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Microfluidics

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https://www.readbyqxmd.com/read/28728010/advances-in-point-of-care-technologies-for-molecular-diagnostics
#1
REVIEW
Mohammad Zarei
Advances in miniaturization, nanotechnology, and microfluidics, along with developments in cloud-connected point-of-care (POC) diagnostics technologies are pushing the frontiers of POC devices toward low-cost, user-friendly, and enhanced sensitivity molecular-level diagnostics. The combination of various bio-sensing platforms within smartphone-integrated electronic readers provides accurate on-site and on-time diagnostics based on various types of chemical and biological targets. Further, 3D printing technology shows a huge potential toward fabrication and improving the performance of POC devices...
July 11, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28728008/pen-on-paper-strategy-for-point-of-care-testing-rapid-prototyping-of-fully-written-microfluidic-biosensor
#2
Zedong Li, Fei Li, Yue Xing, Zhi Liu, Minli You, Yingchun Li, Ting Wen, Zhiguo Qu, Xiao Ling Li, Feng Xu
Paper-based microfluidic biosensors have recently attracted increasing attentions in point-of-care testing (POCT) territories benefiting from their affordable, accessible and eco-friendly features, where technologies for fabricating such biosensors are preferred to be equipment free, easy-to-operate and capable of rapid prototyping. In this work, we developed a pen-on-paper (PoP) strategy based on two custom-made pens, i.e., a wax pen and a conductive-ink pen, to fully write paper-based microfluidic biosensors through directly writing both microfluidic channels and electrodes...
July 1, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28727759/use-of-a-microfluidic-platform-to-uncover-basic-features-of-energy-and-environmental-stress-responses-in-individual-cells-of-bacillus-subtilis
#3
Matthew T Cabeen, Jonathan R Russell, Johan Paulsson, Richard Losick
Bacteria use a variety of stress-sensing systems to sense and respond to diverse stressors and to ensure their survival under adverse conditions. The gram-positive bacterium Bacillus subtilis responds to energy stress (ATP depletion) and to environmental stressors using two distinct stress-sensing pathways that converge on the alternative sigma factor σB to provoke a general stress response. Past efforts to study the σB stress response in bulk culture and on agarose pads were unable to visualize the responses of individual cells under tightly controlled conditions for extended periods of time...
July 20, 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28727559/a-microfluidic-cytometer-for-complete-blood-count-with-a-3-2-megapixel-1-1-%C3%AE-m-pitch-super-resolution-image-sensor-in-65-nm-bsi-cmos
#4
Xu Liu, Xiwei Huang, Yu Jiang, Hang Xu, Jing Guo, Han Wei Hou, Mei Yan, Hao Yu
Based on a 3.2-Megapixel 1.1- μm-pitch super-resolution (SR) CMOS image sensor in a 65-nm backside-illumination process, a lens-free microfluidic cytometer for complete blood count (CBC) is demonstrated in this paper. Backside-illumination improves resolution and contrast at the device level with elimination of surface treatment when integrated with microfluidic channels. A single-frame machine-learning-based SR processing is further realized at system level for resolution correction with minimum hardware resources...
July 18, 2017: IEEE Transactions on Biomedical Circuits and Systems
https://www.readbyqxmd.com/read/28727438/a-wettability-metric-for-characterization-of-capillary-flow-on-textured-superhydrophilic-surfaces
#5
Taylor P Allred, Justin A Weibel, Suresh V Garimella
Surface wettability is typically characterized by measuring the static contact angle of a sessile droplet placed on the surface. For extremely wetting surfaces on which liquid spontaneously spreads into a thin liquid film, the near-zero static contact angle is not amenable to measurement and does not fully describe the wetting behavior. There are unmet needs in microfluidics, boiling heat transfer enhancement, and anti-fogging applications for a metric to characterize highly wetting (i.e., superhydrophilic) textured surfaces based on their capillary-driven liquid pumping performance, as a supplement to the contact angle for this highly wetting regime...
July 20, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28726927/custom-3d-printer-and-resin-for-18-%C3%AE-m-%C3%A3-20-%C3%AE-m-microfluidic-flow-channels
#6
Hua Gong, Bryce P Bickham, Adam T Woolley, Gregory P Nordin
While there is great interest in 3D printing for microfluidic device fabrication, to-date the achieved feature sizes have not been in the truly microfluidic regime (<100 μm). In this paper we demonstrate that a custom digital light processor stereolithographic (DLP-SLA) 3D printer and a specifically-designed, low cost, custom resin can readily achieve flow channel cross sections as small as 18 μm × 20 μm. Our 3D printer has a projected image plane resolution of 7.6 μm and uses a 385 nm LED, which dramatically increases the available selection of UV absorbers for resin formulation compared to 3D printers with 405 nm LEDs...
July 20, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28726923/robust-manufacturing-of-lipid-polymer-nanoparticles-through-feedback-control-of-parallelized-swirling-microvortices
#7
Michael J Toth, Taeyoung Kim, YongTae Kim
A variety of therapeutic and/or diagnostic nanoparticles (NPs), or nanomedicines, have been formulated for improved drug delivery and imaging applications. Microfluidic technology enables continuous and highly reproducible synthesis of NPs through controlled mixing processes at the micro- and nanoscale. Yet, the inherent low-throughput remains a critical roadblock, precluding the probable applications of new nanomedicines for clinical translation. Here we present robust manufacturing of lipid-polymer NPs (LPNPs) through feedback controlled operation of parallelized swirling microvortex reactors (SMRs)...
July 20, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28726916/a-novel-3-d-bio-microfluidic-system-mimicking-in-vivo-heterogeneous-tumour-microstructures-reveals-complex-tumour-stroma-interactions
#8
Qihui Fan, Ruchuan Liu, Yang Jiao, Chunxiu Tian, James D Farrell, Wenwen Diao, Xiaochen Wang, Fengrong Zhang, Wei Yuan, Haibo Han, Jinfeng Chen, Yue Yang, Xixiang Zhang, Fangfu Ye, Ming Li, Zhongcan Ouyang, Liyu Liu
A 3-D microfluidic system consisting of microchamber arrays embedded in a collagen hydrogel with tuneable biochemical gradients that mimics the tumour microenvironment of mammary glands was constructed for the investigation on the interactions between invasive breast cancer cells and stromal cells. The hollow microchambers in collagen provide a very similar 3-D environment to that in vivo that regulates collective cellular dynamics and behaviour, while the microfluidic channels surrounding the collagen microchamber arrays allow one to impose complex concentration gradients of specific biological molecules or drugs...
July 20, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28726728/a-novel-physical-sensing-principle-for-liquid-characterization-using-paper-based-hygro-mechanical-systems-pb-hms
#9
Angel Perez-Cruz, Ion Stiharu, Aurelio Dominguez-Gonzalez
In recent years paper-based microfluidic systems have emerged as versatile tools for developing sensors in different areas. In this work; we report a novel physical sensing principle for the characterization of liquids using a paper-based hygro-mechanical system (PB-HMS). The PB-HMS is formed by the interaction of liquid droplets and paper-based mini-structures such as cantilever beams. The proposed principle takes advantage of the hygroscopic properties of paper to produce hygro-mechanical motion. The dynamic response of the PB-HMS reveals information about the tested liquid that can be applied to characterize certain properties of liquids...
July 20, 2017: Sensors
https://www.readbyqxmd.com/read/28726375/nanoscale-hydrodynamic-film-for-diffusive-mass-transport-control-in-compartmentalized-microfluidic-chambers
#10
Minseok Kim, Ji Won Lim, Sung Kuk Lee, Taesung Kim
A compartmentalized microfluidic chamber array that not only offers separate cell culture environments but also independent control of the diffusion of small molecules provides an extremely useful platform for cell cultivations and versatile cellular assays. However, it is challenging to incorporate both cell compartmentalization and active diffusion control in real-time and precise manners. Here, we present a novel nanoscale hydrodynamic film (NHF) that is formed between a solid substrate and a polydimethylsiloxane (PDMS) surface...
July 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28725897/integration-and-application-of-optical-chemical-sensors-in-microbioreactors
#11
Pia Gruber, Marco P C Marques, Nicolas Szita, Torsten Mayr
The quantification of key variables such as oxygen, pH, carbon dioxide, glucose, and temperature provides essential information for biological and biotechnological applications and their development. Microfluidic devices offer an opportunity to accelerate research and development in these areas due to their small scale, and the fine control over the microenvironment, provided that these key variables can be measured. Optical sensors are well-suited for this task. They offer non-invasive and non-destructive monitoring of the mentioned variables, and the establishment of time-course profiles without the need for sampling from the microfluidic devices...
July 20, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28725484/logarithmic-sensing-in-bacillus-subtilis-aerotaxis
#12
Filippo Menolascina, Roberto Rusconi, Vicente I Fernandez, Steven Smriga, Zahra Aminzare, Eduardo D Sontag, Roman Stocker
Aerotaxis, the directed migration along oxygen gradients, allows many microorganisms to locate favorable oxygen concentrations. Despite oxygen's fundamental role for life, even key aspects of aerotaxis remain poorly understood. In Bacillus subtilis, for example, there is conflicting evidence of whether migration occurs to the maximal oxygen concentration available or to an optimal intermediate one, and how aerotaxis can be maintained over a broad range of conditions. Using precisely controlled oxygen gradients in a microfluidic device, spanning the full spectrum of conditions from quasi-anoxic to oxic (60 n mol/l-1 m mol/l), we resolved B...
2017: NPJ Systems Biology and Applications
https://www.readbyqxmd.com/read/28724996/dynamics-of-high-viscosity-contrast-confluent-microfluidic-flows
#13
Michael E Kurdzinski, Berrak Gol, Aaron Co Hee, Peter Thurgood, Jiu Yang Zhu, Phred Petersen, Arnan Mitchell, Khashayar Khoshmanesh
The laminar nature of microfluidic flows is most elegantly demonstrated via the confluence of two fluids forming two stable parallel flows within a single channel meeting at a highly stable interface. However, maintenance of laminar conditions can become complicated when there is a large viscosity contrast between the neighbouring flows leading to unique instability patterns along their interface. Here, we study the dynamics of high viscosity contrast confluent flows - specifically a core flow made of highly viscous glycerol confined by sheath flows made of water within a microfluidic flow focusing system...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28723908/sorting-cells-by-their-density
#14
Nazila Norouzi, Heran C Bhakta, William H Grover
Sorting cells by their type is an important capability in biological research and medical diagnostics. However, most cell sorting techniques rely on labels or tags, which may have limited availability and specificity. Sorting different cell types by their different physical properties is an attractive alternative to labels because all cells intrinsically have these physical properties. But some physical properties, like cell size, vary significantly from cell to cell within a cell type; this makes it difficult to identify and sort cells based on their sizes alone...
2017: PloS One
https://www.readbyqxmd.com/read/28723694/exosomes-a-cancer-theranostics-road-map
#15
Angeliki Panagiotara, Athina Markou, Evi S Lianidou, George P Patrinos, Theodora Katsila
Interindividual variability is yet to be fully characterized, and for this, optimum patient stratification and companion diagnostics are still lacking. Especially when complex disease phenotypes and/or polygenic diseases are considered, patient monitoring and disease management become rather challenging, while acquired resistance to therapy and/or toxicity events are among the unmet needs in the clinic. No doubt, biomarkers are of great importance to disease management and tailor-made theranostics. Microfluidics has gathered great attention lately, mostly due to its low-invasive nature compared to tissue biopsies...
July 20, 2017: Public Health Genomics
https://www.readbyqxmd.com/read/28723271/development-of-three-orthogonal-assays-suitable-for-the-identification-and-qualification-of-pikfyve-inhibitors
#16
Kylie Fogarty, Mohammed Kashem, Andras Bauer, Alexandra Bernardino, Debra Brennan, Brian Cook, Neil Farrow, Teresa Molinaro, Richard Nelson
FYVE-type zinc finger-containing phosphoinositide kinase (PIKfyve) catalyzes the formation of phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) from phosphatidylinositol 3-phosphate (PI(3)P). PIKfyve has been implicated in multiple cellular processes, and its role in the regulation of toll-like receptor (TLR) pathways and the production of proinflammatory cytokines has sparked interest in developing small-molecule PIKfyve inhibitors as potential therapeutics to treat autoimmune and inflammatory diseases. We developed three orthogonal assays to identify and qualify small-molecule inhibitors of PIKfyve: (1) a purified component microfluidic enzyme assay that measures the conversion of fluorescently labeled PI(3)P to PI(3,5)P2 by purified recombinant full-length human 6His-PIKfyve (rPIKfyve); (2) an intracellular protein stabilization assay using the kinase domain of PIKfyve expressed in HEK293 cells; and (3) a cell-based functional assay that measures the production of interleukin (IL)-12p70 in human peripheral blood mononuclear cells stimulated with TLR agonists lipopolysaccharide and R848...
July 2017: Assay and Drug Development Technologies
https://www.readbyqxmd.com/read/28723204/crossed-surface-relief-gratings-as-nanoplasmonic-biosensors
#17
Srijit Nair, Carlos Escobedo, Ribal Georges Sabat
We present an original, low-cost nanoplasmonic (bio)sensor based on crossed surface relief gratings (CSRGs) generated from orthogonally superimposed surface relief gratings (SRGs) on gold-coated azo-glass substrate. This surface plasmon resonance (SPR)-based sensing approach is unique, since the light transmitted through a CSRG is zero except in the narrow bandwidth where the SPR conversion occurs, enabling quantitative monitoring of only the plasmonic signal from biomolecular interactions in real time. We validated the individual SRG plasmonic signature of CSRGs by observing their respective SPR excitation peaks, and tested them to detect both bulk and near-surface refractive index (RI) changes...
March 24, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723191/highly-enriched-controllable-continuous-aerosol-sampling-using-inertial-microfluidics-and-its-application-to-real-time-detection-of-airborne-bacteria
#18
Jeongan Choi, Seung Chan Hong, Woojin Kim, Jae Hee Jung
We report a novel microfluidic technique for sampling of aerosols into liquids. The two-phase fluid, sampling air and collecting liquid, forms a stratified flow in the curved microchannel. By passing fluids through the curved region, the particles are transferred from air into the liquid phase by the particle centrifugal and drag forces. This microfluidic-based aerosol-into-liquid sampling system, called the MicroSampler, is driven by particle inertial differences. To evaluate the physical particle collection efficiency of the MicroSampler, we used standard polystyrene-latex (PSL) particles ranging in size from 0...
April 28, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723167/sensitive-detection-of-mmp9-enzymatic-activities-in-single-cell-encapsulated-microdroplets-as-an-assay-of-cancer-cell-invasiveness
#19
Zhao Yu, Lu Zhou, Ting Zhang, Rui Shen, Chenxi Li, Xu Fang, Gareth Griffiths, Jian Liu
Matrix metalloproteinases (MMPs) are typically up-regulated in cancer cells, and play a critical role in assisting metastasis by the breakdown of the extracellular matrix. Here we report an effective strategy for cell invasiveness assay by integrating MMP9 functional activity analysis with single cell-encapsulated microdroplets. A flow focusing capillary microfluidic device has been assembled using "off-the-shelf" fluidic components for high-throughput generation of microdroplets. Tumor cells, MMP9 specific peptides, and other cofactors can be loaded into the device and encapsulated into individual droplets as dynamic microreactors for proteolytic cleavage of the substrate...
May 26, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723166/automated-3-d-printed-arrays-to-evaluate-genotoxic-chemistry-e-cigarettes-and-water-samples
#20
Karteek Kadimisetty, Spundana Malla, James F Rusling
A novel, automated, low cost, three-dimensional (3-D) printed microfluidic array was developed to detect DNA damage from metabolites of chemicals in environmental samples. The electrochemiluminescent (ECL) detection platform incorporates layer-by-layer (LbL) assembled films of microsomal enzymes, DNA and an ECL-emitting ruthenium metallopolymer in ∼10 nm deep microwells. Liquid samples are introduced into the array, metabolized by the human enzymes, products react with DNA if possible, and DNA damage is detected by ECL with a camera...
May 26, 2017: ACS Sensors
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