Detection of exosomes via an electrochemical biosensor based on C60-Au-Tb composite

As a new serum biomarker, the sensitive detection of exosomes is significant for the early diagnosis of diseases. In this paper, a novel electrochemical biosensor for the sensitive detection of exosomes was constructed utilizing a novel C 60 hybrid as a tracer. Firstly, the epidermal growth factor receptor (EGFR) antibody was immobilized on the electrode surface via Au-NH 2 bonding with Nafion AuNPs substrate. After specific capture of exosomes, C 60 -Au-Tb was grafted onto the surface of exosomes through “carboxyl-Zr 4+ -phosphate” chemistry, causing a change in the current signal. Under the optimal conditions, there was a linear relationship between the SWV signal and the logarithm of exosomes concentration from 5 × 10 4 exosomes/mL to 5 × 10 9 exosomes/mL, and the detection limit was 2.67 × 10 4 exosomes/mL. In addition, the biosensor had the advantages of high specificity, strong anti-interference ability, good repeatability, and stability. In conclusion, this method had great potential in diagnosing early cancers associated with exosomes.