Quantification of EGFR and EGFR-overexpressed cancer cells based on carbon dots@bimetallic CuCo Prussian blue analogue

A new bimetallic CuCo Prussian blue analogue (CuCo PBA) loaded with carbon dots (CDs) was prepared (represented by CD@CuCoPBA) and developed as a scaffold for anchoring the epidermal growth factor receptor (EGFR) aptamer to detect EGFR and living EGFR-overexpressed cancer cells. The basic characterizations revealed CuCo PBA exhibited nanocube shape and still remained its nanostructure and physical/chemical properties after coupling with large amounts of CDs. As compared with the pristine CuCo PBA, the CD@CuCoPBA displayed good electrochemical activity, strong binding interaction toward aptamer, and high stability of aptamer-EGFR G-quadruplex in aqueous solution. As such, the results of electrochemical impedance spectroscopy measurements indicated that the CD@CuCoPBA-based aptasensor displayed an ultra-low detection limit toward EGFR (0.42 fg mL−1) and living EGFR-overexpressed MCF-7 cancer cells (80 cell per mL), as well as high selectivity, good reproducibility, high stability, repeatability, and acceptable applicability. Consequently, the constructed CD@CuCoPBA-based aptasensor can be extended to be a promising universal method for early diagnosis of cancers.