Sonochemical synthesis of magnetic Fe3O4/graphene nanocomposites for label-free electrochemical biosensors

This work reports on sonochemical synthesis of carbon paste electrodes modified with magnetic Fe3O4/graphene nanocomposites as a label-free electrochemical biosensor for prostate-specific antigen detection. To optimize their properties as a biosensor, the compositions of both Fe3O4 and graphene were varied. The as-synthesized nanocomposites possess good crystallinity and purity with Fe3O4 nanoparticles attached onto the graphene surface. From voltammetry measurements, the modified electrode shows an increase of reduction peaks as compared to the bare electrode which promisingly led to a more sensitive biosensing detection. The modified electrode was then used for biomarker detection through the immobilization of the anti-prostate-specific antigen (anti-PSA) antibodies onto it. The results showed that the electrochemical signal increased linearly against PSA concentration, from 1 to 150 ng/mL, with a detection limit of 0.38 ng/mL. Having all these characteristics, the Fe3O4/graphene nanocomposites offer a promising path towards the development of highly sensitive prostate biosensors, especially for cancer detection.