Self-Assembled Cationic Micelles Based on PEG-PLL-PLLeu Hybrid Polypeptides as Highly Effective Gene Vectors

Abstract

Developing safe and effective nonviral gene vector is highly crucial for successful gene therapy. In the present study, we designed a series of biodegradable micelles based on hybrid polypeptide copolymers of poly(ethylene glycol)-b-poly(l-lysine)-b-poly(l-leucine) (PEG-PLL-PLLeu) for efficient gene delivery. A group of amphiphilic PEG-PLL-PLLeu hybrid polypeptide copolymers were synthesized by ring-opening polymerization of N-carboxyanhydride, and the chemical structure of each copolymer was characterized by (1)H NMR and FT-IR spectroscopy measurement. The PEG-PLL-PLLeu micelles were positively charged with tunable sizes ranging from 40 to 90 nm depending on the length of PLL and PLLeu segment. Compared with PEG-PLL copolymers, PEG-PLL-PLLeu micelles demonstrated significantly higher transfection efficiency and less cytotoxicity. Furthermore, the transfection efficiency and biocompatibility of the micelles can be simultaneously improved by tuning the length of PLL and PLLeu segments. The transfection efficiency of PEG-PLL-PLLeu micelles in vivo was two to three times higher than that of PEI(25k), which was attributable to their capability of promoting DNA condensation and cell internalization as well as successful lysosome escape. Hence well-defined PEG-PLL-PLLeu micelles would serve as highly effective nonviral vectors for in vivo gene delivery.

Self‐assembly and responsiveness of polypeptide‐based block copolymers: How “Smart” behavior and topological complexity yield unique assembly in aqueous media

“…Cai et al showed the synthesis of ABCs using poly(ethylene glycol)-NH 2 to initiate ROP of poly(Z-Lysine) followed by subsequent polymerization of a second monomer, L-leucine NCA. 95 Jing et al synthesized a PEG-poly(L-Lactide)-PLGA (PEG-PLA-PLGA) terpolymer again using a macrointiator approach, whereby PEG-PLA-NH 2 initiated polymerization of c-benzyl-L-glutamate NCA. 96 Ten Cate and Borner employed solid state peptide synthesis and a solid-supported PEG-NH 2 to synthesize PEG-poly(arginine)-NH 2 .…”

“…A few studies have been devoted to studying the aqueous self-assembly of peptide-containing ABC triblocks. [95][96][97] Jing and coworkers demonstrated pH-induced morphology transitions for amphiphilic poly(ethylene glycol) 17 -poly(L-lactide) 23 -PLGA 60 (PEG 17 -PLL 23 -PLGA 60 ). 96 A sphere-to-connected rod transition was driven by the hydrophilicity of the PLGA block.…”

“…95 The sizes of the spherical micelles were effectively tuned between 40 and 90 nm by changing the block lengths of lysine and leucine. This model terpolymer was found to effectively complex DNA through association with the positively charged PLys middle block, whereby the placement of the PLys block promoted internalization of the DNA allowing for protection against lysosomes.…”

Polyethylene glycol–poly(ε-benzyloxycarbonyl-L-lysine)-conjugated VEGF siRNA for antiangiogenic gene therapy in hepatocellular carcinoma

“…34 Researchers have designed various types of novel copolymers, such as pH-sensitive, temperature-sensitive, light-sensitive, magnetic-sensitive, ultrasound-sensitive, redox-sensitive, and enzyme-degraded copolymers, in order to solve the issue of low transfection efficiency of the PEGylated nanoparticles. [35][36][37][38] In this study, redox-sensitive PEG-SS-PLL was synthesized and used to deliver the novel nanoparticle complex PEG-SS-PLL/siVEGF. We investigated the transfection efficiency, cytotoxicity in vitro, tumor-inhibitory effect in vivo, and the mechanism of antitumor effect of the complex.…”

Synthesis and characterization of low-toxicity N-caprinoyl-N-trimethyl chitosan as self-assembled micelles carriers for osthole

“…39,40 In this study, two tumor cell lines and a human normal liver cell line were used to evaluate the cytotoxicity of CA-TMC by MTT assay.…”