Preparation of a sensing membrane for C-reactive protein

11,11′-dithiobis(undecanyl succinate) (DS11SACOOH) was synthesized to develop a new surface for immobilization of proteins or antibodies on a gold substrate. DS11SACOOH is a bifunctional linker that has a disulfide group to form SAM (self-assembled monolayer) on a gold substrate and two carboxylic moieties for reaction with biomolecules such as peptide, DNA, etc. After preparation of SAM on a gold-coated quartz cell with DS11SACOOH, the SAM surface was activated with NHS (N-hydroxysuccimide). The terminal NHS ester was reacted with anti-CRP (C-reactive protein). The binding behavior of CRP on the surface was monitored by use of SPR (surface plasmon resonance) sensor system.