ROS-responsive polypeptides for intracellular protein delivery and CRISPR/Cas9 gene editing

Protein therapeutics have emerged as a rapidly growing class of medicine in recent years due to the high potency and specificity. However, protein drugs acting on intracellular targets are currently unavailable due to their membrane impermeability. There is a great demand to develop efficient carriers for intracellular protein delivery. Here, we reported a reactive oxygen species responsive material based on biodegradable polypeptide for this purpose. Boronate moieties were decorated on polypeptides via a p-hydroxybenzylcarbamate self-immolative spacer. The modified polypeptide could catch cargo proteins via ionic interaction and nitrogen/boronate coordination to form uniform nanoparticles, and efficiently release the bound proteins under hydrogen peroxide (H₂O₂) through the oxidation of boronate ligands. The lead polymer efficiently delivered diverse cargo proteins enter living cells and retained their protein activity. In addition, it efficiently transported Cas9 ribonucleoprotein (RNP) into cells for CRISPR/Cas9 gene editing and achieved liver repair against acetaminophen (APAP)-induced liver injury in mice. The results provided a facile strategy to construct efficient, responsive and biodegradable polymers for cytosolic protein delivery.