Sensitive electrochemical detection of A549 exosomes based on DNA/ferrocene-modified single-walled carbon nanotube complex

Exosome is an emerging tumor marker, whose concentration level can reflect the occurrence and development of tumors. The development of rapid and sensitive exosome detection platform is of great significance for early warning of cancer occurrence. Here, a strategy for electrochemical detection of A549-cell-derived exosomes was established based on DNA/ferrocene-modified single-walled carbon nanotube complex (DNA/SWCNT-Fc). DNA/ SWCNT-Fc complexes function as a signal amplification platform to promote electron transfer between elec-trochemical signal molecules and electrodes, thereby improving sensitivity. At the same time, the exosomes can be attached to DNA/SWCNT-Fc nanocomposites via the established POq-Ti4+-POq method. Moreover, the application of EGFR antibody, which can specifically capture A549 exosomes, could improve the accuracy of this sensing system. Under optimal experimental conditions, the biosensor showed good linear relationship between the peak current and the logarithm of exosomes concentration from 4.66 x 106 to 9.32 x 109 exosomes/mL with a detection limit of 9.38 x 104 exosomes/mL. Furthermore, this strategy provides high selectivity for exosomes of different cancer cells, which can be applied to the detection of exosomes in serum samples. Thus, owing to its advantages of high sensitivity and good selectivity, this method provides a diversified platform for exosomes identification and has great potential in early diagnosis and biomedical applications.

Automated summary

An electrochemical detection strategy for exosomes was established based on DNA/ferrocene-modified single-walled carbon nanotube complex. The method showed high sensitivity and good selectivity, providing a potential platform for early diagnosis and biomedical applications.