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Biomedical Microdevices

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https://www.readbyqxmd.com/read/28074385/use-of-a-cd-laser-pickup-head-to-fabricate-microelectrodes-in-polymethylmethacrylate-substrates-for-biosensing-applications
#1
Jehú López-Aparicio, Mathieu Hautefeuille, Sara Herrera-Domínguez, Adriana Razo-de-León, Mariel Cano-Jorge, Ixchetl Rojas-Benito, Mariana Centeno-Sierra, Tatiana Fiordelisio-Coll, Catalina Elizabeth Stern-Forgach
In this work, we report a simple fabrication method for microelectrodes on a polymethylmethacrylate substrate, using a low-cost laser platform based on a CD-DVD unit for direct rapid-prototyping. We used this laser microfabrication technique to etch any desired design on polymethylmethacrylate substrates to produce microchannels with controlled geometry, with a highly repeatable micron-scale resolution. Those shallow microchannels were then filled with a conductive paste of material of our choice that was converted into microelectrodes of desired shapes and geometries after drying...
March 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28074384/microfluidic-gut-liver-chip-for-reproducing-the-first-pass-metabolism
#2
Aerim Choe, Sang Keun Ha, Inwook Choi, Nakwon Choi, Jong Hwan Sung
After oral intake of drugs, drugs go through the first pass metabolism in the gut and the liver, which greatly affects the final outcome of the drugs' efficacy and side effects. The first pass metabolism is a complex process involving the gut and the liver tissue, with transport and reaction occurring simultaneously at various locations, which makes it difficult to be reproduced in vitro with conventional cell culture systems. In an effort to tackle this challenge, here we have developed a microfluidic gut-liver chip that can reproduce the dynamics of the first pass metabolism...
March 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28070698/drug-coated-microneedles-for-rapid-and-painless-local-anesthesia
#3
Sung-Hyun Baek, Ju-Hyung Shin, Yeu-Chun Kim
This study showed that drug-coated PLLA (Poly (L-lactide)) microneedle arrays can induce rapid and painless local anesthesia. Microneedle arrays were fabricated using a micro-molding technique, and the needle tips were coated with 290.6 ± 45.9 μg of lidocaine, the most widely used local anesthetic worldwide. A dip-coating device was newly designed for the coating step using an optimized coating formulation. Lidocaine coated on the arrays was released rapidly into PBS within 2 min, and its stability in storage lasted 3 weeks at 4, 25, and 37°C...
March 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28070697/development-of-a-dsred-expressing-heparg-cell-line-for-real-time-monitoring-of-hepatocyte-like-cell-differentiation-by-fluorescence-imaging-with-application-in-screening-of-novel-geometric-microstructured-cell-growth-substrates
#4
Mihaela Uta, Livia E Sima, Patrik Hoffmann, Valentina Dinca, Norica Branza-Nichita
The bipotent nature of the HepaRG cell line is a unique property among human hepatoma-derived cells. Cell treatment with specific differentiation inducers results in a mixture of hepatocyte- and biliary-like cells, accompanied by upregulation of liver-specific proteins, drug metabolizing enzymes, transcription regulators, membrane receptors or innate immune response effectors. These features make the HepaRG cells a suitable and handy replacement for primary hepatocytes, to study hepatic functions in vitro. However, cell differentiation is a long, variable process, requiring special culture conditions, while the resulting mixed cell populations is usually a major drawback...
March 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28070696/an-ionic-liquid-based-strain-sensor-for-large-displacement-measurement
#5
Grim Keulemans, Frederik Ceyssens, Robert Puers
A robust and low cost ionic liquid based strain sensor is fabricated for high strain measurements in biomedical applications (up to 40 % and higher). A tubular 5 mm long silicone microchannel with an inner diameter of 310 µm and an outer diameter of 650 µm is filled with an ionic liquid. Three ionic liquids have been investigated: 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, ethylammonium nitrate and cholinium ethanoate. When the channel is axially stretched, geometrical deformations change the electrical impedance of the liquid channel...
March 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/27975186/an-integrated-microfluidic-pcr-system-with-immunomagnetic-nanoparticles-for-the-detection-of-bacterial-pathogens
#6
Irisappan Ganesh, Buu Minh Tran, Yonghee Kim, Jaewon Kim, Hua Cheng, Nae Yoon Lee, Sungsu Park
There is growing interest in rapid microbial pre-concentration methods to lower the detection limit of bacterial pathogens of low abundance in samples. Here, we report an integrated microfluidic PCR system that enables bacterial cells of interest in samples to be concentrated prior to PCR. It consists of two major compartments: a preconcentration chamber for the immunomagnetic separation of bacterial cells, and a PCR chamber for the DNA amplification of the concentrated cells. We demonstrate the feasibility of the system for the detection of microbial pathogens by preconcentrating the human pathogen Escherichia coli O157:H7, and also amplifying its DNA...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27943003/maskless-wafer-level-microfabrication-of-optical-penetrating-neural-arrays-out-of-soda-lime-glass-utah-optrode-array
#7
Ronald W Boutte, Steve Blair
Borrowing from the wafer-level fabrication techniques of the Utah Electrode Array, an optical array capable of delivering light for neural optogenetic studies is presented in this paper: the Utah Optrode Array. Utah Optrode Arrays are micromachined out of sheet soda-lime-silica glass using standard backend processes of the semiconductor and microelectronics packaging industries such as precision diamond grinding and wet etching. 9 × 9 arrays with 1100μ m × 100μ m optrodes and a 500μ m back-plane are repeatably reproduced on 2i n wafers 169 arrays at a time...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27921279/biocompatibility-of-fluids-for-multiphase-drops-in-drops-microfluidics
#8
Aishah Prastowo, Alexander Feuerborn, Peter R Cook, Edmond J Walsh
This paper addresses the biocompatibility of fluids and surfactants in the context of microfluidics and more specifically in a drops-in-drops system for mammalian cell based drug screening. In the drops-in-drops approach, three immiscible fluids are used to manipulate the flow of aqueous microliter-sized drops; it enables merging of drops containing cells with drops containing drugs within a Teflon tube. Preliminary tests showed that a commonly-used fluid and surfactant combination resulted in significant variability in gene expression levels in Jurkat cells after exposure to a drug for four hours...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27909898/two-dimensional-polyaniline-nanostructure-to-the-development-of-microfluidic-integrated-flexible-biosensors-for-biomarker-detection
#9
Pei Liu, Yisi Zhu, Seung Hee Lee, Minhee Yun
In this work, we report a flexible field-effect-transistor (FET) biosensor design based on two-dimensional (2-D) polyaniline (PANI) nanostructure. The flexible biosensor devices were fabricated through a facile and inexpensive method that combines top-down and bottom-up processes. The chemically synthesized PANI nanostructure showed excellent p-type semiconductor properties as well as good compatibility with flexible design. With the 2-D PANI nanostructure being as thin as 80 nm and its extremely large surface-area-to-volume (SA/V) ratio due to the intrinsic properties of PANI chemical synthesis, the developed flexible biosensor exhibited outstanding sensing performance in detecting B-type natriuretic peptide (BNP) biomarkers, and was able to achieve high specificity (averagely 112 folds) with the limit of detection as low as 100 pg/mL...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27900618/3d-carbon-nanofiber-microelectrode-arrays-fabricated-by-plasma-assisted-pyrolysis-to-enhance-sensitivity-and-stability-of-real-time-dopamine-detection
#10
Wenwen Yi, Yuanyuan Yang, Parastoo Hashemi, Mark Ming-Cheng Cheng
In this paper, we have fabricated 3D carbon nanofiber microelectrode arrays (MEAs) with highly reproducible and rich chemical surface areas for fast scan cyclic voltammetry (FSCV). Carbon nanofibers are created from negative photoresist by a new process called dual O2 plasma-assisted pyrolysis. The proposed approach significantly improves film adhesion and increases surface reactivity. We showcase our sensor's compatibility with FSCV analysis by demonstrating highly sensitive and stable FSCV dopamine measurements on a prototype 4-channel array...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27864741/an-ultrasensitive-label-free-nanobiosensor-platform-for-the-detection-of-cardiac-biomarkers
#11
Durga Prakash Matta, Suryasnata Tripathy, Siva Rama Krishna Vanjari, Chandra Shekhar Sharma, Shiv Govind Singh
We report the fabrication of a label free nano biosensor platform comprising single nanofiber that is derived out of multi-walled carbon nanotubes (MWCNTs) embedded SU-8 photoresist, for the detection of three important human cardiac biomarkers viz., myoglobin (Myo), cardiac Troponin I (cTn I) and Creatine Kinase-MB (CK-MB). These composite nanofibers were synthesized using electrospinning process. Single nanofibers were aligned between pairs of electrodes in-situ during the electrospinning process. The target proteins were detected using chemiresistive detection methodology...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27834053/a-high-accuracy-cantilever-array-sensor-for-early-liver-cancer-diagnosis
#12
Jingjing Wang, Lihao Wang, Yinfang Zhu, Jinying Zhang, Ju Liao, Shuaipeng Wang, Jinling Yang, Fuhua Yang
Early liver cancer diagnosis has clinical significance in treating cancer. Joint detection of multiple biomarkers has been considered as an effective and reliable method for early cancer diagnosis. In this work, a novel biosensor based on microcantilever array was batch-fabricated for multiple liver cancer biomarkers detection with high sensitivity, high accuracy, high throughput, and high specification. A micro-cavity was designed in the free end of the cantilever for local reaction between antibody and antigen, which can dramatically reduce the effect of adsorption-induced stiffness coefficient k variation...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27830455/optimization-of-an-endovascular-magnetic-filter-for-maximized-capture-of-magnetic-nanoparticles
#13
Sravani Kondapavulur, Andre M Cote, Kiel D Neumann, Caroline D Jordan, David McCoy, Marc C Mabray, Derek Liu, Chia-Hung Sze, Ayushi Gautam, Henry F VanBrocklin, Mark Wilson, Steven W Hetts
To computationally optimize the design of an endovascular magnetic filtration device that binds iron oxide nanoparticles and to validate simulations with experimental results of prototype devices in physiologic flow testing. Three-dimensional computational models of different endovascular magnetic filter devices assessed magnetic particle capture. We simulated a series of cylindrical neodymium N52 magnets and capture of 1500 iron oxide nanoparticles infused in a simulated 14 mm-diameter vessel. Device parameters varied included: magnetization orientation (across the diameter, "D", along the length, "L", of the filter), magnet outer diameter (3, 4, 5 mm), magnet length (5, 10 mm), and spacing between magnets (1, 3 mm)...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27830454/ethosomes-and-organogels-for-cutaneous-administration-of-crocin
#14
Elisabetta Esposito, Markus Drechsler, Nicolas Huang, Gabriella Pavoni, Rita Cortesi, Debora Santonocito, Carmelo Puglia
The present study describes the production and characterization of phosphatidylcholine based ethosomes and organogels, as percutaneous delivery systems for crocin. Crocin presence did not influence ethosome morphology, while the drug slightly increased ethosome mean diameter. Importantly, the poor chemical stability of crocin has been found to be long controlled by organogel. To investigate the performance of phosphatidylcholine lipid formulations as crocin delivery system, in vivo studies, based on tape stripping and skin reflectance spectrophotometry, were performed...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27830453/facile-modulation-of-cell-adhesion-to-a-poly-ethylene-glycol-diacrylate-film-with-incorporation-of-polystyrene-nano-spheres
#15
Wenguang Yang, Haibo Yu, Gongxin Li, Yuechao Wang, Lianqing Liu
Poly(ethylene glycol) diacrylate (PEGDA) is a common hydrogel that has been actively investigated for various tissue engineering applications owing to its biocompatibility and excellent mechanical properties. However, the native PEGDA films are known for their bio-inertness which can hinder cell adhesion, thereby limiting their applications in tissue engineering and biomedicine. Recently, nano composite technology has become a particularly hot topic, and has led to the development of new methods for delivering desired properties to nanomaterials...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27830452/fabrication-of-self-expandable-niti-thin-film-devices-with-micro-electrode-array-for-bioelectric-sensing-stimulation-and-ablation
#16
Christoph Bechtold, Rodrigo Lima de Miranda, Christoph Chluba, Eckhard Quandt
Self-expandable medical devices provide mechanical functionality at a specific location of the human body and are viable for minimal invasive procedures. Besides radiopaque markers and drug-eluting coatings, next generation self-expandable devices can be equipped with additional functionality, such as conductive and flexible electrodes, which enables chronic recording of bioelectrical signals, stimulating or ablating tissue. This promises new therapeutic options in various medical fields, among them in particular neuromodulation (e...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27819128/human-pancreatic-stellate-cells-modulate-3d-collagen-alignment-to-promote-the-migration-of-pancreatic-ductal-adenocarcinoma-cells
#17
Cole R Drifka, Agnes G Loeffler, Corinne R Esquibel, Sharon M Weber, Kevin W Eliceiri, W John Kao
A hallmark of pancreatic ductal adenocarcinoma (PDAC) is the ability for cancer cells to aggressively infiltrate and navigate through a dense stroma during the metastatic process. Key features of the PDAC stroma include an abundant population of activated pancreatic stellate cells (PSCs) and highly aligned collagen fibers; however, important questions remain regarding how collagen becomes aligned and what the biological manifestations are. To better understand how PSCs, aligned collagen, and PDAC cells might cooperate during the transition to invasion, we utilized a microchannel-based in vitro tumor model and advanced imaging technologies to recreate and examine in vivo-like heterotypic interactions...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27796676/microfluidic-advances-in-phenotypic-antibiotic-susceptibility-testing
#18
Jennifer Campbell, Christine McBeth, Maxim Kalashnikov, Anna K Boardman, Andre Sharon, Alexis F Sauer-Budge
A strong natural selection for microbial antibiotic resistance has resulted from the extensive use and misuse of antibiotics. Though multiple factors are responsible for this crisis, the most significant factor - widespread prescription of broad-spectrum antibiotics - is largely driven by the fact that the standard process for determining antibiotic susceptibility includes a 1-2-day culture period, resulting in 48-72 h from patient sample to final determination. Clearly, disruptive approaches, rather than small incremental gains, are needed to address this issue...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27796675/manufacturing-methods-and-applications-of-membranes-in-microfluidics
#19
Xueye Chen, Jienan Shen, Zengliang Hu, Xuyao Huo
Applications of membranes in microfluidics solved many thorny problems for analytical chemistry and bioscience, so that the use of membranes in microfluidics has been a topic of growing interest. Many different examples have been reported, demonstrating the versatile use of membranes. This work reviews a lot of applications of membranes in microfluidics. Membranes in microfluidics for applications including chemical reagents detection, gas detection, drug screening, cell, protein, microreactor, electrokinetical fluid, pump and valve and fluid transport control and so on, have been analyzed and discussed...
December 2016: Biomedical Microdevices
https://www.readbyqxmd.com/read/27787764/a-magnetically-actuated-anchoring-system-for-a-wireless-endoscopic-capsule
#20
Hao Zhou, Gursel Alici, Fredy Munoz
In this study, we propose a new magnetically actuated anchoring system for wireless capsule endoscopes (WCE) by employing the principle of a switchable magnetic spring. A force model is derived to predict the magnetic force needed to support the interaction between the anchors and the intestinal lumen. The theoretical and experimental analysis conducted shows that the magnetic spring is capable of providing the force needed to activate the anchoring mechanism, which consists of four foldable legs. A prototype capsule with a size comparable with the size of a commercial WCE was designed, fabricated, and tested...
December 2016: Biomedical Microdevices
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