Pub Date : 2021-04-16DOI: 10.3390/MICROMACHINES2021-09589
R. R. Souza, V. Faustino, I. Gonçalves, J. Miranda, A. Moita, A. Moreira, M. Bañobre‐López, R. Lima
: Fluids containing nanometer-sized particles (nanofluids, NFs) are potential candidates to improve the performance and efficiency of several thermal devices at micro- and macro-scale levels. However, the problem of sedimentation and instability of these colloidal dispersions has been the biggest obstacle for industrial-scale applications. In this work, two different NFs were tested using distilled water (DI-Water) as the base fluid. The first is a traditional NF formed by Al2O3 nanoparticles (NPs) with 50 nm diameter, and the second is a novel NF formed by poly (acrylic acid)-coated iron oxide NPs (Fe3O4@PAA) with ~10 nm diameter, obtained through a hydrothermal synthesis process. The main objective of this study was to evaluate the colloidal stability of these NFs over time using different volume fractions and compare it with DI-Water. Results involving sedimentation studies and zeta potential measurements showed that the proposed Fe3O4@PAA NF presents a higher colloidal stability compared to that of the Al2O3 NF. Additionally, thermal conductivity measurements were performed in both Fe3O4@PAA and Al2O3 NFs at different NP concentrations, using the transient plane source technique. Results showed higher thermal conductivity values for the Fe3O4@PAA NFs compared to those of Al2O3 NFs. However, a linear enhancement of thermal conductivity with increasing NPs concentration was observed for the Al2O3 NF over the whole range of NP concentrations tested, whereas two different regimes were observed for the Fe3O4@PAA NF.
{"title":"Experimental studies of the sedimentation, stability and thermal conductivity of two different nanofluids","authors":"R. R. Souza, V. Faustino, I. Gonçalves, J. Miranda, A. Moita, A. Moreira, M. Bañobre‐López, R. Lima","doi":"10.3390/MICROMACHINES2021-09589","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09589","url":null,"abstract":": Fluids containing nanometer-sized particles (nanofluids, NFs) are potential candidates to improve the performance and efficiency of several thermal devices at micro- and macro-scale levels. However, the problem of sedimentation and instability of these colloidal dispersions has been the biggest obstacle for industrial-scale applications. In this work, two different NFs were tested using distilled water (DI-Water) as the base fluid. The first is a traditional NF formed by Al2O3 nanoparticles (NPs) with 50 nm diameter, and the second is a novel NF formed by poly (acrylic acid)-coated iron oxide NPs (Fe3O4@PAA) with ~10 nm diameter, obtained through a hydrothermal synthesis process. The main objective of this study was to evaluate the colloidal stability of these NFs over time using different volume fractions and compare it with DI-Water. Results involving sedimentation studies and zeta potential measurements showed that the proposed Fe3O4@PAA NF presents a higher colloidal stability compared to that of the Al2O3 NF. Additionally, thermal conductivity measurements were performed in both Fe3O4@PAA and Al2O3 NFs at different NP concentrations, using the transient plane source technique. Results showed higher thermal conductivity values for the Fe3O4@PAA NFs compared to those of Al2O3 NFs. However, a linear enhancement of thermal conductivity with increasing NPs concentration was observed for the Al2O3 NF over the whole range of NP concentrations tested, whereas two different regimes were observed for the Fe3O4@PAA NF.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127711671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-16DOI: 10.3390/MICROMACHINES2021-09576
S. Saddow
Silicon Carbide (SiC) is a highly versatile semiconductor material that has long been used in harsh applications such as space, corrosive and high-temperature environments and, more recently, the human body. The impressive and highly advantageous materials properties of SiC have shown that this material is ideally suited for medical applications due to its proven bio- and hemocompatibility. Indeed, SiC appears to be quite unique for use in the human brain whereby implants made using SiC coatings have demonstrated vastly improved performance with virtually no human body immune response which plagues Silicon technology. After over two decades of focused research and development SiC is now ready for use in the healthcare sector and this paper provides an up to date assessment of SiC devices for long-term human use. First the plethora of applications that SiC is uniquely positioned for in human healthcare is reviewed so that healthcare professionals will be fully aware of the significant opportunities now possible with the rapid development of this technology. Next progress in two areas will be presented: Neural implants and deep-tissue cancer therapy using SiC nanotechnology.
{"title":"Silicon Carbide for Advanced In-Vivo Medical Devices","authors":"S. Saddow","doi":"10.3390/MICROMACHINES2021-09576","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09576","url":null,"abstract":"Silicon Carbide (SiC) is a highly versatile semiconductor material that has long been used in harsh applications such as space, corrosive and high-temperature environments and, more recently, the human body. The impressive and highly advantageous materials properties of SiC have shown that this material is ideally suited for medical applications due to its proven bio- and hemocompatibility. Indeed, SiC appears to be quite unique for use in the human brain whereby implants made using SiC coatings have demonstrated vastly improved performance with virtually no human body immune response which plagues Silicon technology. After over two decades of focused research and development SiC is now ready for use in the healthcare sector and this paper provides an up to date assessment of SiC devices for long-term human use. First the plethora of applications that SiC is uniquely positioned for in human healthcare is reviewed so that healthcare professionals will be fully aware of the significant opportunities now possible with the rapid development of this technology. Next progress in two areas will be presented: Neural implants and deep-tissue cancer therapy using SiC nanotechnology.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121669755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-16DOI: 10.3390/MICROMACHINES2021-09594
M. Pustan, C. Bîrleanu, F. Șerdean
The influence of the driving electrode positions on the dynamic response of polysilicon MEMS resonators used in biosensing applications is studied as a function of the operating conditions (vacuum versus free-air operating mode). The scope of this research work is orientated to identify the effect of driving electrode position on the dynamic response of sensing MEMS used in bio-mass detection. The mass-deposition detection is based on the change in the resonant frequency of vibrating elements considering a biological detection film deposited on the oscillating structure. The operating conditions, such as medium pressure, change the behavior of the dynamic response including the resonant frequency, the amplitude, and the velocity of oscillations as well as the quality factor and the loss of energy. The change in the dynamic response of the investigated MEMS cantilevers as function of the lower electrode position and operating conditions is evaluated using a Polytec Laser Vibrometer. The decrease in the amplitude and velocity of the oscillations if the lower electrode is moved from the beam free-end toward the beam anchor is experimentally monitored. The changes in the response of samples in vacuum are slightly influenced by the electrode position compared with the response of the same sample in ambient conditions. Moreover, the effect of oscillating modes (1st, 2nd and 3rd modes) is taken into consideration to improve the dynamical detection of the investigated samples. The obtained results indicate that, different responses of MEMS resonators can be achieved if the position of the driving electrode is moved from the cantilever free-end toward the anchor. Indeed, the resonator stiffness, velocity and amplitude of oscillations are significantly modified for samples oscillating in ambient conditions for biological detection compared with their response in vacuum.
{"title":"Dynamic characterization of biosensing MEMS cantilevers with different position of the driving electrode - vacuum response versus ambient conditions","authors":"M. Pustan, C. Bîrleanu, F. Șerdean","doi":"10.3390/MICROMACHINES2021-09594","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09594","url":null,"abstract":"The influence of the driving electrode positions on the dynamic response of polysilicon MEMS resonators used in biosensing applications is studied as a function of the operating conditions (vacuum versus free-air operating mode). The scope of this research work is orientated to identify the effect of driving electrode position on the dynamic response of sensing MEMS used in bio-mass detection. The mass-deposition detection is based on the change in the resonant frequency of vibrating elements considering a biological detection film deposited on the oscillating structure. The operating conditions, such as medium pressure, change the behavior of the dynamic response including the resonant frequency, the amplitude, and the velocity of oscillations as well as the quality factor and the loss of energy. The change in the dynamic response of the investigated MEMS cantilevers as function of the lower electrode position and operating conditions is evaluated using a Polytec Laser Vibrometer. The decrease in the amplitude and velocity of the oscillations if the lower electrode is moved from the beam free-end toward the beam anchor is experimentally monitored. The changes in the response of samples in vacuum are slightly influenced by the electrode position compared with the response of the same sample in ambient conditions. Moreover, the effect of oscillating modes (1st, 2nd and 3rd modes) is taken into consideration to improve the dynamical detection of the investigated samples. The obtained results indicate that, different responses of MEMS resonators can be achieved if the position of the driving electrode is moved from the cantilever free-end toward the anchor. Indeed, the resonator stiffness, velocity and amplitude of oscillations are significantly modified for samples oscillating in ambient conditions for biological detection compared with their response in vacuum.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130881406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-16DOI: 10.3390/MICROMACHINES2021-09588
Maryam Fatehifar, A. Revell, M. Jabbari
Microfluidics enables generating series of isolated droplets for high-throughput screening. As many biological/chemical solutions are of shear thinning non-Newtonian nature, we studied non-Newtonian droplet generation to improve the reliability of simulation results in real-life assays. We considered non-Newtonian power-law behaviour for Xanthan gum aqueous solution as the dispersed phase, and Newtonian canola oil as the continuous phase. Simulations were performed in OpenFOAM, using the inter foam solver and volume of fluid (VOF) method. A cross-junction geometry with each inlet and outlet channel height (H) and width (W) equal to 50 micrometers with slight contractions in the conjunctions was used to gain a better monodispersity. Following validation of the numerical setup, we conducted a series of tests to provide novel insight into this configuration. With a capillary number, of 0.01, dispersed phase to continuous phase flow-rate ratio of 0.05, and contact angle of 160°, simulations revealed that, by increasing the Xanthan gum concentration (0, 800, 1500, 2500 ppm) or, in other words, decreasing the n-flow behaviour index from 1 to 0.491, 0.389, and 0.302 in power-law model, (a) breakup of the dispersed phase thread occurred at 0.0365, 0.0430, 0.0440, and 0.0450 s; (b) the dimensionless width of the thread at the main channel entrance increased from 0 to 0.066, 0.096, and 0.16; and (c) the dimensionless droplet diameter decreased from 0.76 to 0.72, 0.68, and 0.67, respectively. Our next plan is to study effect of shear-thinning behaviour on droplet generation in different Ca and flow-rate ratios.
{"title":"Droplet formation in a cross-junction microfluidic channel with non-Newtonian dispersed phase","authors":"Maryam Fatehifar, A. Revell, M. Jabbari","doi":"10.3390/MICROMACHINES2021-09588","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09588","url":null,"abstract":"Microfluidics enables generating series of isolated droplets for high-throughput screening. As many biological/chemical solutions are of shear thinning non-Newtonian nature, we studied non-Newtonian droplet generation to improve the reliability of simulation results in real-life assays. We considered non-Newtonian power-law behaviour for Xanthan gum aqueous solution as the dispersed phase, and Newtonian canola oil as the continuous phase. Simulations were performed in OpenFOAM, using the inter foam solver and volume of fluid (VOF) method. A cross-junction geometry with each inlet and outlet channel height (H) and width (W) equal to 50 micrometers with slight contractions in the conjunctions was used to gain a better monodispersity. Following validation of the numerical setup, we conducted a series of tests to provide novel insight into this configuration. With a capillary number, of 0.01, dispersed phase to continuous phase flow-rate ratio of 0.05, and contact angle of 160°, simulations revealed that, by increasing the Xanthan gum concentration (0, 800, 1500, 2500 ppm) or, in other words, decreasing the n-flow behaviour index from 1 to 0.491, 0.389, and 0.302 in power-law model, (a) breakup of the dispersed phase thread occurred at 0.0365, 0.0430, 0.0440, and 0.0450 s; (b) the dimensionless width of the thread at the main channel entrance increased from 0 to 0.066, 0.096, and 0.16; and (c) the dimensionless droplet diameter decreased from 0.76 to 0.72, 0.68, and 0.67, respectively. Our next plan is to study effect of shear-thinning behaviour on droplet generation in different Ca and flow-rate ratios.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124594691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-16DOI: 10.3390/MICROMACHINES2021-09584
Inês C. F. Pereira, H. Wyss, H. Beckers, J. Toonder
Glaucoma is the second leading cause of preventable blindness worldwide, following cataract formation. A rise in the intraocular pressure (IOP) is a major risk factor for this disease, and results from an elevated resistance to aqueous humor outflow from the anterior chamber of the eye. Glaucoma drainage devices provide an alternative pathway through which the aqueous humor can effectively exit the eye, thereby lowering the IOP. However, post-operative IOP is unpredictable and current implants are deficient in maintaining IOP at optimal levels. To address this deficiency, we are developing an innovative, non-invasive magnetically actuated glaucoma implant with a hydrodynamic resistance that can be adjusted following surgery. This adjustment is achieved by integrating a magnetically actuated microvalve into the implant, which can open or close fluidic channels using an external magnetic stimulus. This microvalve was fabricated from poly(styrene–block–isobutylene–block–styrene), or ‘SIBS’, containing homogeneously dispersed magnetic microparticles. “Micro-pencil” valves of this material were fabricated using a combination of femtosecond laser machining with hot embossing. The glaucoma implant is comprised of a drainage tube and a housing element fabricated from two thermally bonded SIBS layers with the microvalve positioned in between. Microfluidic experiments involving actuating the magnetic micro-pencil with a moving external magnet confirmed the valving function. A pressure difference of around 6 mmHg was achieved, which is sufficient to overcome hypotony (i.e., too low IOP)—one of the most common post-operative complications following glaucoma surgery.
{"title":"Magnetically actuated glaucoma drainage device with adjustable flow properties after implantation","authors":"Inês C. F. Pereira, H. Wyss, H. Beckers, J. Toonder","doi":"10.3390/MICROMACHINES2021-09584","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09584","url":null,"abstract":"Glaucoma is the second leading cause of preventable blindness worldwide, following cataract formation. A rise in the intraocular pressure (IOP) is a major risk factor for this disease, and results from an elevated resistance to aqueous humor outflow from the anterior chamber of the eye. Glaucoma drainage devices provide an alternative pathway through which the aqueous humor can effectively exit the eye, thereby lowering the IOP. However, post-operative IOP is unpredictable and current implants are deficient in maintaining IOP at optimal levels. To address this deficiency, we are developing an innovative, non-invasive magnetically actuated glaucoma implant with a hydrodynamic resistance that can be adjusted following surgery. This adjustment is achieved by integrating a magnetically actuated microvalve into the implant, which can open or close fluidic channels using an external magnetic stimulus. This microvalve was fabricated from poly(styrene–block–isobutylene–block–styrene), or ‘SIBS’, containing homogeneously dispersed magnetic microparticles. “Micro-pencil” valves of this material were fabricated using a combination of femtosecond laser machining with hot embossing. The glaucoma implant is comprised of a drainage tube and a housing element fabricated from two thermally bonded SIBS layers with the microvalve positioned in between. Microfluidic experiments involving actuating the magnetic micro-pencil with a moving external magnet confirmed the valving function. A pressure difference of around 6 mmHg was achieved, which is sufficient to overcome hypotony (i.e., too low IOP)—one of the most common post-operative complications following glaucoma surgery.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115258562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-16DOI: 10.3390/MICROMACHINES2021-09581
Hiromichi Hashimoto, Mitsuru Sentoku, Kento Iida, K. Yasuda
The collective cell migration is thought to be a dynamic and interactive behavior of cell cohorts which is essential for diverse physiological developments in living organisms. Recent studies revealed that topographical properties of the environment regulate the migration modes of cell cohorts, such as diffusion versus contraction relaxation transport and the appearance of vortices in larger available space. However, conventional in vitro assays fail to observe the change in cells behavior in response to the structural changes. Here, we have developed a method to fabricate the flexible three-dimensional structures of capillary microtunnels to examine the behavior of vascular endothelial cells (ECs). The microtunnels with altering diameters were formed inside gelatin-gel by spot heating a portion of gelatin by irradiating the µm-sized absorption at the tip of the microneedle with a focused permeable 1064 nm infrared laser. The ECs moved and spread two-dimensionally on the inner surface of capillary microtunnels as monolayer instead of filling the capillary. In contrast to the 3D straight topographical constraint, which exhibited width dependence migration velocity, leading ECs altered its migration velocity accordingly to the change in supply of the cells behind the leading ECs, caused by the progression through the diameter altering structure. Our findings provide insights into the collective migration properties in 3D confinement structures as fluid-like behavior with conservation of cell numbers.
{"title":"Development of Gelatin-Based Flexible Three-Dimensional Capillary Pattern Microfabrication Technology for Analysis of Collective Cell Migration","authors":"Hiromichi Hashimoto, Mitsuru Sentoku, Kento Iida, K. Yasuda","doi":"10.3390/MICROMACHINES2021-09581","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09581","url":null,"abstract":"The collective cell migration is thought to be a dynamic and interactive behavior of cell cohorts which is essential for diverse physiological developments in living organisms. Recent studies revealed that topographical properties of the environment regulate the migration modes of cell cohorts, such as diffusion versus contraction relaxation transport and the appearance of vortices in larger available space. However, conventional in vitro assays fail to observe the change in cells behavior in response to the structural changes. Here, we have developed a method to fabricate the flexible three-dimensional structures of capillary microtunnels to examine the behavior of vascular endothelial cells (ECs). The microtunnels with altering diameters were formed inside gelatin-gel by spot heating a portion of gelatin by irradiating the µm-sized absorption at the tip of the microneedle with a focused permeable 1064 nm infrared laser. The ECs moved and spread two-dimensionally on the inner surface of capillary microtunnels as monolayer instead of filling the capillary. In contrast to the 3D straight topographical constraint, which exhibited width dependence migration velocity, leading ECs altered its migration velocity accordingly to the change in supply of the cells behind the leading ECs, caused by the progression through the diameter altering structure. Our findings provide insights into the collective migration properties in 3D confinement structures as fluid-like behavior with conservation of cell numbers.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125886379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-16DOI: 10.3390/MICROMACHINES2021-09590
Jacob L. Binsley, E. L. Martin, Thomas O Myers, S. Pagliara, F. Ogrin
Many lab-on-a-chip devices require a connection to an external pumping system in order to perform their function. While this is not problematic in typical laboratory environments, it is not always practical when applied to point-of-care testing, which is best utilised outside of the laboratory. Therefore, there has been a large amount of ongoing research into producing integrated microfluidic components capable of generating effective fluid flow from on-board the device. This research aims to introduce a system which can produce practical flow rates, and be easily fabricated and actuated using readily available techniques and materials. We show how an asymmetric elasto-magnetic system, inspired by Purcell’s 3-link swimmer can provide this solution through the generation of non-reciprocal motion in an enclosed environment. The device is fabricated monolithically within a microfluidic channel at the time of manufacture, and is actuated using a weak, oscillating magnetic field. The flow rate can be altered dynamically, and the resultant flow direction can be reversed by adjusting the frequency of the driving field. The device is proven, experimentally and numerically, to operate effectively when applied to fluids with a range of viscosities. Such a device may be able to replace external pumping systems in more portable applications.
{"title":"Elasto-Magnetic Pumps Integrated within Microfluidic Devices","authors":"Jacob L. Binsley, E. L. Martin, Thomas O Myers, S. Pagliara, F. Ogrin","doi":"10.3390/MICROMACHINES2021-09590","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09590","url":null,"abstract":"Many lab-on-a-chip devices require a connection to an external pumping system in order to perform their function. While this is not problematic in typical laboratory environments, it is not always practical when applied to point-of-care testing, which is best utilised outside of the laboratory. Therefore, there has been a large amount of ongoing research into producing integrated microfluidic components capable of generating effective fluid flow from on-board the device. This research aims to introduce a system which can produce practical flow rates, and be easily fabricated and actuated using readily available techniques and materials. We show how an asymmetric elasto-magnetic system, inspired by Purcell’s 3-link swimmer can provide this solution through the generation of non-reciprocal motion in an enclosed environment. The device is fabricated monolithically within a microfluidic channel at the time of manufacture, and is actuated using a weak, oscillating magnetic field. The flow rate can be altered dynamically, and the resultant flow direction can be reversed by adjusting the frequency of the driving field. The device is proven, experimentally and numerically, to operate effectively when applied to fluids with a range of viscosities. Such a device may be able to replace external pumping systems in more portable applications.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127739049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-15DOI: 10.3390/micromachines2021-09572
Gungun Lin, Yuan Liu, Guan Huang, Yinghui Chen, D. Makarov, D. Jin
Magnetic microrobots with versatile mechanical motion will enable many ex- and in vivo applications. Unfortunately, monolithic integration of multiple functions in a streamlined microrobotic body is still challenging due to the compromise between fabrication throughput, device footprints, and material choices. In this talk, I will present a unified framework architecture for microrobotic functionalization to enable magnetically steered locomotion, chemical sensing and in vivo tracking. This has been achieved through stratifying stimuli-responsive nanoparticles in a hydrogelmicro-disk. We uncovered the key mechanism of leveraging spatially alternating magnetic energy potential to control a Euler’s disk-like microrobot to locomote swiftly on its sidewall. The results suggest great potential for microrobots to locomote while cooperating a wide range of functions, tailorable for universal application scenarios.
{"title":"Rotating Micromachines with Stratified Disk Architecture for Dynamic Bioanalysis","authors":"Gungun Lin, Yuan Liu, Guan Huang, Yinghui Chen, D. Makarov, D. Jin","doi":"10.3390/micromachines2021-09572","DOIUrl":"https://doi.org/10.3390/micromachines2021-09572","url":null,"abstract":"Magnetic microrobots with versatile mechanical motion will enable many ex- and in vivo applications. Unfortunately, monolithic integration of multiple functions in a streamlined microrobotic body is still challenging due to the compromise between fabrication throughput, device footprints, and material choices. In this talk, I will present a unified framework architecture for microrobotic functionalization to enable magnetically steered locomotion, chemical sensing and in vivo tracking. This has been achieved through stratifying stimuli-responsive nanoparticles in a hydrogelmicro-disk. We uncovered the key mechanism of leveraging spatially alternating magnetic energy potential to control a Euler’s disk-like microrobot to locomote swiftly on its sidewall. The results suggest great potential for microrobots to locomote while cooperating a wide range of functions, tailorable for universal application scenarios.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127467355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-14DOI: 10.3390/micromachines2021-09545
W. Yeo, Nathan Rodeheaver
Wearable electronics are changing healthcare and increasing possibilities for human-machine interfaces. Soft electronics, directly mounted on the skin, can monitor long-term heart rate trends or direct smart prosthetics' motion. However, these capabilities are only as good as the signal quality obtained. These wearable devices are worn in the real world, often suffering from motion artifacts not previously found when measured in a stationary setting such as a clinic or laboratory. Motion artifacts can mimic many biosignals by having a similar amplitude and frequency range, making them hard to filter out. A significant source of motion artifacts is from relative motion between the sensor and the signal source. Given human tissue's elastic nature, most body-mounted sensors undergo more relative motion than on a comparable rigid machine. Here, this work introduces a comprehensive study of materials, methods, and optimized designs that can significantly reduce motion artifacts via strain isolation, increased adhesion, and enhanced breathability for long-term recordings. Skin strain is another source of motion artifacts that can disturb electrodes' contact impedance and temporarily change the biopotential within the skin. We present a prototype electrocardiogram (ECG) device that uses a strain isolating layer to reduce skin strain at the electrode. This strategic integration of soft and hard materials reduces motion artifacts by stabilizing the electrode, while allowing freedom of movement elsewhere to maintain gentle contact with the skin. These solutions are demonstrated for long-term ECG collection but have application for any skin-mounted wearable device.
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Pub Date : 2021-04-14DOI: 10.3390/MICROMACHINES2021-09570
K. Uchino
Energy harvesting from wasted or unused power has been a topic of discussion for a long time. We developed ‘damper devices’ for precision machinery and automobile engine mats in the 1980s. However, in the 1990s we realized that electric energy dissipation on its own was useless, and started to accumulate the converted electric energy into a rechargeable battery. Historically, this was the starting point of ‘piezoelectric energy harvesting devices’.
{"title":"Misconceptions in Piezoelectric Energy Harvesting System Development","authors":"K. Uchino","doi":"10.3390/MICROMACHINES2021-09570","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09570","url":null,"abstract":"Energy harvesting from wasted or unused power has been a topic of discussion for a long time. We developed ‘damper devices’ for precision machinery and automobile engine mats in the 1980s. However, in the 1990s we realized that electric energy dissipation on its own was useless, and started to accumulate the converted electric energy into a rechargeable battery. Historically, this was the starting point of ‘piezoelectric energy harvesting devices’.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117114121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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