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https://www.readbyqxmd.com/read/28330099/thermomyces-lanuginosus-lipase-catalyzed-synthesis-of-natural-flavor-esters-in-a-continuous-flow-microreactor
#1
Ahmad Mohammed Gumel, M S M Annuar
Enzymatic catalysis is considered to be among the most environmental friendly processes for the synthesis of fine chemicals. In this study, lipase from Thermomyces lanuginosus (Lecitase Ultra™) was used to catalyze the synthesis of flavor esters, i.e., methyl butanoate and methyl benzoate by esterification of the acids with methanol in a microfluidic system. Maximum reaction rates of 195 and 115 mM min(-1) corresponding to catalytic efficiencies (k cat/K M) of 0.30 and 0.24 min(-1) mM(-1) as well as yield conversion of 54 and 41 % were observed in methyl butanoate and methyl benzoate synthesis, respectively...
June 2016: 3 Biotech
https://www.readbyqxmd.com/read/28327746/combination-of-microfluidic-high-throughput-production-and-parameter-screening-for-efficient-shaping-of-gold-nanocubes-using-dean-flow-mixing
#2
Matthias Thiele, Andrea Knauer, Daniéll Malsch, Andrea Csáki, Thomas Henkel, J Michael Köhler, Wolfgang Fritzsche
Metal nanoparticles and their special optical properties, the so-called localized surface plasmon resonance (LSPR), facilitate many applications in various fields. Due to the strong dependency of the LSPR on particle geometry, their synthesis is a challenging and time-consuming procedure especially for non-spherical shapes. In contrast, micromixers offer new experimental approaches and therefore enable the simplification of several processes. By using a zigzag micromixer (Dean-Flow-Mixer, DFM) that induces Dean-flow secondary flow patterns, we theoretically and experimentally show the mixing efficiency...
March 22, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28326222/acupuncture-injection-combined-with-electrokinetic-injection-for-polydimethylsiloxane-microfluidic-devices
#3
Ji Won Ha
We recently reported acupuncture sample injection that leads to reproducible injection of nL-scale sample segments into a polydimethylsiloxane (PDMS) microchannel for microchip capillary electrophoresis. The advantages of the acupuncture injection in microchip capillary electrophoresis include capability of minimizing sample loss and voltage control hardware and capability of introducing sample plugs into any desired position of a microchannel. However, the challenge in the previous study was to achieve reproducible, pL-scale sample injections into PDMS microchannels...
2017: Journal of Analytical Methods in Chemistry
https://www.readbyqxmd.com/read/28326132/continuous-flow-synthesis-of-highly-functionalized-imidazo-oxadiazoles-facilitated-by-microfluidic-extraction
#4
Ananda Herath, Nicholas D P Cosford
A versatile continuous-flow synthesis of highly functionalized 1,2,4-oxadiazoles starting from carboxylic acids is reported. This process was applied to the multistep synthesis of imidazo[1,2-a]pyridin-2-yl-1,2,4-oxadiazoles, using a three reactor, multistep continuous-flow system without isolation of intermediates. This continuous-flow method was successfully combined with a single-step liquid-liquid microextraction unit to remove high boiling point polar solvents and impurities and provides the target compounds in high purity with excellent overall yields...
2017: Beilstein Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28325895/simulation-assisted-design-of-microfluidic-sample-traps-for-optimal-trapping-and-culture-of-non-adherent-single-cells-tissues-and-spheroids
#5
Nassim Rousset, Frédéric Monet, Thomas Gervais
This work focuses on modelling design and operation of "microfluidic sample traps" (MSTs). MSTs regroup a widely used class of microdevices that incorporate wells, recesses or chambers adjacent to a channel to individually trap, culture and/or release submicroliter 3D tissue samples ranging from simple cell aggregates and spheroids, to ex vivo tissue samples and other submillimetre-scale tissue models. Numerous MST designs employing various trapping mechanisms have been proposed in the literature, spurring the development of 3D tissue models for drug discovery and personalized medicine...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28324958/ultrafast-oscillatory-flow-pcr-for-amplication-of-urine-short-tandem-repeats
#6
Haoyu Tang, Tao Dong
The short tandem repeats (STRs) in human urine which is the most sensitive body fluid can be serviced as biomarkers for the individual identification. PCR microchips are automated, sensitive and rapid. In this report, COMSOL with Finite Element Analysis (FEA) is employed to study the temperature distribution of the base layer to optimize the structure of the microfluidic chip. Meanwhile, the oscillatory PCR microdevice is preliminary tested by DNA samples extracted from urine with the FTA papers and CSF1PO, TPOX, TH01 Multiplex kits...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28324717/fabrication-of-oriented-wrinkles-on-polydopamine-polystyrene-bilayer-films
#7
Rong Wang, Yuhua Long, Tang Zhu, Jing Guo, Chao Cai, Ning Zhao, Jian Xu
Wrinkles exist widely in nature and our life. In this paper, wrinkles on polydopamine (PDA)/polystyrene (PS) bilayer films were formed by thermal annealing due to the different thermal coefficients of expansion of each layer. The factors that influenced the dimensions of wrinkles were studied. We found that oriented wrinkles could be formed if the bilayer films were patterned with micro-grooves, and the degree of the orientation depended on the thickness of the PDA and the dimensions of the grooves. Combined with the strong adhesion, biocompatibility and reactivity of PDA, the oriented wrinkles on PDA/PS patterned bilayers may find potential application in diffraction gratings, optical sensors and microfluidic devices...
March 6, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28324241/numerical-simulation-and-scaling-of-droplet-deformation-in-a-hyperbolic-flow
#8
Erfan Kadivar, Atefeh Alizadeh
Motivated by a recent experiment (C. Ulloa et al., Phys. Rev. E 89, 033004 (2014)), droplet deformation in a flat microfluidic channel having a cross intersection with two inlet channels and two outlet channels, i.e. hyperbolic flow, is numerically investigated. Employing the boundary element method (BEM), we numerically solve the Darcy equation in the two dimensions and investigate droplet motion and droplet deformation as the droplet enters the cross intersection. We numerically find that the maximum deformation of droplet depends on droplet size, capillary number, viscosity ratio and flow rate ratio of the two inlets...
March 2017: European Physical Journal. E, Soft Matter
https://www.readbyqxmd.com/read/28323354/ultrathin-double-shell-capsules-for-high-performance-photon-upconversion
#9
Ji-Hwan Kang, Sang Seok Lee, Josefa Guerrero, Alberto Fernandez-Nieves, Shin-Hyun Kim, Elsa Reichmanis
Triplet-fusion-based photon upconversion capsules with ultrathin double shells are developed through a single dripping instability in a microfluidic flow-focusing device. An inner separation layer allows use of a brominated hydrocarbon oil-based fluidic core, demonstrating significantly enhanced upconversion quantum yield. Furthermore, a perfluorinated photocurable monomer serves as a transparent shell phase with remote motion control through magnetic nanoparticle incorporation.
March 21, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28322552/one-step-fabrication-of-a-microfluidic-device-with-an-integrated-membrane-and-embedded-reagents-by-multimaterial-3d-printing
#10
Feng Li, Petr Smejkal, Niall P Macdonald, Rosanne M Guijt, Michael C Breadmore
One of the largest impediments in the development of microfluidic-based smart sensing systems is the manufacturability of integrated, complex devices. Here, we propose multimaterial 3D printing for the fabrication of such devices in a single step. A microfluidic device containing an integrated porous membrane and embedded liquid reagents was made by 3D printing and applied for the analysis of nitrate from soil. The manufacture of the integrated, sealed device was realised as a single print within 30 min. The body of the device was printed in transparent acrylonitrile butadiene styrene (ABS), and contained a 400 μm wide structure printed from a commercially available composite filament...
March 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28322517/materials-for-microfluidic-immunoassays-a-review
#11
REVIEW
Lei Mou, Xingyu Jiang
Conventional immunoassays suffer from at least one of these following limitations: long processing time, high costs, poor user-friendliness, technical complexity, poor sensitivity and specificity. Microfluidics, a technology characterized by the engineered manipulation of fluids in channels with characteristic lengthscale of tens of micrometers, has shown considerable promise for improving immunoassays that could overcome these limitations in medical diagnostics and biology research. The combination of microfluidics and immunoassay can detect biomarkers with faster assay time, reduced volumes of reagents, lower power requirements, and higher levels of integration and automation compared to traditional approaches...
March 21, 2017: Advanced Healthcare Materials
https://www.readbyqxmd.com/read/28322404/device-and-programming-abstractions-for-spatiotemporal-control-of-active-micro-particle-swarms
#12
Amy T Lam, Karina G Samuel-Gama, Jonathan Griffin, Matthew Loeun, Lukas C Gerber, Zahid Hossain, Nate J Cira, Seung Ah Lee, Ingmar H Riedel-Kruse
We present a hardware setup and a set of executable commands for spatiotemporal programming and interactive control of a swarm of self-propelled microscopic agents inside a microfluidic chip. In particular, local and global spatiotemporal light stimuli are used to direct the motion of ensembles of Euglena gracilis, a unicellular phototactic organism. We develop three levels of programming abstractions (stimulus space, swarm space, and system space) to create a scripting language for directing swarms. We then implement a multi-level proof-of-concept biotic game using these commands to demonstrate their utility...
March 21, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28322402/open-channel-water-in-oil-emulsification-in-paper-based-microfluidic-devices
#13
C Li, M Boban, A Tuteja
Open-channel microfluidic devices have shown great potential in achieving a high degree of fluid control, at relatively low-cost, while enabling the opportunity for rapid fabrication. However, thus far, work in open channel microfluidics has largely focused on controlling the flow of water or other aqueous solutions. In this work we present new open channel microfluidic devices based on surfaces with patterned wettabilty that are capable of controlling the flow of virtually all high and low surface tension liquids...
March 21, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28322268/universal-sensitivity-of-speckle-intensity-correlations-to-wavefront-change-in-light-diffusers
#14
KyungDuk Kim, Hyeonseung Yu, KyeoReh Lee, YongKeun Park
Here, we present a concept based on the realization that a complex medium can be used as a simple interferometer. Changes in the wavefront of an incident coherent beam can be retrieved by analyzing changes in speckle patterns when the beam passes through a light diffuser. We demonstrate that the spatial intensity correlations of the speckle patterns are independent of the light diffusers, and are solely determined by the phase changes of an incident beam. With numerical simulations using the random matrix theory, and an experimental pressure-driven wavefront-deforming setup using a microfluidic channel, we theoretically and experimentally confirm the universal sensitivity of speckle intensity correlations, which is attributed to the conservation of optical field correlation despite multiple light scattering...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28322047/thiol-ene-monolithic-pepsin-microreactor-with-a-3d-printed-interface-for-efficient-uplc-ms-peptide-mapping-analyses
#15
Alexander Jönsson, Rasmus R Svejdal, Nanna B Bøgelund, Tam T T N Nguyen, Henrik Flindt, Jörg P Kutter, Kasper D Rand, Josiane Penelope Lafleur
To improve the sample handling, and reduce cost and preparation time, of peptide mapping LC-MS workflows in protein analytical research, we here investigate the possibility of replacing conventional enzymatic digestion methods with a polymer microfluidic chip-based enzyme reactor. Off-stoichiometric thiol-ene is utilized as both bulk material and as a monolithic stationary phase for immobilization of the proteolytic enzyme pepsin. The digestion efficiency of the, thiol-ene based, immobilized enzym reactor (IMER) is compared to that of a conventional, agarose packed bed, pepsin IMER column commonly used in LC-MS-based protein analyses...
March 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28322015/compartmentalized-spherical-collagen-microparticles-for-anisotropic-cell-culture-microenvironments
#16
Satoru Yoshida, Masahiro Takinoue, Hiroaki Onoe
This paper describes a new fabrication method for obtaining anisotropic spherical hydrogel microparticles with different types of extracellular matrix (ECM) hemispheres for use in 3D cell culture. To fabricate the microparticles, a mixture of an ECM precursor solution and sodium alginate is ejected into a calcium chloride solution under large centrifugal acceleration by a centrifuge-based microfluidic device; the calcium alginate hydrogel plays a significant role as a "sacrificial gelation template" to maintain the ECM molecules in each hemisphere...
March 21, 2017: Advanced Healthcare Materials
https://www.readbyqxmd.com/read/28321583/microfluidic-encapsulation-of-ovarian-follicles-for-3d-culture
#17
Xiaoming He
The ovarian follicle that contains one single oocyte is the fundamental functional tissue unit of mammalian ovary. Therefore, isolation and in vitro culture of ovarian follicles to obtain fertilizable oocytes are regarded as a promising strategy for women to combat infertility. In this communication, we performed a brief survey of studies on microfluidic encapsulation of ovarian follicles in core-shell hydrogel microcapsules for biomimetic 3D culture. These studies highlighted that recapitulation of the mechanical heterogeneity of the extracellular matrix in ovary is crucial for in vitro culture to develop early pre-antral follicles to the antral stage, and for the release of cumulus-oocyte complex (COC) from antral follicles in vitro...
March 20, 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/28320523/roles-of-fluid-shear-stress-and-retinoic-acid-in-the-differentiation-of-primary-cultured-human-podocytes
#18
Seung Hee Yang, Jin Woo Choi, Dongeun Huh, Hyung Ah Jo, Sejoong Kim, Chun Soo Lim, Jung Chan Lee, Hee Chan Kim, Hyug Moo Kwon, Chang Wook Jeong, Cheol Kwak, Kwon Wook Joo, Yon Su Kim, Dong Ki Kim
Due to the distinct features that distinguish immortalized podocyte cell lines from their in vivo counterparts, primary cultured human podocytes might be a superior cell model for glomerular disease studies. However, the podocyte de-differentiation that occurs in culture remains an unresolved problem. Here, we present a method to differentiate primary cultured podocytes using retinoic acid (RA) and fluid shear stress (FSS), which mimic the in vivo environment of the glomerulus. RA treatment induced changes in the cell shape of podocytes from a cobblestone-like morphology to an arborized configuration with enhanced mobility...
March 16, 2017: Experimental Cell Research
https://www.readbyqxmd.com/read/28319900/bipolar-electrochemiluminescence-on-thread-a-new-class-of-electroanalytical-sensors
#19
Rui Liu, Cuiling Liu, Huijie Li, Min Liu, Dan Wang, Chunsun Zhang
This paper introduces a new and simple concept for fabricating low-cost, easy-to-use capillary microchannel (CMC) assisted thread-based microfluidic analytical devices (CMCA-μTADs) for bipolar electrochemiluminescence (BP-ECL) application. The thread with patterns of carbon screen-printed electrodes and bare thread zones (BTZs) is embedded into a CMC. Such CMCA-μTADs can produce a strong and stable BP-ECL signal, and have an extremely low cost ($0.01 per device). Interestingly, the CMCA-μTADs are ultraflexible, and can be bent with a 135° bending angle at the BTZ or with a 150° bending angle at the middle of bipolar electrode (BPE), with no loss of analytical performance...
March 7, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28319898/immunodetection-of-salivary-biomarkers-by-an-optical-microfluidic-biosensor-with-polyethylenimine-modified-polythiophene-c70-organic-photodetectors
#20
Tao Dong, Nuno Miguel Matos Pires
This work reports a novel optical microfluidic biosensor with highly sensitive organic photodetectors (OPDs) for absorbance-based detection of salivary protein biomarkers at the point of care. The compact and miniaturized biosensor has comprised OPDs made of polythiophene-C70 bulk heterojunction for the photoactive layer; whilst a calcium-free cathode interfacial layer, made of linear polyethylenimine, was incorporated to the photodetectors to enhance the low cost. The OPDs realized onto a glass chip were aligned to antibody-functionalized chambers of a poly(methyl methacrylate) microfluidic chip, in where immunogold-silver assays were conducted...
March 6, 2017: Biosensors & Bioelectronics
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