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Analysis of Single Cells Using Lab-on-a-Chip Systems
Published in Frances S. Ligler, Jason S. Kim, The Microflow Cytometer, 2019
Microfluidics holds the promise to overcome many limitations of today's research. The reduction of scale saves reagents and sample, and often allows an enhanced degree of automation. Flow cytometry has become a method of choice for rapidly analyzing large numbers of cells individually using light-scattering, fluorescence, and absorbance measurements. The power of this method lies in the wide range of cellular parameters that can be determined and in the ability to obtain information on how these parameters are distributed in the cell population. Recently, several groups have demonstrated that chip-based systems can be used for flow cytometry.3-5 Researchers have either used pressure-driven or electrokinetic flow to pump fluids and cells in microfluidic devices. Pressure driven flow seems more suitable for the analysis of eukaryotic cells since it does less damage to the cells than an electric field and is less dependent on ion content of the buffer.12
Detection Technology
Published in Rick Houghton, William Bennett, Emergency Characterization of Unknown Materials, 2020
Rick Houghton, William Bennett
Cytometry is the measurement of physical and chemical characteristics of individual cells. Flow cytometry technology measures the characteristics of the particles in a stream of fluid with laser light-scattering detection and with dyes bound to certain parts of the cell that fluoresce. Properties of scattered laser light can be interpreted to indicate the size and number of particles in the stream of fluid as well as the amount of DNA, presence of specific nucleotide sequences, and cellular proteins.
Quantitative Cell Culture Techniques
Published in Jay L. Nadeau, Introduction to Experimental Biophysics, 2017
An important principle of flow cytometry data analysis is called gating. This is when the cells with desirable values of a given parameter are used in the analysis, while other cells are eliminated. For example, gating on live cells would eliminate the cells identified as dead by scattering as in Figure 10.9a; gating on monocytes would eliminate all but those identified as such in Figure 10.9b.
Classification and recognition method of white blood cells subclasses in batches based on phase characteristics with non-orthogonal phase imaging
Published in Journal of Modern Optics, 2022
Yuanyuan Xu, Hao Han, Yang Zou, Yawei Wang, Jingrong Liao
It is well-known that the number and morphology of cells is highly significant. Detection systems [6,7] include flow cytometry [8,9], traditional optical microscopy, and fluorescence microscopy [10–13]. Flow cytometry is the most common blood analysis method in clinical medicine; it can provide many cell parameters such as number, relative ratio, protein content, volume, and morphological characteristics of various blood cells per unit volume. Nevertheless, flow cytometry cannot accurately observe the morphological characteristics of individual cells, and the detection results are only a statistical distribution. Due to the special structure of blood cells that are translucent, traditional optical microscopy cannot clearly observe their morphological characteristics, especially the distribution of substructures. Furthermore, microscopic examination of blood cells generally needs to be achieved with the help of fluorescence labels, and fluorescence microscopy. However, the fluorescence technology is not a non-invasive imaging technology, which may affect the behaviour of cells.
Effect of poly(dimethylsiloxane)-block-poly(oligo (ethylene glycol) methacrylate) amphiphilic block copolymers on dermal fibroblast viability and proliferation
Published in Journal of Biomaterials Science, Polymer Edition, 2019
Milad Ebtedaei, Kiyumars Jalili, Najibeh Alizadeh, Hakimeh Ghaleh, Farhang Abbasi
A flow cytometer has the capability of measuring thousands of fluorescent-labeled cells within seconds based on their size, density and relative fluorescence intensity. Annexin V FITC-A vs Propidium Iodide-A plots from the gated cells show the populations corresponding to viable and non-apoptotic (Annexin V–PI–), early (Annexin V+PI–), and late (Annexin V+PI+) apoptotic cells (Figure 12). When samples treated with PDMS20-b-POEGMA1 (1 wt%) for 48 h the majority of cells (84.60%) were viable and non-apoptotic (Annexin V–PI–). In contrast, when cells were treated with PDMS6-b-POEGMA1 (1 wt%) for 48 h, 8.72% of Annexin V–PI– cells were observed. There was an great increase in early apoptotic cell populations (Annexin V+PI–) with PDMS6-b-POEGMA1 (81.21%) in comparison to PDMS20-b-POEGMA1 sample (5.40%) demonstrating that PDMS6-b-POEGMA1 is effective for hypertrophic scars remediation. A slight increase in the Annexin V+PI+ population was also observed with PDMS6-b-POEGMA1 which indicates late apoptotic or dead cells. During apoptosis, cell shrinkage occurred, which was associated with a decrease in forward scatter.
Protective effect of a protease inhibitor from Agaricus bisporus on Saccharomyces cerevisiae cells against oxidative stress
Published in Preparative Biochemistry and Biotechnology, 2019
Reena Vishvakarma, Abha Mishra
Flow cytometry is a swift and consistent method for evaluating the expression of cell surface and intracellular molecules, studying the cell size and the volume and to quantify viable cells. It measures the fluorescence intensity produced by fluorescent-labeled ligands and dyes.[35] Depending upon the type, the dyes effortlessly penetrate the damaged, permeable membranes of non-living cells.[36] Oxidative stress can be inferred by quantifying the cells undergoing apoptosis. This purpose can be fulfilled using propidium iodide, PI as it intercalates the nucleic acid of the dead or dying cells. Hence, it evaluates cell death and apoptosis.[35] Similarly, 4′, 6-diamidino-2-phenylindole, DAPI also binds to the DNA not only of the dead cells but also live cells but with less efficiency.[30] This property of DAPI can be utilized to study both the damaged as well as normal viable cells. 2′, 7′-dichlorofluorescein, DCF dye, which determines the reactive oxygen species within the cell, can be used to quantify the live cell population under the stressed condition.