PANI-modified Ti-doped CVD diamond as promising conductive platform to mimic bioelectricity functions

This study is devoted to synthesizing and modifying conductive Ti-doped diamond (TiD) biosubstrates with polyaniline (PANI) to provide a soft interface with high ionic conductivity and charge storage capacity for developing advanced scaffolds and implantable electrode materials. The diamond supports are prepared by an ad-hoc chemical vapor deposition methodology allowing for the synthesis and contemporary doping of diamond lattice. An optimized potentiostatic electropolymerization method assures the growth of a homogenous PANI coating on a diamond surface. Scanning electron microscopy, atomic force microscopy, Raman, and reflectance infrared spectroscopy characterizations guarantee the production of nanostructured diamond layers with high surface electrical conductivity and good phase quality as well as of a rough polymer film in the conductive emeraldine form. Cyclic voltammetry and electrochemical impedance spectroscopy measurements point out a quasi-reversible electron transfer among polymer chains ruled by the bulky dodecyl sulfate anion chosen as polymer dopant. This induces a cation exchange with the solution upon backbone redox reactions. The capability of the PANI-TiD system to transduce ionic current into electronic current and vice versa via redox reaction with the surroundings can be reliably exploited to reproduce electrical stimulation processes through which to mimic the original bioelectricity functions of the human body for advanced biomedical applications.