Fenton Reaction-Mediated Endolysosomal Disruption for Efficient Cytosolic Protein Delivery

Endolysosomal entrapment is still the major obstacle in cytosolic protein delivery. Methods that can efficiently promote endolysosomal escape are thus highly demanded. Herein, the possibility of transferring proteins from endolysosomes into the cytosol by Fenton reaction-mediated endolysosomal disruption was examined. Proteins and iron ions were loaded in calcium carbonate nanoparticles, and the intracellular distribution and bioactivities of proteins after cellular uptake were analyzed. This technology, termed chemodynamic internalization (CDI), was found to efficiently deliver various proteins, including ribonuclease A, green fluorescent protein, β-galactosidase, and horseradish peroxidase, into the cytosol by mitochondrial calcium overload-enhanced Fenton reaction-mediated lipid peroxidation and ensuing rupture of endolysosomal membranes, maintaining the bioactivity of delivered proteins. Therefore, CDI provides an efficient and general tool for cytosolic protein delivery and may advance protein-related basic research and drug development.