A novel GSH-capping MXene QD-based ECL biosensor for the detection of miRNA221 in triple-negative breast cancer tumor

In this work, we have constructed a novel electrochemiluminescence (ECL) biosensor for the detection of miRNA221 based on glutathione-capped MXene-derived quantum dots (GSH-MQDs) and magnetic biomimic vesicles. Glutathione is used as precursor in the synthesis of MXene-derived QDs, which effectively improves the oxidation resistance of MXene. In the sensing system, GSH-MQDs still possess the advantages of MXene, including the excellent electrical conductivity and good electrochemical activity. The combination of the metal atoms on the MXene and the sulfhydryl group of GSH further reduce the defects in nanostructures of MXene-derived QDs. As a result, the stability and the luminescent properties of GSH-MQDs as ECL emitter have been significantly improved. Furthermore, magnetic biomimic vesicles are prepared as sensing platform to improve the feasibility and sensitivity for the miRNA221 detection. Moreover, a sensing strategy for miRNA221 detection is designed based on the cyclic amplification with T7 exonuclease. The biosensor is used to detect miRNA221 in the triple-negative breast cancer tumor tissues. The satisfactory results have indicated that this sensing strategy on the basis of GSH-MQD and magnetic biomimic vesicles possesses great potential for clinical analysis.