Cell sorting
The homogeneous cell population obtained after sorting can be used for a variety of applications including research, diagnosis, and therapy.
A cell of interest that should be sorted is measured at the sensing zone and moves down the stream to the breakoff point.
[2] Flow cytometry cell-sorting yields very high specificity according to one or several surface markers, but one limitation is constituted by the number of cells that can be processed during a work day.
Another aspect to be considered is that droplet-generation inside the instrument could lead to aerosol formations that are hazardous to the operator when using infectious samples.
Researchers can use a variety of fluorescent dyes to design multi-color panels to achieve successful, simultaneous sorting of multiple, precisely defined cell types.
This technology is based on the attachment of small, inert, supra-magnetic particles to mAbs specific for antigens on the target cell population.
On the other hand, this technique allows cells to separate based only on a single marker, and cannot discriminate between different levels of protein expression (quantitative analysis).
[5] Immunomagnetic cell sorting has also been used in assistance with reproduction (artificial insemination) and retinal transplant treatment.
[6] This type of treatment has shown to be more effective when done repeatedly, increasing the amount of non-apoptotic cells present during insemination.
[6] A 2018 study done in France (with the support of multiple individuals and agencies including: the Institut de la Vision in Paris and the Retina France Association) used rats and the immunomagnetic cell-sorting method to show that photoreceptors (cells in the retina which respond to light) may be transplanted to cure blindness.
[7] When a CD73+ antigen expressed itself with RCVRN+ cells (calcium-binding proteins in the eye), it showed researchers that this combination of CD73+ and RCVRN+ could be used with post-mitotic PR precursors for repair.
[7] This success in cell separation and pairing through transplantation shows promise for a potential cure for retinal diseases including total blindness.
Research into microfluidic cell-sorter designs often employ soft lithography techniques utilizing materials such as polydimethylsiloxane (PDMS).
A key benefit of microfluidic sorters is the potential to perform fluorescence-activated cell sorting in a closed single-use sterile cartridge.
Active microfluidic cell-sorters involve the deflection of individual cells following their measurement using cytometric methods, including fluorescent labelling, light-scatter and image analysis.
[39] The fluid in a colloidal solution is subject to a velocity profile due to the interactions of the fluid with the walls of the channel; the cells in the solution are subject to various drag and inertial forces that are dependent on the size of the cell and balance accordingly at different locations along the velocity profile.
[43] These included antibody- and complement-mediated cell separation, polystyrene immunoaffinity devices, and the CellPro CEPRATE® SC System which employed immobilised antibodies in a porous column.
Scientists apply machine-learning methods (mainly clustering analysis) on the single-cell RNA-Seq data to divide the cells into different categories.
All the methods are modified to resolve the problems in RNA-Seq data such as dropout of low-expression genes and ambiguous cell markers in the presence of technical biases.
State-of-the-art methods include SC3.,[47] CIDR.,[48] Seurat and for more detailed information, please refer to the Wiki page: Single Cell RNA-Seq Clustering.
