1 research outputs found
Continuous Sorting of Cells Based on Differential P Selectin Glycoprotein Ligand Expression Using Molecular Adhesion
Cell surface molecular
adhesions govern many important physiological
processes and are used to identify cells for analysis and purifications.
But most effective cell adhesion separation technologies use labels
or long-term attachments in their application. While label-free separation
microsystems typically separate cells by size, stiffness, and shape,
they often do not provide sufficient specificity to cell type that
can be obtained from molecular expression. We demonstrate a label-free
microfluidic approach capable of high throughput separation of cells
based upon surface molecule adhesion. Cells are flowed through a microchannel
designed with angled ridges at the top of the channel and coated with
adhesive ligands specific to target cell receptors. The ridges slightly
compress passing cells such that adhesive contact can be made with
sufficient surface area without unduly affecting cell trajectories
because of cell stiffness. Thus, sorting is sensitive to cell adhesion
but not to stiffness or cell size. The enforced interactions between
the cells and the ridges ensure that a high flow rate can be used
without lift forces quenching adhesion. As a proof of principle of
the method, we separate both Jurkat and HL60 cell lines based on their
differential expression of PSGL-1 ligand by using a ridged channel
coated with P selectin. We demonstrate 26-fold and 3.8-fold enrichment
of PSGL-1 positive and 4.4-fold and 3.2-fold enrichment of PSGL-1
negative Jurkat and HL60 cells, respectively. Increasing the number
of outlets to five allows for greater resolution in PSGL-1 selection
resulting in fractionation of a single cell type into subpopulations
of cells with high, moderate, and low PSGL-1 expression. The cells
can flow at a rate of up to 0.2 m/s, which corresponds to 0.045 million
cells per minute at the designed geometry, which is over 2 orders
of magnitude higher than previous adhesive-based sorting approaches.
Because of the short interaction time of the cells with the adhesive
surfaces, the sorting method does not further activate the cells due
to molecular binding. Such an approach may find use in label-free
selection of cells for a highly expressed molecular phenotype