共查询到20条相似文献,搜索用时 0 毫秒
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Detwiler DA Dobes NC Sims CE Kornegay JN Allbritton NL 《Analytical and bioanalytical chemistry》2012,402(3):1083-1091
Despite identification of a large number of adult stem cell types, current primary cell isolation and identification techniques
yield heterogeneous samples, making detailed biological studies challenging. To identify subsets of isolated cells, technologies
capable of simultaneous cell culture and cloning are necessary. Micropallet arrays, a new cloning platform for adherent cell
types, hold great potential. However, the microstructures composing these arrays are fabricated from an epoxy photoresist
1002F, a growth surface unsuitable for many cell types. Optimization of the microstructures’ surface properties was conducted
for the culture of satellite cells, primary muscle cells for which improved cell isolation techniques are desired. A variety
of surface materials were screened for satellite cell adhesion and proliferation and compared to their optimal substrate,
gelatin-coated Petri dishes. A 1-μm thick, polystyrene copolymer was applied to the microstructures by contact printing. A
negatively charged copolymer of 5% acrylic acid in 95% styrene was found to be equivalent to the control Petri dishes for
cell adhesion and proliferation. Cells cultured on control dishes and optimal copolymer-coated surfaces maintained an undifferentiated
state and showed similar mRNA expression for two genes indicative of cell differentiation during a standard differentiation
protocol. Experiments using additional contact-printed layers of extracellular matrix proteins collagen and gelatin showed
no further improvements. This micropallet coating strategy is readily adaptable to optimize the array surface for other types
of primary cells. 相似文献
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In this paper, we demonstrate how to apply recently discovered ferromagnetic nematic liquid crystal for visualisation of magnetic fields. The material exhibits strong optical response to both external electric and magnetic fields, which gives us an opportunity to use it for the detection of an area of magnetic vector field in a way that both, the magnitude and the direction of a given field can be simultaneously measured. We discuss the physical model that describes the behaviour of ferromagnetic liquid crystal placed in a liquid crystal cell and demonstrate the method of extracting the information about an arbitrary magnetic field from the combination of magneto-optic and electro-optic response of the sample placed in that field. We have applied the principle to a special case, where magnetic field was visualised on a 2D area near a cylindrical permanent magnet. 相似文献
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Yuanbo Chen Bo Jiang Yechen Hu Nan Deng Baofeng Zhao Xiao Li Zhen Liang Lihua Zhang Yukui Zhang 《Electrophoresis》2019,40(16-17):2135-2141
The binding coverage of aptamer was an important restricted factor for aptamer‐based affinity enrichment strategy for capturing target molecules. Herein, we designed and prepared aptamer functionalized graphene oxide based nanocomposites (GO/NH2‐NTA/Fe3O4/PEI/Au), and the coverage density of aptamer was high to 33.1 nmol/mg. The high aptamer coverage density was contributed to the large surface area of graphene oxide. The successive modification of Nα,Nα‐Bis(carboxymethyl)‐L‐lysine, magnetic nanoparticles, polyethylenimine, and Au nanoparticles ensured the histone purification with fast speed and high purity. Histones could be captured rapidly and specifically from nucleoproteins by our aptamer based purification strategy, while traditional acid‐extraction could not specifically enrich histones. Compared with traditional acid‐extraction method, rapid and efficient discovery of histones and their post‐translational modifications, such as several kinds of methylation at H3.1K9 and H3.1K27, were achieved confidently. It demonstrated that our aptamer functionalized magnetic graphene oxide nanocomposites have a great potential for histone analysis. 相似文献
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Q Zhou Y Liu DS Shin J Silangcruz N Tuleuova A Revzin 《Langmuir : the ACS journal of surfaces and colloids》2012,28(34):12544-12549
Aptamers have recently emerged as an excellent alternative to antibodies because of their inherent stability and ease of modification. In this paper, we describe the development of an aptamer-based surface for capture of cells expressing CD4 antigen. The glass or silicon surfaces were modified with amine-terminated silanes and then modified with thiolated RNA aptamer against CD4. Modification of the surface was first characterized by ellipsometry to demonstrate assembly of biointerface components and to show specific capture of recombinant CD4 protein. Subsequently, surfaces were challenged with model lymphocytes (cell lines) that were either positive or negative for CD4 antigen. Our experiments show that aptamer-functionalized surfaces have similar capture efficiency to substrates containing anti-CD4 antibody. To mimick capture of specific T-cells from a complex cell mixture, aptamer-modified surfaces were exposed to binary mixtures containing Molt-3 cells (CD4+) spiked into Daudi B cells (CD4-). 94% purity of CD4 cells was observed on aptamer-containing surfaces from an initial fraction of 15% of CD4. Given the importance of CD4 cell enumeration in HIV/AIDS diagnosis and monitoring, aptamer-based devices may offer an opportunity for novel cell detection strategies and may yield more robust and less expensive blood analysis devices in the future. 相似文献
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《国际化学动力学杂志》2018,50(9):615-632
The present study has established the direct pseudo–first‐order reaction kinetics of different aqueous‐based single and blended amines over the temperature range of 298.15‐313.15 K using stopped‐flow techniques. The single amines include one primary amine (monoethanolamine, MEA), two secondary amines (diethanolamine, DEA and 2‐ethyl(amino)ethanol, 2EAE), four tertiary amines (N‐methyldiethanolamine, MDEA, 1‐dimethylamino‐2‐propanol, 1DMA2P, 3‐dimethylamino‐1‐propanol, 3DMA1P, and 2‐dimethylaminoethanol, 2DMAE), one sterically hindered amine (2‐amino‐2‐methyl‐1‐propanol, AMP), and one cyclic diamine (piperazine, PZ). The blend systems used are MEA/PZ, DEA/PZ, MDEA/PZ, AMP/PZ, MEA/AMP, MDEA/2EAE, 1DMA2P/2EAE, 3DMA1P/2EAE, and 2DMAE/2EAE. Different reaction mechanisms for the reaction of CO2 with aqueous solutions of amines, such as base‐catalysis, zwitterion, termolecular, hybrid of zwitterion, hybrid of base‐catalysis‐zwitterion, and hybrid of base‐catalysis‐termolecular reaction mechanisms, are used to correlate the experimental data. For the single amines, the zwitterion mechanism is well suited to fit the experimental data of primary, secondary, sterically hindered and cyclic amines with an absolute average deviation (AAD%) less than 5%. The base‐catalysis mechanism fits the experimental data of all the tertiary amines well with an AAD less than 5%. For the blends, the hybrid of zwitterion mechanism fits the experimental data of MEA/PZ, DEA/PZ, AMP/PZ, and MEA/AMP well with an AAD less than 5%, whereas the hybrid of base‐catalysis‐zwitterion mechanism fits the experimental data of MDEA/PZ, MDEA/2EAE, 1DMA2P/2EAE, 3DMA1P/2EAE, and 2DMAE/2EAE well with an AAD less than 5%. 相似文献
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Zhao L Wu R Han G Zhou H Ren L Tian R Zou H 《Journal of the American Society for Mass Spectrometry》2008,19(8):1176-1186
The highly selective capture of phosphopeptides from proteolytic digests is a great challenge for the identification of phosphoproteins
by mass spectrometry. In this work, the zirconium phosphonate-modified magnetic Fe3O4/SiO2 core/shell nanoparticles have been synthesized and successfully applied for the selective capture of phosphopeptides from
complex tryptic digests of proteins before the analysis of MALDI-TOF mass spectrometry with the desired convenience of sample
handling. The ratio of magnetic nanoparticle to protein and the incubation time for capturing phosphopeptides from complex
proteolytic digests were investigated, and the optimized nanoparticle-to-protein ratio and incubation time were between 15:1
to 30:1 and 30 min, respectively. The excellent detection limit of 0.5 fmol β-casein has been achieved by MALDI-TOF mass spectrometry
with the specific capture of zirconium phosphonate-modified magnetic Fe3O4 nanoparticles. The great specificity of zirconium phosphonate-modified magnetic Fe3O4 nanoparticles to phosphopeptides was demonstrated by the selective capture of phosphopeptides from a complex tryptic digest
of the mixture of α-casein and bovine serum albumin at molar ratio of 1 to 100 in MALDI-TOF-MS analysis. An application of the magnetic nanoparticles
to selective capture phosphopeptides from a tryptic digest of mouse liver lysate was further carried out by combining with
nano-LC-MS/MS and MS/MS/MS analyses, and a total of 194 unique phosphopeptides were successfully identified. 相似文献
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A simple three-dimensional (3D) hydrodynamic focusing microfluidic device integrated with continuous sampling, rapid dynamic lysis, capillary electrophoretic (CE) separation and detection of intracellular content is presented. One of the major difficulties in microfluidic cell analysis for adherent cells is that the cells are prone to attaching to the channel surface. To solve this problem, a cross microfluidic chip with three sheath-flow channels located on both sides of and below the sampling channel was developed. With the three sheath flows around the sample solution-containing cells, the formed soft fluid wall prevents the cells from adhering to the channel surface. Labeled cells were 3D hydrodynamically focused by the sheath-flow streams and smoothly introduced into the cross-section one by one. The introduction of sheath-flow streams not only ensured single-cell sampling but avoided blockage of the sampling channel by adherent cells as well. The maximum rate for introduction of individual cells into the separation channel was about 151 cells min(-1). With electric field applied on the separation channel, the aligned cells were driven into the separation channel and rapidly lysed within 400 ms at the entry of the channel by sodium dodecylsulfate (SDS) added in the sheath-flow solution. The microfluidic system was evaluated by analysis of reduced glutathione (GSH) and reactive oxygen species (ROS) in single HepG2 cells. The average analysis throughput of ROS and GSH in single cells was 16-18 cells min(-1). 相似文献
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Culturing cells at microscales allows control over microenvironmental cues, such as cell-cell and cell-matrix interactions; the potential to scale experiments; the use of small culture volumes; and the ability to integrate with microsystem technologies for on-chip experimentation. Microfluidic perfusion culture in particular allows controlled delivery and removal of soluble biochemical molecules in the extracellular microenvironment, and controlled application of mechanical forces exerted via fluid flow. There are many challenges to designing and operating a robust microfluidic perfusion culture system for routine culture of adherent mammalian cells. The current literature on microfluidic perfusion culture treats microfluidic design, device fabrication, cell culture, and micro-assays independently. Here we systematically present and discuss important design considerations in the context of the entire microfluidic perfusion culture system. These design considerations include the choice of materials, culture configurations, microfluidic network fabrication and micro-assays. We also present technical issues such as sterilization; seeding cells in both 2D and 3D configurations; and operating the system under optimized mass transport and shear stress conditions, free of air-bubbles. The integrative and systematic treatment of the microfluidic system design and fabrication, cell culture, and micro-assays provides novices with an effective starting point to build and operate a robust microfludic perfusion culture system for various applications. 相似文献
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《Electrophoresis》2018,39(7):981-988
In this paper, we demonstrate the effectiveness of a new 3D printed magnet holder that enables capture of magnetic microparticles in commercially available capillary electrophoresis equipment with a liquid or air based coolant system. The design as well as the method to capture magnetic microparticles inside the capillary are discussed. This setup was tested at temperature and pH values suitable for performing enzymatic reactions. To demonstrate its applicability in CE‐ immobilized microenzyme reactors (IMER) development, human flavin‐containing monooxygenase 3 and bovine serum albumin were immobilized on amino functionalized magnetic microparticles using glutaraldehyde. These microparticles were subsequently used to perform in‐line capillary electrophoresis with clozapine as a model substrate. This setup could be used further to establish CE‐IMERs of other drug metabolic enzymes in a commercially available liquid based capillary coolant system. The CE‐IMER setup was successful, although a subsequent decrease in enzyme activity was observed on repeated runs. 相似文献
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An integrated smart microfluidic device consisting of nickel micropillars, microvalves, and microchannels was developed for specific capture and sorting of cells. A regular hexagonal array of nickel micropillars was integrated on the bottom of a microchannel by standard photolithography, which can generate strong induced magnetic field gradients under an external magnetic field to efficiently trap superparamagnetic beads (SPMBs) in a flowing stream, forming a bed with sufficient magnetic beads as a capture zone. Fluids could be manipulated by programmed controlling the integrated air-pressure-actuated microvalves, based on which in situ bio-functionalization of SPMBs trapped in the capture zone was realized by covalent attachment of specific proteins directly to their surface on the integrated microfluidic device. In this case, only small volumes of protein solutions (62.5 nL in the capture zone; 375 nL in total volume needed to fill the device from inlet A to the intersection of outlet channels F and G) can meet the need for protein! The newly designed microfluidic device reduced greatly chemical and biological reagent consumption and simplified drastically tedious manual handling. Based on the specific interaction between wheat germ agglutinin (WGA) and N-acetylglucosamine on the cell membrane, A549 cancer cells were effectively captured and sorted on the microfluidic device. Capture efficiency ranged from 62 to 74%. The integrated microfluidic device provides a reliable technique for cell sorting. 相似文献
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Köster S Angilè FE Duan H Agresti JJ Wintner A Schmitz C Rowat AC Merten CA Pisignano D Griffiths AD Weitz DA 《Lab on a chip》2008,8(7):1110-1115
We use microfluidic devices to encapsulate, incubate, and manipulate individual cells in picoliter aqueous drops in a carrier fluid at rates of up to several hundred Hz. We use a modular approach with individual devices for each function, thereby significantly increasing the robustness of our system and making it highly flexible and adaptable to a variety of cell-based assays. The small volumes of the drops enables the concentrations of secreted molecules to rapidly attain detectable levels. We show that single hybridoma cells in 33 pL drops secrete detectable concentrations of antibodies in only 6 h and remain fully viable. These devices hold the promise of developing microfluidic cell cytometers and cell sorters with much greater functionality, allowing assays to be performed on individual cells in their own microenvironment prior to analysis and sorting. 相似文献