Enhanced Gene Expression Promoted by Hybrid Magnetic/Cationic Block Copolymer Micelles

Abstract

We report on novel gene delivery vector systems based on hybrid polymer-magnetic micelles. The hybrid micelles were prepared by codissolution of hydrophobically surface modified iron oxide and amphiphilic polystyrene-b-poly(quaternized 2-vinylpyridine) block copolymer (PS-b-P2QVP) in organic solvent. After extensive dialysis against water, micelles with positively charged hydrophilic corona of PQVP and hydrophobic PS core were prepared, in which magnetic nanoparticles were randomly distributed. The hybrid micelles were used to form complexes with linear (salmon sperm, 2000 bp, corresponding to M(w) of 1.32 × 10(6) Da) and plasmid (pEGFP-N1, 4730 bp, corresponding to M(w) of 3.12 × 10(6) Da) DNA. The resulting magnetopolyplexes of phosphate:amine (P/N) ratios in the 0.05-20 range were characterized by light scattering, ζ-potential measurements, and transmission electron microscopy as well as cytotoxicity and gel retardation assays. The investigated systems displayed a narrow size distribution, particle dimensions below 360 nm, whereas their ζ-potential values varied from positive to negative depending of the P/N ratio. The resulting vector nanosystems exhibited low toxicity. They were able to introduce pEGFP-N1 molecules into the cells. The application of a magnetic field markedly boosted the transgene expression efficiency of the magnetopolyplexes, which was even superior to those of commercial transfectants such as Lipofectamine and dendritic polyethylenimine.

Asymmetric Flow Field-Flow Fractionation Investigation of Magnetopolyplexes

“…Hence, the two peaks can be assigned to unbound DNA and magnetopolyplexes. The results are in good agreement with agarose gel electrophoresis performed earlier showing presence of unbound DNA at those ratios.…”

“…After extensive dialysis against water for 7 d, micelles with positively charged hydrophilic shell of PQVP and hydrophobic PS core loaded with magnetic nanoparticles were obtained. The detailed procedure is described elsewhere . The concentration of magnetic nanoparticles was 10% in respect to the PS block.…”

“…In a recent paper, we reported on novel gene delivery vector systems based on cationic block copolymer micelles loaded with magnetic nanoparticles . The hybrid micelles were used to form complexes with linear and plasmid DNA.…”

Thermo‐Responsive Complexes of c‐Myc Antisense Oligonucleotide with Block Copolymer of Poly(OEGMA) and Quaternized Poly(4‐Vinylpyridine)

“…Polymers of vinylpyridines may form complexes with the genetic material after quaternization of tertiary amine groups in their pyridine rings or protonation at pH values lower than 5. Polyelectrolyte complexes of quaternized poly(4‐vinylpyridine) (P4VP) or poly(2‐vinylpyridine) with genetic material, such as plasmid DNA, were already investigated and it was shown that this polymer may be used in gene therapy studies.…”

Application of cationic polymer micelles for the dispersal of bacterial biofilms

“…The micelles formed thereof have previously been used as gene delivery vector systems manifesting low cytotoxicity to eukaryotic cells and high cells internalization [16,17]. Block copolymers based on quaternized poly (2-vinylpyridine) (PQVP) and poly (2-(dimethylamino)ethyl methacrylate) (PDMAEMA) cationic moieties were used.…”