Aptamer decorated magnetic graphene oxide nanoparticles for effective capture of exosomes

Exosomes secreted by most cells possese many biological functions and arouse great interest in biomedical research. However, the effective and convenient methods for the capture of exosomes from clinical samples or cultured cells is still scarce. In this work, we developed novel magnetic graphene oxide nanoparticles (MGONs) for the efficient capture of exosomes, in which Fe3O4@SiO2 magnetic nanoparticles (NPs) were decorated with GO through dopamine. CD63 aptamers were attached to the surface of MGONs, which could recognize and bound to CD63 on the exosome membrane. The number of exosomes adsorbed onto the MGONs surface was 1.5 times that attached to the Fe3O4@SiO2 surface. The capture rate of exosomes reached as high as 89.4% within 15 min at room temperature. Moreover, exosomes can be effectively enriched and isolated under external magnetic field and the capture process did not affect their morphological structure and biological functions. Through hybridizing with a FAM-labelled single-stranded DNA probe, the concentration of captured exosomes could also be recorded by measuring the fluorescence intensity, and the limit of detection of this system reached 2.4 x 10(7) particles/ml. These aptamer-decorated MGONs also showed potential in high-effieient capture of exosomes using cancer patients samples, which demonstrated that the resultant MGONs had significant practical values in early disease diagnosis and the related clinical applications.