Affinity Binding of EMR2 Expressing Cells by Surface-Grafted Chondroitin Sulfate B

Abstract

The propensity of glycosaminoglycans to mediate cell-cell and cell-matrix interactions opens the door to capture cells, including circulating blood cells, onto biomaterial substrates. Chondroitin sulfate (CS)-B is of particular interest, since it interacts with the receptor (EGF)-like module-containing mucin-like hormone receptor-like 2 precursor (EMR2) displayed on the surface of leukocytes and endothelial progenitor cells. Herein, CS-B and its isomer CS-A were covalently immobilized onto heptylamine plasma polymer films via three different binding chemistries to develop platform technology for the capture of EMR2 expressing cells onto solid carriers. Surface characterization verified the successful immobilization of both glycosaminoglycans. The EMR2 expressing human myeloid cell line U937 preferentially bound onto CS-B-modified substrates, and U937 cells preincubated with CS-B in solution exhibited reduced affinity for the substrate. The direct capture of hematopoietic and blood-circulating endothelial cell types via a glycosaminoglycan-binding surface receptor opens an unexplored route for the development of biomaterials targeted at these cell types.