Aptamer-Based electrochemiluminescent detection of MCF-7 cancer cells based on carbon quantum dots coated mesoporous silica nanoparticles

Graphical abstract: - Highlights: • Aptamers have many advantages over antibodies, such as low molecular weight, easy but reproducible production and low cost. • Mesoporous silica nanoparticles (MSNs) were prepared to load more CQDs for signal amplification which has a large surface area and high pore volume, ordered porous channels, a uniform and tunable pore structure, and a great diversity in surface functionalization • 3D-GR@AuNPs was prepared as biointerface for the immobilization of cancer cells due to their good biological compatibility, excellent conductivity and large surface area. • This new aptasensor may be quite promising, with potential broad applications in cancer early diagnosis due to the excellent analytical performance. - Abstract: In this work, we developed a novel electrochemiluminescence (ECL) platform for ultrasensitive and selective detection of MCF-7 cancer cells. To construct the platform, three-dimensional macroporous AuNPs@graphene complex was prepared through freeze drying process to modify glassy carbon electrode, which provided an effective matrix for concanavalin A to capture cancer cells due to its high surface area-to-weight ratio and excellent mechanical properties. The carbon quantum dots (CQDs) coated mesoporous silica nanoparticles were used as excellent ECL tracers due to their low cytotoxicity and good biocompatibility. Then, the prepared tracers were conjugated with mucin1 aptamer to specifically bind mucin1 on cancer cells with high stability and bioactivity. Structure characterization was obtained by means of transmission electron microscopy and scanning electron microscopy images. The proposed method showed a good analytical performance for the detection of MCF-7 cancer cells ranging from 500 to 2 × 10⁷ cells·mL⁻¹ with a detection limit of 230 cells mL⁻¹. The as-proposed device has the advantages of high sensitivity, nice specificity, and good stability and could offer great promise for sensitive detection of MCF-7 cancer cells in response to therapy