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Yingtong Zong, Kaitao Li, Rui Tian, Yanjun Lin, Chao Lu
The adsorption of dyes in contaminated water is an effective approach to solving the environmental crisis. Layered double hydroxide (LDH) and its calcinated product layered double oxide (LDO) show great potential as adsorbents. However, the conventional preparation of LDH or LDO typically suffers from aggregation and blocked active sites, hampering the adsorption efficiency of the adsorbent. Herein, three-dimensional, hollow MgFe-LDO spheres were constructed through the sacrifice of a carbon template. The hollow structure and the monodisperse state provided MgFe-LDO with sufficient microchannels and abundant active sites for adsorption...
December 5, 2018: Nanoscale
Xian Luo, Wenyue Xie, Ruijie Wang, Xiaoshuai Wu, Ling Yu, Yan Qiao
Microfluidic microbial fuel cells (MMFCs) are promising green power sources for future ultra-small electronic devices. The MMFCs with co-laminar microfluidic structure are superior to other MMFCs according to their low internal resistance and relative high power density. However, the area for interfacial electron transfer between the bacteria and the anode is quite limited in the typical Y-shaped device, which apparently restricts the current generation performance. In this study, we developed a membraneless MMFC with serpentine microchannel to enhance the interfacial electron transfer and promote the power generation of the device...
2018: Frontiers in Microbiology
Sungil Kim, Jeongtae Kim, Yeun-Ho Joung, Jiyeon Choi, Chiwan Koo
We present a rapid and highly reliable glass (fused silica) microfluidic device fabrication process using various laser processes, including maskless microchannel formation and packaging. Femtosecond laser assisted selective etching was adopted to pattern microfluidic channels on a glass substrate and direct welding was applied for local melting of the glass interface in the vicinity of the microchannels. To pattern channels, a pulse energy of 10 μJ was used with a scanning speed of 100 mm/s at a pulse repetition rate of 500 kHz...
December 3, 2018: Micromachines
Surjendu Maity, Joydip Chaudhuri, Shirsendu Mitra, Saptak Rarotra, Dipankar Bandyopadhyay
We explore the improvements in yield and conversion of a chemical reaction inside a two-phase microfluidic reactor when subjected to an externally applied alternating current (AC) electric field. A computational fluid dynamic (CFD) framework has been developed to incorporate the descriptions of the two-phase flow, multicomponent transport and reaction, and the Maxwell's stresses generated at oil-water interface owing to the presence of the externally applied electric field. The CFD model ensures that the reactants are flown into a microchannel together with the oil and water phases before the reaction takes place at the interface and products diffuse back to the bulk phases...
December 4, 2018: Electrophoresis
Liang-Liang Fan, Xiao-Liang Zhu, Qing Yan, Jiang Zhe, Liang Zhao
A passive microfluidic device is reported for continuous microparticle enrichment. The microparticle is enriched based on the inertial effect in a microchannel with contracting-expanding structures on one side where microparticles/cells are subjected to the inertial lift force and the momentum-change-induced inertial force induced by highly curved streamlines. Under the combined effect of the two forces, yeast cells and microparticles of different sizes were continuously focused in the present device over a range of Reynolds numbers from 16...
November 28, 2018: Electrophoresis
Ling Xia, Debashis Dutta
It is well known that the resolving power of capillary zone electrophoretic separations may be improved with an increase in the applied electric field strength and separation time. While large electric fields may be realized in short analysis channels commonly employed in microfluidic systems, this experimental design is not suitable for achieving long separation times. In this chapter, we describe the use of a steady and/or a periodic pressure-driven backflow to increase the separation time in short microchannels thereby enabling the analysis of closely related species on microchip devices...
2019: Methods in Molecular Biology
Prithviraj Mukherjee, Xiao Wang, Jian Zhou, Ian Papautsky
A wide range of microfluidic devices for single stream focusing of cells and particles has emerged in recent years, based on both passive and active methods. Inertial microfluidics offers an attractive alternative to these methods, providing efficient and sheathless passive focusing of cells and beads. Nevertheless, in rectangular microchannels, the presence of multiple equilibrium positions necessitates complicated solutions involving manipulation of the 3D structure in order to achieve single stream flows...
November 29, 2018: Lab on a Chip
Yongjie Lu, Yau Kei Chan, Long Hei Lau, Youchuang Chao, Kendrick Co Shih, Shiu Ming Lai, David Wong, Ho Cheung Shum
PURPOSE: Silicone oil (SiO) with additives of high-molecular-weight (HMW) SiO molecules, eases both the injection and removal. When used inside an eye, it remains unclear how increasing extensional viscosity of SiO might reduce emulsification. Using cell-lined models, this study aims to understand the reason why SiO with HMW is less prone to emulsification. METHODS: The adhesion of SiO was studied and recorded in a cell-coated microchannel by optical microscopy...
November 28, 2018: Acta Ophthalmologica
Sinem Orbay, Adem Ozcelik, Hunter Bachman, Tony Jun Huang
We present on-chip acoustic actuation of in situ fabricated artificial cilia. Arrays of cilia structures are UV polymerized inside a microfluidic channel using a photocurable polyethylene glycol (PEG) polymer solution and photomasks. During polymerization, cilia structures are attached to a silane treated glass surface inside the microchannel. Then, the cilia structures are actuated using acoustic vibrations at 4.6 kHz generated by piezo transducers. As a demonstration of a practical application, DI water and fluorescein dye solutions are mixed inside a microfluidic channel...
February 2018: Journal of Micromechanics and Microengineering: Structures, Devices, and Systems
Binita Nath, Asif Raza, Vishal Sethi, Amaresh Dalal, Siddhartha Sankar Ghosh, Gautam Biswas
To understand the burgeoning challenges of metastasis, a microchannel of 35 μm diameter, constricted to 7 μm for a distance of 200 μm in a total length of 3 mm, was designed and fabricated using a mask aligner made of polydimethylsiloxane (PDMS) to mimic in vivo capillaries. A thin glass cover-slide was mounted on top to monitor the motion of single or aggregated malignant HeLa cells (size 17-30 μm) microscopically through the constricted microchannel at a constant flow rate of 30 μl/h. Quantitative deconvolution of high-speed videographs of a single cell of 30 μm revealed cellular deformation while passing through constriction, having elongation index, average transit velocity and entry time of 2...
November 26, 2018: Scientific Reports
Junyao Wang, Lu-Lu Han, Ye-Ming Sun, Tian-Yi Su
In this paper, a direct pre-bonding technology after alignment of the chip is presented to avoid the post-misalignment problem caused by the transferring process from an alignment platform to a heating oven. An alignment system with a high integration level including a microscope device, a vacuum device, and an alignment device is investigated. To align the chip, a method of 'fixing a chip with microchannels and moving a chip with nanochannels' is adopted based on the alignment system. With the alignment system and the assembly method, the micro/nanofluidic chip was manufactured with little time and low cost...
November 24, 2018: Micromachines
Kiran Raj M, Soumya Bhattacharya, Sunando DasGupta, Suman Chakraborty
Understanding the dynamics of blood flow in physiologically relevant confinements turns out to be an outstanding proposition in biomedical research. Despite the large number of studies being reported to theoretically elucidate the dynamics of red blood cells (RBCs) in confined geometries, in vitro experimental studies unveiling the implications of the collective dynamics of red blood cells in physiologically relevant bio-mimetic microfluidic channels remain elusive. Here, we investigate the implications of complex dynamvic interactions between the whole blood and a deformable channel wall fabricated using a hydrogel matrix...
November 26, 2018: Lab on a Chip
L M Lambert, I I Pipinos, B T Baxter, Y S Chatzizisis, S J Ryu, R I Leighton, T Wei
This paper presents micro-particle tracking velocimetry measurements over cultured bovine aortic endothelial cell monolayers in microchannels. The objective was to quantify fluid forces and cell morphology at the sub-cellular scale for monolayers subjected to steady shear rates of 5, 10, and 20 dyn/cm2 . The ultimate goal of this study was to develop an experimental methodology for in vitro detailed study of physiologically realistic healthy and diseased conditions. Cell topography, shear stress, and pressure distributions were calculated from sets of velocity fields made in planes parallel to the microchannel wall...
November 2018: Biomicrofluidics
Alberto Claudio Miano, Meliza Lindsay Rojas, Pedro Esteves Duarte Augusto
This work aimed to demonstrate the internal and external structural changes in potato cylinders caused by different times of ultrasound pretreatment. In addition, the structural changes were associated with the viscoelasticity and mass transfer. For which, potato cylinders were immersed in distilled water and pretreated with and without ultrasound (ultrasonic bath of 91 W/L and 25 kHz) up to 120 min. Then, the microstructure was evaluated by stereoscopic observation as a direct method, and by viscoelasticity and mass transfer evaluation (pigment diffusion and drying) as indirect methods...
November 15, 2018: Ultrasonics Sonochemistry
Josquin Courte, Renaud Renault, Audric Jan, Jean-Louis Viovy, Jean-Michel Peyrin, Catherine Villard
Microfluidic devices for controlling neuronal connectivity in vitro are extremely useful tools for deciphering pathological and physiological processes occurring in neuronal networks. These devices allow the connection between different neuronal populations located into separate culture chambers through axon-selective microchannels. In order to implement specific features of brain connectivity such as directionality, it is necessary to control axonal growth orientation in these devices. Among the various strategies proposed to achieve this goal, one of the most promising and easily reproducible is the use of asymmetric microchannels...
2018: Methods in Cell Biology
Gabriel Amselem, Sébastien Sart, Charles N Baroud
The ability to encapsulate cells individually in droplets has many potential applications, for example for observing the heterogeneity of behaviors within a population. However, implementing operations on moving droplets require feedback control and instruments that provide precise timing. These technical difficulties impede the adoption of droplet microfluidic protocols in nonspecialist labs. In this chapter we describe an approach to produce and manipulate droplets that remain stationary within a microfluidic chamber, by fabricating a microfluidic device having three-dimensional topography...
2018: Methods in Cell Biology
Bryant Thompson, Nareh Movsesian, Christine Cheng, Prathamesh Karandikar, Malancha Gupta, Noah Malmstadt
For many engineering applications such as manipulating two phase flows, generating single and double emulsions, and passively propelling liquids through channels, control over the surface energy of microfluidic channels is essential. In particular, double emulsion formation, which benefits from alternating hydrophobic and hydrophilic sections of channel, represents a challenge in fabricating controlled microfluidic channel surface properties. As double emulsions find further applications in single-cell handling and analysis, straightforward methods for generating them increase in value...
2018: Methods in Cell Biology
Lindong Weng, Gloria Y Lee, Jie Liu, Ravi Kapur, Thomas L Toth, Mehmet Toner
Human infertility can be treated using assisted reproductive technology (ART) such as intracytoplasmic sperm injection (ICSI). But current ART techniques suffer from multiple cumbersome processes requiring technically skilled personnel. Microfluidics technologies offer unique opportunities to streamline ART procedures, reduce stress imposed upon gametes and embryos, and minimize the operator-to-operator variability. However, there have been no automated and continuous processing systems that can reduce the dependence on well-trained embryologists to obtain ICSI-ready oocytes from patients...
November 22, 2018: Lab on a Chip
Jimmy Faivre, Alexandra Montembault, Guillaume Sudre, Buddha Ratna Shrestha, Guojun Xie, Krzysztof Matyjaszewski, Stéphane Benayoun, Xavier Banquy, Thierry Delair, Laurent David
We report the fabrication and the use of a bioinspired synovial fluid acting as a lubricant fluid and anti-wear agent at soft and porous chitosan hydrogel tribopairs. This synthetic synovial fluid is composed of sodium hyaluronate (HA) and a bottle-brush polymer (BB) having a polycationic attachment group and polyzwitterionic pendant chains. 2.5 %w/w chitosan hydrogel plugs are organized in a bilayered structure exposing a thin and dense superficial zone (SZ), covering a porous deep zone (DZ) and exhibiting microchannels perpendicularly aligned to the SZ...
November 21, 2018: Biomacromolecules
Shima Abarghoei, Neda Fakhri, Yasaman Sadat Borghei, Morteza Hosseini, Mohammad Reza Ganjali
Citrate is currently considered a preferred biomarker for the early stage detection of prostate cancer. In the present work, based on the highly efficient catalytic properties of gold nanoclusters, a novel system for optical determination of citrate was successfully established under optimized conditions. Cysteine-capped gold nanoclusters (Cys-AuNCs) are shown to have an intrinsic peroxidase-mimetic activity. In the presence of H2 O2, Cys-AuNCs nanostructures are able to catalyse the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) with high efficiency to produce a blue dye (with an absorbance maximum at 650 nm)...
November 15, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
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