Journal of controlled release : official journal of the Controlled Release SocietyJun 6, 2006

Nanoparticles made from two polymers for gene delivery: how charge and size affect particle formation, cell safety, and gene transfer

mRNA Technology Weekly Brief ↗PubMed ↗DOI ↗

Updated Apr 6, 2026

Abstract

Nanoparticles loaded with DNA remained under 160 nm in size after preparation.

Two types of nanoparticles were created to explore how charge affects their ability to deliver genes.
The nanoparticles maintained spherical shapes even after incorporating DNA.
AMPEG/PCL nanoparticles were consistently smaller than MPEG/PCL nanoparticles at the same molecular weight after DNA loading.
The optimal ratio of copolymers to DNA varied between 4:1 and 1:2 based on specific molecular characteristics.
In vitro tests showed that the DNA-loaded nanoparticles did not cause significant harm to normal human fibroblasts.
Transfection efficiencies of the DNA-loaded nanoparticles increased by approximately 3.4 to 12.9 times in serum conditions.

Simplified

Two types of nanoparticles containing pGL3-Control (plasmid DNA) were prepared using nonionic amphiphlic block copolymers and ionic amphiphilic block copolymers containing a terminal cationic group to investigate the effect of charge on the vehicle properties for systemic gene delivery. Methoxy poly(ethylene glycol) (MPEG)/poly(epsilon-caprolactone) (PCL) diblock copolymers were synthesized by the ring-opening polymerizatrion of epsilon-caprolactone in the presence of a catalyst-free MPEG homopolymer. The hydroxy groups of MPEG/PCL block copolymer were then modified into an amine group to synthesize an amine-terminated MPEG/PCL diblock copolymer (AMPEG/PCL). DNA was incorporated into the polymeric nanoparticles by physical entrapment and electrostatic interaction. All nanoparticle samples exhibited spherical structures and although their sizes increased slightly after DNA-loading, they remained less than 160 nm. The AMPEG/PCL nanoparticles exhibited smaller particle sizes than the MPEG/PCL nanoparticles of the same molecular weight after DNA-loading. The optimum mixing ratio of MPEG/PCL and AMPEG/PCL copolymers to DNA ranged from 4:1 to 1:2 depending on the molecular weight of the block copolymer, the composition of MPEG and PCL and terminal amine group. Based on in vitro cytotoxicity tests, the DNA-loaded MPEG/PCL and AMPEG/PCL nanoparticles did not induce any remarkable cytotoxicity against normal human fibroblasts. Transfection efficiencies of DNA-loaded nanoparticles were improved about 3.4 - 12.9 times under serum conditions.

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Nanoparticles made from two polymers for gene delivery: how charge and size affect particle formation, cell safety, and gene transfer

Abstract

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