Development of delivery carriers for plasmid DNA by conjugation of a helical template to oligoarginine

Abstract

Arginine (Arg)-rich peptides can penetrate the cell membrane and deliver nucleic acid-based therapeutics into cells. In this study, a helical template designed with a repeating sequence composed of two l-leucines (l-Leu) and a 2-aminoisobutyric acid (Aib) (l-Leu-l-Leu-Aib) was conjugated to nona-arginine on either the C- or N- terminus, designated as Block 1 and Block 2. Each terminal modification induced helical structure formation and improved the physicochemical properties of peptide/plasmid DNA (pDNA) complexes, resulting in efficient intracellular pDNA delivery. The introduction of a helical template may be effective for the endosomal escape of pDNA and pDNA release from complexes in cells. These results emphasized the potency of a helical template for the development of novel cell-penetrating peptides for pDNA delivery.