Reactions of Surface Amines with Heterobifunctional Cross-Linkers Bearing Both Succinimidyl Ester and Maleimide for Grafting Biomolecules

Abstract

Surface reactions of amines with a series of heterobifunctional cross-linkers containing both maleimide and succinimidyl ester groups were investigated with infrared reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS), and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). A specific surface derived from N-succinimidyl 6-maleimidylhexanoate (SMH) presents two linking groups, maleimide and succinimidyl ester, while surfaces from other cross-linkers present predominantly maleimide-pendant groups. An expected surface product by reaction of the cystamine monolayer with SMH, N,N‘-bis(6-maleimidylhexanoyl)cystamine (BMHC), was synthesized independently, self-assembled, and characterized for further supporting the above conclusion. Finally, a peptide, H-Gly-Arg-Gly-Asp-Ser-Pro-Cys-OH (GRGDSPC), was immobilized on a maleimide-pendant surface as an amino-terminated structure and on a binary group (maleimide and succinimidyl ester) modified surface as a bridging structure.