A fluorescent immunosensor for determination and imaging of circulating tumor cells based on a bifunctional DNA nanomachine.

Abstract

A fluorescent platform was developed for the determination and visualization of circulating tumor cells by a toehold-mediated bifunctional DNA nanomachine. In the presence of target tumor cells, the DNA nanomachine was activated. Multiple DNA products were formed, including dendritic DNA products and double-strand DNA products. Dendritic DNA products bound to their target cells for the visualization, while double-strand DNA products were released for the determination of tumor cells. At fluorescence excitation and emission wavelengths of 530 and 550nm, this method could detect as low as 43 cells/mL (S/N = 3) with a linear range of 100 to 10,000 cells/mL. In clinical hydrothorax samples, this platform exhibited high reliability with a recovery of 93 to 116%. At the fluorescence excitation and emission wavelengths of 490 and 515nm, the specificity and biocompatibility of this method were further verified by tumor cells imaging. Furthermore, the robustness of the toehold-mediated bifunctional DNA nanomachine was demonstrated by the specific gene mutation detection in single-cell analysis. Graphical abstract Schematic illustration of the fluorescent immunosensor for determination and imaging of circulating tumor cells. The method is based on aptamer-based recognition and toehold-mediated bifunctional DNA nanomachine.