Deep view of Polyethylenimine polymer as a non-viral vector for gene therapy

Abstract

Polyethylenimine (PEI) is a general-purpose polycationic polymer which has received much attention as a non-viral vector for therapeutic nucleic acid delivery in medicine. The high level of amine groups enables electrostatic complexation with negatively charged genetic material, leading to the formation of polyplex and higher cellular uptake. Once internalized, PEI can facilitate endosomal escape because of its buffering capacity and or its ability to destabilize cellular membranes, which promotes efficient delivery of DNA and RNA. Recent use of PEI-based systems for gene delivery (DNA and small interfering RNA) and other gene therapy and neurological applications are emphasized. The transfection efficiency is high, but clinical translation is hindered by its cytotoxicity and low biodegradability and systemic stability. Current strategies, namely molecular modification, crosslinking, surface shielding and structural optimization of PEI-based gene-delivery system are then explored for enhancing the safety and therapeutic promise of this platform. This review focuses on major forms of PEI, molecular structure, physicochemical properties influence gene-delivery performance and applications on non-viral gene delivery.