Electrochemical and Biological Evaluation of Patterned TiO₂@TiC-Nanowires for Bio-Interface Electrode

The next generation of bioelectronic interfaces demands materials that integrate biocompatibility, robust electrochemical performance and architectural functionality. Here, we introduce a low-temperature fabrication approach for patterned titanium oxide-coated titanium carbide nanowires (P-TiO₂@TiC-NWs), utilizing room-temperature sputter deposition, avoiding high-temperature carbide synthesis. TiO₂@TiC-NWs combine the high-aspect-ratio architecture of TiO₂-NWs with the electrochemical performance of TiC, providing a tunable platform for bioelectronic interface design. By tuning sputtering pressure and duration, distinct TiC shell morphologies and compositions were engineered. Low-pressure deposition produced a uniform conductive shell, favoring faster charge dynamics and a more ideal capacitive response, while high-pressure deposition generated a carbon-rich, cauliflower-like morphology that increased electrochemically accessible surface area. TiO₂@TiC-NWs reached areal capacitances of 1.01 and 2.25 mF cm^{- 2} for 20 min deposition at 3 and 10 mTorr, respectively, compared with 117 µF cm^{- 2} and 1.35 mF cm^{- 2} for the corresponding planar TiC films. After 3000 cycles in physiological buffer, the 10 mTorr, 20 min sputtered sample retained 86% capacitance, while the 3 mTorr retained 75%. C2C12 myotubes cultured on P-TiO₂@TiC-NW substrates exhibited preferential adhesion and directional alignment along the nanowire stripe axis, demonstrating the capacity of nanoscale surface topography to instruct anisotropic cell organization. Together, these features highlight P-TiO₂@TiC-NWs as promising bioelectronic interfaces.