Pub Date : 2021-04-23DOI: 10.3390/micromachines2021-09617
L. Baraban
Synergy between, physics, material sciences and biotechnology during last decade has led to a tremendous scientific progress in the fields of biodetection and nanomedicine. This tight interaction led to the emergence of a new class of bioinspired systems that enables to bring the area of biosensorics e.g. for cell or molecular diagnostics and analytics to the new level. The advances are expected in terms of (i) possibility of early diagnostics of diseases due to the increased sensitivity of the detectors, (ii) real time and high throughput analysis offered by combination of integrated electronics and microfluidic approach, and (iii) establishing the new functional formats for the bioassays. One of the most promising candidates for the future diagnostics are the electronic nanobiosensors that have attracted great attention in the last decades since they provide rich quantitative information for medical and biotechnological assays without pre-treatment and specific optical labelling of the detected species. At the same time, to bring state‐of‐the‐art biomedical diagnostic devices to the hands of the people, it is important to reduce the price of the devices and allow for their high‐volume delivery in a cost‐efficient manner, e.g., container transportation. For the latter, a crucial aspect is to reduce the weight of the device. This can be achieved by replacing the conventional rigid substrates, like Si or glass by light weight and large area polymeric foils. Here I will focus on two flexible diagnostic platforms for the analysis at the micro- and nanoscale, represented by (a) silicon nanowires based field effect transistors and (b) 2D materials based on molybdenum disulfide. [1] Karnaushenko, et al., Adv. Healthc. Mater. 4(10), 1517 (2015). [2] Zhang, et al., Small 15 (23), 1901265 (2019). [3] Baraban, et al. Advanced Science 6 (15), 1900522 (2019).
{"title":"Nanoscopic Biosensors in Microfluidics","authors":"L. Baraban","doi":"10.3390/micromachines2021-09617","DOIUrl":"https://doi.org/10.3390/micromachines2021-09617","url":null,"abstract":"Synergy between, physics, material sciences and biotechnology during last decade has led to a tremendous scientific progress in the fields of biodetection and nanomedicine. This tight interaction led to the emergence of a new class of bioinspired systems that enables to bring the area of biosensorics e.g. for cell or molecular diagnostics and analytics to the new level. The advances are expected in terms of (i) possibility of early diagnostics of diseases due to the increased sensitivity of the detectors, (ii) real time and high throughput analysis offered by combination of integrated electronics and microfluidic approach, and (iii) establishing the new functional formats for the bioassays. One of the most promising candidates for the future diagnostics are the electronic nanobiosensors that have attracted great attention in the last decades since they provide rich quantitative information for medical and biotechnological assays without pre-treatment and specific optical labelling of the detected species. \u0000At the same time, to bring state‐of‐the‐art biomedical diagnostic devices to the hands of the people, it is important to reduce the price of the devices and allow for their high‐volume delivery in a cost‐efficient manner, e.g., container transportation. For the latter, a crucial aspect is to reduce the weight of the device. This can be achieved by replacing the conventional rigid substrates, like Si or glass by light weight and large area polymeric foils. \u0000Here I will focus on two flexible diagnostic platforms for the analysis at the micro- and nanoscale, represented by (a) silicon nanowires based field effect transistors and (b) 2D materials based on molybdenum disulfide. \u0000 \u0000[1] Karnaushenko, et al., Adv. Healthc. Mater. 4(10), 1517 (2015). \u0000[2] Zhang, et al., Small 15 (23), 1901265 (2019). \u0000[3] Baraban, et al. Advanced Science 6 (15), 1900522 (2019).","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127475059","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 : 2021-04-21DOI: 10.3390/MICROMACHINES2021-09605
R. Parra-Saldívar, V. H. Perez‐Gonzalez, C. M. Galicia‐Medina, Matías Vázquez-Piñón, S. Camacho-Léon, G. S. Alemán-Nava, R. C. Gallo-Villanueva, S. Martínez-Chapa, M. Madou, J. Garcia-Perez, D. Esquivel-Hernández
: The use of microalgae as a biomass source for biofuel production has drawn the attention of many scientists due to several associated environmental advantages over conventional terrestrial crops, including microalgae growing using wastewaters and a higher CO 2 fixation rate, contributing to the reduction of atmospheric concentration. Consequently, a reliable cytoplasmic lipid screening process in microalgae is a valuable asset for harvesting optimization in mass production processes. In this study, the heterogeneous cytoplasmic lipid content of Neochloris oleoabundans was dielec-trophoretically assorted in a microfluidic device using castellated carbon microelectrodes. The ex-periments carried out over a wide frequency window (100 kHz to 30 MHz) at a fixed amplitude of 7 VPP showed a significant contrast between the dielectrophoretic behavior of high lipid content and low lipid content cells at the low frequency range (100–800 kHz). A weak response for the mid and high frequency ranges (1–30 MHz) was also identified for high and low lipid content samples, allowing one to establish an electrokinetic footprint of the studied strain. These results suggest that the development of a reliable screening process for harvesting optimization is possible through a fast and straightforward mechanism, such as dielectrophoresis, which is a low-cost and easy-to-machine material that employs glassy carbon. The experimental setup in this study involved in vitro culturing of nitrogen-replete (N+) and nitrogen-deplete (N-) cell suspensions to promote low and high lipid production in cells, respectively. Cell populations were monitored using spectrophotom-etry, and the resulting lipid development among cells was quantified by Nile red fluorescence.
{"title":"Rapid lipid content screening in Neochloris Oleoabundans by carbon-based dielectrophoresis","authors":"R. Parra-Saldívar, V. H. Perez‐Gonzalez, C. M. Galicia‐Medina, Matías Vázquez-Piñón, S. Camacho-Léon, G. S. Alemán-Nava, R. C. Gallo-Villanueva, S. Martínez-Chapa, M. Madou, J. Garcia-Perez, D. Esquivel-Hernández","doi":"10.3390/MICROMACHINES2021-09605","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09605","url":null,"abstract":": The use of microalgae as a biomass source for biofuel production has drawn the attention of many scientists due to several associated environmental advantages over conventional terrestrial crops, including microalgae growing using wastewaters and a higher CO 2 fixation rate, contributing to the reduction of atmospheric concentration. Consequently, a reliable cytoplasmic lipid screening process in microalgae is a valuable asset for harvesting optimization in mass production processes. In this study, the heterogeneous cytoplasmic lipid content of Neochloris oleoabundans was dielec-trophoretically assorted in a microfluidic device using castellated carbon microelectrodes. The ex-periments carried out over a wide frequency window (100 kHz to 30 MHz) at a fixed amplitude of 7 VPP showed a significant contrast between the dielectrophoretic behavior of high lipid content and low lipid content cells at the low frequency range (100–800 kHz). A weak response for the mid and high frequency ranges (1–30 MHz) was also identified for high and low lipid content samples, allowing one to establish an electrokinetic footprint of the studied strain. These results suggest that the development of a reliable screening process for harvesting optimization is possible through a fast and straightforward mechanism, such as dielectrophoresis, which is a low-cost and easy-to-machine material that employs glassy carbon. The experimental setup in this study involved in vitro culturing of nitrogen-replete (N+) and nitrogen-deplete (N-) cell suspensions to promote low and high lipid production in cells, respectively. Cell populations were monitored using spectrophotom-etry, and the resulting lipid development among cells was quantified by Nile red fluorescence.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132892914","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 : 2021-04-21DOI: 10.3390/micromachines2021-09606
B. Jurado‐Sánchez, A. Escarpa, Kaisong Yuan
Janus micromotors are a unique class of materials whose surfaces have two or more distinct physical properties, allowing thus for two types of chemistry to occur simultaneously. Judicious design of the micromotor structure allows to incorporate different functionalities in a single unit to adapt the propulsion behaviour along with the incorporation of specific receptors for a myriad of applications. Herein we report the preparation of graphene oxide (GO)/PtNPs/Fe2O3 Janus micromotors for highly selective capture/inactivation of gram-positive bacteria units and biofilms. The strategy is based on the combination of a lanbiotic (Nisin) with Janus micromotors. Lanbiotics are peptides composed of methyllanthionine residues with a highly selective antimicrobial activity towards multidrug resistant bacteria. Nisin is a natural compound normally used for food preservation, which display specific antimicrobial activity towards gram-positive bacteria. Such peptide can bind to lipid II unit of the bacteria membranes, damaging its morphology and releasing its contents. The coating of micromotors with GO impart them with a Janus structure for the subsequent asymmetric assembly of catalytic (PtNPs) and magnetic (Fe2O3) engines and results in an active rough layer for a higher loading of Nisin via covalent interactions. The micromotors possess adaptative propulsion mechanisms, including catalytic mode (PtNPs) in peroxide solutions or magnetic actuation (fuel free) by the action of an external magnetic field. The enhanced movement and localized delivery of the micromotors (both in catalytic and magnetic actuated mode) results in a 2-fold increase of the capture/killing ability towards Staphylococcus Aureus bacteria in raw media (juice, serum and tap water samples), as compared with free Nisin and static counterparts. The micromotor strategy display also high selectivity towards such bacteria, as illustrated by the dramatically lower capture/killing ability towards gram-negative Escherichia Coli. Unlike previous micromotors based strategies, this approach displays higher selectivity towards a type of bacteria along with enhanced stability, prolonged use and adaptative propulsion modes, holding considerable promise to treat methicillin resistant antibiotic infections, for environmental remediation or food safety, among others applications.
{"title":"Magneto-Catalytic Janus Micromotors for Selective Inactivation of Bacteria Biofilms","authors":"B. Jurado‐Sánchez, A. Escarpa, Kaisong Yuan","doi":"10.3390/micromachines2021-09606","DOIUrl":"https://doi.org/10.3390/micromachines2021-09606","url":null,"abstract":"Janus micromotors are a unique class of materials whose surfaces have two or more distinct physical properties, allowing thus for two types of chemistry to occur simultaneously. Judicious design of the micromotor structure allows to incorporate different functionalities in a single unit to adapt the propulsion behaviour along with the incorporation of specific receptors for a myriad of applications. Herein we report the preparation of graphene oxide (GO)/PtNPs/Fe2O3 Janus micromotors for highly selective capture/inactivation of gram-positive bacteria units and biofilms. The strategy is based on the combination of a lanbiotic (Nisin) with Janus micromotors. Lanbiotics are peptides composed of methyllanthionine residues with a highly selective antimicrobial activity towards multidrug resistant bacteria. Nisin is a natural compound normally used for food preservation, which display specific antimicrobial activity towards gram-positive bacteria. Such peptide can bind to lipid II unit of the bacteria membranes, damaging its morphology and releasing its contents. The coating of micromotors with GO impart them with a Janus structure for the subsequent asymmetric assembly of catalytic (PtNPs) and magnetic (Fe2O3) engines and results in an active rough layer for a higher loading of Nisin via covalent interactions. The micromotors possess adaptative propulsion mechanisms, including catalytic mode (PtNPs) in peroxide solutions or magnetic actuation (fuel free) by the action of an external magnetic field. The enhanced movement and localized delivery of the micromotors (both in catalytic and magnetic actuated mode) results in a 2-fold increase of the capture/killing ability towards Staphylococcus Aureus bacteria in raw media (juice, serum and tap water samples), as compared with free Nisin and static counterparts. The micromotor strategy display also high selectivity towards such bacteria, as illustrated by the dramatically lower capture/killing ability towards gram-negative Escherichia Coli. Unlike previous micromotors based strategies, this approach displays higher selectivity towards a type of bacteria along with enhanced stability, prolonged use and adaptative propulsion modes, holding considerable promise to treat methicillin resistant antibiotic infections, for environmental remediation or food safety, among others applications.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"188 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131563678","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/MICROMACHINES2021-09583
Mohammad Ahmadi, Wei Liu, A. Henzen, H. Wyss
Electrokinetic displays are among the most important display technologies because of their low power consumption, wide viewing angle, and outdoor readability. As a result, they are regarded as excellent candidates for electronic paper. These types of displays are based on the controlled movement of charged pigment particles in a non-polar liquid under the influence of an electric field. Free charges practically do not exist in nonpolar colloids due to their low dielectric constant. However, the addition of a surfactant to non-polar colloids often leads to considerable charge-induced effects, such as increased electrical conductivity and particle stabilization. In this project, we aim to develop a novel electrokinetically driven display. An unprecedented display device is proposed, based on the concerted action of electro-osmosis and electrophoresis in a non-polar fluid. This method could reduce the switching time required to display information, and extend the applications of electrokinetic displays, enabling increased video speed and full color in the future.
{"title":"Electro-optical full color display based on nano-particle dispersions","authors":"Mohammad Ahmadi, Wei Liu, A. Henzen, H. Wyss","doi":"10.3390/MICROMACHINES2021-09583","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09583","url":null,"abstract":"Electrokinetic displays are among the most important display technologies because of their low power consumption, wide viewing angle, and outdoor readability. As a result, they are regarded as excellent candidates for electronic paper. These types of displays are based on the controlled movement of charged pigment particles in a non-polar liquid under the influence of an electric field. Free charges practically do not exist in nonpolar colloids due to their low dielectric constant. However, the addition of a surfactant to non-polar colloids often leads to considerable charge-induced effects, such as increased electrical conductivity and particle stabilization. In this project, we aim to develop a novel electrokinetically driven display. An unprecedented display device is proposed, based on the concerted action of electro-osmosis and electrophoresis in a non-polar fluid. This method could reduce the switching time required to display information, and extend the applications of electrokinetic displays, enabling increased video speed and full color in the future.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"77 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":"134050171","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/MICROMACHINES2021-09593
Lillian N. Usadi, S. Firebaugh, H. Elbidweihy, S. Yee
The advent of micro/nanorobotics promises to transform the physical, chemical, and biological domains by harnessing opportunities otherwise limited by size. Most notable is the biomedical field in which the ability to manipulate micro/nanoparticles has numerous applications in biophysics, drug delivery, tissue engineering, and microsurgery. Acoustics, the physics of vibrational waves through matter, offers a precise, accurate, and minimally invasive technique to manipulate microrobots or microparticles (stand-ins for microrobots). One example is through the use of flexural vibrations induced in resonant structures such as Chladni plates. In this research, we developed a platform for precise two-dimensional microparticle manipulation via acoustic forces arising from Chladni figures and resonating microscale membranes. The project included two distinct phases: (1) macroscale manipulation with a Chladni plate in air and (2) microscale manipulation using microscale membranes in liquid. In the first phase (macroscale in air), we reproduced previous studies in order to gain a better understanding of the underlying physics and to develop control algorithms based on statistical modeling techniques. In the second phase (microscale in liquid), we developed and tested a new setup using custom microfabricated structures. The macroscale statistical modeling techniques were integrated with microscale autonomous control systems. It is shown that control methods developed on the macroscale can be implemented and used on the microscale with good precision and accuracy.
{"title":"Manipulation of Microrobots using Chladni Plates and Multimode Membrane Resonators","authors":"Lillian N. Usadi, S. Firebaugh, H. Elbidweihy, S. Yee","doi":"10.3390/MICROMACHINES2021-09593","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09593","url":null,"abstract":"The advent of micro/nanorobotics promises to transform the physical, chemical, and biological domains by harnessing opportunities otherwise limited by size. Most notable is the biomedical field in which the ability to manipulate micro/nanoparticles has numerous applications in biophysics, drug delivery, tissue engineering, and microsurgery. \u0000Acoustics, the physics of vibrational waves through matter, offers a precise, accurate, and minimally invasive technique to manipulate microrobots or microparticles (stand-ins for microrobots). One example is through the use of flexural vibrations induced in resonant structures such as Chladni plates. \u0000In this research, we developed a platform for precise two-dimensional microparticle manipulation via acoustic forces arising from Chladni figures and resonating microscale membranes. The project included two distinct phases: (1) macroscale manipulation with a Chladni plate in air and (2) microscale manipulation using microscale membranes in liquid. In the first phase (macroscale in air), we reproduced previous studies in order to gain a better understanding of the underlying physics and to develop control algorithms based on statistical modeling techniques. In the second phase (microscale in liquid), we developed and tested a new setup using custom microfabricated structures. The macroscale statistical modeling techniques were integrated with microscale autonomous control systems. It is shown that control methods developed on the macroscale can be implemented and used on the microscale with good precision and accuracy.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"40 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":"127829515","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/micromachines2021-09586
V. Nerguizian, R. Salazar
Lipid-based nanoparticles have demonstrated to be a versatile vehicle for drugs, genetic material, and labels. These particles are often made of biocompatible and biodegradable materials, enabling a safe interaction with biological systems. The importance of this type of delivery vehicle has been shown recently, as the two leading vaccines are based on lipid-nanoparticles encapsulating mRNA. Passive micromixers produce lipid nanoparticles in a reproducible and controllable way. However, micromixers suffered at the beginning of low production rate, and complicated designs which were difficult to produce and prone to clogging. In recent years, the exploration of different mixing strategies based on the use of curvilinear paths to induce centripetal forces and vortex formation at high speeds as well as the increase of the microchannel cross-sectional area while keeping laminar flow regimes has led to designs capable of producing lipid-based nanoparticles on an industrial-scale. However, there are still challenges in the field which include the removal or substitution of the organic solvents that still need to be addressed. In this presentation, we introduce a general overview of lipid nanoparticle or liposome production in micromixers, the principles of mixing using curvilinear paths, the key variables controlling lipid-based nanoparticle physicochemical characteristics and approaches that help to substitute toxic solvent residues.
{"title":"Lipid-based nanoparticle production in Micromixers","authors":"V. Nerguizian, R. Salazar","doi":"10.3390/micromachines2021-09586","DOIUrl":"https://doi.org/10.3390/micromachines2021-09586","url":null,"abstract":"Lipid-based nanoparticles have demonstrated to be a versatile vehicle for drugs, genetic material, and labels. These particles are often made of biocompatible and biodegradable materials, enabling a safe interaction with biological systems. The importance of this type of delivery vehicle has been shown recently, as the two leading vaccines are based on lipid-nanoparticles encapsulating mRNA. \u0000Passive micromixers produce lipid nanoparticles in a reproducible and controllable way. However, micromixers suffered at the beginning of low production rate, and complicated designs which were difficult to produce and prone to clogging. In recent years, the exploration of different mixing strategies based on the use of curvilinear paths to induce centripetal forces and vortex formation at high speeds as well as the increase of the microchannel cross-sectional area while keeping laminar flow regimes has led to designs capable of producing lipid-based nanoparticles on an industrial-scale. \u0000However, there are still challenges in the field which include the removal or substitution of the organic solvents that still need to be addressed. \u0000In this presentation, we introduce a general overview of lipid nanoparticle or liposome production in micromixers, the principles of mixing using curvilinear paths, the key variables controlling lipid-based nanoparticle physicochemical characteristics and approaches that help to substitute toxic solvent residues.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"10 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":"132314211","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/MICROMACHINES2021-09599
I. Gonçalves, R. Lima, Miguel Madureira, Inês Miranda, H. Schütte, A. Moita, G. Minas, S. Gassmann
: The diagnosis of several diseases can be performed by analyzing the blood plasma of a patient. Despite extensive research work, there is still a need to improve current low-cost fabrication techniques and devices for the separation of plasma from blood cells. Microfluidic biomedical devices have great potential for that process. Hence, a microfluidic device made by micromilling and sealed with an oxygen plasma technique was tested by means of two different blood analogue fluids. The device has four microchannels with similar geometries but different channel depths. A high-speed video microscopy system was used for the visualization and acquisition of the flow of the analogue fluids throughout the microchannels of the device. Then, the separation of particles and plasma was evaluated with the ImageJ software by measuring and comparing the grey values at the entrance and the exit of the channel. The device showed a significant reduction of the amount of cells between the entrance and the exit of the microchannels. The depth of the channels and the size of the particles were not found to exert any major influence on the separation process. However, it was found that the flow rate affected the separation results, as the best results were obtained for a flow rate of 100 μ L/min. Though these results are promising, further analyses and optimizations of microfluidic devices, as well as comparisons between devices sealed using different methods such as the solvent bonding technique, will be conducted in future works.
{"title":"Separation microfluidic device fabricated by micromilling techniques","authors":"I. Gonçalves, R. Lima, Miguel Madureira, Inês Miranda, H. Schütte, A. Moita, G. Minas, S. Gassmann","doi":"10.3390/MICROMACHINES2021-09599","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09599","url":null,"abstract":": The diagnosis of several diseases can be performed by analyzing the blood plasma of a patient. Despite extensive research work, there is still a need to improve current low-cost fabrication techniques and devices for the separation of plasma from blood cells. Microfluidic biomedical devices have great potential for that process. Hence, a microfluidic device made by micromilling and sealed with an oxygen plasma technique was tested by means of two different blood analogue fluids. The device has four microchannels with similar geometries but different channel depths. A high-speed video microscopy system was used for the visualization and acquisition of the flow of the analogue fluids throughout the microchannels of the device. Then, the separation of particles and plasma was evaluated with the ImageJ software by measuring and comparing the grey values at the entrance and the exit of the channel. The device showed a significant reduction of the amount of cells between the entrance and the exit of the microchannels. The depth of the channels and the size of the particles were not found to exert any major influence on the separation process. However, it was found that the flow rate affected the separation results, as the best results were obtained for a flow rate of 100 μ L/min. Though these results are promising, further analyses and optimizations of microfluidic devices, as well as comparisons between devices sealed using different methods such as the solvent bonding technique, will be conducted in future works.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"10 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":"123320018","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/MICROMACHINES2021-09580
Ilaria Buja, Erika Sabella, A. Monteduro, M. Chiriacò, S. Rizzato, L. Bellis, A. Luvisi, G. Maruccio
Phytopathological adversities are often attributable to human activities (as a consequence of the globalization of trade or tourism mass, changes in common agricultural practices and climate change), adding food losses due to pathogens such as fungi, bacteria, viruses etc. For this, we are developing a lab-on-chip as a diagnostic approach to phytopathological problems caused by infectious agents capable of spreading in agro-ecosystems, such as the Xylella fastidiosa epidemic in Puglia (Chiriaco et al., 2018) or other bacteriosis and virosis such as Grapevine leafroll-associated virus 3 (GLRaV-3). In particular, grapevine leafroll disease (GLD) is one of the most important grapevine viral diseases, affecting grapevines worldwide. Several viruses from the family Closteroviridae are associated with it and Grapevine leafroll-associated virus 3(GLRaV-3) is considered as the most important causative agent. Symptoms of GLD can vary greatly with the season, grape cultivar, and climatic conditions and some varieties can be completely symptomless. (Maree et al., 2013). There is no cure for the virus but only preventive actions. In fact, fighting strategy is based exclusively on the use of plant material free from virus, such as the use of certified material. These pathogens can have serious economic and environmental repercussions on two of the major cultivated woody plant of Mediterranean basin, due to the absence of therapeutic techniques and the need of rapid, in-field and low-cost detection methods. Here we present a lab-on-chip platform coupled with microfluidic module, based on an electrochemical transduction method, able to recognize serial dilutions of Grapevine leafroll-associated virus 3. LOC represents smart and versatile devices due to their miniaturization. They require small sample volumes, allowing a rapid detection of the targets, offering also the opportunity to study biomechanical properties of plants (Nezhad et al., 2013) and other plant cells studies (Nezhad et al., 2014; Julich et al., 2011). In particular, thanks the aid of a microfluidic component, such as polydimethylsiloxane (PDMS), is possible to realize biochemistry conventional laboratories functions such as sample preparation, reaction, separation and detection (McDonald et al, 2000). This device can show competitive performances with conventional diagnostic methods in terms of reliability, with further advantages of portability, low costs and ease of use, making the difference in real time detection of the pathogens.
植物病理逆境通常可归因于人类活动(由于贸易或旅游业的全球化、常见农业做法的变化和气候变化)，加上真菌、细菌、病毒等病原体造成的粮食损失。为此，我们正在开发一种芯片实验室，作为一种诊断方法，用于诊断由能够在农业生态系统中传播的传染性病原体引起的植物病理学问题，例如Puglia的木杆菌流行(Chiriaco等人，2018)或其他细菌病和病毒病，例如葡萄藤叶卷相关病毒3 (glav -3)。特别是葡萄叶卷病(GLD)是影响世界各地葡萄的最重要的葡萄病毒性病害之一。来自Closteroviridae科的几种病毒与该病有关，其中葡萄叶相关病毒3(glav -3)被认为是最重要的病原体。GLD的症状随季节、葡萄品种和气候条件的不同而有很大差异，有些品种可能完全没有症状。(Maree et al.， 2013)。这种病毒无法治愈，只能采取预防措施。事实上，防治战略完全基于使用无病毒的植物材料，例如使用经认证的材料。由于缺乏治疗技术和需要快速、现场和低成本的检测方法，这些病原体可能对地中海盆地的两种主要栽培木本植物产生严重的经济和环境影响。在此，我们提出了一个基于电化学转导方法的芯片实验室平台，结合微流控模块，能够识别一系列稀释度的葡萄叶相关病毒3。由于其小型化，LOC代表了智能和多功能设备。它们需要小样品量，允许快速检测目标，也提供了研究植物生物力学特性的机会(Nezhad等人，2013)和其他植物细胞研究(Nezhad等人，2014;Julich et al.， 2011)。特别是，借助微流体组件，如聚二甲基硅氧烷(PDMS)，可以实现生物化学常规实验室功能，如样品制备、反应、分离和检测(McDonald et al, 2000)。该设备在可靠性方面可与传统诊断方法相媲美，并具有便携性、低成本和易于使用的优势，在病原体的实时检测方面具有重要意义。
{"title":"Lab-on-chip platform for on-field analysis of Grapevine leafroll-associated virus 3","authors":"Ilaria Buja, Erika Sabella, A. Monteduro, M. Chiriacò, S. Rizzato, L. Bellis, A. Luvisi, G. Maruccio","doi":"10.3390/MICROMACHINES2021-09580","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09580","url":null,"abstract":"Phytopathological adversities are often attributable to human activities (as a consequence of the globalization of trade or tourism mass, changes in common agricultural practices and climate change), adding food losses due to pathogens such as fungi, bacteria, viruses etc. \u0000For this, we are developing a lab-on-chip as a diagnostic approach to phytopathological problems caused by infectious agents capable of spreading in agro-ecosystems, such as the Xylella fastidiosa epidemic in Puglia (Chiriaco et al., 2018) or other bacteriosis and virosis such as Grapevine leafroll-associated virus 3 (GLRaV-3). \u0000In particular, grapevine leafroll disease (GLD) is one of the most important grapevine viral diseases, affecting grapevines worldwide. Several viruses from the family Closteroviridae are associated with it and Grapevine leafroll-associated virus 3(GLRaV-3) is considered as the most important causative agent. Symptoms of GLD can vary greatly with the season, grape cultivar, and climatic conditions and some varieties can be completely symptomless. (Maree et al., 2013). There is no cure for the virus but only preventive actions. In fact, fighting strategy is based exclusively on the use of plant material free from virus, such as the use of certified material. These pathogens can have serious economic and environmental repercussions on two of the major cultivated woody plant of Mediterranean basin, due to the absence of therapeutic techniques and the need of rapid, in-field and low-cost detection methods. \u0000Here we present a lab-on-chip platform coupled with microfluidic module, based on an electrochemical transduction method, able to recognize serial dilutions of Grapevine leafroll-associated virus 3. LOC represents smart and versatile devices due to their miniaturization. They require small sample volumes, allowing a rapid detection of the targets, offering also the opportunity to study biomechanical properties of plants (Nezhad et al., 2013) and other plant cells studies (Nezhad et al., 2014; Julich et al., 2011). In particular, thanks the aid of a microfluidic component, such as polydimethylsiloxane (PDMS), is possible to realize biochemistry conventional laboratories functions such as sample preparation, reaction, separation and detection (McDonald et al, 2000). \u0000This device can show competitive performances with conventional diagnostic methods in terms of reliability, with further advantages of portability, low costs and ease of use, making the difference in real time detection of the pathogens.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"30 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":"114739635","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/MICROMACHINES2021-09598
L. Francis, Roselien Vercauteren, A. Leprince, J. Mahillon
: The rapid detection of hazardous bacteria is important for healthcare situations, where such identification can lead to substantial gains for patient treatment and recovery and a reduced usage of broad-spectrum antibiotics. Potential biosensors must be able to provide a fast, sensitive and selective response with as little sample preparation as possible. Indeed, some of these pathogens, such as Staphylococcus aureus, can be yet harmful at very low concentrations in the blood stream, e.g., below 10 colony forming units per mL (CFU/mL). These stringent requirements limit the number of candidates, especially for point-of-care applications. Amongst several biosensing techniques, optical sensing using porous silicon (PSi) substrate has been widely suggested in recent years thanks to unique features such as a large surface area, tunable optical characteristics, and above all relatively easy and affordable fabrication techniques. In most configurations, PSi optical biosensors are close-ended porous layers; this limits their sensitivity and responsiveness due to diffusion-limited infiltration of the analytes in the porous layer. Also, PSi is a reactive material, its oxidation in buffer solutions results in time-varying shifts. Despite its attractive properties, several challenges must still be overcome in order to reach practical applications. Our work addresses three main improvement points. The first one is the stability over time in saline solutions helped by atomic layer deposition of metal oxides inside the pores. Besides a better stability, our solution is helping with an increase of the optical signal to noise ratio, thus reducing the limit of detection. The second one is to perform the lysis of the bacteria prior to its exposure to the sensor, such that the selective detection is based upon the percolation of bacterial residues inside the pores rather than the bacteria themselves. The third one is to remove the bulk silicon below a PSi layer to create a membrane, that allows for flow-through of the analytes, thus enhancing the interactions between the lysate and the sensor’s surface. This approach allows us to avoid the step of surface functionalization used in classical biosensors. We tested thanks to these improvements the selective detection of Bacillus cereus lysate with concentrations between 103 and 105 CFU/mL. Future works are dedicated to further improvements, including optical signal enhancement techniques and dielectrophoretic assisted percolation in the porous silicon membrane.
{"title":"Stable Porous Silicon Membranes for Fast Bacterial Detection","authors":"L. Francis, Roselien Vercauteren, A. Leprince, J. Mahillon","doi":"10.3390/MICROMACHINES2021-09598","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09598","url":null,"abstract":": The rapid detection of hazardous bacteria is important for healthcare situations, where such identification can lead to substantial gains for patient treatment and recovery and a reduced usage of broad-spectrum antibiotics. Potential biosensors must be able to provide a fast, sensitive and selective response with as little sample preparation as possible. Indeed, some of these pathogens, such as Staphylococcus aureus, can be yet harmful at very low concentrations in the blood stream, e.g., below 10 colony forming units per mL (CFU/mL). These stringent requirements limit the number of candidates, especially for point-of-care applications. Amongst several biosensing techniques, optical sensing using porous silicon (PSi) substrate has been widely suggested in recent years thanks to unique features such as a large surface area, tunable optical characteristics, and above all relatively easy and affordable fabrication techniques. In most configurations, PSi optical biosensors are close-ended porous layers; this limits their sensitivity and responsiveness due to diffusion-limited infiltration of the analytes in the porous layer. Also, PSi is a reactive material, its oxidation in buffer solutions results in time-varying shifts. Despite its attractive properties, several challenges must still be overcome in order to reach practical applications. Our work addresses three main improvement points. The first one is the stability over time in saline solutions helped by atomic layer deposition of metal oxides inside the pores. Besides a better stability, our solution is helping with an increase of the optical signal to noise ratio, thus reducing the limit of detection. The second one is to perform the lysis of the bacteria prior to its exposure to the sensor, such that the selective detection is based upon the percolation of bacterial residues inside the pores rather than the bacteria themselves. The third one is to remove the bulk silicon below a PSi layer to create a membrane, that allows for flow-through of the analytes, thus enhancing the interactions between the lysate and the sensor’s surface. This approach allows us to avoid the step of surface functionalization used in classical biosensors. We tested thanks to these improvements the selective detection of Bacillus cereus lysate with concentrations between 103 and 105 CFU/mL. Future works are dedicated to further improvements, including optical signal enhancement techniques and dielectrophoretic assisted percolation in the porous silicon membrane.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"10 Suppl 1 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":"126110877","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/MICROMACHINES2021-09591
Kenan Muhamedagic, A. Tucak, M. Sirbubalo, O. Rahić, Lamija Hindija, J. Hadžiabdić, E. Vranić, A. Çekiç
Microneedles (MNs) have been manufactured using a variety of methods from a range of materials, but most of them are expensive and time-consuming for screening new designs and making any modifications. Therefore, stereolithography (SLA) has emerged as a promising approach for MN fabrication due to its numerous advantages, including simplicity, low cost, and the ability to manufacture complex geometrical products at any time, including modifications to the original designs. This work aimed to print MNs using SLA technology and investigate the effects of post-printing curing conditions on the mechanical properties of 3D-printed MNs. Solid MNs were designed using CAD software and printed with grey resin (Formlabs, UK) using Form 3 printer (Formlabs, UK). MNs dimensions were 1.2 × 0.4 × 0.05 mm, arranged in 6 rows and 6 columns on a 10 × 10 mm baseplate. MNs were then immersed in an isopropyl alcohol bath to remove unpolymerized resin residues and cured in a UV-A heated chamber (Formlabs, UK). In total, nine samples were taken for each combination of curing temperature (35°C, 50°C, and 70°C) and curing time (5 min, 20 min, and 60 min). Fracture tests were conducted using a hardness apparatus TB24 (Erweka, Germany). MNs were placed on the moving probe of the machine and compressed until fracture. The optimization of the SLA process parameters for improving the strength of MNs was performed using the Taguchi method. The design of experiments was carried out based on the Taguchi L9 orthogonal array. Experimental results showed that the curing temperature has a significant influence on MN strength improvements. Improvement of the MN strength can be achieved by increasing the curing temperature and curing time.
{"title":"Optimization of Manufacturing Parameters of 3D Printed Solid Microneedles for Transdermal Drug Delivery","authors":"Kenan Muhamedagic, A. Tucak, M. Sirbubalo, O. Rahić, Lamija Hindija, J. Hadžiabdić, E. Vranić, A. Çekiç","doi":"10.3390/MICROMACHINES2021-09591","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09591","url":null,"abstract":"Microneedles (MNs) have been manufactured using a variety of methods from a range of materials, but most of them are expensive and time-consuming for screening new designs and making any modifications. Therefore, stereolithography (SLA) has emerged as a promising approach for MN fabrication due to its numerous advantages, including simplicity, low cost, and the ability to manufacture complex geometrical products at any time, including modifications to the original designs. This work aimed to print MNs using SLA technology and investigate the effects of post-printing curing conditions on the mechanical properties of 3D-printed MNs. \u0000Solid MNs were designed using CAD software and printed with grey resin (Formlabs, UK) using Form 3 printer (Formlabs, UK). MNs dimensions were 1.2 × 0.4 × 0.05 mm, arranged in 6 rows and 6 columns on a 10 × 10 mm baseplate. MNs were then immersed in an isopropyl alcohol bath to remove unpolymerized resin residues and cured in a UV-A heated chamber (Formlabs, UK). In total, nine samples were taken for each combination of curing temperature (35°C, 50°C, and 70°C) and curing time (5 min, 20 min, and 60 min). Fracture tests were conducted using a hardness apparatus TB24 (Erweka, Germany). MNs were placed on the moving probe of the machine and compressed until fracture. \u0000The optimization of the SLA process parameters for improving the strength of MNs was performed using the Taguchi method. The design of experiments was carried out based on the Taguchi L9 orthogonal array. Experimental results showed that the curing temperature has a significant influence on MN strength improvements. Improvement of the MN strength can be achieved by increasing the curing temperature and curing time.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"40 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":"130995462","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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