Immobilization coupling with aptamer assisted dual cycle amplification for sensitive exosome isolation and analysis

Abstract Purpose Precise identification of exosomes is crucial for improving disease diagnosis and treatments. However, accurate isolation and simultaneously quantification of exosomes remain a huge challenge. We have introduced a new technique that combines immobilization with aptamer-assisted dual cycle amplification to isolate and analyze exosomes with high sensitivity. Methods In this method, the CD9 protein antibody is attached to the plate's surface for the initial identification of exosomes, while an aptamer probe is used to detect the exosomal surface protein CD63. We have created an exosome-surface method that combines target recognition initiated signal recycling and rolling circle amplification (RCA) for signal amplification. This approach allows for the “AND” logic analysis of dual biomarkers, enabling both exosome quantification and tracing. Results The proposed approach has a broad detection range and a low limit of detection. Moreover, the established method showed good stability in detecting exosomes with a low coefficient of variation. Conclusion Our method can effectively isolate certain exosomes and accurately identify them, making it suitable for many uses in biological science, biomedical engineering, and personalized medicine.