Intracellular Nanodelivery of DNA with Enzyme-Degradable and pH-Responsive Peptide Dendrons

Effective DNA delivery requires functional materials to package and transport genetic cargo into cells. However, many synthetic systems rely on heterogeneous mixtures, lack biodegradability, and pose toxicity concerns. Here, we introduce a peptide dendron single-molecule transfection reagent that enables targeted DNA delivery via pH-responsive, degradable nanoparticles with minimal toxicity. Peptide dendrons for intracellular delivery (PDIDs) incorporate ionizable non-natural amino acids for DNA binding and pH sensitivity. PDIDs formed stable nanoparticles that released DNA upon lysosomal acidification, facilitating cytoplasmic entry and subsequent gene expression. Rationally designed triamino acid blocks promoted protease degradation, reducing toxicity in preclinical models. Targeting ligands further enhanced the transfection efficiency by increasing cell uptake. In a lung metastasis model, targeted PDID-DNA nanoparticles selectively delivered therapeutic gene cargo to the lung, reducing tumor burden and extending survival. This platform demonstrates the potential to integrate natural and non-natural peptide features to enable safe and efficient DNA delivery in vivo.