Cytochrome c is accumulated into a film of TiO 2 nanoparticles and phytate by adsorption from an aqueous solution into the mesoporous structure. Stable voltammetric responses and high concentrations of redox protein within the TiO 2 phytate layer can be achieved. Two types of electrode systems are reported with (i) the modified TiO 2 phytate film between electrode and aqueous solution phase and (ii) the modified TiO 2 phytate film buried under a porous gold electrode (‘porotrode’).The electrical conductivity of TiO 2 phytate films is measured and compared in the dry and in the wet state. Although in the dry state essentially insulating, the TiO 2 phytate film turns into an electrical conductor (with approximately 4 Ω cm specific resistivity assuming ohmic behaviour) when immersed in aqueous 0.1 M phosphate buffer solution at pH 7. The redox protein cytochrome c is therefore directly connected to the electrode via diffusion and migration of electrons in the three dimensional mesoporous TiO 2 phytate host structure. Electron transfer from cytochrome c to TiO 2 is proposed to be the rate-determining step for this conduction mechanism.