361-6439/ad5cfd
Srinivasan Raman and Ravi Sankar A
The integration of electronic functionalities into textiles has been under extensive research as its application is witnessed in various fields, including sensing, energy generation, storage, displays, and interfaces. Textiles endowed with flexibility, comfort, lightweight, and washability have been tested as reliable base materials to implement various physical sensors, of which strain and pressure sensors have shown great potential in applications such as healthcare, fitness tracking, and human-machine interaction. Piezoresistive physical sensors have considerable advantages over capacitive and piezoelectric sensors made of textiles. Apart from fibers, yarns, and threads, two-dimensional textile stripes occupy a significant share as substrates in these sensors. This review article discusses the recent progress of 2D textile-based piezoresistive strain and pressure sensors. It covers the latest works in this domain, focusing on different textile choices, conductive material combinations, fabrication methods, additional functionalities like heating, features like hydrophobic properties, and various applications, with tabulations of key performance metrics. For researchers seeking an update on the state of the field, this review would be helpful as it offers insights into trends for further research and product development aimed at meeting the demands of advanced healthcare and other applications.
{"title":"Recent progress in 2D textile-based piezoresistive strain and pressure sensors","authors":"Srinivasan Raman and Ravi Sankar A","doi":"10.1088/1361-6439/ad5cfd","DOIUrl":"https://doi.org/10.1088/1361-6439/ad5cfd","url":null,"abstract":"The integration of electronic functionalities into textiles has been under extensive research as its application is witnessed in various fields, including sensing, energy generation, storage, displays, and interfaces. Textiles endowed with flexibility, comfort, lightweight, and washability have been tested as reliable base materials to implement various physical sensors, of which strain and pressure sensors have shown great potential in applications such as healthcare, fitness tracking, and human-machine interaction. Piezoresistive physical sensors have considerable advantages over capacitive and piezoelectric sensors made of textiles. Apart from fibers, yarns, and threads, two-dimensional textile stripes occupy a significant share as substrates in these sensors. This review article discusses the recent progress of 2D textile-based piezoresistive strain and pressure sensors. It covers the latest works in this domain, focusing on different textile choices, conductive material combinations, fabrication methods, additional functionalities like heating, features like hydrophobic properties, and various applications, with tabulations of key performance metrics. For researchers seeking an update on the state of the field, this review would be helpful as it offers insights into trends for further research and product development aimed at meeting the demands of advanced healthcare and other applications.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"40 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141567685","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}
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