Anti-fouling and anti-coagulation capabilities of PEDOT-biopolymer coating by in-situ electrochemical copolymerization

Abstract

In this study, 3,4-ethylenedioxythiophene (EDOT), polystyrene sulfonate (PSS), chondroitin sulfate (CHS), and carboxymethyl-hexanoyl chitosan (CHC) nanohybrids were coated on nitrogen plasma pre-treated SUS316L stainless steel using in-situ electrochemically copolymerization. The negatively charged PSS, CHS, and CHC were used to repel the negatively charged proteins, platelets, and cell walls of bacteria (E. coli) to achieve anti-fouling and anti-clotting capabilities. The anti-fouling capabilities of the poly-3,4-ethylenedioxythiophene (PEDOT) derivative coatings had the following order: PEDOT/CHC/CHS > PEDOT/CHS > PEDOT/CHS/PSS > PEDOT/PSS > pristine SUS316L. In particular, with the addition of CHC, the PEDOT/CHC/CHS coating could decrease the adhesion of platelets and bacteria using the functional group (-COOH) of CHC. The blood clotting time (activated partial thromboplastin time) of the PEDOT/CHC/CHS substrates was prolonged to 48 s, compared to the 32 s required for the pristine SUS316L stainless steel, showing the good hemocompatibility. Furthermore, cytotoxicity tests showed that PEDOT and its derivatives exhibited very good biocompatibility. Thus, they could potentially be applied in anti-clotting, anti-fouling, and anti-bacterial biomedical devices such as cardiovascular stents.