Electrochemical aptasensor for exosomal proteins profiling based on DNA nanotetrahedron coupled with enzymatic signal amplification

Exosomes are extracellular nanovesicles for transferring and delivering membrane and cytosolic molecules between cells. Detection and profiling of exosomal proteins can provide direct information on disease progression, which is important to the early diagnosis and monitoring of diseases. Herein, a well-designed electrochemical aptasensor was fabricated for the profiling of cancerous exosomal proteins based on DNA nanotetrahedron (NTH) coupled with Au nanoparticles (NPs) and enzymatic signal amplification. In this assay, the aptamer modified DNA NTHs were used as the recognition and capture unit, Au NPs-DNA conjugates coupled with horseradish peroxidase were used to realize signal amplification. This aptasensor achieves a detection limit down to 1.66 × 104 particles/mL for HepG2 liver cancer exosomes. In addition, the analysis of plasma-derived exosomes in HepG2 liver cancer bearing mice at different cancer stages was also achieved. More importantly, the aptasensor can be used to profile four kinds of exosomal proteins by using the corresponding aptamer. The proposed electrochemical aptasensor may be served as a potential platform for exosome detection and exosomal proteins profiling.