Metal decorated graphene nanosheets as immobilization matrix for amperometric glucose biosensor

Amperometric glucose biosensors have been fabricated by using platinum–gold (Pt–Au) and gold (Au) nanoparticle spacers decorated graphene nanosheets. Functionalized graphene (f-G) sheets have been prepared by exfoliation of graphitic oxide and it has been decorated with crystalline (Pt–Au)/Au metal nanoparticles using a simple chemical reduction method. The immobilization of glucose oxidase (GOD) over Nafion-solubilized metal nanoparticles dispersed graphene f-G-(Pt–Au) and f-G-(Au) electrode has been achieved by physical adsorption. The resultant bioelectrode retains its biocatalytic activity and offers fast and sensitive glucose quantification. The performances of the biosensor have been investigated by electrochemical method at an optimum potential of +0.8 V in pH 7.0 phosphate buffer. The fabricated f-G-(Au) based glucose biosensor exhibits best sensing performance with a linear response up to 30 mM with an excellent detection limit of 1 μM. The elimination of restacking of f-G by using (Pt–Au) and (Au) nanoparticle spacers resulted in the increase in the surface area and glucose sensing performance.