A paper-based electrochemiluminescence electrode as an aptamer-based cytosensor using PtNi@carbon dots as nanolabels for detection of cancer cells and for in-situ screening of anticancer drugs.

A paper-based portable and disposable cyto-device was fabricated for the purpose of detecting cancer cells and in-situ screening of anticancer drugs. The device was prepared as follows: (a) Au@Pd paper electrodes were prepared by growing Au@Pd nanoparticles on cellulose; (b) the aptamer against MCF-7 cells was immobilized on the paper electrodes; (c) PtNi alloy particles were loaded with carbon dots to form a PtNi@C-dot composite acting as the ECL label, (d) concanavalin A (Con A) was labeled with the ECL label and then dropped on sensor surface carrying cancer cell. Con A can specifically recognize the mannose on the cancer cell surface. The assay is performed in the following way: (1) The aptamer-modified electrode is placed in a solution containing MCF-7 cancer cells; (2) buffer containing peroxodisulfate is added; (3) a potential sweep (from −0.5 to −1.8 V) is applied to the electrode, and ECL intensity is recorded. ECL intensity is related to the number of captured MCF-7 cells in the 480 to 2.0 × 10 cells⋅mL‾ concentration range. The electrode was applied to design a screening method for anti-cancer drugs. This is accomplished by monitoring the number of apoptotic cancer cells after exposing the cells on the electrode to a drug-containing medium. In our perception, the method presented here has a wide range of potential applications in cancer diagnosis and treatment. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]