Adlayer-Mediated Antibody Immobilization to Stainless Steel for Potential Application to Endothelial Progenitor Cell Capture

This work describes the straightforward surface modification of 316L stainless steel with BTS, S-(11-trichlorosilylundecanyl)-benzene­thiosulfonate, a thiol-reactive trichlorosilane cross-linker molecule designed to form intermediary coatings with subsequent biofunctionalization capability. The strategy is more specifically exemplified with the immobilization of intact antibodies and their Fab′ fragments. Both surface derivatization steps are thoroughly characterized by means of X-ray photoelectron spectroscopy. The antigen binding capability of both types of biofunctionalized surfaces is subsequently assessed by fluorescence microscopy. It was determined that BTS adlayers achieve robust immobilization of both intact and fragmented antibodies, while preserving antigen binding activity. Another key finding was the observation that the Fab′ fragment immobilization strategy would constitute a preferential option over that involving intact antibodies in the context of in vivo capture of endothelial progenitor cells in stent applications.