Side-chain engineering drives biocompatibility in polythiophenes

Abstract

With the development of organic bioelectronics, there is an increasing demand for materials that can efficiently interact with the biological nvironment. We present a synthesis of polythiophenalkanoates with amino-acid-bearing (lysine-terminated) oligo(ethylene glycol) (oEG) side chains designed to enhance biocompatibility and electronic functionality. Using an oxidative direct aryl polymerization method, we have achieved a high degree of regioregularity (up to 80%) while reducing environmental trace (atom economy and less synthetic steps) compared to traditional polymerization methods such as Stille or Suzuki polymerization. The incorporation of lysine into the main chain of the polymer linked to oligo(ethylene glycol) chains increased its hydrophilic character. The materials were thoroughly investigated using various analytical techniques including UV/vis absorption and emission, thermogravimetric analysis (TGA), gel permeation chromatography (GPC), size exclusion chromatography coupled with multiangle light scattering (SEC-MALS), water contact angle and cyclic voltammetry. Most of the synthetized polymers exerted good potential for biocompatibility as evidenced in tests with MS1 endothelial cells. This work presents an innovative strategy to synthesis of organic conjugated polymers bearing original biocompatibilising side chains for the development of interfaces between biotic and artificial milieu.