A reactive polythiophene for protein immobilization

The reaction between a polythiophene with pendant N-hydroxysuccinimide ester moieties and amine-containing molecules in solution and on a surface is described. 3-(N-succinimidoacetate)thiophene was polymerized with FeCI₃ in chloroform and the resulting polythiophene was characterized by NMR, FT-IR, and GPC. Both n-butylamine and 2-amino(2-ethoxy)ethanol were reacted with the polythiophene in a chloroform solution as confirmed by UV-vis and FT-IR spectroscopy. The polythiophene prepared as a film on a gold substrate was treated with the amine-containing molecules and the surface modification was investigated by contact angle measurement. Anti-CRP (C-reactive protein) was immobilized by using the reactive polythiophene on a gold-coated quartz cell and the binding behavior of CRP was monitored by using surface plasmon resonance (SPR) sensor system.