A Dual Antibody-modified Nanochannel Biosensor for Capture and Identification of Exosomes

Since exosomes carry the genetic information of their parental cells, there is an increasing need for new technologies capable of detecting exosomes with high sensitivity and accuracy. In this study, we propose a dual antibody-modified nanochannel biosensor for rapid, sensitive analysis of exosomes. Two antibodies (anti-CD63 and anti-EpCAM) were simultaneously immobilized on the surface of the porous anodic alumina (PAA) nanochannel to combine with proteins overexpressed on the exosomal membrane. As such, exosomes could be efficiently captured by the dual antibody-modified nanochannel. The captured exosomes effectively covered the nanochannel inlet, leading to remarkable block of ion flow through the channel. Based on this principle, the captured exosomes could be sensitively and accurately detected using a picoammeter. It was found that the use of two antibodies greatly increased the capture efficiency of exosomes compared to that of a single antibody. The results showed that exosomes down to 7.3 × 103 particles/mL were successfully detected by the nanochannel. Moreover, exosomes were successfully detected from plasma samples using a nanochannel biosensor modified with dual antibody, and the results showed significant differences in the exosomes content in plasma samples of cancer patients and healthy people, so as to initially distinguish cancer patients from healthy people.