An aqueous media based approach for the preparation of a biosensor platform composed of graphene oxide and Pt-black

The combination of Pt nanoparticles and graphene was more effective in enhancing biosensing than either nanomaterial alone according to previous reports. Based on the structural similarities between water soluble graphene oxide (GrOx) and graphene, we report the fabrication of an aqueous media based GrOx/Pt-black nanocomposite for biosensing enhancement. In this approach GrOx acted as a nanoscale molecular template for the electrodeposition of Pt-black, an amorphously nanopatterned isoform of platinum metal. Scanning electron microscopy (SEM) images and energy-dispersive X-ray spectroscopy (EDS) showed that Pt-black was growing along GrOx. The effective surface area and electrocatalytic activity towards H2O2 oxidation of GrOx/Pt-black microelectrodes were significantly higher than for Pt-black microelectrodes. When used to prepare a bio-nanocomposite based on protein functionalization with the enzyme glucose oxidase (GOx), the GrOx/Pt-black microbiosensors exhibited improved sensitivity over the Pt-black microbiosensors. This suggested that the GrOx/Pt-black nanocomposite facilitated an increase in electron transfer, and/or minimized mass transport limitations as compared to Pt-black used alone. Glucose microbiosensors based on GrOx/Pt-black exhibited high sensitivity (465.9±48.0 nA/mM), a low detection limit of 1 μM, a linear response range of 1 μM–2 mM, and response time of ∼4 s. Additionally the sensor was stable and highly selective over potential interferents.

► We developed GrOx/Pt-black nanocomposite as a platform for biosensors.
► GrOx acted as a nanoscale molecular template for the electrodeposition of Pt-black.
► Effective surface area and electrocatalytic activity were significantly improved.
► GrOx/Pt-black glucose microbiosensors exhibited an LOD of 1 μM.