Immobilization of drugs and biomolecules on in situ copolymerized active ester polypyrrole coatings for biomedical applications

Abstract

Among the plethora of polymers being exploited and employed currently for biomedical applications, polypyrrole as a conducting polymer holds a key position since it offers several advantages including good specific conductivity, chemical stability, polymerizability and compatibility with mammalian cells; however, it also suffers from a few limitations that restrict it from being an obvious winner as a coating material. In order to overcome these limitations, pyrrole derivatives have been tried as potential alternatives. These synthesized derivatives facilitate the immobilization/coupling of biomolecules and drugs on to the surface so as to improve the biocompatibility and performance of implantable medical devices. In this work, N-succinimidyl ester pyrrole (PyNSE) has been synthesized and characterized. A synthesized monomer was copolymerized with pyrrole (Py) in different ratios to obtain smooth and adherent copolymer coatings on the metal surface. Results suggest that among the different coatings obtained, pure active ester functionalized polypyrrole (PPyNSE) coating is smoother and more adherent than its different copolymers with pyrrole. The activity of the coating was tested by attaching BSA and a model drug (p-nitroaniline) on the surface which indicated that the concentration of these molecules on the surface can be varied by varying the concentration of monomers, i.e. Py and PyNSE, during electropolymerization. These active coatings may serve as a potential platform for attaching drugs and biomolecules for various biomedical applications.