A CRISPR/Cas12a-responsive dual-aptamer DNA network for specific capture and controllable release of circulating tumor cells.

The separation and detection of circulating tumor cells (CTCs) have a significant impact on clinical diagnosis and treatment by providing a predictive diagnosis of primary tumors and tumor metastasis. But the responsive release and downstream analysis of live CTCs will provide more valuable information about molecular markers and functional properties. To this end, specific capture and controllable release methods, which can achieve the highly efficient enrichment of CTCs with strong viability, are urgently needed. DNA networks create a flexible, semi-wet three-dimensional (3D) microenvironment for cell culture, and have the potential to minimize the loss of cell viability and molecular integrity. More importantly, responsive DNA networks can be reasonably designed as smart sensors and devices to change shape, color, disassemble, and giving back to external stimuli. Here, a strategy for specifically collecting cells using a dual-aptamer DNA network is designed. The proposed strategy enables effective capture, 3D encapsulation, and responsive release of CTCs with strong viability, which can be used for downstream analysis of live cells. The programmability of CRISPR/Cas12a, a powerful toolbox for genome editing, is used to activate the responsive release of captured CTCs from the DNA network. After activation by a specified double-strand DNA (dsDNA) input, CRISPR/Cas12a cleaves the single-stranded DNA regions in the network, resulting in molecular to macroscopic changes in the network. Accompanied by the deconstruction of the DNA network into fragments, controllable cell release is achieved. The viability of released CTCs is well maintained and downstream cell analysis can be performed. This strategy uses the enzymatic properties of CRISPR/Cas12a to design a platform to improve the programmability and versatility of the DNA network, providing a powerful and effective method for capturing and releasing CTCs from complex physiological samples.