Leveraging the “Grafting-Through” Approach for the Synthesis of “Rod-graft-Coil” Conducting Polymers Suitable as Biomedical Materials: Polythiophene Grafted with Oligo-(D,L-Lactide) ^†

The development and industrial application of synthetic polymers have had a great impact on society as these materials are used virtually everywhere. Synthetic polymers in particular are widely used as biomaterials, but in recent decades, advanced bioapplications, which require subtle responses, have needed numerous innovative, increasingly diverse materials that promise high added value. In this context, the polymer architecture—one physical attribute that is central to polymer science—can be used to tune the properties of next-generation functional biomaterials. Conjugated electroconducting polymers (CPs), designed for electronic applications, are also endowed with a multitude of well-suited properties to function as intelligent, specialized biomaterials.

In this paper, it is demonstrated that by combining polythiophene—a typical CP—with the bioresourced, biocompatible, and biodegradable oligo-(D,L-lactide), in a “rod-g-coil”-type architecture, a multifunctional material can be obtained by polymerizing a thiophene-containing macromonomer. This study focuses on the investigation of the resultant copolymer enzymatic bioerosion (evaluated using different methods—FT-IR, GPC, and AFM) and the manipulation of films’ surface morphology and properties by changing the specificity of the solvents from which they are deposited on supports of different rigidity (glass or PLA sheets) or the dispersion concentrations or via copolymer doping with LiClO₄.

In addition, the undoped and doped films’ surface interaction with the BSA protein was investigated by the Quartz Crystal Microbalance with Dissipation (QCM-D) technique, which revealed that the protein-binding process might be “switched on–off” by the doping state of the conjugated oligomer. Moreover, the good biocompatibility and non-cytotoxic effect of the copolymer over normal human gingival fibroblasts (NHGFs) were shown, highlighting its potential functionality as a suitable biointerfacing material for different related bioapplications.