▎ 摘　　要

Titania nanoparticles modified reduced graphene oxide (TiO(2)NPs-rGO) nanocomposite with a double-layered structure has been synthesized and used to immobilize hemoglobin (Hb) in order to fabricate a mediator-free biosensor. The morphology and structure of the TiO(2)NPs-rGO nanocomposite were characterized by scanning electron microscopy, X-ray diffraction and Raman spectra. Spectroscopic and electrochemical researches revealed that the TiO(2)NPs-rGO nanocomposite could be an excellent immobilization matrix with biocompatibility for redox protein, affording good protein bioactivity and stability. Due to the special double-layered structure of TiO(2)NPs-rGO, the direct electron transfer of Hb is facilitated and the prepared biosensor exhibited a good performance for the detection of H2O2, with a extremely low detection limit of 10 nM, as well as a wide linear range of 0.1-140 mu M. The TiO(2)NPs-rGO nanocomposite with the double-layered structure could be a promising matrix for the fabrication of mediator-free biosensors, and may find wide potential applications in biomedical detection and environmental analysis. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.