Magnetic reversible microfluidic chip and MOF based electrochemical sensor for efficient isolation and detection of tumor derived extracellular vesicles

The efficient isolation and detection of tumor-derived extracellular vesicles (T-EVs) are vital for the early diagnosis of cancer. Herein, a magnetic reversible aptamer microfluidic chip (MRA-Chip) combined with a MOF-based electrochemical sensor was developed for the efficient isolation and detection of T-EVs. First, the aptamer-functionalized magnetic beads (MBs) were fixed in the herringbone chip to construct a magnetic reversible affinity interface, which improves the capture efficiency of T-EVs by 115 % compared with traditional affinity interfaces due to the enhanced interface collision induced by the vortex mixing effect of the herringbone structure and the high density of MBs distributed on the capture interface. Subsequently, magnet withdrawing induced T-EVs release with high efficiency. The Zr metal-organic framework (MOF) loaded with methylene blue binds to the EVs through the interaction of the Zr–O–P bond. Then, the EVs were quantitatively analyzed based on the electrochemical signal of Zr MOF@methylene blue, and the limit of detection is as low as 6.5 particles/μL. At last, this method has been successfully applied to the detection of clinical samples and can effectively distinguish between cancer patients and healthy individuals with 100 % accuracy. This method opens a new avenue for isolation and detection of T-EVs, and has great application prospects in the early diagnosis and treatment of cancer.