A novel mediator-free biosensor based on hemoglobin immobilized in the Au nanoparticals and TiO2 nanosheets co-modified graphene nanocomposite

Au nanoparticals and TiO2 nanosheets co-modified reduced graphene oxide nanocomposite (Au-TiO2 NSs-rGO) have been synthesized through a simple synthetic route and employed to immobilize hemoglobin (Hb) in order to fabricate a mediator-free biosensor. The experimental results reveal that the Au-TiO2 NSs- rGO can be an immobilization support for Hb, affording good protein stability and bioactivity. Meanwhile, due to the special structure of Au-TiO2 NSs-rGO, the direct electron transfer of Hb was facilitated and the resulting biosensor displays good performance for the detection of H2O2, with both a wide linear range of 7.5-250 mu M and a low detection limit of 3 mu M, as well as fast response and good stability. (C) 2020 Elsevier B.V. All rights reserved.