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Updated: Jun 8, 2026
Assembly and Characterization of Polyelectrolyte Complex Micelles
Published on: March 2, 2020
Polyplex micelles prepared from ω-cholesteryl PEG-polycation block copolymers for systemic gene delivery
Makoto Oba1, Kanjiro Miyata, Kensuke Osada
1Department of Clinical Vascular Regeneration, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Cholesterol-modified polyplex micelles (PEG-PAsp(DET)-Chole) enhance plasmid DNA (pDNA) delivery for gene therapy. These improved micelles show increased stability and effective tumor suppression in vivo, offering a promising systemic gene vector for solid tumors.
Area of Science:
- Biomaterials Science
- Gene Therapy
- Nanotechnology
Background:
- Polyplex micelles composed of plasmid DNA (pDNA) and poly(ethylene glycol)-block-poly{N-[N-(2-aminoethyl)-2-aminoethyl]aspartamide} (PEG-PAsp(DET)) demonstrate effective endosomal escape for local gene transfer.
- The di-protonation of diamine side chains in PEG-PAsp(DET) at lower pH facilitates endosomal escape, improving transfection efficiency.
Purpose of the Study:
- To enhance PEG-PAsp(DET) polyplex micelles for systemic gene delivery by introducing cholesterol (Chole) to create PEG-PAsp(DET)-Chole.
- To evaluate the stability, gene transfer efficiency, and in vivo therapeutic potential of PEG-PAsp(DET)-Chole micelles as systemic vectors.
Main Methods:
- PEG-PAsp(DET)-Chole micelles were synthesized by incorporating cholesterol into the ω-terminus of PEG-PAsp(DET).
- The association of block copolymers with pDNA and micelle stability in proteinous medium and blood were assessed.
- In vitro gene transfer efficiency was evaluated, focusing on cellular uptake and endosomal escape.
- In vivo anti-tumor efficacy was tested by intravenous injection of PEG-PAsp(DET)-Chole micelles carrying therapeutic pDNA into mice with subcutaneous pancreatic tumors.
Main Results:
- Cholesterol incorporation enhanced the association of block copolymers with pDNA, leading to improved micelle stability in biological fluids compared to PEG-PAsp(DET) micelles.
- PEG-PAsp(DET)-Chole polyplex micelles exhibited high in vitro gene transfer efficiency at low concentrations due to efficient cellular uptake and endosomal escape.
- Intravenous administration of PEG-PAsp(DET)-Chole micelles resulted in significant suppression of tumor growth in a preclinical pancreatic cancer model.
Conclusions:
- PEG-PAsp(DET)-Chole polyplex micelles represent an improved systemic gene vector with enhanced stability and efficacy.
- These cholesterol-modified micelles demonstrate significant potential for the systemic gene therapy of solid tumors, including pancreatic cancer.
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