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Biomedical Microdevices

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https://www.readbyqxmd.com/read/29308571/2dep-cytometry-distributed-dielectrophoretic-cytometry-for-live-cell-dielectric-signature-measurement-on-population-level
#1
P Fikar, V Georgiev, G Lissorgues, M Holubova, D Lysak, D Georgiev
In this work, a novel force equilibrium method called distributed dielectrophoretic cytometry (2DEP cytometry) was developed. It uses a dielectrophoresis (DEP)-induced vertical translation of live cells in conjunction with particle image velocimetry (PIV) in order to measure probabilistic distribution of DEP forces acting on an entire cell population. The method is integrated in a microfluidic device. The bottom of the microfluidic channel is lined with an interdigitated electrode array. Cells passing through the micro-channel are acted on by sedimentation forces, while DEP forces either oppose sedimentation, support sedimentation, or neither, depending on the dielectric (DE) signatures of the cells...
January 8, 2018: Biomedical Microdevices
https://www.readbyqxmd.com/read/29305767/finite-element-modeling-to-analyze-teer-values-across-silicon-nanomembranes
#2
Tejas S Khire, Barrett J Nehilla, Jirachai Getpreecharsawas, Maria E Gracheva, Richard E Waugh, James L McGrath
Silicon nanomembranes are ultrathin, highly permeable, optically transparent and biocompatible substrates for the construction of barrier tissue models. Trans-epithelial/endothelial electrical resistance (TEER) is often used as a non-invasive, sensitive and quantitative technique to assess barrier function. The current study characterizes the electrical behavior of devices featuring silicon nanomembranes to facilitate their application in TEER studies. In conventional practice with commercial systems, raw resistance values are multiplied by the area of the membrane supporting cell growth to normalize TEER measurements...
January 5, 2018: Biomedical Microdevices
https://www.readbyqxmd.com/read/29305659/development-of-micro-mechanical-device-having-two-dimensional-array-of-micro-chambers-for-cell-stretching
#3
K Minami, T Hayashi, K Sato, T Nakahara
This paper presents a novel cell stretching micro device having two-dimensional array of micro chambers. It enables an in situ time-lapse observation of stretched cell by using an optical microscope with high measurement efficiency. The presented device consists of a cell culture dish and the array of micro chambers made of silicone elastomer and extension structures made of photocurable resin, and is fabricated with MEMS technology. The fabrication process of the thin micro chamber array combines photoresist mold and lift-off process based on conventional photolithography...
January 5, 2018: Biomedical Microdevices
https://www.readbyqxmd.com/read/29294210/structuring-a-multi-nodal-neural-network-in-vitro-within-a-novel-design-microfluidic-chip
#4
Rosanne van de Wijdeven, Ola Huse Ramstad, Ulrich Stefan Bauer, Øyvind Halaas, Axel Sandvig, Ioanna Sandvig
Neural network formation is a complex process involving axon outgrowth and guidance. Axon guidance is facilitated by structural and molecular cues from the surrounding microenvironment. Micro-fabrication techniques can be employed to produce microfluidic chips with a highly controlled microenvironment for neural cells enabling longitudinal studies of complex processes associated with network formation. In this work, we demonstrate a novel open microfluidic chip design that encompasses a freely variable number of nodes interconnected by axon-permissible tunnels, enabling structuring of multi-nodal neural networks in vitro...
January 2, 2018: Biomedical Microdevices
https://www.readbyqxmd.com/read/29288278/two-photon-fabrication-of-hydrogel-microstructures-for-excitation-and-immobilization-of-cells
#5
Nils Frederik Hasselmann, Michael Jona Hackmann, Wolfgang Horn
We investigate in vitro fabrication of hydrogel microstructures by two photon laser lithography for single cell immobilization and excitation. Fluorescent yeast cells are embedded in water containing the hydrogel precursor mixtures and cross-linking is used to selectively immobilize a particular cell. Cell viability within the hydrogel precursor is estimated using a life/dead assay and elastic and stiff hydrogel structures are fabricated, immobilizing cells in a microfluidic environment. Additionally, we demonstrate the illumination of cells by on-the-fly fabricated hydrogel waveguide networks connected to an external light source, thereby exciting a fluorescence signal in a single immobilized cell...
December 29, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29256185/lab-on-a-chip-device-made-by-autohesion-bonded-polymers
#6
Firas Awaja, Tsz-Ting Wong, Benedicta Arhatari
Polymers have the obvious advantages of flexibility in design and cost effectiveness to fabricate a lab-on-a-chip (LOC) device. Polyether ether ketone (PEEK) in particular is very attractive choice as it adds biocompatibility in addition to the possibility of hematic sealing in a 3D design. Hereby, we extend our previous successful technology of autohesive hermetic bonding of medical implants into lab-on-a-chip devices. We explore a conceptual 3D micro channels design with hermetic potential using PEEK and PS sheets...
December 18, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29185049/a-radial-pillar-device-rapid-for-continuous-and-high-throughput-separation-of-multi-sized-particles
#7
Ninad Mehendale, Oshin Sharma, Claudy D'Costa, Debjani Paul
Pillar-based microfluidic sorting devices are preferred for isolation of rare cells due to their simple designs and passive operation. Dead-end pillar filters can efficiently capture large rare cells, such as, circulating tumor cells (CTCs), nucleated red blood cells (NRBCs), CD4 cells in HIV patients, etc., but they get clogged easily. Cross flow filters are preferred for smaller rare particles (e.g. separating bacteria from blood), but they need additional buffer inlets and a large device footprint for efficient operation...
November 28, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29177803/cytotoxic-and-antimicrobial-effects-of-biosynthesized-zno-nanoparticles-using-of-chelidonium-majus-extract
#8
Renata Dobrucka, Jolanta Dlugaszewska, Mariusz Kaczmarek
The basic goal of this study was to synthesize zinc oxide nanoparticles using the Chelidonium majus extract and asses their cytotoxic and antimicrobial properties. The synthesized ZnO NPs were characterized by UV-Vis, Scanning Electron Microscopy (SEM) with EDS profile, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM). The aforementioned methods confirmed that the size of synthesized ZnO nanoparticles was at the range of 10 nm...
November 27, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29170867/a-novel-fabrication-method-of-carbon-electrodes-using-3d-printing-and-chemical-modification-process
#9
Pan Tian, Chaoyang Chen, Jie Hu, Jin Qi, Qianghua Wang, Jimmy Ching-Ming Chen, John Cavanaugh, Yinghong Peng, Mark Ming-Cheng Cheng
Three-dimensional (3D) printing is an emerging technique in the field of biomedical engineering and electronics. This paper presents a novel biofabrication method of implantable carbon electrodes with several advantages including fast prototyping, patient-specific and miniaturization without expensive cleanroom. The method combines stereolithography in additive manufacturing and chemical modification processes to fabricate electrically conductive carbon electrodes. The stereolithography allows the structures to be 3D printed with very fine resolution and desired shapes...
November 23, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29164403/a-novel-photodynamic-therapy-based-drug-delivery-system-layered-on-a-stent-for-treating-cholangiocarcinoma
#10
Po-Chin Liang, Kai-Wen Huang, Chien-Chih Tung, Ming-Chu Chang, Fuh-Yu Chang, Jau-Min Wong, Yu-Ting Chang
This study aimed to investigate the drug delivery efficacy and bio-effectiveness of a novel photodynamic therapy (PDT)-matrix drug delivery system for cholangiocarcinoma (CCA). Metallic stents were coated with polyurethane (PU) as the first layer. A 2-hydroxyethyl methacrylate (2-HEMA)/ethylene glycol dimethacrylate (EGDMA)/benzoyl peroxide (BPO) layer and a poly(ethylene-co-vinyl acetate) (PEVA)/poly(n-butyl methacrylate) (PBMA)/polyvinylpyrrolidone K30 (K30) layer containing various concentrations of Photofrin were then incorporated onto the stent as the second and third layers...
November 22, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29159519/full-wafer-in-situ-fabrication-and-packaging-of-microfluidic-flow-cytometer-with-photo-patternable-adhesive-polymers
#11
Koen de Wijs, Chengxun Liu, Bivragh Majeed, Karolien Jans, John M O'Callaghan, Josine Loo, Erik Sohn, Sara Peeters, Ruben Van Roosbroeck, Tomokazu Miyazaki, Kenji Hoshiko, Isao Nishimura, Katsuhiko Hieda, Liesbet Lagae
Integration of microelectronics with microfluidics enables sophisticated lab-on-a-chip devices for sensing and actuation. In this paper, we investigate a novel method for in-situ microfluidics fabrication and packaging on wafer level. Two novel photo-patternable adhesive polymers were tested and compared, PA-S500H and DXL-009. The microfluidics fabrication method employs photo lithographical patterning of spin coated polymer films of PA or DXL and direct bonding of formed microfluidics to a top glass cover using die-to-wafer level bonding...
November 21, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29159513/molybdenum-coated-su-8-microneedle-electrodes-for-transcutaneous-electrical-nerve-stimulation
#12
Ramin Soltanzadeh, Elnaz Afsharipour, Cyrus Shafai, Neda Anssari, Behzad Mansouri, Zahra Moussavi
Electrophysiological devices are connected to the body through electrodes. In some applications, such as nerve stimulation, it is needed to minimally pierce the skin and reach the underneath layers to bypass the impedance of the first layer called stratum corneum. In this study, we have designed and fabricated surface microneedle electrodes for applications such as electrical peripheral nerve stimulation. We used molybdenum for microneedle fabrication, which is a biocompatible metal; it was used for the conductive layer of the needle array...
November 21, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29138988/irreversible-electroporation-of-the-uterine-cervix-in-a-rabbit-model
#13
Wei Chai, Wenlong Zhang, Zhentong Wei, Ying Xu, Jian Shi, Xiaomei Luo, Jianying Zeng, Manhua Cui, Jiannan Li, Lizhi Niu
The aim of this study was to evaluate the effects of irreversible electroporation (IRE) on the uterine cervix in a rabbit model. IRE ablation was performed in the cervices of 48 New Zealand rabbits, with one ablation lesion in each animal. Gross pathology, transmission electron microscopy, hematoxylin and eosin (H&E), Masson's trichrome (MT) stain, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays were performed at pre-set time points (0 h, 12 h, 1 d, 2 d, 4 d, 7 d, 14 d, and 28 d post-IRE)...
November 14, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29134412/engineered-bone-scaffolds-with-dielectrophoresis-based-patterning-using-3d-printing
#14
Zhijie Huan, Henry K Chu, Hongbo Liu, Jie Yang, Dong Sun
Patterning of cells into a specific pattern is an important procedure in tissue engineering to facilitate tissue culture and ingrowth. In this paper, a new type of 3D-printed scaffold utilizing dielectrophoresis (DEP) for active cell seeding and patterning was proposed. This scaffold adopted a concentric-ring design that is similar to native bone tissues. The scaffold was fabricated with a commercial three-dimensional (3D) printer. Polylactic Acid (PLA) was selected as the material for the printer and the fabricated scaffold was coated with gold to enhance the conductivity for DEP manipulation...
November 13, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29128921/a-microfluidic-in-line-elisa-for-measuring-secreted-protein-under-perfusion
#15
Qiyue Luan, Stacey Cahoon, Agnes Wu, Shyam Sundhar Bale, Martin Yarmush, Abhinav Bhushan
Recent progress in the development of microfluidic microphysiological systems such as 'organs-on-chips' and microfabricated cell culture is geared to simulate organ-level physiology. These tissue models leverage microengineering technologies that provide capabilities of presenting cultured cells with input signals in a more physiologically relevant context such as perfused flow. Proteins that are secreted from cells have important information about the health of the cells. Techniques to quantify cellular proteins include mass spectrometry to ELISA (enzyme-linked immunosorbent assay)...
November 11, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29116458/3d-gut-liver-chip-with-a-pk-model-for-prediction-of-first-pass-metabolism
#16
Dong Wook Lee, Sang Keun Ha, Inwook Choi, Jong Hwan Sung
Accurate prediction of first-pass metabolism is essential for improving the time and cost efficiency of drug development process. Here, we have developed a microfluidic gut-liver co-culture chip that aims to reproduce the first-pass metabolism of oral drugs. This chip consists of two separate layers for gut (Caco-2) and liver (HepG2) cell lines, where cells can be co-cultured in both 2D and 3D forms. Both cell lines were maintained well in the chip, verified by confocal microscopy and measurement of hepatic enzyme activity...
November 7, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29116415/a-microfluidic-device-for-quantitative-investigation-of-zebrafish-larvae-s-rheotaxis
#17
Amir Reza Peimani, Georg Zoidl, Pouya Rezai
Zebrafish is a model organism for various sensory-motor biological studies. Rheotaxis, or the ability of zebrafish to orient and swim against the water stream, is a common behavior that involves multiple sensory-motor processes such as their lateral line and visual systems. Due to the lack of a controllable and easy-to-use assay, zebrafish rheotaxis at larval stages is not well-understood. In this paper, we report a microfluidic device that can be used to apply the flow stimulus precisely and repeatedly along the longitudinal axis of individual zebrafish larvae to study their coaxial rheotaxis...
November 7, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29116412/fabrication-of-flexible-thin-polyurethane-membrane-for-tissue-engineering-applications
#18
A Arefin, J-H Huang, D Platts, V D Hypes, J F Harris, R Iyer, P Nath
Thin and flexible polymeric membranes play a critical role in tissue engineering applications for example organs-on-a-chip. These flexible membranes can enable mechanical stretch of the engineered tissue to mimic organ-specific biophysical features, such as breathing. In this work, we report the fabrication of thin (<20 μm), stretchable, and biocompatible polyurethane (PU) membranes. The membranes were fabricated using spin coating technique on silicon substrates and were mounted on a frame for ease of device integration and handling...
November 7, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29103075/measurement-of-cell-traction-force-with-a-thin-film-pdms-cantilever
#19
Merrel T Holley, Ashkan YekrangSafakar, Mazvita Maziveyi, Suresh K Alahari, Kidong Park
Adherent cells produce cellular traction force (CTF) on a substrate to maintain their physical morphologies, sense external environment, and perform essential cellular functions. Precise characterization of the CTF can expand our knowledge of various cellular processes as well as lead to the development of novel mechanical biomarkers. However, current methods that measure CTF require special substrates and fluorescent microscopy, rendering them less suitable in a clinical setting. Here, we demonstrate a rapid and direct approach to measure the combined CTF of a large cell population using thin polydimethylsiloxane (PDMS) cantilevers...
November 4, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/29098446/correction-to-polymer-based-interconnection-cables-to-integrate-with-flexible-penetrating-microelectrode-arrays
#20
Keonghwan Oh, Donghak Byun, Sohee Kim
The original version of this article unfortunately contained a mistake. In Eqs. (1) to (3), the gas constant 'R' should be replaced with Boltzmann constant 'k B.' This change accompanies the change in the paragraph following Eq. (3) as below.
November 2, 2017: Biomedical Microdevices
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