Tyrosinase immobilization on ZnO nanorods for phenol detection.

Directly using zinc powders as source material, ZnO nanorods were fabricated on gold wire by hydrothermal reaction without any other surfacant and stabilizing agent. The gold wire was skillfully treated to improve the nucleation for growth of ZnO nanostructures and to further improve the performance of the biosensor, which was construct by immobilizing tyrosinase (Tyr) on the ZnO nanorods for phenol detection. Electrochemical measurement, Fourier transform infrared and scanning electron microscopic analyses demonstrated that the Tyr was stably adsorbed on the ZnO nanorods surface with bioactivity for phenol oxidization. The biosensor reached 95% of steady-state current within 5s, and the sensitivity was as high as 103.08 microA/mM at C(phenol) > 20 microM and was 40.76 microA/mM at C(phenol) < 20 microM. The detection limit of 0.623 microM was obtained at a signal/noise ratio of 3.