Gold nanoparticles engineered nanoporous membrane with sandwich structure for sensitive electrochemical quantification of exosome

Abstract

Exosome has been identified as an excellent potential biomarker for tumor diagnosis. Herein, electrochemical aptasensor for exosome detection was developed via a sandwich-structured nanoporous membrane which was fabricated by assembling multilayer gold nanoparticles (mulAu) and monolayer gold nanoparticles (monAu) on the opposite side of a nanoporous alumina membrane (NAM). The tumor-derived exosomes can be efficiently captured by the specific probes confined on the monAu side of the membrane. And the mulAu side that was tightly attached with a Si wafer allowed the electrochemical exosome detection by monitoring the amperometric signal of ferricyanide that transported across the nanochannel array of the membrane. After optimization of pore diameter of the NAM, base sequence of the capture probe and incubation temperature as well as incubation time for exosomes, this NAM-based electrochemical aptasensor was applied to the quantification of the MCF-7 cells-derived exosomes. The steady state current displayed linearity relationship with the concentration of the exosomes in a broad range of 103 to 107 particles μL−1, along with a detection limit of 2.8 × 102 particles μL−1. By changing capture probe, this sandwich-structured membrane could be further extended to label-free, sensitive and rapid quantification of other tumor-associated vesicles.