Versatile biomimetic conductive polypyrrole films doped with hyaluronic acid of different molecular weights

Abstract

Electrically conductive polypyrrole (PPy) is an intriguing biomaterial capable of efficient electrical interactions with biological systems. Especially, biomimetic PPy-based biomaterials incorporating biomolecules, such as hyaluronic acid (HA), can impart the characteristic biological interactions with living cells/tissues to the conductive biomaterials. Here we report the effects of the molecular weight (MW) of HA on PPy-based biomaterials. We utilized HA of a wide range of MW (35 x 10(3) Da-3 x 10(6) Da) as dopants during the electrochemical production of PPy/HA films and their characterization of materials and cellular interactions. With increases in the MWs of HA dopants, PPy/HA exhibited more hydrophilic, higher electrochemical activity and lower impedance. In vitro studies revealed that PPy films doped with low MW HA were supportive to cell adhesion and growth, while PPy films doped with high MW HA were resistant to cell attachment. Subcutaneous implantation of the PPy/HA films for 4 weeks revealed that all the PPy/HA films were tissue compatible. We successfully demonstrate the importance of HA dopant MWs in modulating the chemical and electrical properties of the materials and cellular responses to the materials. Such materials have potential for various biomedical applications, including as tissue engineering scaffolds and as electrodes for neural recording and neuromodulation. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.