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  • NLM标题： Biomicrofluidics
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共1461条结果
  • 1.

    【2hr】Continuous flow microreactor for protein PEGylation

    包量

    机译 连续流动微反应器，用于蛋白质聚乙二醇化
    摘要：PEGylation is increasingly being utilized to enhance the therapeutic efficacy of biopharmaceuticals. Various chemistries and reaction conditions have been established to synthesize PEGylated proteins and more are being developed. Both the extent of conversion and selectivity of protein PEGylation are highly sensitive to process variables and parameters. Therefore, microfluidic-based high-throughput screening platforms would be highly suitable for optimization of protein PEGylation. As part of this study, a poly-dimethylsiloxane-based continuous flow microreactor system was designed and its performance was compared head-to-head with a batch reactor. The reactants within the microreactor were contacted by passive micromixing based on chaotic advection generated by staggered herringbone grooves embedded in serpentine microchannels. The microreactor system was provided with means for on-chip reaction quenching. Lysozyme was used as the model protein while methoxy-polyethylene glycol-(CH2)5COO-NHS was used as the PEGylation reagent. Full mixing was achieved close to the microreactor inlet, making the device suitable for protein PEGylation. The effect of mixing type, i.e., simple stirring versus chaotic laminar mixing on PEGylation, was investigated. Higher selectivity (as high as 100% selectivity) was obtained with the microreactor while the conversion was marginally lower.
  • 2.

    【2hr】“Do-it-in-classroom” fabrication of microfluidic systems by replica moulding of pasta structures

    包量

    机译 通过复制意大利面结构，“在课堂上做”微流体系统的制造
    摘要：Here, we describe a novel method for fabrication of microfluidic structures in classroom environments. This method is based on replica moulding of pasta structures in polydimethylsiloxane. Placing pasta structures on a petroleum jelly base layer enables templating round-shaped structures with controllable cross-sectional profiles. The pasta structures can be easily deformed and combined to create more complex 3D microfluidic structures. Proof-of-concept experiments indicate the capability of this method for studying the mixing of neighbouring flows, generation of droplets, lateral migration of particles, as well as culturing, shear stress stimulation, and imaging of cells. Our “do-it-in-classroom” method bridges the gap between the classroom and the laboratory.
  • 3.

    【2hr】Impact of bacterial streamers on biofouling of microfluidic filtration systems

    包量

    机译 细菌流光对微流体过滤系统生物污染的影响
    摘要：We investigate the effect of biofouling in a microfluidic filtration system. The microfluidic platform consists of cylindrical microposts with a pore-spacing of 2 μm, which act as the filtration section of the device. One of our key findings is that there exists a critical pressure difference above which pronounced streamer formation is observed, which eventually leads to rapid clogging of the device with an accompanying exponential decrease in permeate flow. Moreover, when streamers do form, de-clogging of pores also occurs intermittently, which leads to small time scale fluctuations [O(101 s)] superimposed upon the large time scale [O(102 min)] clogging of the system. These de-clogging phenomena lead to a sharp increase in water permeation through the microfluidic filtration device but rates the water quality as biomass debris is transported in the permeate. Streamer-based clogging shares similarities with various fouling mechanisms typically associated with membranes. Finally, we also show that the pH of the feed strongly affects biofouling of the microfluidic filtration system.
  • 4.

    【2hr】Magnetophoretic lensing by concentric topographic cylinders of perpendicular magnetic anisotropy multilayers

    包量

    机译 垂直磁各向异性多层的同心形地形圆柱的磁透透镜
    摘要：Colloidal magnetophoretic lensing of water suspended micrometer-sized superparamagnetic beads (SPBs) above a topographically patterned magnetic thin film system with perpendicular magnetic anisotropy is demonstrated. The magnetic pattern consisting of concentric annuli of micron-sized widths has been superimposed with a rotating external magnetic field, and it is shown that the trajectories of the SPBs above this structure are similar to light rays in an optical focusing lens. SPB trajectories converge towards the central region and have divergent trajectories while passing the center. The experimental findings are corroborated by a quantitative model for the SPB trajectories. The magnetophoretic lensing effect leads to a high SPB concentration in the center of the pattern and may be useful for applications where SPBs have to approach each other in a controlled way.
  • 5.

    【2hr】Impact of poloxamer 188 (Pluronic F-68) additive on cell mechanical properties, quantification by real-time deformability cytometry

    包量

    机译 泊洛沙姆188（Pluronic F-68）添加剂对细胞力学性能的影响，通过实时可变形性细胞术进行定量
    摘要：Advances in cellular therapies have led to the development of new approaches for cell product purification and formulation, e.g., utilizing cell endogenous properties such as size and deformability as a basis for separation from potentially harmful undesirable by-products. However, commonly used additives such as Pluronic F-68 and other poloxamer macromolecules can change the mechanical properties of cells and consequently alter their processing. In this paper, we quantified the short-term effect of Pluronic F-68 on the mechanotype of three different cell types (Jurkat cells, red blood cells, and human embryonic kidney cells) using real-time deformability cytometry. The impact of the additive concentration was assessed in terms of cell size and deformability. We observed that cells respond progressively to the presence of Pluronic F-68 within first 3 h of incubation and become significantly stiffer (p-value < 0.001) in comparison to a serum-free control and a control containing serum. We also observed that the short-term response manifested as cell stiffening is true (p-value < 0.001) for the concentration reaching 1% (w/v) of the poloxamer additive in tested buffers. Additionally, using flow cytometry, we assessed that changes in cell deformability triggered by addition of Pluronic F-68 are not accompanied by size or viability alterations.
  • 6.

    【2hr】A compact low-cost low-maintenance open architecture mask aligner for fabrication of multilayer microfluidics devices

    包量

    机译 紧凑的低成本，低维护的开放式结构掩模对准器，用于制造多层微流控器件
    摘要：A custom-built mask aligner (CBMA), which fundamentally covers all the key features of a commercial mask aligner, while being low cost and light weight and having low power consumption and high accuracy, is constructed. The CBMA is composed of a custom high fidelity light emitting diode light source, a vacuum chuck, a mask holder, high-precision translation and rotation stages, and high resolution digital microscopes. The total cost of the system is under $7500, which is over ten times cheaper than a comparable commercial system. It produces a collimated ultraviolet illumination of 1.8–2.0 mW cm−2 over an area of a standard 4-in. wafer, at the plane of photoresist exposure, and the alignment accuracy is characterized to be <3 μm, which is sufficient for most microfluidic applications. Moreover, this manuscript provides detailed descriptions of the procedures needed to fabricate multilayered master molds using our CBMA. Finally, the capabilities of the CBMA are demonstrated by fabricating two- and three-layer masters for micro-scale devices, commonly encountered in biomicrofluidic applications. The former is a flow-free chemical gradient generator, and the latter is an addressable microfluidic stencil. Scanning electron microscopy is used to confirm that the master molds contain the intended features of different heights.
  • 7.

    【2hr】Publisher's Note: “Migration of magnetotactic bacteria in porous media” [Biomicrofluidics 12, 011101 (2018)]

    包量

    机译 发行人注：“多孔介质中趋磁细菌的迁移” [Biomicrofluidics 12，011101（2018）]
    摘要：
  • 8.

    【2hr】Publisher's Note: “Micropipette-powered droplet based microfluidics” [Biomicrofluidics 12, 044106 (2018)]

    包量

    机译 发行人注：“基于微移液管的液滴微流控技术” [Biomicrofluidics 12，044106（2018）]
    摘要：
  • 9.

    【2hr】ELIPatch, a thumbnail-size patch with immunospot array for multiplexed protein detection from human skin surface

    包量

    机译 ELIPatch，具有免疫斑点阵列的缩略图大小的贴片，可从人的皮肤表面进行多重蛋白质检测
    摘要：Proteins secreted by skin have great potential as biomarkers for interpreting skin conditions. However, inconvenience in handling and bulky size of existing methods are existing limitations. Here, we describe a thumb-nail sized patch with the array of microdisks which captures multiple proteins from the skin surface. Microdisks with antibody on the surface enable multiplexed immunoassay. By self-assembly, microdisks are placed into 2-dimensional arrays on adhesive tape. The proposed Enzyme-Linked Immunospot array on a Patch shows sufficient sensitivity for IL-1α, IL1RA, IL-17A, IFN-g, and TNF-α, while IL-6 and IL-1β are non-detectable in some cases. As demonstrations, we quantified cytokines from different skin regions and volunteers in a high-spatial-resolution.
  • 10.

    【2hr】Hierarchical shape-by-shape assembly of microparticles for micrometer-scale viral delivery of two different genes

    包量

    机译 微粒的逐层组装，用于两个不同基因的微米级病毒传递
    摘要：Understanding tissue engineering using a bottom-up approach has been hindered by technical limitations because no platform can demonstrate the controlled formation of a heterogeneous population of cells in microscale. Here, we demonstrate hierarchical shape-by-shape assembly of virus-laden particles into larger ones to transfect two different genes on the seeded cells. We show that smaller daughter particles with different sizes and shapes can be assembled into the matching indentations of larger parent particles with different sizes and shapes. Then, we transfected a population of cells with two different gene-transfecting viruses, each of which was laden on the parent or daughter particles.
  • 11.

    【2hr】Recent advances and current challenges in magnetophoresis based micro magnetofluidics

    包量

    机译 基于磁泳的微磁流体技术的最新进展和当前挑战
    摘要：The combination of magnetism and microscale fluid flow has opened up a new era for handling and manipulation of samples in microfluidics. In particular, magnetophoresis, the migration of particles in a magnetic field, is extremely attractive for microfluidic handling due to its contactless nature, independence of ionic concentration, and lack of induced heating. The present paper focuses on recent advances and current challenges of magnetophoresis and highlights the key parameters affecting the manipulation of particles by magnetophoresis. The magnetic field is discussed according to their relative motion to the sample as stationary and dynamic fields. The migration of particles is categorized as positive and negative magnetophoresis. The applications of magnetophoresis are discussed according to the basic manipulation tasks such as mixing, separation, and trapping of particles or cells. Finally, the paper highlights the limitations of current approaches and provides the future perspective for this research area.
  • 12.

    【2hr】Membrane isolation of repeated-use sweat stimulants for mitigating both direct dermal contact and sweat dilution

    包量

    机译 重复使用的汗液兴奋剂的膜隔离，可减少直接皮肤接触和汗液稀释
    摘要：With the device integration of sweat stimulation, sweat becomes a stronger candidate for non-invasive continuous biochemical sensing. However, sweat stimulants are cholinergenic agents and non-selective to just the sweat glands, and so, direct placement of sweat stimulants poses additional challenges in the possibility for uncontrollable transport of the stimulant into the body and challenges in contamination of the sweat sample. Reported here is membrane isolation of repeated-use sweat stimulants for mitigating direct dermal contact, dilution of the sweat stimulant, and contamination of the sweat sample. The membrane dramatically reduces passive diffusion of the sweat stimulant carbachol by roughly two orders of magnitude, while still allowing repeated sweat stimulation by iontophoretic delivery of the carbachol through the membrane and into the skin. Both in-vivo and in-vitro validation reveal feasibility for reliable integration of sweat stimulants within a wearable device for use periods of 24 h or more. In addition, advanced topics and confounding issues such as stimulant gel design, osmotic pressure, and ionic impurities are speculatively and theoretically discussed.
  • 13.

    【2hr】Engineered microfluidic bioreactor for examining thethree-dimensional breast tumor microenvironment

    包量

    机译 工程微流生物反应器用于检查三维乳腺肿瘤微环境
    摘要：The interaction of cancer cells with the stromal cells and matrix in the tumor microenvironment plays a key role in progression to metastasis. A better understanding of the mechanisms underlying these interactions would aid in developing new therapeutic approaches to inhibit this progression. Here, we describe the fabrication of a simple microfluidic bioreactor capable of recapitulating the three-dimensional breast tumor microenvironment. Cancer cell spheroids, fibroblasts, and endothelial cells co-cultured in this device create a robust microenvironment suitable for studying in real time the migration of cancer cells along matrix structures laid down by fibroblasts within the 3D tumor microenvironment. This system allows for ready evaluation of response to targeted therapy.
  • 14.

    【2hr】A novel dual-well array chip for efficiently trapping single-cell in large isolated micro-well without complicated accessory equipment

    包量

    机译 一种新颖的双孔阵列芯片，无需复杂的附属设备即可有效地捕获大型孤立微孔中的单细胞
    摘要：Conventional cell-sized well arrays have advantages of high occupancy, simple operation, and low cost for capturing single-cells. However, they have insufficient space for including reagents required for cell treatment or analysis, which restricts the wide application of cell-sized well arrays as a single-cell research tool alone. Here, we present a novel dual-well array chip, which integrates capture-wells (20 μm in diameter) with reaction-wells (100 μm in diameter) and describe a flow method for convenient single-cell analysis requiring neither complicated infra-structure nor high expenditure, while enabling highly efficient single cell trapping (75.8%) with only 11.3% multi-cells. Briefly, the cells are first loaded into the dual-wells by gravity and then multi-cells in the reaction-wells are washed out by phosphate buffer saline. Next, biochemical reagents are loaded into reaction-wells using the scraping method and the chip is packed as a sandwich structure. We thereby successfully measured intracellular β-galactosidase activity of K562 cells at the single-cell level. We also used computational simulations to illustrate the working principle of dual-well structure and found out a relationship between the wall shear stress distribution and the aspect ratio of the dual-well array chip which provides theoretical guidance for designing multi-wells chip for convenient single-cell analysis. Our work produced the first dual-well chip that can simultaneously provide a high occupancy rate for single cells and sufficient space for reagents, as well as being low in cost and simple to operate. We believe that the feasibility and convenience of our method will enhance its use as a practical single-cell research tool.
  • 15.

    【2hr】Tapered lateral flow immunoassay based point-of-care diagnostic device for ultrasensitive colorimetric detection of dengue NS1

    包量

    机译 基于锥形侧流免疫分析的即时诊断装置，用于登革热NS1的超灵敏比色检测
    摘要：Dengue virus, a Flaviviridae family member, has emerged as a major worldwide health concern, making its early diagnosis imperative. Lateral flow immunoassays have been widely employed for point-of-care diagnosis of dengue because of their rapid naked eye readouts, ease of use, and cost-effectiveness. However, they entail a drawback of low sensitivity, limiting their usage in clinical applications. Herein, we report a novel lateral flow immunoassay for detection of dengue leveraging on the benefits of gold decorated graphene oxide sheets as detection labels and a tapered nitrocellulose membrane. The developed assay allows for rapid (10 min) and sensitive detection of dengue NS1 with a detection limit of 4.9 ng mL−1, ∼11-fold improvement over the previously reported values. Additionally, the clinical application of the developed assay has been demonstrated by testing it for dengue virus spiked in human serum. The reported lateral flow immunoassay shows significant promise for early and rapid detection of several target diseases.
  • 16.

    【2hr】A simple microdevice for single cell capture, array, release, and fast staining using oscillatory method

    包量

    机译 使用振荡方法进行单细胞捕获，阵列，释放和快速染色的简单微设备
    摘要：Microchips that perform single cell capture, array, and identification have become powerful tools for single cell studies, which can reveal precise underlying mechanisms among bulk cell populations. However, current single cell capture and on-chip immunostaining methods consume more time and reagent than desired. To optimize this technology, we designed a novel trap structure for single cell capture, array, and release, and meanwhile an oscillatory method was used to perform rapid on-chip cell immunostaining. The trap structure array used equal distribution of lateral flow to achieve single cell array in high velocity flows and decrease the risk of clogging. A length of glass capillary with a sealed bubble was inserted into the outlet so that it could act in a manner analogous to that of a capacitor in an RC circuit. By applying one periodic air pressure to the inlet, oscillation motion was generated, which significantly enhanced the on-chip reaction efficiency. In addition, the oscillation performance could be easily regulated by changing the length of the capillary. The trapped cells could maintain their positions during oscillation; hence, they were able to be tracked in real time. Through our trap microchip, 12 μm microbeads were successfully trapped to form a microarray with a capture efficiency of ∼92.7% and 2 μm microbeads were filtered. With an optimized oscillation condition (Ppush = 0.03 MPa, f = 1 Hz, L = 3 cm), fast on-chip immunostaining was achieved with the advantages of less time (5 min) and reagent (2 μl) consumption. The effectiveness of this method was demonstrated through quantitative microbead and qualitative Caco-2 cell experiments. The device is simple, flexible, and efficient, which we believe provides a promising approach to single cell heterogeneity studies, drug screening, and clinical diagnosis.
  • 17.

    【2hr】Comparison of the degradation behavior of PLGA scaffolds in micro-channel, shaking, and static conditions

    包量

    机译 比较PLGA支架在微通道，摇动和静态条件下的降解行为
    摘要：Degradation of scaffolds is an important problem in tissue regeneration management. This paper reports a comparative study on degradation of the printed 3D poly (lactic-co-glycolic acid) scaffold under three conditions, namely, micro-channel, incubator static, and incubator shaking in the phosphate buffer saline (PBS) solution. In the case of the micro-channel condition, the solution was circulated. The following attributes of the scaffold and the solution were measured, including the mass or weight loss, water uptake, morphological and structural changes, and porosity change of the scaffold and the pH value of the PBS solution. In addition, shear stress in the scaffold under the micro-channel condition at the initial time was calculated with Computational Fluid Dynamics (CFD) to see how the shear stress factor may affect the morphological change of the scaffold. The results showed that the aforementioned attributes in the condition of the micro-channel were significantly different from the other two conditions. The mechanisms that account for the results were proposed. The reasons behind the results were explored. The main contributions of the study were (1) new observations of the degradation behavior of the scaffold under the micro-channel condition compared with the conditions of incubator static and incubator shaking along with underlying reasons, (2) new understanding of the role of the shear stress in the scaffold under the condition of the micro-channel to the morphological change of the scaffold, and (3) new understanding of interactions among the attributes pertinent to scaffold degradation, such as weight loss, water uptake, pH value, porosity change, and morphological change. This study sheds important light on the scaffold degradation to be controlled more precisely.
  • 18.

    【2hr】Dotette: Programmable, high-precision, plug-and-play droplet pipetting

    包量

    机译 Dotette：可编程，高精度，即插即用的液滴移液
    摘要：Manual micropipettes are the most heavily used liquid handling devices in biological and chemical laboratories; however, they suffer from low precision for volumes under 1 μl and inevitable human errors. For a manual device, the human errors introduced pose potential risks of failed experiments, inaccurate results, and financial costs. Meanwhile, low precision under 1 μl can cause severe quantification errors and high heterogeneity of outcomes, becoming a bottleneck of reaction miniaturization for quantitative research in biochemical labs. Here, we report Dotette, a programmable, plug-and-play microfluidic pipetting device based on nanoliter liquid printing. With automated control, protocols designed on computers can be directly downloaded into Dotette, enabling programmable operation processes. Utilizing continuous nanoliter droplet dispensing, the precision of the volume control has been successfully improved from traditional 20%–50% to less than 5% in the range of 100 nl to 1000 nl. Such a highly automated, plug-and-play add-on to existing pipetting devices not only improves precise quantification in low-volume liquid handling and reduces chemical consumptions but also facilitates and automates a variety of biochemical and biological operations.
  • 19.

    【2hr】Automatic cell fusion via optically-induced dielectrophoresis and optically-induced locally-enhanced electric field on a microfluidic chip

    包量

    机译 在微流控芯片上通过光诱导介电泳和光诱导局部增强电场实现自动细胞融合
    摘要：Cell fusion technology has been exploited in a wide variety of biomedical applications, and physical, chemical, and biological approaches can all be used to fuse two different types of cells; however, no current technique is adept at inducing both cell pairing and fusion at high efficiencies and yields. Hence, we developed a new method featuring the use of optically induced dielectrophoresis (ODEP) in conjunction with an optically induced, locally enhanced electric field for accurate and automatic cell pairing and fusion on a microfluidic device. After pairing cells via ODEP, a locally enhanced electric field generated by “virtual electrodes” by projecting light patterns was enacted to induce a proper transmembrane potential at the cell contact area such that cell fusion could be triggered by white light exposure. As a fusion yield of 9.67% was achieved between Pan1 and A549 cells, we believe that this may be a promising technique for automatically fusing different cell types.
  • 20.

    【2hr】Layered acoustofluidic resonators for the simultaneous optical and acoustic characterisation of cavitation dynamics, microstreaming, and biological effects

    包量

    机译 分层声流体谐振器，用于同时对空化动力学，微流和生物效应进行光学和声学表征
    摘要：The study of the effects of ultrasound-induced acoustic cavitation on biological structures is an active field in biomedical research. Of particular interest for therapeutic applications is the ability of oscillating microbubbles to promote both cellular and tissue membrane permeabilisation and to improve the distribution of therapeutic agents in tissue through extravasation and convective transport. The mechanisms that underpin the interaction between cavitating agents and tissues are, however, still poorly understood. One challenge is the practical difficulty involved in performing optical microscopy and acoustic emissions monitoring simultaneously in a biologically compatible environment. Here we present and characterise a microfluidic layered acoustic resonator (μLAR) developed for simultaneous ultrasound exposure, acoustic emissions monitoring, and microscopy of biological samples. The μLAR facilitates in vitro ultrasound experiments in which measurements of microbubble dynamics, microstreaming velocity fields, acoustic emissions, and cell-microbubble interactions can be performed simultaneously. The device and analyses presented provide a means of performing mechanistic in vitro studies that may benefit the design of predictable and effective cavitation-based ultrasound treatments.
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