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Eng. Proc., 2021, ICMA 2021

The 1st International Conference on Micromachines and Applications

Online | 15–30 April 2021

Volume Editor:
Ion Stiharu, Concordia University, Canada

Number of Papers: 48
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Cover Story (view full-size image): The first international conference on Micromachines and Applications is held under these unusual circumstances was enabled by the great MDPI editorial team of Micromachines The scope of this [...] Read more.
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132 KiB  
Abstract
Misconceptions in Piezoelectric Energy-Harvesting System Development
by Kenji Uchino
Eng. Proc. 2021, 4(1), 1; https://doi.org/10.3390/Micromachines2021-09570 - 14 Apr 2021
Cited by 1 | Viewed by 567
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 [...] Read more.
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’. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
119 KiB  
Abstract
Magnetically Actuated Glaucoma Drainage Device with Adjustable Flow Properties after Implantation
by Inês C. F. Pereira, Hans M. Wyss, Henny J. M. Beckers and Jaap M. J. den Toonder
Eng. Proc. 2021, 4(1), 3; https://doi.org/10.3390/Micromachines2021-09584 - 16 Apr 2021
Cited by 1 | Viewed by 942
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 [...] Read more.
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. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
117 KiB  
Abstract
Flexible Microfabrication on a Chip during Cultivation for a Neuronal Network Direction Control Using Stepwise Photo-Thermal Etching of an Agarose Architecture
by Yuhei Tanaka, Haruki Watanabe, Kenji Shimoda and Kenji Yasuda
Eng. Proc. 2021, 4(1), 4; https://doi.org/10.3390/Micromachines2021-09582 - 16 Apr 2021
Viewed by 594
Abstract
Control over spatial distributions and patterns of individual neurons and their neurites provides an essential tool for studying the meaning of neuronal network patterns. Moreover, the complete direction control of synaptic connections between cells in each neuronal network is also essential to investigate [...] Read more.
Control over spatial distributions and patterns of individual neurons and their neurites provides an essential tool for studying the meaning of neuronal network patterns. Moreover, the complete direction control of synaptic connections between cells in each neuronal network is also essential to investigate detailed information on the relationship between the forward and feedback signaling among the cells. Here, we have developed a method for topographical control of the direction of synaptic connections within a living neuronal network using a new type of individual-cell-based on-chip cell-cultivation system with an agarose microfabrication technology. The advantages of this system include the ability to control positions and number of cultured cells, as well as flexible control of the direction of elongation of axons and dendrites with stepwise melting of a thin agarose layer coated on the cultivation chip with a focused infrared laser beam even during cultivation without any destructive damage on cells. Using this system, we succeeded in forming a fully direction-controlled single-cell-based neuronal network from individual rat hippocampal cells. In this meeting, we discuss the potential damage of heat to cells during stepwise melting of agarose and demonstrate the ability of our on-chip agarose microfabrication method for individual cell-based neural networks. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
111 KiB  
Abstract
Precise Layer Separation of Two-Dimensional Nanomaterials for Scalable Optoelectronics
by Joohoon Kang
Eng. Proc. 2021, 4(1), 5; https://doi.org/10.3390/Micromachines2021-09553 - 14 Apr 2021
Viewed by 632
Abstract
The biggest challenge in the field of low-dimensional nanomaterials, in terms of practical application, is scalable production with structural uniformity. As the size of materials is becoming smaller, the tendency of their structure-dependent properties, which directly affects the device reliability of largescale applications, [...] Read more.
The biggest challenge in the field of low-dimensional nanomaterials, in terms of practical application, is scalable production with structural uniformity. As the size of materials is becoming smaller, the tendency of their structure-dependent properties, which directly affects the device reliability of largescale applications, is to become stronger due to quantum confinement effects. For example, one-dimensional (1D) carbon nanotubes have various electrical/optical properties based on their structures (e.g., diameter, chirality, etc.). Likewise, two-dimensional (2D) layered materials also exhibit different properties based on their thickness. To overcome such structural heterogeneity, isopycnic density gradient ultracentrifugation (i-DGU) will be introduced to achieve monodispersity of nanomaterials in structure based on their buoyant density differentiations. The i-DGU approach makes it possible to sort 1D carbon nanotubes and 2D layered materials such as graphene, transition metal dichalcogenides and hexagonal boron nitride with high structural purity, based on their structure. Various largescale optoelectronic applications, electrically driven light emitters and photodetectors demonstrated based on the monodisperse nanomaterials will be discussed. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
156 KiB  
Abstract
Development of Aqueous Two-Phase Systems Based on Deep Eutectic Solvents for Continuous Protein Extraction in a Microextractor
by Anabela Ljubić, Anita Šalić and Bruno Zelić
Eng. Proc. 2021, 4(1), 6; https://doi.org/10.3390/Micromachines2021-09546 - 14 Apr 2021
Viewed by 702
Abstract
Currently, lipases are one of the most widely used enzymes, especially in catalysis, mostly due to their high activity in mild conditions and wide specificity. Therefore, obtaining the highest possible catalytic activity, which can be achieved through purification, is becoming more and more [...] Read more.
Currently, lipases are one of the most widely used enzymes, especially in catalysis, mostly due to their high activity in mild conditions and wide specificity. Therefore, obtaining the highest possible catalytic activity, which can be achieved through purification, is becoming more and more important. Since most of the purification techniques are time consuming, aqueous two-phase protein extraction is often investigated as a promising alternative. Additionally, this kind of extraction can be carried out in microextractors, which provides not only a continuous processing of raw materials, but also significantly higher efficiencies due to a high surface-to-volume ratio of microchannels. Extraction with deep eutectic solvents (DESs) fulfills all green chemistry principles, because DESs are biodegradable, non-toxic, and recyclable. In this research, the aqueous two-phase system based on natural DES for continuous protein extraction in a microextractor was investigated. The impact of salt concentration on extraction efficiency was investigated in batch experiments with six different previously characterized DESs. After determination of the optimal two-phase system features, the process was transferred to a microextractor. In addition, the selected DES was tested for recyclability while the developed extraction method was verified using raw lipase produced by Thermomyces lanuginosus solid-state cultivation on hull-less pumpkin oil pomace. The highest protein extraction efficiency achieved in a batch reactor was 94.70% for 30 min, while in a microextractor, the highest extraction efficiency obtained was 98.50% for 30 s. Obviously, the extraction process was significantly intensified by continuous microextraction. Additionally, the DES used in the microextraction experiments was efficiently reused in several extraction cycles. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
157 KiB  
Abstract
Fabrication of Micro-Structured Surface Topologies for the Promotion of Marine Bacteria Biofilm
by Ariadni Droumpali, Jörg Hübner, Lone Gram and Rafael Taboryski
Eng. Proc. 2021, 4(1), 7; https://doi.org/10.3390/Micromachines2021-09579 - 16 Apr 2021
Viewed by 646
Abstract
Several marine bacteria of the Roseobacter group can inhibit other microorganisms and are especially antagonistic when growing in biofilms. This aptitude to naturally compete with other bacteria can reduce the need for antibiotics in large scale aquaculture units, providing that their culture can [...] Read more.
Several marine bacteria of the Roseobacter group can inhibit other microorganisms and are especially antagonistic when growing in biofilms. This aptitude to naturally compete with other bacteria can reduce the need for antibiotics in large scale aquaculture units, providing that their culture can be promoted and controlled. Micropatterned surfaces may facilitate and promote the biofilm formation of species from the Roseobacter group, due to the increased contact between the cells and the surface material. Our research goal is to fabricate a biofilm with optimal micro patterned surfaces and investigate the relevant length scales for surface topographies, as well as the surface chemistry, which can promote growth and biofilm formation of the Roseobacter group. In a preliminary study, silicon surfaces comprising arrays of pillars and pits with different periodicities, diameters and depths were produced by UV lithography and deep reactive ion etching (DRIE) on single-side polished silicon wafers. The resulting surface microscale topologies were characterized using optical profilometry and scanning electron microscopy (SEM). Screening of the bacterial biofilm on the patterned surfaces was performed using green fluorescent staining (SYBR green I) and confocal laser scanning microscopy (CLSM). Different series of experiments were conducted by changing several parameters, such as growth time, shear stress corresponding to particular revolution per minute (rpm) and growth media. Preliminary results indicate that there is a correlation between the surface morphology, and the spatial organization of the bacterial biofilm. Our results indicate that further investigation leading to optimization of surface topology and surface chemistry will allow us to microfabricate polymer material surfaces where biofilm colonization is enhanced. Such surfaces will enable the introduction of beneficial bacteria in a variety of industrial processes, including aquaculture. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
158 KiB  
Abstract
Microswimmers for Biomedical Applications: Focus on Light
by Ada-Ioana Bunea, Einstom Engay, Alexandre Emmanuel Wetzel and Rafael Taboryski
Eng. Proc. 2021, 4(1), 8; https://doi.org/10.3390/Micromachines2021-09578 - 16 Apr 2021
Viewed by 666
Abstract
Microswimmers are microscopic objects that can move and perform tasks in liquid environments. [...] Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
108 KiB  
Abstract
Silicon Carbide for Advanced In-Vivo Medical Devices
by Stephen E. Saddow
Eng. Proc. 2021, 4(1), 10; https://doi.org/10.3390/Micromachines2021-09576 - 16 Apr 2021
Viewed by 659
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 [...] Read more.
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. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
117 KiB  
Abstract
Development of Gelatin-Based Flexible Three-Dimensional Capillary Pattern Microfabrication Technology for Analysis of Collective Cell Migration
by Hiromichi Hashimoto, Mitsuru Sentoku, Kento Iida and Kenji Yasuda
Eng. Proc. 2021, 4(1), 11; https://doi.org/10.3390/Micromachines2021-09581 - 16 Apr 2021
Viewed by 551
Abstract
Collective cell migration is thought to be a dynamic and interactive behavior of cell cohorts that is essential for diverse physiological developments in living organisms. Recent studies revealed that the topographical properties of the environment regulate the migration modes of cell cohorts, such [...] Read more.
Collective cell migration is thought to be a dynamic and interactive behavior of cell cohorts that is essential for diverse physiological developments in living organisms. Recent studies revealed that the 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 changes in cell behavior in response to the structural changes. In this study, we developed a method to fabricate the flexible three-dimensional structures of capillary microtunnels to examine the behavior of vascular endothelial cells (ECs). Microtunnels with altering diameters were formed inside gelatin gel through 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 the capillary microtunnels as a monolayer instead of filling the capillary. In contrast to the 3D straight topographical constraint, which exhibited width-dependent migration velocity, the leading ECs altered its migration velocity according to the change in the supply of cells behind the leading ECs, caused by their progression through the diameter-altering structure. Our findings provide insights into the collective migration modes inside 3D confinement structures, including their fluid-like behavior and the conservation of cell numbers. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
144 KiB  
Abstract
Hollow AFM Cantilever with Holes
by Wujoon Cha, Matthew F. Campbell, Akshat Jain and Igor Bargatin
Eng. Proc. 2021, 4(1), 13; https://doi.org/10.3390/Micromachines2021-09544 - 14 Apr 2021
Viewed by 589
Abstract
Since its invention, atomic force microscopy (AFM) has enhanced our understanding of physical and biological systems at sub-micrometer scales [...] Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
115 KiB  
Abstract
Electro-Optical Full-Color Display Based on Nano-Particle Dispersions
by Mohammad Khorsand Ahmadi, Wei Liu, Alex Henzen and Hans Wyss
Eng. Proc. 2021, 4(1), 14; https://doi.org/10.3390/Micromachines2021-09583 - 16 Apr 2021
Viewed by 596
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 [...] Read more.
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. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
118 KiB  
Abstract
Bioinspired Microstructures Polymer Surfaces with Antireflective Properties
by Alexandre Emmanuel Wetzel, Ada-Ioana Bunea, Einstom Engay, Nikolaj Kofoed Mandsberg, Nuria del Castillo Iniesta, Anja Boisen, Kirstine Berg-Sørensen and Rafael Taboryski
Eng. Proc. 2021, 4(1), 15; https://doi.org/10.3390/Micromachines2021-09548 - 14 Apr 2021
Viewed by 756
Abstract
Antireflective (AR) coatings have been around for more than a century, with the simplest form dating back to Lord Rayleigh’s 1886 tarnished glass. Different approaches to obtaining AR coatings exploit index-matching, interference, or absorbing phenomena. In 2002, a novel super black surface was [...] Read more.
Antireflective (AR) coatings have been around for more than a century, with the simplest form dating back to Lord Rayleigh’s 1886 tarnished glass. Different approaches to obtaining AR coatings exploit index-matching, interference, or absorbing phenomena. In 2002, a novel super black surface was developed by Brown et al. at the National Physical Laboratory in the UK and soon gained significant interest among both academia and industry. Since then, scientists have been competing in a race to produce the blackest material. Although extremely valuable, existing solutions usually require complicated fabrication procedures and post-application treatments. Structural colors are ubiquitous in nature, so an interesting approach to developing AR coatings is biomimicry. Moth-eye structures are well-known for their AR properties, and they have been successfully replicated using micro- and nanofabrication methods and employed as AR coatings. Interestingly, recent studies from Harvard University highlight two types of microstructures that lead to super black coloring in nature, i.e., barbule microstructures on birds of paradise and cuticular bumps on peacock spiders. These publications provide detailed information on the shape of such natural super black microstructures and mechanisms behind the observed super black effect. Although the replication of such structures should prove extremely valuable, it has not yet been demonstrated. In this paper, we present the fabrication and characterization of AR microarrays inspired by the peacock spiders’ super black structures encountered in nature. Fabrication is done by super-resolution three-dimensional (3D) printing using two-photon polymerization of an acrylic resin. The optical properties of microstructure arrays with different shape design parameters are then characterized using a homemade reflectance/transmittance setup, which allows wavelength-dependent investigations in the ultraviolet, visible, and near-infrared ranges. The influence of the shape design parameters on the optical properties of the microarrays is then discussed with experimental measurements as well as simulations. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
171 KiB  
Abstract
Lab-on-Chip Platform for On-Field Analysis of Grapevine Leafroll-Associated Virus 3
by Ilaria Buja, Erika Sabella, Anna Grazia Monteduro, Maria Serena Chiriacò, Silvia Rizzato, Luigi De Bellis, Andrea Luvisi and Giuseppe Maruccio
Eng. Proc. 2021, 4(1), 16; https://doi.org/10.3390/Micromachines2021-09580 - 16 Apr 2021
Viewed by 753
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), resulting in food losses due to pathogens such as fungi, bacteria, viruses, etc. For this reason, [...] Read more.
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), resulting in food losses due to pathogens such as fungi, bacteria, viruses, etc. For this reason, we are developing lab-on-chip devices as diagnostic tools to identify and manage phytopathological problems caused by infectious agents capable of spreading in agro-ecosystems, such as the Xylella fastidiosa epidemic in Puglia [1] or other bacteriosis and virosis such as Grapevine leafroll-associated virus 3 (GLRaV-3).  [...] Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
112 KiB  
Abstract
A Piezo-MEMS Device for Fatigue Testing of Thin Metal Layers
by Aldo Ghisi, Nicolò Boni, Roberto Carminati and Stefano Mariani
Eng. Proc. 2021, 4(1), 17; https://doi.org/10.3390/Micromachines2021-09559 - 14 Apr 2021
Viewed by 576
Abstract
Several micro devices, such as micro-mirrors, are subjected to working conditions featuring alternating loadings that can possibly induce fatigue in the thin metal layers, which represent critical structural parts. The quantification of the degradation of the material properties under fatigue loading is a [...] Read more.
Several micro devices, such as micro-mirrors, are subjected to working conditions featuring alternating loadings that can possibly induce fatigue in the thin metal layers, which represent critical structural parts. The quantification of the degradation of the material properties under fatigue loading is a time-consuming task, and the effects of environmental conditions (e.g., humidity) and load characteristics (e.g., frequency, stress ratio) must be properly accounted for. In this work, we propose and assess the efficiency of an on-chip test device based on piezoelectric actuators, able to generate a time-varying (sinusoidal) strain in the mentioned thin metal layers and lead to fatigue. The aim of the research activity is the characterization of the stress/strain-induced degradation process of a thin layer located on the top of a lead zirconate titanate (PZT) actuation system. The characterization has been carried out through measurements of resistivity and roughness, carried out via an ohmmeter and a confocal microscope, respectively. The proposed testing device has shown capability to qualitatively highlight the degradation of the metal layers. A re-design of the on-chip device is also discussed in order to also carry out quantitative evaluations. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
111 KiB  
Abstract
On-Chip Assessment of Scattering in the Response of Si-Based Microdevices
by Aldo Ghisi and Stefano Mariani
Eng. Proc. 2021, 4(1), 18; https://doi.org/10.3390/Micromachines2021-09555 - 14 Apr 2021
Viewed by 496
Abstract
The response of micromachines to the external actions is typically affected by a scattering, which is, on its own, induced by their microstructure and by stages of the microfabrication process. The progressive reduction in size of the mechanical components, forced by a path [...] Read more.
The response of micromachines to the external actions is typically affected by a scattering, which is, on its own, induced by their microstructure and by stages of the microfabrication process. The progressive reduction in size of the mechanical components, forced by a path towards (further) miniaturization, has recently enhanced the outcomes of the aforementioned scattering, and provided a burst in research activities to address issues linked to its assessment. In this work, we discuss the features of an on-chip testing device that we purposely designed to efficiently estimate the two major sources of scattering affecting inertial, polysilicon-based micromachines: the morphology of the silicon film constituting the movable parts of the device, and the etch defect or over-etch induced by microfabrication. The coupled electro-mechanical behavior of the statically determinate movable (micro)structure of the on-chip device has been modeled via beam bending theory, within which the aforementioned sources of scattering have been accounted for through local fluctuating fields in the compliant part of the structure itself, namely the supporting spring. The proposed stochastic model is shown to outperform former ones available in the literature, which neglected the simultaneous and interacting effects of the two mentioned sources on the measure response. The model can fully catch the scattering in the C–V plots up to pull-in, hence, also in the nonlinear working regime of the device. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
134 KiB  
Abstract
Photocatalytic Oxygenation of Heterostilbenes in Microflow Reactors
by Matea Bačić, Milena Mlakić, Anita Šalić, Irena Škorić and Bruno Zelić
Eng. Proc. 2021, 4(1), 20; https://doi.org/10.3390/Micromachines2021-09585 - 16 Feb 2021
Viewed by 507
Abstract
Photochemistry involves processes in which light, the principal reagent, and photocatalysts open pathways to diversifying photochemical products. Promising results are obtained in reactions where porphyrin complexes coordinated with certain metals are used as catalysts. The most common porphyrin complexes used in various organic [...] Read more.
Photochemistry involves processes in which light, the principal reagent, and photocatalysts open pathways to diversifying photochemical products. Promising results are obtained in reactions where porphyrin complexes coordinated with certain metals are used as catalysts. The most common porphyrin complexes used in various organic reactions were manganese porphyrins. Nowadays, batch reactors used for photochemical reactions are commonly replaced with flow reactors. Microflow reactors are one of the reactor types, whose main characteristic is the micro-dimension of channels (max. diameter of 500 μm). Flow chemistry performed on a microscale brings improvements in many aspects of photochemical reactions, such as efficient and fast phase mixing and heat transfer, precise retention time control, homogeneous use of light irradiation throughout the reaction mixture, process safety, and potentially simple scale-up. In this research, anionic/cationic manganese(III) porphyrins were used as photocatalysts. The reactions were first performed in a batch reactor, where complete conversion of the substrate was observed after 2 h for furostilbene and 16 h for thienostilbene substrate. As a result, the formation of formyl, epoxy, carbonyl, or hydroxy derivatives was observed. A step forward in process development was made by replacing batch with microflow reactors. A total of four different tubular microflow reactors were studied and compared with results obtained in a batch reactor based on substrate conversion and reaction time. Reactions were significantly accelerated in the microflow reactors, where the complete substrate conversion for furostilbene substrate was observed in a residence time of 0.7 min and for thienostilbene substrate in 3.5 min. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
115 KiB  
Abstract
Droplet Formation in a Cross-Junction Microfluidic Channel with Non-Newtonian Dispersed Phase
by Maryam Fatehifar, Alistair Revell and Masoud Jabbari
Eng. Proc. 2021, 4(1), 21; https://doi.org/10.3390/Micromachines2021-09588 - 16 Apr 2021
Viewed by 787
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 [...] Read more.
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. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
140 KiB  
Abstract
Optimization of Manufacturing Parameters of 3D Printed Solid Microneedles for Transdermal Drug Delivery
by Kenan Muhamedagić, Amina Tucak, Merima Sirbubalo, Ognjenka Rahić, Lamija Hindija, Jasmina Hadžiabdić, Edina Vranić and Ahmet Čekić
Eng. Proc. 2021, 4(1), 22; https://doi.org/10.3390/Micromachines2021-09591 - 16 Apr 2021
Viewed by 748
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 [...] Read more.
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 a 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, 50, and 70 °C) and curing time (5, 20, 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. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
110 KiB  
Abstract
Piezoelectric Ultrasonic Micromotor
by Giorgio Casiraghi, Daniele Caltabiano, Andrea Picco and Stefano Mariani
Eng. Proc. 2021, 4(1), 24; https://doi.org/10.3390/Micromachines2021-09560 - 14 Apr 2021
Viewed by 700
Abstract
Ultrasonic motors are characterized by low speed and high-torque operation, without the need for gear trains. They can be compact and lightweight, and they can also work in the absence of applied loads, due to the frictional coupling between the rotor and the [...] Read more.
Ultrasonic motors are characterized by low speed and high-torque operation, without the need for gear trains. They can be compact and lightweight, and they can also work in the absence of applied loads, due to the frictional coupling between the rotor and the stator induced by the traveling wave. In this work, we discuss a concept design based on thin piezoelectric films, sol-gel directly deposited onto a silicon substrate to provide high-torque motors compatible with wafer integration technologies. Due to the large dielectric constants and the enhanced breakdown strengths of thin piezoelectric films, such ultrasonic micromotors can lead to meaningful improvements over electrostatic ones in terms of energy density. As far as the fabrication of the micromotor at the mm-scale is concerned, an integrated approach is proposed with significant improvements regarding: the comb-tooth structure, to maximize/optimize the motor torque; a back and front etch lithographic process; and the design of the electrodes, which provide the electric signal at the central anchor of the stator, taking advantage of low-temperature soldering. The proposed design has been assessed through multiphysics simulations, carried out to evaluate the resonant behavior of the stator and the motor performance in terms of angular velocity, torque, and output power, and it is shown to lead to promising results. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
141 KiB  
Abstract
Purification of Biodiesel Produced by Lipase Catalysed Transesterification by Two-Phase Systems Based on Deep Eutectic Solvents in a Microextractor: Selection of Solvents and Process Optimization
by Sara Anđelović, Marko Božinović, Željka Ćurić, Martin Gojun, Kristina Zagajski Kučan, Anita Šalić and Bruno Zelić
Eng. Proc. 2021, 4(1), 25; https://doi.org/10.3390/Micromachines2021-09592 - 16 Apr 2021
Viewed by 1156
Abstract
The most important and the most used process of biodiesel synthesis is transesterification. The main byproduct formed in the biodiesel synthesis by transesterification is glycerol. Biodiesel produced by transesterification is not suitable for application in engines since it contains soap (if biodiesel is [...] Read more.
The most important and the most used process of biodiesel synthesis is transesterification. The main byproduct formed in the biodiesel synthesis by transesterification is glycerol. Biodiesel produced by transesterification is not suitable for application in engines since it contains soap (if biodiesel is produced by chemical catalysis), traces of the catalyst, methanol, metals, water, oil, and glycerides. All those impurities must be removed in order to reach the standards (ASTM D6751 and EN 14214). The most dominant industrial method for biodiesel purification is wet washing, which generates up to 10 L of wastewater per 1 L of purified biodiesel. Therefore, cheaper and more efficient solutions for biodiesel purification should be found. Deep eutectic solvents (DESs) have been already demonstrated as viable options in biodiesel purification. DESs, a mixture of two or more components with a lower melting point than each individual component, are considered less toxic to the environment, non-volatile, biodegradable, and more stable; in other words, they are economically and environmentally friendly in comparison with organic solvents. In this study, purification of biodiesel produced by lipase catalysed transesterification by DESs was performed by two-phase liquid extraction in a microextractor. A total of 13 different DESs were synthesized and used for biodiesel purification in order to find the one that provides the best glycerol extraction efficiency. After initial screening, three DESs were selected and used for the optimization of process conditions for extraction performed in a microsystem. A three-level-four-factor Box–Behnken experimental design was employed to define the optimal process conditions (biodiesel–DES mass ratio, temperature, residence time). At optimal process conditions, the glycerol content in biodiesel was reduced below 0.02% (w/w), which is the value specified by standards (ASTM D6751 and EN 14214). Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
1 pages, 139 KiB  
Abstract
The Effect of Micromixer Geometry on the Diameters of Emulsion Droplets: NIR Spectroscopy and Artificial Neural Networks Modeling
by Tamara Jurina, Ivana Čulo, Maja Benković, Jasenka Gajdoš Kljusurić, Davor Valinger and Ana Jurinjak Tušek
Eng. Proc. 2021, 4(1), 26; https://doi.org/10.3390/Micromachines2021-09658 - 27 Apr 2021
Viewed by 797
Abstract
In this work, teardrop micromixer and swirl micromixer were used for preparation of oil-in-water (O/W) emulsions with Tween 20 and PEG 2000 as emulsifiers (concentrations: 2% and 4%) at different total flow rates (20–280 µL/min). Stability of the prepared O/W emulsions was evaluated [...] Read more.
In this work, teardrop micromixer and swirl micromixer were used for preparation of oil-in-water (O/W) emulsions with Tween 20 and PEG 2000 as emulsifiers (concentrations: 2% and 4%) at different total flow rates (20–280 µL/min). Stability of the prepared O/W emulsions was evaluated based on the droplet size of the dispersed phase. For determination of the droplet size, the average Feret diameter was used. Furthermore, near infrared (NIR) spectra of all prepared samples were collected. Obtained results showed that the change in the droplet size followed the same trend for both micromixers used in the experiment. At higher total flow rates, emulsification resulted in smaller values of the average Feret diameter. Values of the average Feret diameter were higher for emulsions prepared in the swirl micromixer, compared to the teardrop micromixer. Artificial Neural Network (ANNs) models, based on the recorded NIR spectra of emulsions, were developed to predict the droplet size of the dispersed phase. The obtained ANN models have high values of R2 for training, test, and validation, with small error values and show that NIR spectroscopy, in combination with ANNs, could be efficiently used for evaluation of the stability of oil-in-water emulsions. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
115 KiB  
Abstract
A Deep Learning-Based Approach to Uncertainty Quantification for Polysilicon MEMS
by José Pablo Quesada-Molina and Stefano Mariani
Eng. Proc. 2021, 4(1), 27; https://doi.org/10.3390/Micromachines2021-09556 - 14 Apr 2021
Viewed by 613
Abstract
The path towards miniaturization for micro-electro-mechanical systems (MEMS) has recently increased the effects of stochastic variability at the (sub)micron scale on the overall performance of the devices. We recently proposed and designed an on-chip testing device to characterize two sources of variability that [...] Read more.
The path towards miniaturization for micro-electro-mechanical systems (MEMS) has recently increased the effects of stochastic variability at the (sub)micron scale on the overall performance of the devices. We recently proposed and designed an on-chip testing device to characterize two sources of variability that majorly affect the scattering in response to the external actions of inertial (statically determinate) micromachines: the morphology of the polysilicon film constituting the movable parts of the device, and the environment-affected over-etch linked to the microfabrication process. A fully stochastic model of the entire device has been set to account for these two sources on the measurable response of the devices, e.g., in terms of the relevant C-V curves up to pull-in. A complexity in the mentioned model is represented by the need to assess the stochastic (local) stiffness of polysilicon, depending on its unknown (local) microstructure. In this work, we discuss a deep learning approach to the micromechanical characterization of polysilicon films, based on densely connected neural networks (NNs). Such NNs extract relevant features of the polysilicon morphology from SEM-like Voronoi tessellation-based digital microstructures. The NN-based model or surrogate is shown to correctly catch size effects at a varying ratio between the characteristic size of the structural components of the device, and the morphology-induced length scale of the aggregate of silicon grains. This property of the model looks to indeed be necessary to prove the generalization capability of the learning process, and to next feed Monte Carlo simulations resting on the model of the entire device. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
115 KiB  
Abstract
The Internal Cracks’ Influence on The Stress Behavior of Al2O3 Tribo-Mechanical System Under Contact Pressures
by Corina Birleanu, Marius Pustan and Florina Serdean
Eng. Proc. 2021, 4(1), 28; https://doi.org/10.3390/Micromachines2021-09565 - 14 Apr 2021
Viewed by 457
Abstract
Ceramic materials have properties such as: high hardness; high ratio between mechanical resistance/density, wear and corrosion resistance; high stability to the action of corrosive agents; and relatively low price. However, the use of technical ceramics has a rather limited area, determined essentially by [...] Read more.
Ceramic materials have properties such as: high hardness; high ratio between mechanical resistance/density, wear and corrosion resistance; high stability to the action of corrosive agents; and relatively low price. However, the use of technical ceramics has a rather limited area, determined essentially by its tribo-mechanical behavior. The machine parts may fail and not fulfill their functional role due to some limit factors. This paper is based on the behavior of aluminum ceramics in terms of stress and strain in the contact area, and the tribological behavior of these materials. A mathematical concept, including multi-objective optimization based on the cuckoo search algorithm of breaking ceramic materials in which there are defects in the form of internal cracks, has been developed. A defect criterion has been formulated to allow the evaluation of the propagation of the semicircular crack which shapes the places where there are natural defects in the ceramic mass. The model highlighted is the contact between two curved surfaces, specific to the ball–ring contact in the bearings. It has highlighted tensions stress and the stress factors, taking into account the coefficient of conformity and the influence of the friction effects. The experimental study of the mechanical stress state in the contact areas was carried out with the ceramic friction couple ball-bearing ring (Al2O3—99.7% with the addition of SiO2, Fe2O and MgO). A large number of experimental tests were performed. The results of this research work are useful for mechanical designers to identify the crack effect on mechanical parts’ lifetime and to improve reliability. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
140 KiB  
Abstract
Nanotribological Investigation of the Poly(3-hydroxybutyrate) Films Manufactured from the Storage Polyesters Produced by Halomonas elongata DSM 2581T
by Marius Pustan, Corina Bîrleanu, Adorján Cristea and Horia Leonard Banciu
Eng. Proc. 2021, 4(1), 29; https://doi.org/10.3390/Micromachines2021-09564 - 14 Apr 2021
Viewed by 552
Abstract
Poly(3-hydroxybutyrate) (PHB) is a natural and biodegradable storage polyester, produced by numerous bacteria, which is considered a potential substituent for conventional plastics in the packaging industry. The improvement of the PHB material lifetime often involves mechanical and tribological characterization, which can be accurately [...] Read more.
Poly(3-hydroxybutyrate) (PHB) is a natural and biodegradable storage polyester, produced by numerous bacteria, which is considered a potential substituent for conventional plastics in the packaging industry. The improvement of the PHB material lifetime often involves mechanical and tribological characterization, which can be accurately performed on thin films. In this study, we aimed at the evaluation of the tribological properties, such as adhesion force, friction coefficient and wear resistance, of different polyester films, fabricated via the solvent casting method. Three polyester films were designed in this study, each containing 1% w/v constituents as follows: a PHBh film prepared out of the PHB, extracted from the extremely halotolerant bacteria, Halomonas elongata DSM2581T, a PHBc film fabricated using a commercially available PHB, and a PHBVc film generated using the commercial poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The spectroscopy-in-point of AFM was used for adhesion force measurement based on multiple tests performed in a matrix, and the AFM lateral operating mode was applied for friction analysis under a controlled normal load. The fabricated PHBh film presented a thickness between 5 and 7 µm, a lower adhesion force (14 nN) as well as a smaller friction coefficient (0.15) compared to the PHBc and PHBVc. The tribological investigations of PHBh film revealed a biodegradable material with low roughness, as well as small adhesion and friction forces. Further optimization can be performed for the improvement of the PHBh film by copolymerization with other polymers, polyesters, and reinforcers, thus generating a feasible material with advanced tribo-mechanical features. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
112 KiB  
Abstract
Dynamic Characterization of Biosensing MEMS Cantilevers with Different Position of the Driving Electrode—Vacuum Response Versus Ambient Conditions
by Marius Pustan, Corina Birleanu and Florina Serdean
Eng. Proc. 2021, 4(1), 30; https://doi.org/10.3390/Micromachines2021-09594 - 16 Apr 2021
Viewed by 538
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 towards identifying [...] Read more.
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 towards identifying the effect of driving electrode position on the dynamic response of sensing MEMS used in biomass 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 a 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 (first, second and third 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. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
116 KiB  
Abstract
Biodegradable and Transparent PVA/Starch-Based Composite Films for Wound Dressing Applications
by Mohammad Mohsen Delavari and Ion Stiharu
Eng. Proc. 2021, 4(1), 31; https://doi.org/10.3390/Micromachines2021-09547 - 14 Apr 2021
Viewed by 922
Abstract
Industrial plastic production has the significant benefits of convenience, safety, and low cost. Further to the benefits are added the aesthetic qualities, the mechanical strength and the capability to mix with other materials such as fibers. All these contributed to the rapid expansion [...] Read more.
Industrial plastic production has the significant benefits of convenience, safety, and low cost. Further to the benefits are added the aesthetic qualities, the mechanical strength and the capability to mix with other materials such as fibers. All these contributed to the rapid expansion of plastics (polystyrene and nylon) in multiple applications and various purposes, such as biomedical materials, packaging, transport, industry, and agriculture. On the other hand, global warming is now one of the most concerning issues for all people. It is considered that replacing some of the conventional materials in various applications such as wound dressings with biodegradable starch-based films is a step forward in addressing environmental issues. Due to mechanical debriding of tissues, traditional dressings like regular cotton gauzes are counterproductive and end up causing painful wound trauma during dressing procedures. The development of transparent wound dressing films enables a moist healing environment with enhanced bacterial impermeability. The performance of polyvinyl alcohol/starch/citric acid (PVA/St/CA) based composite film for wound dressing applications is addressed in this work. Literature recorded fixed composition of PVA (2.5 w/w%), starch (2.5 w/w%), and glycerol (2 w/w%) during 70–80 °C casting temperature. Different citric acid concentrations (0.5 to 2 g) were investigated during the development of composite film solution casting. Prepared samples have been characterized by swelling index, solubility-dependent biodegradability, and tensile strength (TS). The film also exhibits enhanced combinations of the water vapor transmission rate and antibacterial efficiency against the bacterial flora (various bacteria existent in the air). As an extra benefit, such materials are easily degraded in water for up to seven days with a minute footprint. A potential candidate for wound dressing applications has been inferred from the biodegradable PVA/St/CA films with all these useful features. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
125 KiB  
Abstract
Mass Sensitivity Analysis of a Newly Developed Quartz Crystal Microbalance with Ring-Dot Electrode Configuration and Reduced Mass Loading Area
by Siddharth Swaminathan and Arezoo Emadi
Eng. Proc. 2021, 4(1), 32; https://doi.org/10.3390/Micromachines2021-09563 - 14 Apr 2021
Viewed by 608
Abstract
Quartz Crystal Microbalance (QCM) is used for detecting microgram level mass changes in gas and liquid phase. Conventional QCM design comprises a circular electrode configuration with an evenly distributed mass loading area. However, their mass sensitivity distribution is found to be non-uniform due [...] Read more.
Quartz Crystal Microbalance (QCM) is used for detecting microgram level mass changes in gas and liquid phase. Conventional QCM design comprises a circular electrode configuration with an evenly distributed mass loading area. However, their mass sensitivity distribution is found to be non-uniform due to the inherent energy trapping effect. In this paper, the recently developed QCM with a ring electrode and a ring-dot electrode configuration are evaluated. It is shown that this new configuration offers the ability to achieve a uniform mass sensitivity distribution, while attaining a comparable mass sensitivity for a reduced mass loading area. Finite Element Analysis is used to design and evaluate the conventional circular electrode QCM, and the proposed ring electrode and ring-dot electrode QCM configurations, where the mass loading area is reduced by 25% compared with the conventional sensor. Simulations are conducted to determine the sensor’s resonant frequency shifts for an added mass per unit area of 20 μg/mm2. The results indicate that newly designed ring and ring-dot electrode configurations operate at a higher resonant frequency. The observed frequency shift for the designed circular electrode, ring electrode, and ring-dot electrode configurations on a 333 μm thick quartz substrate are 85 kHz, 84 kHz, and 82 kHz, respectively. It is shown that the ring electrode and new ring-dot electrode configurations achieve a higher resonant frequency and offer a comparable sensing performance despite comprising of over 25% reduced mass loading area, in comparison to the conventional circular electrode configuration. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
115 KiB  
Abstract
3D Polymer Structures for the Identification of Optimal Dimensions for Cellular Growth for 3D Lung Alveolar Models
by Christian Maibohm, Alberto Saldana-Lopez, Oscar F. Silvestre and Jana B. Nieder
Eng. Proc. 2021, 4(1), 33; https://doi.org/10.3390/Micromachines2021-09596 - 16 Apr 2021
Cited by 1 | Viewed by 686
Abstract
Organ-on-chips and scaffolds for tissue engineering are vital assay tools for pre-clinical testing and prediction of human response to drugs and toxins, while providing an ethically sound alternative to animal testing and a low-cost alternative to expensive clinical studies. An important success criterion [...] Read more.
Organ-on-chips and scaffolds for tissue engineering are vital assay tools for pre-clinical testing and prediction of human response to drugs and toxins, while providing an ethically sound alternative to animal testing and a low-cost alternative to expensive clinical studies. An important success criterion for these models is the ability to have structural parameters for optimized performance. In this study we show how the two-photon polymerization fabrication method can be used to create 3D test platforms made for analyzing optimal scaffold parameters for cell growth. We design and fabricate a 3D grid structure, designed as a set of wall structures with niches of various dimensions for probing the optimal niche for cell attachment. The 3D grid structures are fabricated from bio-compatible polymer SZ2080 and subsequently seeded with A549 lung epithelia cells. The seeded structures are incubated and imaged with multi-color spectral confocal microscopy at several time points, to determine the volume of cell material present in the different niches of the grid structure. Spectral imaging with linear unmixing is used to separate the auto-fluorescence contribution from the scaffold from the fluorescence of the cells and use it to determine the volume of cell material present in the different sections of the grid structure. The variation in structural parameters influences the incubated A549 cells’ distribution and morphology. In future, this kind of differentiated 3D growth platform could be applied for optimized culture growth, cell differentiation and advanced cell therapies. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
111 KiB  
Abstract
Facile Synthesis of 3D Printed Tailor-Shape Electrode PLA-GnP for Electrochemical Sensing
by Denesh Mohan, Farrah Aida Arris, Mohd Shaiful Sajab and Nurul Nasuha Mansor
Eng. Proc. 2021, 4(1), 34; https://doi.org/10.3390/Micromachines2021-09571 - 15 Apr 2021
Cited by 1 | Viewed by 682
Abstract
Additive manufacturing (AM) has made enormous advancements in technology and materials development, and attention is required for the development of functionalized printed materials. AM can assist in manufacturing complex designed tailored-shaped electrodes efficiently for electrochemical sensing in the food industry. Herein, we used [...] Read more.
Additive manufacturing (AM) has made enormous advancements in technology and materials development, and attention is required for the development of functionalized printed materials. AM can assist in manufacturing complex designed tailored-shaped electrodes efficiently for electrochemical sensing in the food industry. Herein, we used commercial fused deposition modeling (FDM) filament and polylactic acid (PLA) for FDM 3D printing of a self-designed electrode with minimal time and cost compared to commercial electrodes. Surface functionalization on the 3D printed PLA electrode was conducted using GnP to enhance the electrical conductivity. Scanning electron microscopy confirmed the homogenized surface coating of GnP that provides electron flow behavior for the 3D printed electrode. The electrochemically functionalized 3D printed electrode was tested against standard 3-monochloropropane-1,2-diol (3-MCPD) with known concentrations and characterized using cyclic voltammetry and differential pulse voltammetry methods. The results showed a basis for the promising application of detecting and quantifying 3-MCPD, a food contaminant known for its potential of being carcinogenic. The fabrication of functionalized 3D printed polymer electrodes paves the way for the development of complete 3D-printable electrochemical systems. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
122 KiB  
Abstract
Experimental Studies of the Sedimentation, Stability and Thermal Conductivity of Two Different Nanofluids
by Reinaldo Rodrigues de Souza, Vera Faustino, Inês Maia Gonçalves, João Mário Miranda, Ana Sofia Moita, Antônio L. N. Moreira, Manuel Bañobre-López and Rui Lima
Eng. Proc. 2021, 4(1), 35; https://doi.org/10.3390/Micromachines2021-09589 - 16 Apr 2021
Viewed by 791
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. [...] Read more.
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. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
119 KiB  
Abstract
In-Ear Energy Harvesting: Source Characterization and Mechanical Simulator (Part I)
by Michel Demuynck, Aidin Delnavaz, Jérémie Voix, Tigran Avetissian, Adrien Badel and Fabien Formosa
Eng. Proc. 2021, 4(1), 36; https://doi.org/10.3390/Micromachines2021-09568 - 14 Apr 2021
Viewed by 893
Abstract
During daily activities, such as chewing, eating, speaking, and so forth, the human jaw moves, and the earcanal is deformed by its anatomic neighbor called the temporomandibular joint (TMJ). Given the frequency of those jaw joint activities, the earcanal dynamic movement is a [...] Read more.
During daily activities, such as chewing, eating, speaking, and so forth, the human jaw moves, and the earcanal is deformed by its anatomic neighbor called the temporomandibular joint (TMJ). Given the frequency of those jaw joint activities, the earcanal dynamic movement is a promising source of energy in close proximity to the ear, and such energy can be harvested by using a mechanical–electrical transducer dubbed energy harvester. However, the optimal design of such micromachine requires the characterization of the TMJ’s range of motion, its mechanical action on the earcanal, and its mechanical power capability. For that purpose, this research presents two methods for analyzing the earcanal dynamic movements: first, an in situ approach based on the measurement of the pressure variation in a water-filled earplug fitted inside the ear canal, and second, an anatomic-driven mechanism in the form of a chewing test fixture capable of reproducing the TMJ kinematics with great precision. The pressure earplug system provides the earcanal global dynamics, which can be derived as an equivalent displaced volume, while the chewing test fixture provides the discrete displacement along the earcanal wall. Both approaches are complementary and contribute to a better analysis of the interaction between the TMJ and earcanal. Ultimately, knowledge of the maximum displacement area and the derived generated power within the earcanal will lead to the design of a micromachine, allowing for the further investigation of in-ear energy harvesting strategies. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
129 KiB  
Abstract
Separation Microfluidic Device Fabricated by Micromilling Techniques
by Inês Maia Gonçalves, Miguel Madureira, Inês Miranda, Helmut Schütte, Ana Moita, Graça Minas, Stefan Gassmann and Rui Lima
Eng. Proc. 2021, 4(1), 37; https://doi.org/10.3390/Micromachines2021-09599 - 16 Apr 2021
Viewed by 636
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 [...] Read more.
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 μL/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. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
129 KiB  
Abstract
Fiber Optic Sensor for Detecting Neoplastic Lesions in Biological Tissues—A Preliminary Study
by Anna Sękowska-Namiotko
Eng. Proc. 2021, 4(1), 38; https://doi.org/10.3390/Micromachines2021-09595 - 16 Apr 2021
Viewed by 502
Abstract
Tissues affected by neoplastic lesions differ from healthy tissues in terms of functionality and anatomy. These changes affect light’s propagation in tissue by modifying the refractive index, and scattering and absorption coefficients. The primary purpose of this research was to create a system [...] Read more.
Tissues affected by neoplastic lesions differ from healthy tissues in terms of functionality and anatomy. These changes affect light’s propagation in tissue by modifying the refractive index, and scattering and absorption coefficients. The primary purpose of this research was to create a system to detect local changes in the refractive index using a fiber optic sensor. A prototype of a micromachine for biomedical applications has been developed. The measurements were performed using the low-coherence interferometry method, i.e., a measurement technique based on the interference of light waves from a broadband light source. The constructed optical system uses a light source with a central wavelength of 1550 nm, a spectrum analyzer, a fiber optic sensor operating on the basis of a Fabry–Perot interferometer and a silver mirror acting as a reflective layer. Measurements of the interference spectrum of reference oils, used for calibration due to the high stability of their parameters, were performed. It has been shown that the developed fiber optic sensor is able to detect changes in the refractive index based on a shift in the position of the central peak in the interference spectrum. It is also sensitive to changes of the absorption coefficient. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
111 KiB  
Abstract
Manipulation of Microrobots Using Chladni Plates and Multimode Membrane Resonators
by Lillian Ngo Usadi, Steven Yee, Hatem ElBidweihy and Samara Firebaugh
Eng. Proc. 2021, 4(1), 39; https://doi.org/10.3390/Micromachines2021-09593 - 16 Apr 2021
Cited by 2 | Viewed by 730
Abstract
(1) 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, [...] Read more.
(1) 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. (2) 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. (3) 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: (i) macroscale manipulation with a Chladni plate in air; and (ii) 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. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
126 KiB  
Abstract
Sensitivity Analysis of a Portable Wireless PCB-MEMS Permittivity Sensor Node for Non-Invasive Liquid Recognition
by Javier Meléndez-Campos, Matias Vázquez-Piñón and Sergio Camacho-Leon
Eng. Proc. 2021, 4(1), 40; https://doi.org/10.3390/Micromachines2021-09597 - 16 Apr 2021
Viewed by 596
Abstract
Dielectric characteristics are useful to determine crucial properties of liquids and to differentiate between liquid samples with similar physical characteristics. Liquid recognition has found applications in a broad variety of fields, including healthcare, food science, and quality inspection, among others. This work demonstrates [...] Read more.
Dielectric characteristics are useful to determine crucial properties of liquids and to differentiate between liquid samples with similar physical characteristics. Liquid recognition has found applications in a broad variety of fields, including healthcare, food science, and quality inspection, among others. This work demonstrates the fabrication, instrumentation, and functionality of a portable wireless sensor node for permittivity measurement of liquids that require characterization and differentiation. The node incorporates an interdigitated microelectrode array as transducer, and a microcontroller unit with radio communication electronics for data processing and transmission, which enables a wide variety of stand-alone applications. A laser-ablation-based microfabrication technique is applied to fabricate the microelectromechanical systems (MEMS) transducer on a printed circuit board (PCB) substrate. The surface of the transducer is covered with a thin layer of SU-8 polymer by spin coating, which prevents direct contact between the Cu electrodes and the liquid sample. This helps to enhance durability, avoid electrode corrosion and contamination of the liquid sample, and to prevent undesirable electrochemical reactions from arising. The transducer’s impedance was modelled as a Randles cell, having resistive and reactive components determined analytically, using a square wave as stimuli and a resistor as a current-to-voltage converter. To characterize the node sensitivity under different conditions, three different transducer designs were fabricated and tested for four different fluids—i.e., air, isopropanol, glycerin, and distilled water—achieving a sensitivity of 1.6965 +/− 0.2028 εr/pF. The use of laser ablation allowed the reduction of the transducer footprint while maintaining its sensitivity within an adequate value for the targeted applications. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
118 KiB  
Abstract
Rapid Lipid Content Screening in Neochloris Oleoabundans by Carbon-Based Dielectrophoresis
by Cynthia M. Galicia-Medina, Matías Vázquez-Piñón, Sergio Camacho-León, Gibran S. Alemán-Nava, Roberto C. Gallo-Villanueva, Sergio O. Martínez-Chapa, Marc J. Madou, Jonathan S. García-Pérez, Diego A. Esquivel-Hernández, Roberto Parra-Saldivar and Víctor H. Pérez-González
Eng. Proc. 2021, 4(1), 41; https://doi.org/10.3390/Micromachines2021-09605 - 21 Apr 2021
Viewed by 627
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 CO2 fixation rate, contributing to the [...] Read more.
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 CO2 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 dielectrophoretically assorted in a microfluidic device using castellated carbon microelectrodes. The experiments 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 spectrophotometry, and the resulting lipid development among cells was quantified by Nile red fluorescence. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
121 KiB  
Abstract
Comparative Evaluation of Artificial Neural Networks and Data Analysis in Predicting Liposomes’ Size in a Periodic Disturbance Micromixer
by Ixchel Ocampo, Rubén R. Lopéz, Vahée Nerguizian, Ion Stiharu and Sergio Camacho León
Eng. Proc. 2021, 4(1), 42; https://doi.org/10.3390/Micromachines2021-09549 - 17 Feb 2021
Viewed by 531
Abstract
Artificial Neural Networks (ANN) and Data analysis are powerful tools used for supporting decision-making. They have been employed in diverse fields and one of them is nanotechnology used, for example, in predicting particles size. Liposomes are nanoparticles used in different biomedical applications that [...] Read more.
Artificial Neural Networks (ANN) and Data analysis are powerful tools used for supporting decision-making. They have been employed in diverse fields and one of them is nanotechnology used, for example, in predicting particles size. Liposomes are nanoparticles used in different biomedical applications that can be produced in Dean Forces-based Periodic Disturbance Micromixers (PDM). In this work, ANN and data analysis techniques are used to build a liposome size prediction model by using the most relevant variables in a PDM, i.e., Flow Rate Radio (FRR) and Total Flow Rate (TFR). The ANN was designed in MATLAB and fed data from 60 experiments, which were 70% training, 15% validation and 15% testing. For data analysis, regression analysis was used. The model was evaluated; it showed 98.147% of regression number for training and 97.247% in total data compared with 78.89% regression number obtained by data analysis. These results demonstrate that liposomes’ size can be better predicted by ANN with just FRR and TFR as inputs, compared with data analysis techniques when the temperature, solvents, and concentrations are kept constant. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
121 KiB  
Abstract
In-Ear Energy Harvesting: Harvester Design and Validation (Part II)
by Tigran Avetissian, Fabien Formosa, Adrien Badel, Michel Demuynck, Aidin Delnavaz and Jérémie Voix
Eng. Proc. 2021, 4(1), 43; https://doi.org/10.3390/Micromachines2021-09567 - 14 Apr 2021
Viewed by 675
Abstract
The mechanical deformation of the ear canal induced by the temporomandibular joint movement constitutes a promising source of energy to power in-ear devices (hearing aids, communication earpieces, etc.). The large morphological variability of the human ear canal and its intrinsic dynamic characteristics—with displacement [...] Read more.
The mechanical deformation of the ear canal induced by the temporomandibular joint movement constitutes a promising source of energy to power in-ear devices (hearing aids, communication earpieces, etc.). The large morphological variability of the human ear canal and its intrinsic dynamic characteristics—with displacement frequencies below 1.5 Hz with an average volume variation of 60 mm3—motivate the development of non-conventional dedicated energy harvesting methods. This paper demonstrates the concept and design of a modular hydraulic–piezoelectric self-actuated frequency up-conversion micromachine for energy harvesting. The mechanical energy is conveyed using a liquid-filled custom fitted earplug, which can be considered as a hydraulic pump. A hydraulic circuit composed of a pressure amplifier, two driven valves and two check valves allows to drive two micro-pistons. These micro-pistons actuate a bistable oscillator associated to a piezoelectric transducer allowing the low frequency mechanical excitation to be efficiently converted into electric energy through frequency-up conversion. The two integrated passively driven valves are based on tube buckling and allow the pistons to act alternatively on the oscillator to generate a backward and forward run for two jaw movements. A complete theoretical multiphysics model of the machine has been established for the design and evaluation of the potential of the proposed approach. Global analytical and refined FEM approaches have been combined to integrate the fluid and mechanical behaviors. Based on simulation and preliminary experimental data, the harvested energy is expected to be 8 µJ for one jaw closing, with a theoretical 40% end-to-end conversion efficiency. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
125 KiB  
Abstract
Simulation of Different Age Distributions for the Analysis of the Aging Curve of a Population of “S. cerevisiae
by Ivonne Paola Rojas Martínez, David Camilo Durán and Juan Manuel Pedraza
Eng. Proc. 2021, 4(1), 44; https://doi.org/10.3390/Micromachines2021-09577 - 16 Apr 2021
Viewed by 554
Abstract
Newly developed microfluidic devices (“Mother Machines”) have improved data gathering for the study of aging in unicellular models, and thereby the understanding of this process. Each device has different features that cause them to have certain advantages or disadvantages. This has the advantage [...] Read more.
Newly developed microfluidic devices (“Mother Machines”) have improved data gathering for the study of aging in unicellular models, and thereby the understanding of this process. Each device has different features that cause them to have certain advantages or disadvantages. This has the advantage of not using mechanical pressure to trap the cells, but as it starts with a mixed age population it does not guarantee that the cells studied are virgin. One of the basic outputs in these studies is the aging curve, which shows how the fraction of viable cells varies with respect to time. From this it can be deduced how fast or slow the population ages. For devices where it is not possible to work with virgin cells, the age distribution is assumed, but changes in this distribution could affect the analysis of the data. Therefore, the present work seeks to carry out a series of simulations to find the different age distributions that could be present and determine the corresponding changes in the aging curve. We propose two population growth models, synchronous and asynchronous. For each model we will start with the possible age distributions and determine the various curves that can be obtained and then compare these computational results with the experimental data to propose a better interpretation of the data obtained from mother machine devices. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
121 KiB  
Abstract
Stable Porous Silicon Membranes for Fast Bacterial Detection
by Laurent A. Francis, Roselien Vercauteren, Audrey Leprince and Jacques Mahillon
Eng. Proc. 2021, 4(1), 45; https://doi.org/10.3390/Micromachines2021-09598 - 16 Apr 2021
Viewed by 608
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 [...] Read more.
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. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
113 KiB  
Abstract
Rotating Micromachines with Stratified Disk Architecture for Dynamic Bioanalysis
by Gungun Lin, Yuan Liu, Guan Huang, Yinghui Chen, Denys Makarov and Dayong Jin
Eng. Proc. 2021, 4(1), 46; https://doi.org/10.3390/Micromachines2021-09572 - 15 Apr 2021
Viewed by 604
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, [...] Read more.
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. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
125 KiB  
Abstract
Carbon-Origami: Controlling 3D Shapes and Microstructure
by Marc Madou
Eng. Proc. 2021, 4(1), 47; https://doi.org/10.3390/Micromachines2021-09557 - 14 Apr 2021
Viewed by 580
Abstract
Over the last two decades, we have gained more and more insight into how to convert patterned polymer precursors into predicable 3D carbon shapes using pyrolysis/carbonization (carbon origami are a more recent example). Over the last four years, we have started gaining control [...] Read more.
Over the last two decades, we have gained more and more insight into how to convert patterned polymer precursors into predicable 3D carbon shapes using pyrolysis/carbonization (carbon origami are a more recent example). Over the last four years, we have started gaining control over the internal carbon microstructure and its functionality. The key to the latter is a precise control of the polymer precursor chains and the exact polymer atomic composition of the polymer before and during pyrolysis. Contradicting Rosalind Franklin, we have found that it is possible to graphitize even non-graphitizing carbons, simply by applying mechanical stresses to align the polymer precursor chains and stabilizing them in position before pyrolysis. Perhaps the most surprising outcome of this work is the demonstration of the conversion of PAN fibers through pyrolysis into turbostratic graphene-suspended wires with diameters as small as 2 nanometers. The suspended graphene bridges have a conductivity similar to that of multiwall carbon nanotubes (MWCNTs), a Young’s modulus of >400 GPa, and electrochemically the material behaves similarly to graphene doped with nitrogen. The latter material represents a very electroactive electrode ideally suited for energy and sensing applications. The current fabrication process for graphene doped with nitrogen is lengthy and complicated; ours is a one-step, simple process that is easily scalable. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
117 KiB  
Abstract
Elasto-Magnetic Pumps Integrated within Microfluidic Devices
by Jacob L. Binsley, Elizabeth L. Martin, Thomas O. Myers, Stefano Pagliara and Feodor Y. Ogrin
Eng. Proc. 2021, 4(1), 48; https://doi.org/10.3390/Micromachines2021-09590 - 16 Apr 2021
Viewed by 637
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 utilized outside of the [...] Read more.
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 utilized 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 that 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 three-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 direction of the resultant flow can be controlled by adjusting the frequency of the driving field. The device has been 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 portable applications. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)

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Jump to: Research

6 pages, 595 KiB  
Proceeding Paper
Effects of Electrical Stress in Solution-Processed Spin-On Glass Dielectric Films: Frequency Dependence
by Ovier Obregon, Salvador Alcantara, Susana Soto and Miguel A. Dominguez
Eng. Proc. 2021, 4(1), 2; https://doi.org/10.3390/Micromachines2021-09543 - 14 May 2021
Viewed by 1300
Abstract
In this work, the effects of the frequency dependence of transparent dielectric based on Spin-on Glass (SOG) under electrical stress is presented. The SOG thin films were cured at 200 °C in ambient air. The capacitance-voltage and capacitance-frequency characteristics were measured in Metal-Oxide-Semiconductor [...] Read more.
In this work, the effects of the frequency dependence of transparent dielectric based on Spin-on Glass (SOG) under electrical stress is presented. The SOG thin films were cured at 200 °C in ambient air. The capacitance-voltage and capacitance-frequency characteristics were measured in Metal-Oxide-Semiconductor (MOS) capacitors using the SOG thin film. In addition, electrical stress is applied to the MOS capacitors at different voltage values and during a long period of time. The results show, depending on the bias stress applied, a reversible interface charge contribution and an irreversible charge induced by interface states probably generated by the degradation of the film. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
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641 KiB  
Proceeding Paper
Influence of Inductive Effect in Organic Residuals Content in IZO Thin Films and the Performance on the Behavior of MIS Capacitors on Plastic
by Sonia Ceron, Abdu Orduña-Diaz and Miguel A. Dominguez
Eng. Proc. 2021, 4(1), 9; https://doi.org/10.3390/Micromachines2021-09551 - 14 Apr 2021
Cited by 1 | Viewed by 955
Abstract
In this work, zinc oxide and indium-doped zinc oxide thin films at different concentrations were deposited by solution techniques at 200 °C. The thin films were characterized by XRD, Raman, FTIR and the four-point probe technique. Through FTIR spectroscopy, interesting behavior was observed [...] Read more.
In this work, zinc oxide and indium-doped zinc oxide thin films at different concentrations were deposited by solution techniques at 200 °C. The thin films were characterized by XRD, Raman, FTIR and the four-point probe technique. Through FTIR spectroscopy, interesting behavior was observed when the IZO film at 6 wt.% doping showed a lower number of organic residues. Due to an inductive effect, an unusual displacement of bonds was observed. The reduction of organic residuals corroborated with the behavior of flexible metal–insulator–semiconductor (MIS) capacitors. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
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1051 KiB  
Proceeding Paper
Modeling of the Density of States in Field-Effect Zinc Oxide Semiconductor Devices Fabricated by Ultrasonic Spray Pyrolysis on Plastic Substrates
by Ovier Obregon, David Barba and Miguel A. Dominguez
Eng. Proc. 2021, 4(1), 12; https://doi.org/10.3390/Micromachines2021-09552 - 14 Apr 2021
Cited by 1 | Viewed by 706
Abstract
In this work, using a physically based simulator, the modeling of the density of states (DOS) through the fitting of the electrical characteristics in field-effect devices is presented. The transfer characteristic of zinc oxide (ZnO) thin-film transistors is simulated, along with the capacitance–voltage [...] Read more.
In this work, using a physically based simulator, the modeling of the density of states (DOS) through the fitting of the electrical characteristics in field-effect devices is presented. The transfer characteristic of zinc oxide (ZnO) thin-film transistors is simulated, along with the capacitance–voltage curves in metal-insulator-semiconductor capacitors using ZnO as an active layer. The ZnO semiconductor devices were fabricated by high-frequency ultrasonic spray pyrolysis on polyethylene terephthalate plastic substrates. Different aspects were considered and discussed to model the device interfaces. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
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1084 KiB  
Proceeding Paper
Innovative Solving Process Problems of Micro-Turbine Machining Using Computer-Aided Innovation Method
by Pu Huang, Gangfeng Wang and Dong Zhang
Eng. Proc. 2021, 4(1), 19; https://doi.org/10.3390/Micromachines2021-09550 - 20 Feb 2021
Viewed by 721
Abstract
With the increasingly fierce competition in the global market, technological innovation is regarded as an important factor for manufacturing companies to ensure their future competitive advantages. Modern mechanical design and manufacturing technology has become the mainstream trend of the machinery industry, and the [...] Read more.
With the increasingly fierce competition in the global market, technological innovation is regarded as an important factor for manufacturing companies to ensure their future competitive advantages. Modern mechanical design and manufacturing technology has become the mainstream trend of the machinery industry, and the rise of micro-processing production technology is an unstoppable international trend. Therefore, the machinery manufacturing industry must increase its efforts to develop and update micro-processing production technology and keep up with the pace of upgrading of the machinery industry. At present, most of the processing technology innovation activities are highly dependent on the personal knowledge accumulated for a long time in the previous projects, and the success rate of the innovative methods is low. TRIZ theory (Theory of Inventive Problem Solving) provides a systematic theory and method tool for people to discover and solve problems creatively, due to TRIZ theory is mainly applicable to product innovation design, it lacks specific parameters and principles for process innovation. In recent years, the Computer-Aided Process Innovation (CAPI) introduced on the basis of computer technology provides designers with an effective way to obtain process innovation inspiration and improve process technology innovation efficiency. This paper takes the innovative solution of the micro-turbine machining process problem as an example to verify the effectiveness of the computer-aided process innovation solution method. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
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404 KiB  
Proceeding Paper
Antibody Immobilization in ZnO-Thin Film Transistors for Low-Cost Biosensors Applications
by Rafael Antonio Salinas Domínguez, Ovier Obregón Hinostroza, Abdú Orduña Díaz and Miguel Ángel Domínguez Jiménez
Eng. Proc. 2021, 4(1), 23; https://doi.org/10.3390/Micromachines2021-09587 - 06 Mar 2021
Cited by 1 | Viewed by 865
Abstract
The antibody immobilization with low-cost materials and label-free methods are a challenge for the fabrication of biosensor devices. In this work, it was developed a strategy for antibody immobilization on ZnO TFTs over polyethylene terephthalate (PET) as a recyclable plastic substrate. Antibodies were [...] Read more.
The antibody immobilization with low-cost materials and label-free methods are a challenge for the fabrication of biosensor devices. In this work, it was developed a strategy for antibody immobilization on ZnO TFTs over polyethylene terephthalate (PET) as a recyclable plastic substrate. Antibodies were biofunctionalized using a label-free strategy for E. coli detection. The use of a recyclable plastic substrate PET enables the compatibility with flexible electronics that could contribute for a low-cost biosensor useful in rural communities that do not have the necessary infrastructure and trained personnel for pathogenic bacterial detection in food or water. Full article
(This article belongs to the Proceedings of The 1st International Conference on Micromachines and Applications)
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