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Self-assembled biodegradable micellar nanoparticles of amphiphilic and cationic block copolymer for siRNA delivery

Paper ID Volume ID Publish Year Pages File Format Full-Text
9785 646 2008 8 PDF Available
Title
Self-assembled biodegradable micellar nanoparticles of amphiphilic and cationic block copolymer for siRNA delivery
Abstract

A novel amphiphilic and cationic triblock copolymer consisting of monomethoxy poly(ethylene glycol), poly(ɛ-caprolactone) (PCL) and poly(2-aminoethyl ethylene phosphate) denoted as mPEG45-b-PCL100-b-PPEEA12 was designed and synthesized for siRNA delivery. The copolymers were well characterized by 1H NMR spectroscopy and gel permeation chromatography. Micelle nanoparticles' (MNPs) formation of this amphiphilic copolymer in aqueous solution was studied by dynamic light scattering, transmission electron microscopy and fluorescence technique. MNPs took uniform spherical morphology with zeta potential of around 45 mV and were stabilized by hydrophobic–hydrophobic interaction in the PCL core, exhibiting the critical micelle concentration at 2.7 × 10−3 mg/mL. Such MNPs allowed siRNA loading post nanoparticle formation without change in uniformity. The average diameter of nanoparticles after siRNA binding ranged from 98 to 125 nm depending on N/P ratios. The siRNA loaded nanoparticles can be effectively internalized and subsequently release siRNA in HEK293 cells, resulting in significant gene knockdown activities, which was demonstrated by delivering two siRNAs targeting green fluorescence protein (GFP). It effectively silenced GFP expression in 40–70% GFP-expressed HEK293 cells and it was observed that higher N/P ratio resulted in more effective silence which was likely due to better cell internalization at higher N/P ratio. MTT assay demonstrated that neither MNPs themselves nor siRNA loaded MNPs showed cytotoxicity even at high concentrations. Such cationic MNPs made from biocompatible and biodegradable polymers are promising for siRNA delivery.

Keywords
siRNA delivery; Micellar nanoparticles; Biodegradable polymer; Self-assembly; Polyphosphoester
First Page Preview
Self-assembled biodegradable micellar nanoparticles of amphiphilic and cationic block copolymer for siRNA delivery
Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 29, Issue 32, November 2008, Pages 4348–4355
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering