Triggered amplification of gene theranostics with high accuracy and efficacy using metallo-nanoassemblies

RNA-cleaving DNAzymes hold great promise for gene regulation, yet the low in vivo catalytic efficacy and the unavoidable nonspecific response in normal tissues hinder their practical applications. Herein, we develop a DNA prodrug-laden metallo-nanoassembly for sensitive orthogonal activation of DNAzymes to regulate disease gene with high precision and efficacy. With rich positive charges, metallo-nanoassemblies efficiently load DNA prodrugs (functional DNAzyme subunits), and thus improve drug stability and cellular uptake efficacy. Under tumor microenvironment, the cancer-specific biomarker triggers the amplified assembly of DNA prodrugs into active DNAzymes to efficiently cleave tumor-involved mRNA. Meanwhile, these glutathione-responsive metallo-nanoassemblies decompose and release metal ions as self-sufficient DNAzyme cofactors, which are accommodated into the afore-assembled DNAzymes to enhance the gene cleavage activity. Moreover, upon laser stimulus, these photothermal metallo-nanoassemblies can also remarkably promote the catalytic reaction of DNAzymes via the elevated local temperature. Such a smart delivery approach allows disease diagnosis via sensitive fluorescence and photothermal imaging, and achieves the precise and robust gene regulation with photothermal ablation as an auxiliary therapy. These results provide a new route to design programmable and activatable prodrugs for precision nanomedicine.