Spectroelectrochemistry and photochemistry of haem proteins immobilised on nanoporous titanium dioxide films

摘要

We have investigated the use of optically transparent, nanoporous TiO_2 films as substrates for protein immobilisation. We demonstrate that the redox state of two haem proteins, cytochrome c and haemoglobin, immobilised upon such films may be readily monitored by optical spectroscopy. We show that for both immobilised cytochrome c and haemoglobin, the application of a negative potential to the TiO_2 results in the direct electrochemical reduction of protein without the addition of any electron transfer promoters or mediators. We moreover find that bandgap excitation of the TiO_2 film at 337 nm results in the photoreduction of cytochrome c, which we attribute to photoinduced electron transfer from the TiO_2 to the immobilised cytochrome.