Ti3C2 MXene mediated Prussian blue in situ hybridization and electrochemical signal amplification for the detection of exosomes

Exosomes carrying abundant information have aroused great interest as effective biomarkers in liquid biopsy and are therefore ideal candidates for the early diagnosis of cancer and treatment monitoring. Herein, we developed a sensitive electrochemical biosensor using in situ generation of Fe-4[Fe(CN)(6)](3) (Prussian Blue) on the surface of Ti3C2 MXene (two-dimensional transition-metal carbides) as hybrid nanoprobes (PB-MXene) for the detection of exosomes and their surface protein. A CD63 aptamer-modified poly(amidoamine) (PAMAM)-Au NP electrode interface was fabricated that can specifically bind with CD63 protein on the exosomes derived from OVCAR cells. In addition, the CD63-modified Ti3C2 MXene was used as a nanocarrier to accommodate numerous aptamers and was adsorbed on the exosomes. The Ti3C2 MXene can realize the in situ generation and high-efficiency loading of PB and further amplify the electrochemical signal at a low potential, thus avoiding the interference of the electrochemical active species. The dual amplification effect enables highly selective and sensitive electrochemical detection of exosomes. The limit of detection (LOD) was 229 particles mu L-1 with a linear range from 5x 10(2) particles mu L-1 to 5 x 10(5) particles mu L-1. An electrochemical biosensor can detect exosomes secreted by various cancer cells such as HeLa, OVCAR and BT474, and shows a high specificity even in serum samples, thus demonstrating its great potential in the application of clinical diagnostics. This proposed electrochemical biosensor provides a facile and efficient tool for the early diagnosis of cancers.

Automated summary

The study developed a sensitive electrochemical biosensor for the detection of exosomes and their surface proteins, showing high selectivity and sensitivity. Through dual amplification effect, the electrochemical detection of exosomes was realized, demonstrating great potential for clinical diagnostics as an important tool.