Direct Electrochemistry of Hemoglobin on Vertically Aligned Carbon Hybrid TiO2 Nanotubes and Its Highly Sensitive Biosensor Performance

Abstract

AbstractThe present work is focused on developing a novel biomaterial platform to achieve enhanced direct electron transfer (DET) of hemoprotein and higher biosensor performance on vertically aligned carbon hybrid TiO2 nanotubes (C‐TiO2 NTs). Using a simple surfactant‐assisted method, controllable hybridization of TiO2 NTs with conductive amorphous carbon species is realized. The obtained C‐TiO2 NTs is ingeniously chosen to serve as an ideal "vessel" for protein immobilization and biosensor applications. Results show that the appropriate hybridization of C into TiO2 NTs leads to a much better conductivity of TiO2 NTs without destroying their preponderant tubular structures or damaging their excellent biocompatibility and hydrophilicity. When used in loading proteins, the C‐TiO2 NTs can be used as a super vessel for rapid and substantive immobilization of hemoglobin (Hb), with a large surface electroactive Hb coverage (Γ∗︁) of 3.3×10−9 mol·cm−2. Enhanced DET of Hb is commendably observed on the constructed Hb/C‐TiO2 NTs biosensor with a couple of well‐defined redox peaks in a fast electron transfer process. The biosensor further exhibits fast response, high sensitivity and stability for the amperometric biosensing of H2O2 with the detection limit as low as 3.1×10−8 mol/L.