Patent ID: 8586338

Claim:
An article comprising a base substrate and extending from the surfaces thereof grafted ligand groups of the formula: wherein: R 1 is H or C 1 -C 4 alkyl; R 2 is a divalent alkylene; each R 3 is independently H or C 1 -C 4 alkyl; R 4 is H, C 1 -C 4 alkyl or —N(R 3 ) 2 ; X 1 is —O— or —NR 3 —; PI* is the residue of a photoinitiator PI; and PI is a photoinitiator represented by the structure: wherein R 8 is selected from: wherein: R 7 is H or a C 1 to C 4 alkyl group; and each R 9 is independently a hydroxyl group, a phenyl group, a C 1 to C 6 alkyl group, or a C 1 to C 6 alkoxy group.