Alpha-helix peptides self-assemble into VLNs, achieving 91% mRNA transfection and 93% siRNA knockdown.

Efficient and safe delivery of nucleic acids remains a critical bottleneck for the clinical translation of gene therapies. Current delivery systems often struggle with stability, cellular uptake, and crucial intracellular trafficking, particularly escaping the endolysosomal pathway to reach the cytoplasm. Lipid nanoparticles (LNPs) are widely used but can have limitations in terms of immunogenicity and targeting. There is a significant need for programmable, bioinspired nanocarriers that can systematically overcome these extracellular and intracellular barriers, offering a safer and more effective alternative for gene therapy applications.

Researchers designed novel α-helical peptides that self-assemble with lipids and nucleic acids to form core-shell, virus-like nanoparticles (VLNs). These peptides were engineered with a cationic N-terminus for robust nucleic acid binding, an anionic C-terminus for lipid coordination, and incorporated pH-responsive residues to facilitate endolysosomal escape. The VLNs were then evaluated in vitro for their ability to deliver mRNA for transfection and siRNA for gene knockdown. Their performance was directly compared against Lipofectamine 2000, a widely used commercial transfection reagent, to benchmark efficacy.

The de novo designed α-helical peptides successfully coassembled with lipids and nucleic acids, forming stable core-shell virus-like nanoparticles. These VLNs demonstrated exceptional delivery efficiency in vitro. For mRNA delivery, they achieved up to 91.2% transfection efficiency. Similarly, for siRNA-mediated gene silencing, the VLNs resulted in up to 93.1% gene knockdown. This performance significantly outperformed the commercial standard, Lipofectamine 2000, across both mRNA and siRNA delivery metrics. The rational design, incorporating specific functional domains (cationic N-terminus, anionic C-terminus, pH-responsive residues), proved effective in addressing key extracellular and intracellular barriers to nucleic acid therapeutics. This work highlights a programmable strategy for creating highly efficient, virus-mimetic nanocarriers.

The α-helix peptide-based VLNs achieved up to 91.2% mRNA transfection and 93.1% siRNA-mediated gene knockdown in vitro, outperforming Lipofectamine 2000.