Saponin and fluorine-modified polycation as a versatile gene delivery system

Despite the development of many novel carriers for the delivery of various types of genetic material, the lack of a delivery system with high efficiency and low cytotoxicity is a major bottleneck. Herein, low molecular weight polyethylenimine (PEI1.8k) was functionalized with saponin residues using phenylboronic acid (PBA) as an ATP-responsive cross-linker, and a fluorinated side chain to construct PEI-PBA-SAP-F polycation as a highly efficient delivery vector. This vehicle could transfect small plasmid DNA (similar to 3 kb) with outstanding efficiency into various cells, including HEK 293T, NIH3T3, A549, PC12, MCF7 and HT-29, as well as robust transfection of a large plasmid (similar to 9 kb) into HEK 293T cells. The carrier indicated good transfection efficacy even at high concentration of serum and low doses of plasmid. The use of green fluorescent protein (GFP) knock-out analysis demonstrated transfection of different types of CRISPR/Cas9 complexes (Cas9/sgRNA ribonucleoproteins RNP, plasmid encoding Cas9 plus sgRNA targeting GFP, Cas9 expression plasmid plus in vitro-prepared sgRNA). In summary, we report an effective PEI-PBA-SAP-F gene carrier with the appropriate lipophilic/cationic balance for biomedical applications.

Automated summary

In this study, a highly efficient gene carrier, PEI-PBA-SAP-F, was developed. It showed outstanding transfection efficiency for both small plasmid DNA and large plasmid DNA into various cells, even at low plasmid doses and high serum concentrations. Additionally, it successfully delivered different types of CRISPR/Cas9 complexes.