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Light-Driven Microfluidic Systems
Published in George K. Knopf, Kenji Uchino, Light Driven Micromachines, 2018
Noncontact grasping and manipulation of microparticles, biological cells, and subcellular components make OT techniques highly appealing to control the processes on LoC, μTAS, and BioMEMS devices. For example, OT systems can be exploited by microfluidic devices for single cell manipulation (Monat et al. 2008). The optical manipulation technology permits single cell cultivation in the microfluidic devices for producing homogeneous daughter cells that can be exploited by cell therapy (Zhang and Liu 2008). Also, optical traps integrated on microfluidic platforms and LoC devices can be used to explore how individual cells respond to neighboring cells, biomaterials, functionalized surfaces, and a wide variety of chemical/mechanical stimuli. Researchers have also been using OT and microfluidic devices for automated and high-throughput cell sorting. The efficiency of cell sorting can be improved by introducing multiple optical traps on a single platform. Furthermore, near-field optics using the evanescent waves and holographic techniques has been investigated for manipulating numerous microparticles at the same time (Chapin et al. 2006; Garces-Chavez et al. 2006; Mellor and Bain 2006). OT for biological cell transport and sorting will be examined in the next sections.
Surface Chemistry for Cell Capture in Microfluidic Systems
Published in Iniewski Krzysztof, Integrated Microsystems, 2017
ShuQi Wang, Feng Xu, Alexander Chi Fai Ip, Mrudula Somu, Xiaohu Zhao, Altug Akay, Utkan Demirci
Cell separation or sorting plays an important role in basic research and clinical applications such as the differentiation of stem cells [1,2], detection of circulating tumor cells (CTCs) [3,4] and quantification of CD4+ T lymphocytes in peripheral blood [5,6]. Conventionally, fluorescence-activated cell sorting or magnetic cell sorting methods have been widely used to separate cells of interest from a heterogeneous cell mixture. However, these methods require technical support, length sample preparation, and well-trained operators, which limit their applications in resource-limited and point-of-care settings. To address these drawbacks, various microfluidic devices have been designed and tested, targeting increased portability, reduced consumption of samples and reagents, decreased process complexity, and shortened sample-to-result time. In addition, the manufacturing of microfluidic devices can easily be scaled up, significantly reducing the cost of health care, even for developed countries. The microfluidic device can be further integrated into an automated system to reduce human errors. The advantages of microfluidic systems offer opportunities for improving health care in resource-limited settings, such as monitoring AIDS treatments using CD4 cell capturing devices [5,6].
Use of Nanotechnology for Viable Applications in the Field of Medicine
Published in T. S. Srivatsan, T. S. Sudarshan, K. Manigandan, Manufacturing Techniques for Materials, 2018
Mazaher Gholipourmalekabadi, Mohammad Taghi Joghataei, Aleksandra M. Urbanska, Behzad Aghabarari, Aidin Bordbar-Khiabani, Ali Samadikuchaksaraei, Masuod Mozafari
Separation of pure population of stem cells from heterogeneous cells is an essential part and represents a major contribution in tissue engineering. For example, islet 1+ as cardiac progenitor cells exists in the human heart and mouse heart in very small population and is surrounded by differentiated cells of adult heart tissue [149]. A robust and high efficacy method needs to be developed to separate a pure population of rare islet 1+ cell line. In some cases, stem cells should be differentiated in vitro before transplantation, especially in using ESCs. Then, target differentiated cells should be purified and transplanted. Cell-sorting techniques separate cells based on size, density, or affinity (chemical, electrical, or magnetic). Conventional cell separation techniques such as size-based cell sorting, fluorescence-activated cell sorting, and magnetic-activated cell sorting have some disadvantages in terms of cost and time [150]. In modern medicine, miniaturized cell separation systems (microsized/nanosized) have been developed and possess many advantages compared to conventional cell-sorting systems, such as (1) small sample volume, (2) low cost, and (3) portability [150]. Using NPs such as superparamagnetic NPs serves to enhance the resolution. For example, in a study [151], leucocytes (CD 45+ cells) were separated from red blood cells using magnetic-activated cell sorting. After exposure of cells to anti-CD45 conjugated superparamagnetic NPs, CD45+ cells carried about 5000 NPs [151]. Development of a perfect cell-sorting technique for the purpose of separation of rare cells from undesired cells with advantages of high efficacy, low cost, and time is strongly sensed in stem cell biology, and the use of microscale/nanoscale devices enables us to enhance these techniques.
Dependency of hydrogel membrane pores on membrane pressure and concentration: Numerical and experimental investigations
Published in Mechanics of Advanced Materials and Structures, 2023
Eric Langner, Denise Gruner, Ramona Mehling, Franziska Obst, Adrian Ehrenhofer, Stefan Grünzner, Günter K. Auernhammer, Stefan Michel, Andreas Richter, Thomas Wallmersperger
The separation and sorting of cells from complex fluids are among the critical challenges in many areas of the life sciences [1]. In many biomedical applications including diagnostics, therapeutics and cell biology, cell sorting is the first step toward the analysis of pathogens or very rare cells. These can be circulating tumor cells [2], hematopoietic stem cells [3] and fetal cells [4]. Cell sorting includes the separation, enrichment and purification of the target cells. The growing interest in theranostics and personalized medicine, in which treatments are tailored to patients’ individual circumstances, is a strongly driving demand for rapid and high-performance cell sorting [1].
A method for separation and purification of mouse splenocytes by density gradient centrifugation
Published in Preparative Biochemistry & Biotechnology, 2021
Yao Lu, Chenghao Fu, Chao Xia, Shiliang Ma
Spleen is an informative and easy-accessible tissue with complex immunocyte composition. Therefore, character and condition of spleen requires accurate analysis by isolating specific cells. In the process of achieving this, cell separation is a key first step before further biological assays. Traditionally, some cell types can be separated by culturing according to different cellular adhesion and growth property. It is a label-free way to separate suspension cells from adherent cells. This method is easy-operating but has low efficiency and low throughput. Currently, the methods for separating cells mainly include magnet-activated cell sorting (MACS), fluorescence activated cell sorting (FACS) and density gradient centrifugation. MACS and FACS can isolate cells with high specificity by labeling cells exogenously. Clinically, the sorted cells are avoided to be activated by antibodies, which may trigger a series of cell changes. Therefore, MACS especially negative selection has been applied in clinical research[20,21]. Although a large percentage of non-labeled cells can be obtained, there remains a small population of uninterested cells in the target cell suspension and adversely influence the subsequent studies[22]. FACS has also been widely used in biological research. While, the serious limitation of FACS is its expensive price and the damage to cells which may trigger the cell signaling by combining cell surface receptors. Studies also have shown that cell viability and amplification rate were significantly decreased by using FACS[23]. Density gradient centrifugation allows separating cells from a large initial cell sample. And the separation solutions are also gentle on cells. Therefore, it is widely used for clinical cell separation. Besides, it can perform experiments without removing red blood cells in advance, which greatly reduces analysis time. While the current problem of this method is a high purity cannot be obtained under the situation where cell density differences are not significant.