A novel surface plasmon resonance biosensor based on graphene oxide decorated with gold nanorod–antibody conjugates for determination of transferrin

A surface plasmon resonance (SPR) biosensor based on graphene oxide (GO) decorated with gold nanorod (AuNR)–antibody conjugates was developed. Compared with traditional SPR biosensor, GO sheets were assembled on the amino-modified Au film via electrostatic interaction, and then AuNR–antibody conjugates were immobilized via carbodiimide-assisted amidation reaction. The abundant oxygen-containing functional groups, large specific surface area and friendly biocompatibility of GO sheets are beneficial to the immobilization of AuNR–antibody conjugates. Meanwhile, AuNRs are anchored to the GO surface through antibody and function as enhancers for the transferrin determination, which greatly enhance the sensitivity of the detection. As a result, the present biosensor shows a satisfactory response to transferrin in the concentration range of 0.0375–40.00 μg mL−1. The lowest concentration of transferrin that can be determined by this method is about 32-fold lower than that obtained with the sensor based on Au film. This design affords a facile method of controlling the assembly of AuNRs on the GO sheets and can be easily extended to other protein detection by preparing corresponding AuNR–antibody conjugates.

► A SPR biosensor based on GO decorated with AuNR–antibody conjugates was developed. ► GO was assembled on amine-modified Au film for immobilization of conjugates. ► AuNRs were anchored to the GO surface through antibody and acted as enhancers. ► The proposed method permitted 32 times enhancement in sensitivity.