Ultrasensitive and preprocessing-free electrochemical biosensing platform for the detection of cancer-derived exosomes based on spiky-shaped aptamer-magnetic beads

Cancer-derived exosomes, as liquid biopsy markers, have been shown to play an important role in the early screening, diagnosis, and prognosis of cancer. However, existing detection methods have shortcomings such as long-time consumption and low sensitivity. Herein, a sandwich-type electrochemical sensing platform based on Prussian blue/graphene oxide (GO/PB) and spiky Au@Fe3O4 nanoparticles was successfully designed and constructed to detect tumor-derived exosomes with high sensitivity and no preprocessing. In this strategy, nanospike structures were introduced on magnetic beads to form spiky Au@Fe3O4, which was used to enrich exosomes from serum, avoiding the extraction and purification processes of previous detections. The enrichment and signal amplification of spiky Au@Fe3O4 could also greatly improve the detection sensitivity of the sensing platform. Consequently, the concentration of exosomes could be directly quantified by monitoring the electroactive molecules of PB. Therefore, the limit of detection (LOD) of the proposed biosensor was 80 particles center dot mu L-1. Furthermore, this proposed biosensor could realize the high sensitivity analysis of exosomes and effectively save detection time, and provide an effective assistant diagnostic tool for the early diagnosis of cancer.

Automated summary

A novel electrochemical sensing platform was successfully designed in this study for high sensitivity detection of tumor-derived exosomes without the need for preprocessing steps, which has the potential to improve the accuracy of early cancer diagnosis.