Physical and Electrochemical Properties of PEDOT:PSS as a Tool for Controlling Cell Growth

Conducting polymers are promising materials for tissue engineering applications, since they can both provide a biocompatible scaffold for physical support of living cells, and transmit electrical and mechanical stimuli thanks to their electrical conductivity and reversible doping. In this work, thin films of one of the most promising materials for bioelectronics applications, poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS), are prepared using two different techniques, spin coating and electrochemical polymerization, and their oxidation state is subsequently changed electrochemically with the application of an external bias. The electrochemical properties of these different types of PEDOT:PSS are studied through cyclic voltammetry and spectrophotometry to assess the effectiveness of the oxidation process and its stability over time. Their surface physical properties and their dependence on the redox state of PEDOT:PSS are investigated using atomic force microscopy (AFM), water contact angle goniometry and sheet resistance measurements. Finally, human glioblastoma multiforme cells (T98G) and primary human dermal fibroblasts (hDF) are cultured on PEDOT:PSS films with different oxidation states, finding that the effect of the substrate on the cell growth rate is strongly cell-dependent: T98G growth is enhanced by the reduced samples, while hDF growth is more effective only on the oxidized substrates that show a strong chemical interaction with the cell culture medium.