A novel cytosensor for capture, detection and release of breast cancer cells based on metal organic framework PCN-224 and DNA tetrahedron linked dual-aptamer

A convenient and efficient strategy for detecting cancer cells at preclinical stages is one of the dominant challenges in early cancer diagnostics. In this work, a sandwich-type cytosensor was structured to analyze cancer cells based on metal organic framework PCN-224 and DNA tetrahedron linked dual-aptamer. Firstly, the tetrahedral DNA nanostructures linked dual aptamers (AS1411 and MUC1) immobilizing on the gold electrode (GE) surface as bio-recognition elements can capture the MCF-7 cancer cells and improve the density and orientation of surface nanoprobes. Then, the novel metal organic framework PCN-224 homogeneously decorated by Pt nanoparticles was modified by the G-quadruplex/hemin DNAzyme, horseradish peroxidase (HRP) and dual-aptamer. The fabricated nanoprobes were applied to catalyze the oxidation of hydroquinone (HQ) with hydrogen peroxide (H2O2) for amplifying the electrochemical signal. The results indicated that the linear response of the aptasensor ranged from 20 to 1x10(7) cells/mL and the detection limit was 6 cells/mL. Finally, we performed an electrochemical reductive desorption to break gold-thiol bond and release all compounds on the electrode surface for analyzing the viability of collected cells and regenerating the cytosensor. This work can be extended to other cancer cells by using specific type aptamers and has widely applications prospect in point-of-care cancer diagnosis.