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Ying Tu, Norlaily Ahmad, Joe Briscoe, De-Wen Zhang, Steffi Krause
Light-addressable potentiometric sensors (LAPS) are of great interest in bioimaging applications such as the monitoring of concentrations in microfluidic channels or the investigation of metabolic and signaling events in living cells. By measuring the photocurrents at electrolyte-insulator-semiconductor (EIS) and electrolyte-semiconductor structures, LAPS can produce spatiotemporal images of chemical or biological analytes, electrical potentials and impedance. However, its commercial applications are often restricted by their limited AC photocurrents and resolution of LAPS images...
June 22, 2018: Analytical Chemistry
Da Eun Kim, Jong Min Lee, Christian D Ahrberg, Mohammed R Shaker, Ju-Hyun Lee, Woong Sun, Bong Geun Chung
The inability of neurons to undergo mitosis renders damage to the central or peripheral nervous system. Neural stem cell (NSC) therapy could provide a path for treating the neurodegenerative diseases. However, reliable and simple tools for the developing and testing NSC therapy are still required. Here, we show the development of a micropillar-based microfluidic device to trap the uniform-sized neurospheres. The neurospheres trapped within micropillar arrays were largely differentiated into neuronal cells and their neurite networks were observed in the microfluidic device...
June 22, 2018: Electrophoresis
Ranjani Parthasarathy, Callan E Monette, Sabrina Bracero, Margaret S Saha
The growing prevalence of antibiotic resistance poses an increasingly serious threat to human health. Although an important driver of antibiotic resistance is the continuous exposure of bacteria to sublethal concentrations of antibiotics in natural environments, antibiotic pollutants are not currently tracked globally or systematically. This limits the international capacity to address the rise of antibiotic resistance at its source. To address this lack of data, the development of methods to measure antibiotic concentrations on-site is essential...
August 1, 2018: FEMS Microbiology Ecology
Korine A Ohiri, Sean T Kelly, Jeffrey D Motschman, Kevin H Lin, Kris C Wood, Benjamin B Yellen
We demonstrate a hybrid microfluidic system that combines fluidic trapping and acoustic switching to organize an array of single cells at high density. The fluidic trapping step is achieved by balancing the hydrodynamic resistances of three parallel channel segments forming a microfluidic trifurcation, the purpose of which was to capture single cells in a high-density array. Next, the cells were transferred into adjacent larger compartments by generating an array of streaming micro-vortices to move the cells to the desired streamlines in a massively parallel format...
June 22, 2018: Lab on a Chip
Xiaolin Wang, Da Zhao, Duc T T Phan, Jingquan Liu, Xiang Chen, Bin Yang, Christopher C W Hughes, Weijia Zhang, Abraham P Lee
Autonomous and self-powered micropumps are in critical demand for versatile cell- and tissue-based applications as well as for low-cost point-of-care testing (POCT) in microfluidics fields. The hydrostatic pressure-driven passive micropumps are simple and widely used, but they cannot maintain steady and continuous flow for long periods of time. Here, we propose a hydrostatic pressure-driven passive micropump enhanced with siphon-based autofill function, which can realize the autonomous and continuous perfusion with well-controlled steady flow over an extended time without electric power consumption...
June 22, 2018: Lab on a Chip
Ivan Denisov, Kirill Lukyanenko, Anton Yakimov, Igor Kukhtevich, Elena Esimbekova, Peter Belobrov
In the present study, we demonstrate the use of a disposable luciferase-based microfluidic bioassay chip for environmental monitoring and methods for fabrication. The designed microfluidic system includes a chamber with immobilized enzymes of bioluminescent bacteria Photobacterium leiognathi and Vibrio fischeri and their substrates, which dissolve after the introduction of the water sample and thus activate bioluminescent reactions. Limits of detection for copper (II) sulfate, 1,3-dihydroxybenzene and 1,4-benzoquinone for the proposed microfluidic biosensor measured 3 μM, 15 mM, and 2 μM respectively, and these values are higher or close to the level of conventional environmental biosensors based on lyophilized bacteria...
June 21, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
Di-Wei Zheng, Jin-Xuan Fan, Xin-Hua Liu, Xue Dong, Pei Pan, Lu Xu, Xian-Zheng Zhang
Cytotherapy has received considerable attention in the field of cancer therapy, and various chemical or genetic methods have been applied to remold natural cells for improved therapeutic outcome of cytotherapy. A simple method to modify lymphocytes for cancer treatment by using a clinically used molecule, δ-aminolevulinic acid (δ-ALA), is reported here. After incubation with this molecule, tumor-targeted lymphocytes spontaneously synthesize anti-neoplastic drug protoporphyrin X (PpIX), and specifically accumulate in cancer tissue...
June 21, 2018: Advanced Materials
Claudia Dalmastri, Weihua Han, Stefano Vespucci, Liqian Wang, Piero Morales
We describe here one way to achieve hybrid DNA-inorganic nanostructures on rigid flat insulating substrates. We report methods to prepare rectangular DNA origami and incubate them onto arrays of anchoring gold nanodots either in a static solution or in a microfluidic system. We give details on the design and lithographic methods employed to pattern usable arrays of gold nanoanchors on naturally oxidized silicon wafer chips. Scanning electron and atomic force microscopy methodological details are also given for obtaining the relevant characterizations of the immobilized and ordered DNA origami...
2018: Methods in Molecular Biology
Sophie Thamm, Andrea Csàki, Wolfgang Fritzsche
Noble metal nanoparticles are well known for their unique optical properties. Density oscillations of the nanoparticle conduction electrons are induced at a specific frequency by an external incident light beam. This phenomenon is known under the term localized surface plasmon resonance (LSPR). The spectral position of the resonance band is determined by shape, size, and material of the nanoparticle and influenced by changes of the local refractive index of the surrounding medium. The latter gives the opportunity to use noble metal nanoparticles as label-free bioanalytical sensors...
2018: Methods in Molecular Biology
Xin Jin, Rui Chen, Shikun Zhao, Peiyong Li, Bai Xue, Xiang Chen, Xinyuan Zhu
In this article, an attempt for efficient screening of circulating tumor cells (CTCs) with excellent operability on microfluidic chips was reported. A Parsortix™-like cell separation chip was manufactured in our lab. This chip allowed lateral flow of fluid which increased the flow rate of blood. And, an air valve controlled injection pump was manufactured which allowed eight chips working simultaneously. This greatly facilitated the blood treatment process and saved time. As for the mechanism of screening circulating tumor cells, selective size amplification was utilized...
June 20, 2018: Biomedical Microdevices
Yan Teck Ho, Roger D Kamm, James Chen Yong Kah
Transcytosis of nanoparticles (NPs) is emerging as an attractive alternative to the paracellular route in cancer drug delivery with studies suggesting targeting caveolae-mediated endocytosis to maximize NP transcytosis. However, there are limited studies on transcytosis of NPs, especially for corona-coated NPs. Most studies focused on cellular uptake as an indirect measure of the NP's transcellular permeability (Pd). Here, we probed the effect of protein corona on the uptake and transcytosis of 20, 40, 100, and 200 nm polystyrene nanoparticles (pNP-PC) across HUVECs in a microfluidic channel that modelled the microvasculature...
June 21, 2018: Nanoscale
Jian Zhou, Chunlong Tu, Yitao Liang, Bobo Huang, Yifeng Fang, Xiao Liang, Ian Papautsky, Xuesong Ye
Extraction of cells of interest directly from whole blood is in high demand, yet extraordinary challenging due to the complex hemodynamics and hemorheology of the sample. Herein, we describe a new microfluidic platform that exploits the intrinsic complex properties of blood for continuous size-selective focusing and separation of cells directly from unprocessed whole blood. The novel system only requires routinely accessible saline solution to form a sandwiched fluid configuration and to initiate a strong effect of shear-induced diffusion of cells, which is coupled with fluid inertia for effective separation...
June 20, 2018: Scientific Reports
Clément Regnault, Dharmendra S Dheeman, Axel Hochstetter
In this review, we give an overview of the current state of microfluidic-based high-throughput drug assays. In this highly interdisciplinary research field, various approaches have been applied to high-throughput drug screening, including microtiter plate, droplets microfluidics as well as continuous flow, diffusion and concentration gradients-based microfluidic drug assays. Therefore, we reviewed over 100 recent publications in the field and sorted them according to their microfluidic approach. As a result, we are showcasing, comparing and discussing broadly applied approaches as well as singular promising ones that might contribute to shaping the future of this field...
June 20, 2018: High-throughput
Julien Babic, Laurent Griscom, Jeremy Cramer, Damien Coudreuse
BACKGROUND: Real-time monitoring of cellular responses to dynamic changes in their environment or to specific treatments has become central to cell biology. However, when coupled to live-cell imaging, such strategies are difficult to implement with precision and high time resolution, and the simultaneous alteration of multiple parameters is a major challenge. Recently, microfluidics has provided powerful solutions for such analyses, bringing an unprecedented level of control over the conditions and the medium in which cells under microscopic observation are grown...
June 20, 2018: BMC Cell Biology
Venkatesh Inguva, Sagar V Kathuria, Osman Bilsel, Blair James Perot
Kinetic studies of biological macromolecules increasingly use microfluidic mixers to initiate and monitor reaction progress. A motivation for using microfluidic mixers is to reduce sample consumption and decrease mixing time to microseconds. Some applications, such as small-angle x-ray scattering, also require large (>10 micron) sampling areas to ensure high signal-to-noise ratios and to minimize parasitic scattering. Chaotic to marginally turbulent mixers are well suited for these applications because this class of mixers provides a good middle ground between existing laminar and turbulent mixers...
2018: PloS One
Bo Zhang, Giancarlo Pascali, Naomi Wyatt, Lidia Matesic, Mitchell A Klenner, Tiffany R Sia, Adam J Guastella, Massimiliano Massi, Andrea J Robinson, Benjamin H Fraser
Fluorine-18 labelled prosthetic groups (PGs) are often necessary for radiolabelling sensitive biological molecules such as peptides and proteins. Several shortcomings, however, often diminish the final yield of radiotracer. In an attempt to provide higher yielding and operationally efficient tools for radiolabelling biological molecules, we describe herein the first radiochemical synthesis of [18 F] ethenesulfonylfluoride ([18 F] ESF) and its Michael conjugation with amino acids and proteins. The synthesis of [18 F] ESF was optimised using a microfluidic reactor under both carrier-added (c...
June 20, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Die Yang, Craig Priest
We demonstrate an optofluidic screening platform for studying thiosulfate leaching of Au in a transparent microchannel. The approach permits in situ (optical) monitoring of Au thickness, reduced reagent use, rapid optimization of reagent chem-istry, screening of temperature, and determination of the activation energy. The results demonstrate the critical importance of the (1) preparation and storage of the leach solution, (2) deposition and annealing of the Au film, and (3) lixiviant chem-istry. The density of sputter deposited Au films decreased with depth resulting in accelerating leach rates during experiments...
June 20, 2018: Analytical Chemistry
Nanjing Hao, Yuan Nie, Ting Shen, John X J Zhang
Microfluidics brings unique opportunities for the synthesis of nanomaterials toward efficient liquid biopsy. Herein, we developed the microreactor-enabled flow synthesis of immunomagnetic nanomaterials with controllable shapes (sphere, cube, rod, and belt) by simply tuning the flow rates. The particle shape-dependent screening efficiency of circulating tumor cells was first investigated and compared with commercial ferrofluids, providing new insights into the rational design of a particulate system toward the screening and analysis of circulating tumor biomarkers...
June 20, 2018: Lab on a Chip
Virginie Grand-Perret, Jean-René Jacquet, Ingrid Leguerney, Baya Benatsou, Jean-Marc Grégoire, Georges Willoquet, Ayache Bouakaz, Nathalie Lassau, Stephanie Pitre-Champagnat
Tumor microvascularization is a biomarker of response to antiangiogenic treatments and is accurately assessed by ultrasound imaging. Imaging modes used to visualize slow flows include Power Doppler imaging, dynamic contrast-enhanced ultrasonography, and more recently, microvascular Doppler. Flow phantoms are used to evaluate the performance of Doppler imaging techniques, but they do not have a steady flow and sufficiently small channels. We report a novel device for robust and stable microflow measurements and the study of the microvascularization...
June 1, 2018: Ultrasonic Imaging
Qi Chen, Di Li, Amirreza Malekanfard, Quanliang Cao, Jianhan Lin, Mao-Hua Wang, Xiaotao Han, Xiangchun Xuan
There has been an increasing interest in the use of magnetic fluids (e.g., ferrofluids and paramagnetic solutions) to manipulate diamagnetic particles in microfluidic devices. Current methods for diamagnetic particle focusing in magnetic fluids require either a pair of repulsive magnets or a diamagnetic sheath flow. We demonstrate herein a tunable sheathless focusing of diamagnetic particles in a microchannel ferrofluid flow with single overhead permanent magnets. Particles are focused into a single stream near the bottom wall of a straight rectangular microchannel, where a magnetic field minimum is formed due to the magnetization of the ferrofluid...
June 20, 2018: Analytical Chemistry
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