An amphiphilic, heterografted polythiophene copolymer containing biocompatible/biodegradable side chains for use as an (electro)active surface in biomedical applications

Abstract

Given that the copolymers of complex topology and composition are at the forefront of multifunctional materials research, this work reports aboutan amphiphilic random, heterografted copolymer of (A-g-B)m-ran-(A-g-C)ntype, which was designed to work as an efficient and biocompatible electronic interface. The copolymer (henceforth denoted as PTh-g-(PEG-r-PCL) for simplification) was synthesized in hierarchical fashion, having ¿-conjugated polythiophene (PTh) as main chain and polarunits, polyethylene glycol (PEG) and oligo-¿-caprolactone as side chains. Theproperties of the newcopolymer,in solution and in solid state,were evaluated. The applied investigations showed that, due to its amphiphilic character and incompatibility of the side chains, PTh-g-(PEG-r-PCL) experiences microphase separation in solutionand film states. By electronicmicroscopy techniques were evidenced two types of supramolecular structures: (a) porous spherical particles and (b) rod-like structures. When deposited on carbon electrodes,the copolymerpresented a good electroactivity and electrostability.Copolymer's biocompatibility studies, performed by using Cos-1 and Vero cell lines,demonstrated an excellent adhesion when comparing with bare steel electrode while a slight decrease of proliferation was registered, more pronounced for Vero cells, in spite of cells normal growth and morphology. Thanks to its excellent capability for electrochemically interfacing with aqueous electrolytes, the voltammetric oxidation ofNADH coenzyme at PTh-g-(PEG-r-PCL) film-modified carbon electrode revealed that it can be used as selective biosensor of this biomolecule, as well.