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1
De Maria, C., L. Grassi, F. Vozzi, A. Ahluwalia e G. Vozzi. "Development of a novel micro-ablation system to realise micrometric and well-defined hydrogel structures for tissue engineering applications". Rapid Prototyping Journal 20, n. 6 (20 ottobre 2014): 490–98. http://dx.doi.org/10.1108/rpj-03-2012-0022.
Testo completoAbstract (sommario):
Purpose – This paper aims to develop a novel micro-ablation system to realise micrometric and well-defined hydrogel structures. To engineer a tissue it is necessary to evaluate several aspects, such as cell-cell and cell-substrate interactions, its micro-architecture and mechanical stimuli that act on it. For this reason, it is important to fabricate a substrate which presents a microtopology similar to natural tissue and has chemical and mechanical properties able to promote cell functions. In this paper, well-defined hydrogel structures embedding cells were microfabricated using a purposely developed technique, micro-laser ablation, based on a thulium laser. Its working parameters (laser power emission, stepper motor velocity) were optimised to produce shaded “serpentine” pattern on a hydrogel film. Design/methodology/approach – In this study, initially, swelling/contraction tests on agarose and alginate hydrogel in different solutions of main components of cell culture medium were performed and were compared with the MECpH model. This comparison matched with good approximation experimental measurements. Once known how hydrogel changed its topology, microstructures with a well-defined topology were realised using a purposely developed micro-laser ablation system design. S5Y5 neuroblastoma cell lines were embedded in hydrogel matrix and the whole structure was ablated with a laser microfabrication system. The cells did not show damages due to mechanical stress present in the hydrogel matrix and to thermal increase induced by the laser beam. Findings – The hydrogel structure is able to reproduce extracellular matrix. Initially, the hydrogel swelling/contraction in different solutions, containing the main components of the most common cell culture media, was analysed. This analysis is important to evaluate if cell culture environment could alter microtopology of realised structures. Then, the same topology was realised on hydrogel film embedding neuronal cells and the cells did not show damages due to mechanical stress present in the hydrogel matrix and to thermal increase induced by the laser beam. The interesting obtained results could be useful to realise well-defined microfabricated hydrogel structures embedding cells to guide tissue formation Originality/value – The originality of this paper is the design and realisation of a 3D microfabrication system able to microfabricate hydrogel matrix embedding cells without inducing cell damage. The ease of use of this system and its potential modularity render this system a novel potential device for application in tissue engineering and regenerative medicine area.
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Du, L. Q., C. Liu, H. J. Liu, J. Qin, N. Li e Rui Yang. "Design and Fabrication of Micro Hot Embossing Mold for Microfluidic Chip Used in Flow Cytometry". Key Engineering Materials 339 (maggio 2007): 246–51. http://dx.doi.org/10.4028/www.scientific.net/kem.339.246.
Testo completoAbstract (sommario):
Micro hot embossing mold of microfluidic chip used in flow cytometry is designed and microfabricated. After some kinds of microfabrication processes are tried, this paper presents a novel microfabrication technology of micro hot embossing metal mold. Micro metal mold is fabricated by low-cost UV-LIGA surface micro fabrication process using negative thick photoresist, SU-8. Different from other micro hot embossing molds, the micro mold with vertical sidewalls is fabricated by micro nickel electroforming directly on Nickel base. Based on the micro Nickel mold and automation fabrication system, high precision and mass-producing microfluidic chips have been fabricated and they have been used in flow cytometry
3
Han, Lei, Pingmei Ming, Shen Niu, Guangbin Yang, Dongdong Li e Kuaile Cheng. "Microfabricating Mirror-like Surface Precision Micro-Sized Amorphous Alloy Structures Using Jet-ECM Process". Micromachines 15, n. 3 (11 marzo 2024): 375. http://dx.doi.org/10.3390/mi15030375.
Testo completoAbstract (sommario):
Amorphous alloy (AA) is a high-performance metal material generally with significantly excellent mechanical and corrosion resistance properties and thus is considered as a desirable material selection for micro-scale articles. However, the microfabrication of AA still faces a variety of technical challenges mainly because the materials are too hard to process and easily lose their original properties, although at moderately high temperatures. In this study, jet-electrolyte electrochemical machining (Jet-ECM) was proposed to microfabricate the Zr-based AA because it is a low-temperature material-removal process based on the anode dissolution mechanism. The electrochemical dissolution characteristics and material removal mechanism of AA were investigated, and then the optimal process parameters were achieved based on the evaluation of the surface morphologies, surface roughness, geometrical profile, and machining accuracy of the machined micro-dimples. Finally, the feasibility was further studied by using Jet-ECM to fabricate arrayed micro-dimples using the optimized parameters. It was found that Jet-ECM can successfully microfabricate mirror-like surface AA arrayed precision micro-dimples with significantly high dimensional accuracy and geometrical consistency. Jet-ECM is a promisingly advantageous microfabrication process for the hard-to-machine AA.
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Folch, A., A. Ayon, O. Hurtado, M. A. Schmidt e M. Toner. "Molding of Deep Polydimethylsiloxane Microstructures for Microfluidics and Biological Applications". Journal of Biomechanical Engineering 121, n. 1 (1 febbraio 1999): 28–34. http://dx.doi.org/10.1115/1.2798038.
Testo completoAbstract (sommario):
Here we demonstrate the microfabrication of deep (>25 μm) polymeric microstructures created by replica-molding polydimethylsiloxane (PDMS) from microfabricated Si substrates. The use of PDMS structures in microfluidics and biological applications is discussed. We investigated the feasibility of two methods for the microfabrication of the Si molds: deep plasma etch of silicon-on-insulator (SOI) wafers and photolithographic patterning of a spin-coated photoplastic layer. Although the SOI wafers can be patterned at higher resolution, we found that the inexpensive photoplastic yields similar replication fidelity. The latter is mostly limited by the mechanical stability of the replicated PDMS structures. As an example, we demonstrate the selective delivery of different cell suspensions to specific locations of a tissue culture substrate resulting in micropatterns of attached cells.
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Banerjee, Arunav S., Richard Blaikie e Wen Hui Wang. "Microfabrication Process for XYZ Stage-Needle Assembly for Cellular Delivery and Surgery". Materials Science Forum 700 (settembre 2011): 195–98. http://dx.doi.org/10.4028/www.scientific.net/msf.700.195.
Testo completoAbstract (sommario):
In this paper, we present our ongoing work on developing a microfabricated XYZ stage-needle arrayed single crystal silicon (SCS) structure for cellular delivery and surgery. We discuss the device design and working principle based on electrostatic actuation. We also briefly discuss our microfabrication process flow and show some preliminary results of fabricating arrays of microneedles that are 250 µm long and 5 µm at the tip diameter.
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PARK, W. B., J. H. CHOI, C. W. PARK, G. M. KIM, H. S. SHIN, C. N. CHU e B. H. KIM. "FABRICATION OF MICRO PROBE-TYPE ELECTRODES FOR MICROELECTRO-CHEMICAL MACHINING USING MICROFABRICATION". International Journal of Modern Physics B 24, n. 15n16 (30 giugno 2010): 2639–44. http://dx.doi.org/10.1142/s0217979210065398.
Testo completoAbstract (sommario):
In this study, the mass fabrication of microelectrode tools for microelectrochemical machining (MECM) was studied using microfabrication processes. The cantilever type geometry of microelectrodes was defined by photolithography processes, and metal patterns were made for electrical contacts. Various fabrication processes were studied for the fabrication of microelectrode tools, such as wet etching, lift-off, and electroforming for metal layer patterning. MECM test results showed feasibility of the fabricated electrode tools. The microfabricated electrodes can be used as micromachining tools for various electrical micromachining of steel mold and parts of microdevices.
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Liu, Yue, Megan Chesnut, Amy Guitreau, Jacob Beckham, Adam Melvin, Jason Eades, Terrence R. Tiersch e William Todd Monroe. "Microfabrication of low-cost customisable counting chambers for standardised estimation of sperm concentration". Reproduction, Fertility and Development 32, n. 9 (2020): 873. http://dx.doi.org/10.1071/rd19154.
Testo completoAbstract (sommario):
Evaluation of sperm concentration is essential for research and procedures involving AI, cryopreservation and sperm quality assessment. Microfabrication technologies have shown tremendous potential for rapid prototyping and fabrication of devices to assist reproduction and fertility research, but such utility has not yet been made available for most reproduction laboratories. The aim of this study was to evaluate the feasibility of using microfabrication techniques to produce counting chambers for estimation of sperm concentration. Zebrafish (Danio rerio) spermatozoa were used as a model for evaluation of functionality of the chambers. These microfabricated enumeration grid chambers (MEGC) were composed of a polydimethylsiloxane (PDMS) coverslip with grid patterns (100 μm×100 μm) and a PDMS base platform to create a known volume with a 10-μm height to restrict the cells to a single layer. The results of cell counts estimated by two of three prototype MEGC devices tested were not significantly different from the control device, a commercially available Makler chamber. The material cost for a MEGC was less than US$0.10 compared with product costs of approximately US$100 for a standard haemocytometer and US$700 for a Makler counting chamber. This study demonstrates the feasibility of microfabrication in creating low-cost counting chambers to enhance standardisation and strengthen interdisciplinary collaborations.
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Alvarez-Escobar, Marta, Sidónio C. Freitas, Derek Hansford, Fernando J. Monteiro e Alejandro Pelaez-Vargas. "Soft Lithography and Minimally Human Invasive Technique for Rapid Screening of Oral Biofilm Formation on New Microfabricated Dental Material Surfaces". International Journal of Dentistry 2018 (2018): 1–5. http://dx.doi.org/10.1155/2018/4219625.
Testo completoAbstract (sommario):
Introduction. Microfabrication offers opportunities to study surface concepts focused to reduce bacterial adhesion on implants using human minimally invasive rapid screening (hMIRS). Wide information is available about cell/biomaterial interactions using eukaryotic and prokaryotic cells on surfaces of dental materials with different topographies, but studies using human being are still limited. Objective. To evaluate a synergy of microfabrication and hMIRS to study the bacterial adhesion on micropatterned surfaces for dental materials. Materials and Methods. Micropatterned and flat surfaces on biomedical PDMS disks were produced by soft lithography. The hMIRS approach was used to evaluate the total oral bacterial adhesion on PDMS surfaces placed in the oral cavity of five volunteers (the study was approved by the University Ethical Committee). After 24 h, the disks were analyzed using MTT assay and light microscopy. Results. In the present pilot study, microwell structures were microfabricated on the PDMS surface via soft lithography with a spacing of 5 µm. Overall, bacterial adhesion did not significantly differ between the flat and micropatterned surfaces. However, individual analysis of two subjects showed greater bacterial adhesion on the micropatterned surfaces than on the flat surfaces. Significance. Microfabrication and hMIRS might be implemented to study the cell/biomaterial interactions for dental materials.
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Starodubov, Andrey, Roman Torgashov, Viktor Galushka, Anton Pavlov, Vladimir Titov, Nikita Ryskin, Anand Abhishek e Niraj Kumar. "Microfabrication, Characterization, and Cold-Test Study of the Slow-Wave Structure of a Millimeter-Band Backward-Wave Oscillator with a Sheet Electron Beam". Electronics 11, n. 18 (9 settembre 2022): 2858. http://dx.doi.org/10.3390/electronics11182858.
Testo completoAbstract (sommario):
In this paper, the results of the microfabrication, characterization, and cold-test study of the previously proposed truncated sine-waveguide interaction structure with wideband-matched output couplers for the millimeter-band backward-wave oscillator (BWO) driven by a high-current-density sheet electron beam are presented. Computer-numerical-control (CNC) micromilling was used to fabricate the designed interaction structure. The first sample was microfabricated from an aluminum alloy to test the milling process. The final sample was made from oxygen-free copper. Scanning electron microscopy (SEM) and optical microscopy were used to investigate the morphology of the microfabricated samples, and stylus profilometry was used to estimate the level of the surface roughness. Cold S-parameters were measured in Q- and V-bands (40–70 GHz), using a vector network analyzer (VNA). Using the experimentally measured phase data of the transmitted signal, the dispersion of the fabricated interaction structure was evaluated. The experimentally measured dispersion characteristic is in good agreement with the numerically calculated.
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Creff, Justine, Laurent Malaquin e Arnaud Besson. "In vitro models of intestinal epithelium: Toward bioengineered systems". Journal of Tissue Engineering 12 (gennaio 2021): 204173142098520. http://dx.doi.org/10.1177/2041731420985202.
Testo completoAbstract (sommario):
The intestinal epithelium, the fastest renewing tissue in human, is a complex tissue hosting multiple cell types with a dynamic and multiparametric microenvironment, making it particularly challenging to recreate in vitro. Convergence of recent advances in cellular biology and microfabrication technologies have led to the development of various bioengineered systems to model and study the intestinal epithelium. Theses microfabricated in vitro models may constitute an alternative to current approaches for studying the fundamental mechanisms governing intestinal homeostasis and pathologies, as well as for in vitro drug screening and testing. Herein, we review the recent advances in bioengineered in vitro intestinal models.
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Yang, Jian Zhong, Li Chao Pan, C. L. Kang, Gang Liu, Hui Juan Li, Z. You, D. H. Ren e Y. C. Tian. "Advance of the Micro-Magnetometer MEMSMag Research". Advanced Materials Research 60-61 (gennaio 2009): 241–45. http://dx.doi.org/10.4028/www.scientific.net/amr.60-61.241.
Testo completoAbstract (sommario):
The MEMS fluxgate magnetic sensor which is characterized by its small mass, smart volume, high sensitivity and outstanding temperature stability, is often applied on the measurements of weak magnetic fields, such as the geomagnetic field. Therefore, it is widely utilized in the field of aeronautics and aerospace field, especially in Nano-/Pico- satellites. MEMSMag, a novel type of micro fluxgate magnetic sensor (MFGM), which exploits magnetic fluxgate principle, was designed and microfabricated, Based on MEMS technology. The micro sensor probe has symmetrical geometry, and is flexible for electrical connection. MEMSMag would be easily assembled into a 3-axis subminiature magnetometer and will be applied to measure vector of the weak geomagnetic field. The microfabrication process was developed. The UV lithography technology in combination with thick negative hard-cured technology was exploited in the microfabrication. The original samples were produced with the dimension of 1 1 100 . The primary tests have been done. The integrity, conductivity and resist test, as well as transformer effect measurement were completed. The statistics, analysis and conclusion of the experimental results have been obtained.
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Zuchowicz, Nikolas C., Jorge A. Belgodere, Yue Liu, Ignatius Semmes, William Todd Monroe e Terrence R. Tiersch. "Low-Cost Resin 3-D Printing for Rapid Prototyping of Microdevices: Opportunities for Supporting Aquatic Germplasm Repositories". Fishes 7, n. 1 (15 febbraio 2022): 49. http://dx.doi.org/10.3390/fishes7010049.
Testo completoAbstract (sommario):
Germplasm repositories can benefit sustainable aquaculture by supporting genetic improvement, assisted reproduction, and management of valuable genetic resources. Lack of reliable quality management tools has impeded repository development in the past several decades. Microfabricated open-hardware devices have emerged as a new approach to assist repository development by providing standardized quality assessment capabilities to enable routine quality control. However, prototyping of microfabricated devices (microdevices) traditionally relies on photolithography techniques that are costly, time intensive, and accessible only through specialized engineering laboratories. Although resin 3-D printing has been introduced into the microfabrication domain, existing publications focus on customized or high-cost (>thousands of USD) printers. The goal of this report was to identify and call attention to the emerging opportunities to support innovation in microfabrication by use of low-cost (<USD 350) resin 3-D printing for rapid prototyping. We demonstrate that low-cost mask-based stereolithography (MSLA) 3-D printers with straightforward modifications can provide fabrication quality that approaches traditional photolithography techniques. For example, reliable feature sizes of 20 µm with dimensional discrepancy of <4% for lateral dimensions and <5% for vertical dimensions were fabricated with a consumer-level MSLA printers. In addition, alterations made to pre-processing, post-processing, and printer configuration steps improved print quality as demonstrated in objects with sharper edges and smoother surfaces. The prototyping time and cost of resin 3-D printing (3 h with USD 0.5/prototype) were considerably lower than those of traditional photolithography (5 d with USD 80/prototype). With the rapid advance of consumer-grade printers, resin 3-D printing can revolutionize rapid prototyping approaches for microdevices in the near future, facilitating participation in interdisciplinary development of innovative hardware to support germplasm repository development for aquatic species.
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Bakajin, Olgica, Eric Fountain, Keith Morton, Stephen Y. Chou, James C. Sturm e Robert H. Austin. "Materials Aspects in Micro- and Nanofluidic Systems Applied to Biology". MRS Bulletin 31, n. 2 (febbraio 2006): 108–13. http://dx.doi.org/10.1557/mrs2006.24.
Testo completoAbstract (sommario):
AbstractOne of the key problems in microfabrication and especially nanofabrication applied to biology is materials selection. Proper materials must have mechanical stability and the ability to hermetically bond to other surfaces, yet not bind biological molecules. They must also be wettable by water and have good optical properties. In this article, we review some of the attempts to find materials for micro- and nanofluidic systems in biological applications that satisfy these rather conflicting constraints.We discuss the materials properties that make poly (dimethylsiloxane) or non-elastomeric materials more or less suitable for particular applications in biology. We also explore the effects and the importance of surface treatments for integrating biological objects into microfabricated and nanofabricated fluidic devices.
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Ahn, Jeong e Kim. "Emerging Encapsulation Technologies for Long-Term Reliability of Microfabricated Implantable Devices". Micromachines 10, n. 8 (31 luglio 2019): 508. http://dx.doi.org/10.3390/mi10080508.
Testo completoAbstract (sommario):
The development of reliable long-term encapsulation technologies for implantable biomedical devices is of paramount importance for the safe and stable operation of implants in the body over a period of several decades. Conventional technologies based on titanium or ceramic packaging, however, are not suitable for encapsulating microfabricated devices due to their limited scalability, incompatibility with microfabrication processes, and difficulties with miniaturization. A variety of emerging materials have been proposed for encapsulation of microfabricated implants, including thin-film inorganic coatings of Al2O3, HfO2, SiO2, SiC, and diamond, as well as organic polymers of polyimide, parylene, liquid crystal polymer, silicone elastomer, SU-8, and cyclic olefin copolymer. While none of these materials have yet been proven to be as hermetic as conventional metal packages nor widely used in regulatory approved devices for chronic implantation, a number of studies have demonstrated promising outcomes on their long-term encapsulation performance through a multitude of fabrication and testing methodologies. The present review article aims to provide a comprehensive, up-to-date overview of the long-term encapsulation performance of these emerging materials with a specific focus on publications that have quantitatively estimated the lifetime of encapsulation technologies in aqueous environments.
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Wang, Nan, Fu Li Hsiao, Moorthi Palaniapan, Ming Lin Julius Tsai, Jeffrey B. W. Soon, Dim Lee Kwong e Cheng Kuo Lee. "A Novel Micromechanical Resonator Using Two-Dimensional Phononic Crystal Slab". Advanced Materials Research 254 (maggio 2011): 195–98. http://dx.doi.org/10.4028/www.scientific.net/amr.254.195.
Testo completoAbstract (sommario):
Two-dimensional (2-D) Silicon phononic crystal (PnC) slab of a square array of cylindrical air holes in a 10μm thick free-standing silicon plate with line defects is characterized as a cavity-mode PnC resonator. Piezoelectric aluminum nitride (AlN) film is deployed as the inter-digital transducers (IDT) to transmit and detect acoustic waves, thus making the whole microfabrication process CMOS-compatible. Both the band structure of the PnC and the transmission spectrum of the proposed PnC resonator are analyzed and optimized using finite element method (FEM). The measured quality factor (Q factor) of the microfabricated PnC resonator is over 1,000 at its resonant frequency of 152.46MHz. The proposed PnC resonator shows promising acoustic resonance characteristics for RF communications and sensing applications.
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Herrault, Florian, M. Yajima, M. Chen, C. McGuire e A. Margomenos. "Silicon-Embedded RF Micro-Inductors for Ultra-Compact RF Subsystems". Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2015, DPC (1 gennaio 2015): 000939–57. http://dx.doi.org/10.4071/2015dpc-tp44.
Testo completoAbstract (sommario):
Advances in 2.5D and 3D integration technologies are enabling ultra-compact multi-chip modules. In this abstract, we present the design, fabrication, and experimental characterization of RF inductors microfabricated inside deep silicon recesses. Because silicon is often used as a substrate of packaging material for 3D integration and microelectromechanical systems (MEMS), developing microfabrication technologies to embed passive components in the unused volume of the silicon package is a promising approach to realize ultra-compact RF subsystems. Inductors and capacitors are critical in dc-bias circuits for MMICs in order to suppress low-frequency oscillations. Because it is particularly important to have these passive components as close to the MMIC as possible with minimum interconnection parasitics, silicon-embedded passives are an attractive solution. Further, silicon-embedded passives can potentially reduce the overall volume of RF subsystems when compared to modules using discrete passives. Although inductors inside the volume of silicon wafers have previously been reported, they typically operated in the 1–200 MHz frequency range, mostly featuring inductors with wide (50–100 μm) conductors and wide (50–100 μm) interconductor gaps due to fabrication limitations. We first explored process limitations to fabricate structural and electrical features inside 75 to 100-μm-deep silicon cavities. The cavities were etched into the silicon using deep reactive ion etching. Inside these recesses, we demonstrated the fabrication of thin (0.2 μm) and thick (5 μm) gold patterns with 3 μm resolution using lift-off and electroplating processes, respectively. The lift-off process used an image reversal technique, and the plated gold conductors were fabricated through a 6.5-μm-thick photoresist mold. The feature sizes ranged from 3 to 50 μm. For photoresist exposure, an i-line Canon stepper was utilized, and configured specifically to focus at the bottom of the cavities, a key process requirement to achieve high-resolution features. These microfabrication results enabled the design of high-performance RF inductors, which will be discussed in the next section. In addition, we demonstrated the fabrication of 30-μm-deep 3-μm-diameter silicon-etched features inside these cavities, a stepping stone towards achieving high-capacitance-density integrated trench capacitors embedded inside silicon cavities. The silicon-embedded RF inductors were microfabricated on 500-μm-thick high-resistivity (ρ > 20,000 Ω.cm) silicon wafers. First, 75-μm-deep cavities were etched using DRIE. Various two-port coplanar waveguide (CPW) inductor designs were microfabricated. The inductor microfabrication relied on sputtered titanium/gold seed layers, thick AZ4620 photoresist molds, and three 5-μm-thick electroplated gold layers stacked on top of each other to define the inductor conductor and connections. By using a combination of three electroplated layers, high-power-handling low-loss inductors were fabricated. Measurements were performed on a RF probe station, with on-wafer calibration structures. The losses associated with the CPW launchers were de-embedded prior to inductor measurements, and inductor quality factor greater than 40 was measured on various inductors with inductance of approximately 1 nH, and self-resonant frequency at 30 GHz. These results were in agreement with models performed using SONNET simulation package, and are comparable with than that of inductors fabricated on planar silicon wafers.
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Vejella, Sujitha, e Sazzadur Chowdhury. "A MEMS Ultra-Wideband (UWB) Power Sensor with a Fe-Co-B Core Planar Inductor and a Vibrating Diaphragm Capacitor". Sensors 21, n. 11 (3 giugno 2021): 3858. http://dx.doi.org/10.3390/s21113858.
Testo completoAbstract (sommario):
The design of a microelectromechanical systems (MEMS) ultra-wideband (UWB) RMS power sensor is presented. The sensor incorporates a microfabricated Fe-Co-B core planar inductor and a microfabricated vibrating diaphragm variable capacitor on adhesively bonded glass wafers in a footprint area of 970 × 970 µm2 to operate in the 3.1–10.6 GHz UWB frequency range. When exposed to a far-field UWB electromagnetic radiation, the planar inductor acts as a loop antenna to generate a frequency-independent voltage across the MEMS capacitor. The voltage generates a coulombic attraction force between the diaphragm and backplate that deforms the diaphragm to change the capacitance. The frequency-independent capacitance change is sensed using a transimpedance amplifier to generate an output voltage. The sensor exhibits a linear capacitance change induced voltage relation and a calculated sensitivity of 4.5 aF/0.8 µA/m. The sensor can be used as a standalone UWB power sensor or as a 2D array for microwave-based biomedical diagnostic imaging applications or for non-contact material characterization. The device can easily be tailored for power sensing in other application areas such as, 5G, WiFi, and Internet-of-Things (IoT). The foreseen fabrication technique can rely on standard readily available microfabrication techniques.
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Pelaez-Vargas, A., D. Gallego-Perez, N. Ferrell, M. H. Fernandes, D. Hansford e F. J. Monteiro. "Early Spreading and Propagation of Human Bone Marrow Stem Cells on Isotropic and Anisotropic Topographies of Silica Thin Films Produced via Microstamping". Microscopy and Microanalysis 16, n. 6 (22 ottobre 2010): 670–76. http://dx.doi.org/10.1017/s1431927610094158.
Testo completoAbstract (sommario):
AbstractWhile there has been rapid development of microfabrication techniques to produce high-resolution surface modifications on a variety of materials in the last decade, there is still a strong need to produce novel alternatives to induce guided tissue regeneration on dental implants. High-resolution microscopy provides qualitative and quantitative techniques to study cellular guidance in the first stages of cell-material interactions. The purposes of this work were (1) to produce and characterize the surface topography of isotropic and anisotropic microfabricated silica thin films obtained by sol-gel processing, and (2) to compare the in vitro biological behavior of human bone marrow stem cells on these surfaces at early stages of adhesion and propagation. The results confirmed that a microstamping technique can be used to produce isotropic and anisotropic micropatterned silica coatings. Atomic force microscopy analysis was an adequate methodology to study in the same specimen the sintering derived contraction of the microfabricated coatings, using images obtained before and after thermal cycle. Hard micropatterned coatings induced a modulation in the early and late adhesion stages of cell-material and cell-cell interactions in a geometry-dependent manner (i.e., isotropic versus anisotropic), as it was clearly determined, using scanning electron and fluorescence microscopies.
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Hagemann, Cathleen, Matthew C. D. Bailey, Eugenia Carraro, Ksenia S. Stankevich, Valentina Maria Lionello, Noreen Khokhar, Pacharaporn Suklai et al. "Low-cost, versatile, and highly reproducible microfabrication pipeline to generate 3D-printed customised cell culture devices with complex designs". PLOS Biology 22, n. 3 (13 marzo 2024): e3002503. http://dx.doi.org/10.1371/journal.pbio.3002503.
Testo completoAbstract (sommario):
Cell culture devices, such as microwells and microfluidic chips, are designed to increase the complexity of cell-based models while retaining control over culture conditions and have become indispensable platforms for biological systems modelling. From microtopography, microwells, plating devices, and microfluidic systems to larger constructs such as live imaging chamber slides, a wide variety of culture devices with different geometries have become indispensable in biology laboratories. However, while their application in biological projects is increasing exponentially, due to a combination of the techniques, equipment and tools required for their manufacture, and the expertise necessary, biological and biomedical labs tend more often to rely on already made devices. Indeed, commercially developed devices are available for a variety of applications but are often costly and, importantly, lack the potential for customisation by each individual lab. The last point is quite crucial, as often experiments in wet labs are adapted to whichever design is already available rather than designing and fabricating custom systems that perfectly fit the biological question. This combination of factors still restricts widespread application of microfabricated custom devices in most biological wet labs. Capitalising on recent advances in bioengineering and microfabrication aimed at solving these issues, and taking advantage of low-cost, high-resolution desktop resin 3D printers combined with PDMS soft lithography, we have developed an optimised a low-cost and highly reproducible microfabrication pipeline. This is thought specifically for biomedical and biological wet labs with not prior experience in the field, which will enable them to generate a wide variety of customisable devices for cell culture and tissue engineering in an easy, fast reproducible way for a fraction of the cost of conventional microfabrication or commercial alternatives. This protocol is designed specifically to be a resource for biological labs with limited expertise in those techniques and enables the manufacture of complex devices across the μm to cm scale. We provide a ready-to-go pipeline for the efficient treatment of resin-based 3D-printed constructs for PDMS curing, using a combination of polymerisation steps, washes, and surface treatments. Together with the extensive characterisation of the fabrication pipeline, we show the utilisation of this system to a variety of applications and use cases relevant to biological experiments, ranging from micro topographies for cell alignments to complex multipart hydrogel culturing systems. This methodology can be easily adopted by any wet lab, irrespective of prior expertise or resource availability and will enable the wide adoption of tailored microfabricated devices across many fields of biology.
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MIRSHEKARI, GHOLAMREZA, MARTIN BROUILLETTE e LUC G. FRÉCHETTE. "THROUGH SILICON VIAS INTEGRABLE WITH THIN-FILM PIEZOELECTRIC STRUCTURES". International Journal of Nanoscience 11, n. 04 (agosto 2012): 1240015. http://dx.doi.org/10.1142/s0219581x12400157.
Testo completoAbstract (sommario):
This paper reports on the design and microfabrication of novel through silicon vias (TSV) that are compatible with high-temperature processing of piezoelectric structures. The present approach uses metal deposition in cavities etched in the SOI handle layer of the wafer and electrically isolated islands in the device layer. This design avoids the shortcomings of previous TSV designs, which either introduce large topologies on the wafer surface, include metals that cannot sustain high-temperature processing or use poor electrical insulators. TSVs microfabricated using this new approach exhibit good performance, specifically small resistance between the front and backside metal pads, isolation from the ground plane and small capacitance between the vias and the ground. These TSVs are eminently suitable for devices requiring high-temperature processing, such as thin-film piezoelectric sensors and actuators.
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Kudo, Ryota, Shin Usuki, Satoru Takahashi e Kiyoshi Takamasu. "Simulation-Based Analysis of Influence of Error on Super-Resolution Optical Inspection". International Journal of Automation Technology 5, n. 2 (5 marzo 2011): 167–72. http://dx.doi.org/10.20965/ijat.2011.p0167.
Testo completoAbstract (sommario):
Microfabricated structures such as semiconductors and MEMS continue shrinking as nanotechnology expands, demand that measures microfabricated structures has risen. Optics and electron beam have been mainly used for that purpose, but the resolving power of optics is limited by the Rayleigh limit and it is generally low for subwavelength-geometry defects, while scanning electron microscopy requires a vacuum and induces contamination in measurement. To handle these considerations, we propose optical microfabrication inspection using a standing-wave shift. This is based on a super-resolution algorithm in which the inspection resolution exceeds the Rayleigh limit by shifting standing waves with a piezoelectric actuator. While resolution beyond the Rayleigh limit by proposed method has been studied theoretically and realized experimentally, we must understand the influence of experimental error factors and reflect this influence in the calibration when actual application is constructed. The standing-wave pitch, initial phase, and noise were studied as experimental error factors. As a result, it was confirmed that super-resolution beyond the Rayleigh limit is achievable if (i) standingwave pitch error was 5% when standing-wave pitch was 300 nm or less and (ii) if initial phase error was 30° when standing-wave pitch was 300 nm. Noise accumulation was confirmed in studies of the noise effect, and a low-pass filter proved effective against noise influence.
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Chen, Xing, Da Fu Cui, H. Li, H. Y. Cai, J. H. Sun e L. L. Zhang. "Microfluidic Device for Fluorescence Immunoassays by Using Porous Matrix". Advanced Materials Research 216 (marzo 2011): 645–48. http://dx.doi.org/10.4028/www.scientific.net/amr.216.645.
Testo completoAbstract (sommario):
The present work presents the availability of using porous matrix in microfluidic devices as a solid phase matrix for immunoassays. Porous matrixes on the surface of the microchannels were microfabricated by MEMS technology and electrochemical etching technology, which were coated on the wall of the rectangular microchannel in the microdevices to provide a surface-enlarging matrix. The microfabrication process of porous matrixes was investigated and optimized. Then the surface morphology of the porous matrixes was characterized by SEM. Both direct method and dual-antibody sandwich method were used for fluorescence immunoassays. Using sandwich immunoassay, 6.25μg/mL - 25μg/mL human IgG in real samples have been detected with a correlation coefficient of 0.9773. These porous microdevices have shown some advantages over its large-scale counterparts, including lower sample and reagent consumption, lower cost, less analytical time and so on, which enables detection for clinical testing.
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Lee, Seung Jae, Byung Kim, Jin Sang Lee, Sung Won Kim, Min Soo Kim, Joo Sung Kim, Geun Bae Lim e Dong Woo Cho. "Three-Dimensional Microfabrication System for Scaffolds in Tissue Engineering". Key Engineering Materials 326-328 (dicembre 2006): 723–26. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.723.
Testo completoAbstract (sommario):
Understanding chondrocyte behavior inside complex, three-dimensional environments with controlled patterning of geometrical factors would provide significant insights into the basic biology of tissue regenerations. One of the fundamental limitations in studying such behavior has been the inability to fabricate controlled 3D structures. To overcome this problem, we have developed a three-dimensional microfabrication system. This system allows fabrication of predesigned internal architectures and pore size by stacking up the photopolymerized materials. Photopolymer SL5180 was used as the 3D microfabricated scaffolds. The results demonstrate that controllable and reproducible inner-architecture can be fabricated. Chondrocytes from human nasal septum were cultured in 3D scaffolds for cell adhesion behavior. Such 3D scaffolds might provide effective key factors to study cell behavior in complex environments and could eventually lead to optimum design of scaffolds in various tissue regenerations such as cartilage, bone, etc. in a near future.
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Wiley, J. James, Raymond E. Ideker, William M. Smith e Andrew E. Pollard. "Measuring surface potential components necessary for transmembrane current computation using microfabricated arrays". American Journal of Physiology-Heart and Circulatory Physiology 289, n. 6 (dicembre 2005): H2468—H2477. http://dx.doi.org/10.1152/ajpheart.00570.2005.
Testo completoAbstract (sommario):
This study was designed to test the feasibility of using microfabricated electrodes to record surface potentials with sufficiently fine spatial resolution to measure the potential gradients necessary for improved computation of transmembrane current density. To assess that feasibility, we recorded unipolar electrograms from perfused rabbit right ventricular free wall epicardium ( n = 6) using electrode arrays that included 25-μm sensors fabricated onto a flexible substrate with 75-μm interelectrode spacing. Electrode spacing was therefore on the size scale of an individual myocyte. Signal conditioning adjacent to the sensors to control lead noise was achieved by routing traces from the electrodes to the back side of the substrate where buffer amplifiers were located. For comparison, recordings were also made using arrays built from chloridized silver wire electrodes of either 50-μm (fine wire) or 250-μm (coarse wire) diameters. Electrode separations were necessarily wider than with microfabricated arrays. Comparable signal-to-noise ratios (SNRs) of 21.2 ± 2.2, 32.5 ± 4.1, and 22.9 ± 0.7 for electrograms recorded using microfabricated sensors ( n = 78), fine wires ( n = 78), and coarse wires ( n = 78), respectively, were found. High SNRs were maintained in bipolar electrograms assembled using spatial combinations of the unipolar electrograms necessary for the potential gradient measurements and in second-difference electrograms assembled using spatial combinations of the bipolar electrograms necessary for surface Laplacian (SL) measurements. Simulations incorporating a bidomain representation of tissue structure and a two-dimensional network of guinea pig myocytes prescribed following the Luo and Rudy dynamic membrane equations were completed using 12.5-μm spatial resolution to assess contributions of electrode spacing to the potential gradient and SL measurements. In those simulations, increases in electrode separation from 12.5 to 75.0, 237.5, and 875.0 μm, which were separations comparable to the finest available with our microfabricated, fine wire, and coarse wire arrays, led to 10%, 42%, and 81% reductions in maximum potential gradients and 33%, 76%, and 96% reductions in peak-to-peak SLs. Maintenance of comparable SNRs for source electrograms was therefore important because microfabrication provides a highly attractive methods to achieve spatial resolutions necessary for improved computation of transmembrane current density.
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Brunette, D. M., e B. Chehroudi. "The Effects of the Surface Topography of Micromachined Titanium Substrata on Cell Behavior in Vitro and in Vivo". Journal of Biomechanical Engineering 121, n. 1 (1 febbraio 1999): 49–57. http://dx.doi.org/10.1115/1.2798042.
Testo completoAbstract (sommario):
Surface properties, including topography and chemistry, are of prime importance in establishing the response of tissues to biomaterials. Microfabrication techniques have enabled the production of precisely controlled surface topographies that have been used as substrata for cells in culture and on devices implanted in vivo. This article reviews aspects of cell behavior involved in tissue response to implants with an emphasis on the effects of topography. Microfabricated grooved surfaces produce orientation and directed locomotion of epithelial cells in vitro and can inhibit epithelial downgrowth on implants. The effects depend on the groove dimensions and they are modified by epithelial cell–cell interactions. Fibroblasts similarly exhibit contact guidance on grooved surfaces, but fibroblast shape in vitro differs markedly from that found in vivo. Surface topography is important in establishing tissue organization adjacent to implants, with smooth surfaces generally being associated with fibrous tissue encapsulation. Grooved topographies appear to have promise in reducing encapsulation in the short term, but additional studies employing three-dimensional reconstruction and diverse topographies are needed to understand better the process of connective-tissue organization adjacent to implants. Microfabricated surfaces can increase the frequency of mineralized bone-like tissue nodules adjacent to subcutaneously implanted surfaces in rats. Orientation of these nodules with grooves occurs both in culture and on implants. Detailed comparisons of cell behavior on micromachined substrata in vitro and in vivo are difficult because of the number and complexity of factors, such as population density and micromotion, that can differ between these conditions.
26
Chen, Da Feng, He Jun Du, Wei Hua Li e Hai Qing Gong. "Holding Capacity of a Dielectrophoretic Barrier for Microparticles". Key Engineering Materials 326-328 (dicembre 2006): 281–84. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.281.
Testo completoAbstract (sommario):
A dielectrophoretic barrier is generated with two layers of microelectrode structures so called paired electrode array (PEA) constructing face to face on the top and bottom sides of a microchannel. The barrier is designed to control the movement of particles in combination with a fluid flow. Depending on the relative strength of the DEP force and hydrodynamic force, microparticles or cells carrying by a laminar flow can either penetrate the barrier or be deflected from there. The threshold velocity at which the barrier firstly fails to hold back the particles is a significant parameter to validate the performance of the device. This paper presents an experimental study on the performance of the microfabricated paired electrode array. The electrodes were fabricated with conventional microfabrication techniques. Micron-sized latex beads were used in the investigation. The holding capacity was defined by measuring the threshold velocity of the system. The results provide crucial information for the design of the dielectrophoretic barrier for microparticle manipulation and separation.
27
Noori, Y. J., S. Thomas, S. Ramadan, V. K. Greenacre, N. M. Abdelazim, Y. Han, J. Zhang et al. "Electrodeposited WS2 monolayers on patterned graphene". 2D Materials 9, n. 1 (10 dicembre 2021): 015025. http://dx.doi.org/10.1088/2053-1583/ac3dd6.
Testo completoAbstract (sommario):
Abstract The development of scalable techniques to make two-dimensional (2D) material heterostructures is a major obstacle that needs to be overcome before these materials can be implemented in device technologies. Electrodeposition is an industrially compatible deposition technique that offers unique advantages in scaling 2D heterostructures. In this work, we demonstrate the electrodeposition of atomic layers of WS2 over graphene electrodes using a single source precursor. Using conventional microfabrication techniques, graphene was patterned to create micro-electrodes where WS2 was site-selectively deposited to form 2D heterostructures. We used various characterization techniques, including atomic force microscopy, transmission electron microscopy, Raman spectroscopy and x-ray photoelectron spectroscopy to show that our electrodeposited WS2 layers are highly uniform and can be grown over graphene at a controllable deposition rate. This technique to selectively deposit transition metal dichalcogenides over microfabricated graphene electrodes paves the way towards wafer-scale production of 2D material heterostructures for nanodevice applications.
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Mujeeb-U-Rahman, Muhammad, Dvin Adalian e Axel Scherer. "Fabrication of Patterned Integrated Electrochemical Sensors". Journal of Nanotechnology 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/467190.
Testo completoAbstract (sommario):
Fabrication of integrated electrochemical sensors is an important step towards realizing fully integrated and truly wireless platforms for many local, real-time sensing applications. Micro/nanoscale patterning of small area electrochemical sensor surfaces enhances the sensor performance to overcome the limitations resulting from their small surface area and thus is the key to the successful miniaturization of integrated platforms. We have demonstrated the microfabrication of electrochemical sensors utilizing top-down lithography and etching techniques on silicon and CMOS substrates. This choice of fabrication avoids the need of bottom-up techniques that are not compatible with established methods for fabricating electronics (e.g., CMOS) which form the industrial basis of most integrated microsystems. We present the results of applying microfabricated sensors to various measurement problems, with special attention to their use for continuous DNA and glucose sensing. Our results demonstrate the advantages of using micro- and nanofabrication techniques for the miniaturization and optimization of modern sensing platforms that employ well-established electronic measurement techniques.
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Shetty, A., e G. Srinivasan. "MICROFABRICATED ORAL DRUG DELIVERY SYSTEMS". INDIAN DRUGS 52, n. 11 (28 novembre 2015): 5–13. http://dx.doi.org/10.53879/id.52.11.10393.
Testo completoAbstract (sommario):
Microfabrication is a collection of techniques developed to fabricate micron sized features, best suited to develop the novel drug delivery microdevices. microfabrication techniques were originally developed in the microelectronics industry to produce functional devices on the micron scale such as sensors, switches, filters and gears. Approaches like modification of drug itself to improve its permeability/ solubility characters, encapsulation techniques using micro/nanoparticles, use of protease inhibitors to curb proteolytic degradation, and use of intelligent polymers and hydrogels do not offer a complete solution for adequate and safe delivery of drugs, vaccines, peptides, proteins and others. This technology has been applied to the successful fabrication of a variety of implantable and oral drug delivery devices based on silicon, glass, silicone elastomer or plastic materials. These techniques that are utilized at present have developed as a result of integrated circuit manufacturing technologies, such as photolithography, thin film growth/deposition, etching and bonding. Micromachining allows for control over surface features, aspect ratio, particle size, shape and facilitating the development of an engineered particle for drug delivery that can incorporate the advantages of microparticles while avoiding their design flaws. It helps in multi-cell and multi-site attachment, multiple reservoirs of desired size to contain multiple drugs/biomolecules of interest. These fabrication techniques have led to the development of microelectromechanical systems (MEMS), bioMEMS, micro-total analysis systems (μ-TAS), lab-on-a-chip and other microdevices. Microfabricated devices are designed for uni-directional release, to prevent enzyme degradation, precise dosing and better patient compliance. Drug delivery in the form of microparticles and micropatches have been used for targeted delivery as well as in treatment of diseases like diabetes and cancer.
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De Pascali, Chiara, Luca Francioso, Lucia Giampetruzzi, Gabriele Rescio, Maria Assunta Signore, Alessandro Leone e Pietro Siciliano. "Modeling, Fabrication and Integration of Wearable Smart Sensors in a Monitoring Platform for Diabetic Patients". Sensors 21, n. 5 (6 marzo 2021): 1847. http://dx.doi.org/10.3390/s21051847.
Testo completoAbstract (sommario):
The monitoring of some parameters, such as pressure loads, temperature, and glucose level in sweat on the plantar surface, is one of the most promising approaches for evaluating the health state of the diabetic foot and for preventing the onset of inflammatory events later degenerating in ulcerative lesions. This work presents the results of sensors microfabrication, experimental characterization and FEA-based thermal analysis of a 3D foot-insole model, aimed to advance in the development of a fully custom smart multisensory hardware–software monitoring platform for the diabetic foot. In this system, the simultaneous detection of temperature-, pressure- and sweat-based glucose level by means of full custom microfabricated sensors distributed on eight reading points of a smart insole will be possible, and the unit for data acquisition and wireless transmission will be fully integrated into the platform. Finite element analysis simulations, based on an accurate bioheat transfer model of the metabolic response of the foot tissue, demonstrated that subcutaneous inflamed lesions located up to the muscle layer, and ischemic damage located not below the reticular/fat layer, can be successfully detected. The microfabrication processes and preliminary results of functional characterization of flexible piezoelectric pressure sensors and glucose sensors are presented. Full custom pressure sensors generate an electric charge in the range 0–20 pC, proportional to the applied load in the range 0–4 N, with a figure of merit of 4.7 ± 1 GPa. The disposable glucose sensors exhibit a 0–6 mM (0–108 mg/dL) glucose concentration optimized linear response (for sweat-sensing), with a LOD of 3.27 µM (0.058 mg/dL) and a sensitivity of 21 µA/mM cm2 in the PBS solution. The technical prerequisites and experimental sensing performances were assessed, as preliminary step before future integration into a second prototype, based on a full custom smart insole with enhanced sensing functionalities.
31
Shubin, Ivan, John E. Cunningham, Darko Popovic, Hiren Thacker, Xuezhe Zheng, Ying Luo, Jim Mitchell et al. "Ferro-Electrically Enhanced Proximity Communication." International Symposium on Microelectronics 2010, n. 1 (1 gennaio 2010): 000084–92. http://dx.doi.org/10.4071/isom-2010-ta3-paper4.
Testo completoAbstract (sommario):
Capacitively-coupled communication between chips, commonly known as PxC, represents a new class of I-O signaling that offers substantially improved off-chip bandwidth density. However, this form of communication presents a challenge from a packaging perspective, since tight chip alignment tolerances are required to maintain high signal fidelity and avoid cross coupling between neighboring channels. To mitigate the packaging constraints, capacitive coupling between the communication pads can be enhanced with materials that have high dielectric coefficients. Here, ferroelectrics hold promise over contemporary low- and high-k dielectrics, however their processing conditions need to be better understood and the compatibility with CMOS circuitry has to be established during integration with a back end of the line process module. In this paper we present experimental results on microfabrication modules for various families of ferroelectrics when monolithically deposited on Silicon. Additionally, we report their associated dielectric properties as extracted by measured capacitance enhancements in our fabricated devices. In this work Strontium Titanate and Barium Strontium Titanate films are sputter deposited on platinum atop Silicon. Capacitive measurements were accomplished by microfabricating electrodes atop these structures in geometries that are size and shape dependant. Dielectric coefficients as high as 400 times that of air are measured.
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Ollé, Enric Perarnau, Josep Farré-Lladós e Jasmina Casals-Terré. "Advancements in Microfabricated Gas Sensors and Microanalytical Tools for the Sensitive and Selective Detection of Odors". Sensors 20, n. 19 (24 settembre 2020): 5478. http://dx.doi.org/10.3390/s20195478.
Testo completoAbstract (sommario):
In recent years, advancements in micromachining techniques and nanomaterials have enabled the fabrication of highly sensitive devices for the detection of odorous species. Recent efforts done in the miniaturization of gas sensors have contributed to obtain increasingly compact and portable devices. Besides, the implementation of new nanomaterials in the active layer of these devices is helping to optimize their performance and increase their sensitivity close to humans’ olfactory system. Nonetheless, a common concern of general-purpose gas sensors is their lack of selectivity towards multiple analytes. In recent years, advancements in microfabrication techniques and microfluidics have contributed to create new microanalytical tools, which represent a very good alternative to conventional analytical devices and sensor-array systems for the selective detection of odors. Hence, this paper presents a general overview of the recent advancements in microfabricated gas sensors and microanalytical devices for the sensitive and selective detection of volatile organic compounds (VOCs). The working principle of these devices, design requirements, implementation techniques, and the key parameters to optimize their performance are evaluated in this paper. The authors of this work intend to show the potential of combining both solutions in the creation of highly compact, low-cost, and easy-to-deploy platforms for odor monitoring.
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El-Beshlawy, Menna, e Hassan Arida. "Modified Screen-Printed Microchip for Potentiometric Detection of Terbinafine Drugs". Journal of Chemistry 2022 (22 novembre 2022): 1–8. http://dx.doi.org/10.1155/2022/9114162.
Testo completoAbstract (sommario):
The development of miniaturized microchips has widespread and growing interest in manufacturing potentiometric sensors with extremely valuable modifying response characteristics. In this context, here, we demonstrate microfabrication, electrochemical evaluation, and analytical applications of disposable thin-film potentiometric microsensors responsive to terbinafine antifungal medication. Miniaturized microchips have been realized by integration of the sensitive layer membrane modified by carbon nanotubes onto the surface of the plastic screen-printed microchip support using a new approach, which has been recently developed. The sensitive membrane comprises terbinafine HCl: ammonium heptamolybdate complex ion pair as ionophore, o-nitrophenyl octyl ether as a solvent mediator, potassium tetrakis (4-chlorophenyl) borate as an anion excluder, and polyvinyl chloride as support. The microsensor based on this plasticised sensitive membrane provides the Nernstian response and covers a wide concentration range of terbinafine of 10−8–10−2 mole·L−1. The merits offered by the elaborated terbinafine microchip over the bulk-based electrode include reasonable sensitivity (58.5 mV/concentration decade), fast response time (∼30 s.), long-term stability (4 months), integration, and automation feasibility. Furthermore, microfabricated terbinafine chips were successfully applied to the measurements of the investigated medication in some real samples with high accuracy (96.9%) and precision (<3%).
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Erten, Ahmet Can. "Effect of Mold Materials Used During Hot Embossing on Feature Fidelity for Microfabrication in Cyclic Olefin Polymer (COP) Substrate". Afyon Kocatepe University Journal of Sciences and Engineering 24, n. 2 (14 aprile 2024): 457–64. http://dx.doi.org/10.35414/akufemubid.1345104.
Testo completoAbstract (sommario):
During the transition from research to market, the fabrication of microfluidic devices in thermoplastic substrates is inevitable. For short production runs of several hundred products, hot embossing is the typical method before moving on to a typically more expensive injection molding process for higher production volumes. In this work, we investigated the effect of mold material used during hot embossing on feature fidelity for microfabrication in cyclic olefin polymer (COP) substrate. Specifically, we designed a simple flow-focusing microfluidic device and fabricated three different molds using silicon wafer by deep reactive ion etching (DRIE), aluminum filled high temperature epoxy by soft lithography and aluminum by CNC milling. We performed hot embossing experiments with 2mm thick COP substrates and these three different molds using automatic bench top Carver hot press. Finally, we characterized the hot embossed substrates by optical and scanning electron microscopy. Fabrication results demonstrate that the mold material plays a big role in feature fidelity. Among the mold materials used, silicon substrate performed the worst based on defects after demolding. Epoxy and aluminum molds were similar in terms of microfabricated feature defects in the substrate which could be mostly attributed to their coefficient of thermal expansion (CTE). A mold material with a CTE closer to the thermoplastic will result in much better feature fidelity.
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Wei, Peng, Ning Li e Lishuang Feng. "A Type of Two-Photon Microfabrication System and Experimentations". ISRN Mechanical Engineering 2011 (26 gennaio 2011): 1–8. http://dx.doi.org/10.5402/2011/278095.
Testo completoAbstract (sommario):
After the femtosecond laser was invented, two-photon microfabrication technology has been recognized as an important method to fabricate the nanostructure and microstructure. In this paper, the two-photon microfabrication system is described, and some experiments are done. From the experiment results, it can be seen that the resolution of the two-photon microfabrication system can be improved by the expose time, the laser power, and the diffractive superresolution element (DSE). Finally, some three-dimensional (3D) microstructure models are fabricated to show the potential of the two-photon microfabrication method.
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Piyasena, Menake E., e Steven W. Graves. "The intersection of flow cytometry with microfluidics and microfabrication". Lab Chip 14, n. 6 (2014): 1044–59. http://dx.doi.org/10.1039/c3lc51152a.
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Inomata, Naoki, Masaya Toda e Takahito Ono. "Microfabricated Temperature-Sensing Devices Using a Microfluidic Chip for Biological Applications". International Journal of Automation Technology 12, n. 1 (5 gennaio 2018): 15–23. http://dx.doi.org/10.20965/ijat.2018.p0015.
Testo completoAbstract (sommario):
Microelectromechanical systems (MEMS) and micrototal analysis systems (μTAS) have been developed using microfabrication technologies. As MEMS and μTAS contribute to smaller, higher-performance, less expensive, and integrated sensing techniques, they have been applied in many fields. In this paper, we focus on microfabricated thermal detection devices, including a microthermistor fabricated using vanadium oxide (VOx) and a resonant thermal sensor integrated into a microfluidic chip, and we present the research work we have done into biological applications, applications using a unique material and detection method for liquid samples. The VOx thermistor, which has a high temperature coefficient of resistance at –1.3%/K, is mounted onto a thermally insulated membrane in the microfluidic chip. This device is used to detect glucose and cholesterol concentrations in solutions. The resonant thermal sensor is another candidate for obtaining highly sensitive thermal measurements; however, this sensor is difficult to use with liquids because of vibration damping and thermal loss. To solve these problems, we propose a partial vacuum packaging system for the sensor in the microfluidic chip. This technique, which involves silicon resonators, was used to successfully detect the heat from a single brown fat cell. Moreover, the possibility of using a VOx resonant thermal sensor is discussed. The future prospects for MEMS and automation technology are described, with a focus on the Internet of Things/big data for medical and healthcare applications.
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Liang, Shu Hao, Chuen Horng Tsai e Chaug Liang Hsu. "Micro Fabrication Design of a Planar Methanol Sensor". Materials Science Forum 505-507 (gennaio 2006): 1069–74. http://dx.doi.org/10.4028/www.scientific.net/msf.505-507.1069.
Testo completoAbstract (sommario):
This study explains a design of the microfabricated planar methanol sensor and conducts a series of methods to achieve a real device. By utilizing the microfabrication technology, it is possible to develop the miniature planar methanol sensor to integrate with direct methanol fuel cells (DMFC). The electrochemically reactive area can be adjusted effectively to obtain adequate strength of the methanol oxidation current. The innovation of the methanol sensor design is on a matrix detecting area with the in-line monitoring functions. Each detecting holes in matrix has been connected together by a serpentine channel to conduct electrochemical reaction at the surface of electrodes. In front side of wafer, the interdigitate electrode design provides a flexible adjustment in the reactive area for modulating the strength of methanol oxidation current. A compatible fabrication of methanol sensor and DMFC has also been proposed in this work. The serpentine channel and detecting holes of methanol sensor are anticipated to be made in opposite side of DMFC fuel channels. Also, the through holes have to be formed by the combination of front-side and backside Deep RIE etching. Both of them require a precise double-side alignment. At the end, a simple planar methanol sensor has been made for verifying electrochemical characteristics and the integration solution with micro DMFC has been discussed to benefit the micro DMFC system development.
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Wei, P., Yu Zhu, Q. F. Tan, G. H. Duan e G. H. Gao. "Discussion on the Radial Superresolution of the Two-Photon Microfabrication". Key Engineering Materials 329 (gennaio 2007): 601–6. http://dx.doi.org/10.4028/www.scientific.net/kem.329.601.
Testo completoAbstract (sommario):
In order to improve the radial superresolution of the two-photon microfabrication, the superresolution diffraction theory was introduced in detail. The theoretical analysis of the photosensitive resist based on the exciting power and concentration of free radical was given.. And the superresolution diffractive optical element was applied in the two-photon microfabrication system. Simulation results indicated that the radial superresolution of the two-photon microfabrication can be improved with the superresolution diffractive optical element.
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TANIGAWA, Hiroshi. "Semiconductor microfabrication technologies." Journal of the Japan Society for Precision Engineering 54, n. 9 (1988): 1651–55. http://dx.doi.org/10.2493/jjspe.54.1651.
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MATSUI, Shinji. "Electron beam microfabrication." Journal of the Japan Society for Precision Engineering 55, n. 2 (1989): 279–84. http://dx.doi.org/10.2493/jjspe.55.279.
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Weibel, Douglas B., Willow R. DiLuzio e George M. Whitesides. "Microfabrication meets microbiology". Nature Reviews Microbiology 5, n. 3 (marzo 2007): 209–18. http://dx.doi.org/10.1038/nrmicro1616.
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Lutz, B. R., J. Chen e D. T. Schwartz. "Microfluidics without microfabrication". Proceedings of the National Academy of Sciences 100, n. 8 (1 aprile 2003): 4395–98. http://dx.doi.org/10.1073/pnas.0831077100.
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Deckman, H. W. "Microfabrication cellular phosphors". Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures 7, n. 6 (novembre 1989): 1832. http://dx.doi.org/10.1116/1.584675.
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FUJITA, Hiroyuki. "Microfabrication and Micromachines." Kobunshi 44, n. 4 (1995): 230–34. http://dx.doi.org/10.1295/kobunshi.44.230.
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Zhang, Jie, Bo-Ya Dong, Jingchun Jia, Lianhuan Han, Fangfang Wang, Chuan Liu, Zhong-Qun Tian, Zhao-Wu Tian, Dongdong Wang e Dongping Zhan. "Electrochemical buckling microfabrication". Chemical Science 7, n. 1 (2016): 697–701. http://dx.doi.org/10.1039/c5sc02644j.
Testo completoAbstract (sommario):
Isotropic wet chemical etching can be controlled with a spatial resolution at the nanometer scale, especially for the repetitive microfabrication of hierarchical 3D μ-nanostructures on the continuously curved surface of functional materials.
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Shoji, Shuichi, e Masayoshi Esashi. "Microfabrication and microsensors". Applied Biochemistry and Biotechnology 41, n. 1-2 (aprile 1993): 21–34. http://dx.doi.org/10.1007/bf02918525.
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MORIMOTO, Mitsutaka. "Microfabrication for VLSI". Journal of the Society of Mechanical Engineers 92, n. 853 (1989): 1050–55. http://dx.doi.org/10.1299/jsmemag.92.853_1050.
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Gwozdz, P. S. "NSF Microfabrication Workshops". IEEE Transactions on Education 39, n. 2 (maggio 1996): 211–16. http://dx.doi.org/10.1109/13.502068.
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Rötting, O., W. Röpke, H. Becker e C. Gärtner. "Polymer microfabrication technologies". Microsystem Technologies 8, n. 1 (1 marzo 2002): 32–36. http://dx.doi.org/10.1007/s00542-002-0106-9.
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