Abstract
Chemical vapor deposition (CVD) graphene film is a promising electrode-modifying material for fabricating high-performance glucose sensor due to its high electrical conductivity and two-dimensional structure over large area. However, the use of typical metal-based CVD graphene suffers from the residue contamination of polymer transfer-support and heavy metal ions. In this work, we directly grew few-layer graphene on the SiO2/Si substrate without transfer process and then fabricated graphene-based glucose sensors by sequentially immobilizing glucose oxidase and depositing Nafion layer on its surface that was functionalized by oxygen-plasma treatment. Our transfer- and metal-free process shows distinct advantage over the common metal-CVD method in improving the electrochemical performance by eliminating the contamination of transfer-residue. Thus-obtained glucose sensor shows a high sensitivity (16.16 μA mM−1 cm-2) with a detection limit of 124.19 μM. This method is simple and promising for the development of highly sensitive glucose sensors.