Synthesis and characterization of graphene nanosheets attached to spiky MnO2 nanospheres and its application in ultrasensitive immunoassay

An easy approach was reported to synthesize graphene nanosheets attached to spiky MnO2 nanospheres (GS/MnO2) which showed good catalytic activity, electrical conductivity, solubility and processability. The synthetic method was efficient, green and controllable with graphene oxide reduced and MnO2 nanospheres formed in one step. The obtained material was further characterized and used as carriers for signal antibodies (Ab2) to produce an electrochemiluminescent immunosensor based on prepared nanoporous gold-graphene nanosheets platform. With a sandwich-type immunoassay format, the amount of GS/MnO2 labeled Ab2 went up with the increased concentration of antigens in the sample. Such immunosensor exhibited high sensitivity in the detection of carcinoembryonic antigen in serum samples.