An electrochemical biosensor for breast cancer diagnosis based on RCA-enhanced metal-organic framework self-assembly

Circular human epidermal receptor 2 RNA (circ-HER2) has been revealed to be overexpressed in HER2-positive breast cancer, which demonstrates the potential to serve as a potential prognostic biomarker for guiding the treatment of circ-HER2-positive breast cancer patients. But convenient, efficient and low-cost detection of circ-HER2 is rarely explored. Herein, we have fabricated an electrochemical biosensor for the accurate detection of circ-HER2 in breast cancer based on isothermal amplification-enhanced self-assembly of metal-organic frameworks (MOFs). Specifically, to obtain the sensitive detection of circ-HER2, Rolling circle amplification (RCA) initiated by circ-HER2 is introduced on the electrode surface to enhance the self-assembly of MOF PCN-222(Fe), which is preloaded with electrical signal molecules. Ultimately, circ-HER2 can be sensitively quantified with a limit of detection (LOD) of 0.1 fM, and the levels of serum circ-HER2 are verified to be applied for distinguishing HER2-positive breast cancer and TNBC in this work. Therefore, this electrochemical biosensor for circ-HER2 detection has great potential for breast cancer typing and HER2-targeted therapy monitoring.