Abstract
Besides gene-editing, the CRISPR/Cas12a system has also been widely used in in vitro biosensing, but its applications in live-cell biosensing are rare. One reason is lacking appropriate carriers to synchronously deliver all components of the CRISPR/Cas12a system into living cells. Herein, we demonstrate that MnO(2) nanosheets are an excellent carrier of CRISPR/Cas12a due to the two important roles played by them. Through a simple mixing operation, all components of the CRISPR/Cas12a system can be loaded on MnO(2) nanosheets and thus synchronously delivered into cells. Intracellular glutathione (GSH)-induced decomposition of MnO(2) nanosheets not only results in the rapid release of the CRISPR/Cas12a system in cells but also provides Mn(2+) as an accelerator to promote CRISPR/Cas12a-based biosensing of intracellular targets. Due to the merits of highly efficient delivery, rapid intracellular release, and the accelerated signal output reaction, MnO(2) nanosheets work better than commercial liposome carriers in live-cell biosensing analysis of survivin messenger RNA (mRNA), producing much brighter fluorescence images in a shorter time. The use of MnO(2) nanosheets might provide a good carrier for different CRISPR/Cas systems and achieve the rapid and sensitive live-cell biosensing analysis of different intracellular targets, thus paving a promising way to promote the applications of CRISPR/Cas systems in living cells.