Hollow covalent organic framework-sheltering CRISPR/Cas12a as an in-vivo nanosensor for ATP imaging

In addition to applications in genome editing, clustered regularly interspaced short palindromic repeats (CRISPR) have recently been engineered for medical diagnostics based on their trans-cleavage activity owing to their high base resolution and isothermal signal amplification. However, trans-cleavage activity is too fragile to be applied in vivo. Herein, we introduce a hollow covalent organic framework (COF)-sheltering CRISPR/aptamer-based sensor (h-CCS) for ATP imaging in living animals. The CRISPR/aptamer-based complex is comprised of the CRISPR-Cas12a system, fluorophore quencher-labeled single-stranded DNA substrate (ssDNA-FQ), and a DNA activator that pre-hybridizes with ATP aptamer to prevent the trans-cleavage activity of the Cas12a system in the absence of ATP. After being encapsulated in a hollow COF, the constructed nanoreactor is highly robust and can be lit up by ATP for in vivo imaging. Considering the unique properties of h-CCS, this strategy offers great potential to broaden applications of not only CRISPR-Cas systems but also other proteins in porous matrixes for clinical diagnostics, medical research, and biomimetic nanodevices.