Fabricating three-dimensional carbohydrate hydrogel microarray for lectin-mediated bacterium capturing

Herein, a three-dimensional carbohydrate modified polyacrylamide hydrogel microarray (3D carbohydrate hydrogel microarray) has been fabricated and employed as micro-reactor for capturing Escherichia coli (E. coli) by multivalent binding of concanavalin A (Con A) with O-antigen on the cellular surface of E. coli and immobilized monosaccharides on hydrogel spot, and the interactions of type 1 fimbriae of E. coli with immobilized monosaccharides. Because of the transparent performance of polyacrylamide hydrogel, the captured E. coli can be directly observed by a conventional microscope under a bright-field mode. The experimental result demonstrates that α-D-mannopyranoside (Man-α) modified hydrogel surface shows high efficiency of E. coli capturing. The 3D Man-α hydrogel microarray-based assay shows reasonable low detection limit (1.0×104 cells/mL) and large dynamic range (1.0×105 to 1.0×109cells/mL) for detecting E. coli. In addition, bacterial adhesion inhibition assay has been demonstrated by the interactions of E. coli with ten saccharides, and satisfactory results have been obtained.