Comparison of protein immobilisation methods onto oxidised and native carbon nanofibres for optimum biosensor development

The properties of native and oxidised graphene layered carbon nanofibres are compared, and their utilisation in enzyme biosensor systems using different immobilisation methods are evaluated. The efficient oxidation of carbon nanofibres with concentrated H2SO4/HNO3 is confirmed by Raman spectroscopy while the introduction of carboxylic acid groups on the surface of the fibres by titration studies. The oxidised fibres show enhanced oxidation efficiency to hydrogen peroxide, while at the same time they exhibit a more efficient and selective interaction with enzymes. The analytical characteristics of biosensor systems based on the adsorption or covalent immobilisation of the enzyme glucose oxidase on carbon nanofibres are compared. The study reveals that carbon nanofibres are excellent substrates for enzyme immobilisation allowing the development of highly stable biosensor systems.