A promising electrochemical biosensing platform based on graphitized ordered mesoporous carbon

Three dimensional ordered graphitized mesoporous carbon GMC-6 (pore diameter similar to 6 nm) and GMC-13 (pore diameter similar to 13 nm), prepared by a nickel-catalyzed template-assisted method, were explored systematically for the construction of enzyme-based electrochemical biosensors. Comparative studies revealed that GMC-6 offer significant advantages over GMC-13 and graphitized multiwalled carbon nanotubes (CNTs) in facilitating the direct electron transfer of entrapped hemoglobin and improving the performance of fabricated biosensors. The possible factors that affect the biosensing performance of these carbon materials were evaluated comprehensively and comparatively based on the characterization of their physical parameters. The biosensor based on GMC-6 displayed excellent analytical performance over a wide linear range along with good stability and selectivity for the detection of hydrogen peroxide. The "entrapment'' immobilization mode and "interspace confinement effect'' (by restraining the unfolding or conformational change of enzyme molecules from inactivation) provided by GMC can result in pore-size-dependent enzymatic stability and bioactivity, which might be a crucial factor for the superior biosensing performance of GMC-6 to that of CNTs and GMC-13. Graphitized ordered mesoporous carbons with good pore size matching for enzymes proved to be a promising electrochemical biosensing platform.