Intracellular delivery of a molecularly imprinted peroxidase mimicking DNAzyme for selective oxidation

Efficient delivery of protein enzymes and their selective catalysis in living cells is challenging due to their high cost, low stability and large protein size, and the complex intracellular environment. We aimed to develop artificial enzyme mimics that could replace proteins for this purpose. DNAzymes are a type of enzyme mimic made from highly stable DNA. In this study, a molecularly imprinted DNAzyme nanogel was prepared using Amplex Red as the template. The nanogel could selectively oxidize Amplex Red in the presence of H2O2 to form a fluorescent product, while the oxidation of other substrates was inhibited. The activity of this imprinted DNAzyme was even higher than that of the free DNAzyme. The nanogel was efficiently internalized by HeLa cells and intracellular oxidation was also achieved. Therefore, this material provides an integrated solution for biocatalysis inside cells and it might be an interesting solution for intracellular therapeutic applications.