Nano-structured carbon materials for improved biosensing applications

A set of oxidized graphite samples have been newly synthesized using different protocols. Atomic force microscopy, Raman spectroscopy, thermal gravimetric analysis and Brunauer-Emmett-Teller analysis revealed the changes in structure and functionalities of obtained graphite oxidation products (GOPs) compared to pristine graphite. The substances have been tested as electrode materials applicable for bioelectrocatalytic systems using pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH). The application of GOPs allowed achieving the direct electron transfer (DET) from active site of PQQ-GDH to the electrode surface. Needless of additional electron transfer (ET) mediating compounds highly improved features of the biosensors. The efficiency of the biosensors has been evaluated for all types of biosensors varied from 32 mu A/cm(2) to 64 mu A/cm(2) using as electrode materials GOP1 and thermally reduced graphite oxide (TRGO), respectively. TRGO containing function groups (according TGA, similar to 6% of the weight loss) and smallest particles (average diameter was similar to 11 nm and the average height was similar to 0.5 nm) exhibited the higher efficiency for ET acceleration in the biosensor acting on principle of DET. (C) 2014 Elsevier B.V. All rights reserved.