Monitoring the optimized 30 s treated pDPP3T films using EIS in the presence of cells validated the use of UVO surface modification to sustain cellular interaction whilst under bias. As cell density on the surface increased over 120 h, the impedance ratio (relative to the non-seeded film) simultaneously increased. The use of UVO treatment to modulate cellular adhesion offers a valuable opportunity to deepen our understanding of the interplay between ionic diffusion and semiconductor electroactivity in the presence of cell culture media. By optimizing the exposure time for a given material, we believe this technique could be applied to a library of existing conjugated polymers, enabling in-operando studies of OSCs in biological environments.