Amine Species-functionalized Poly(Glycidyi Methacrylate) For Gene Delivery

Successful gene delivery vectors for clinical translation shouldhave high transfection efficiency and minimal toxicity. In this paper, genevectors were syntheised by the ring-opening reaction of the pendantepoxide groups of poly(glycidyl methacrylate) with the amine moieties ofamine species. The details and conclusions are decribed as follows:1. Well-defined poly(2-hydroxyl-3-(2-hydroxyethylamino)propylmethacrylate)(PGEA) vectors with flanking cationic secondary amineand nonionic hydroxyl units were prepared via the ring-opening reactionof the pendant epoxide groups of poly(glycidyl methacrylate) with theamine moieties of ethanolamine. It was found that PGEA possess verylow toxicity (<10%of the toxicity of branched polyethylenimine (PEI,25kDa), while exhibiting surprisingly excellent transfection efficiency(higher than or comparable to that of PEI (25kDa)) in different cell lines.2Different amine species (including1-amino-2-propanol (AP1) forPGAP1,3-amino-2-propanol (AP2) for PGAP2, EA for PGEA,EA/N,N,-dimethylethylenediamine (DED) for PGEADED, DED forPGDED, and its quaternized DED for QPGDED)-functionalized PGMA vectors were proposed and compared for efficient gene delivery. Incomparison with EA, AP1contains an additional methyl group while AP2possesses an additional methylene groups. PGEA, PGAP1and PGAP2exhibited the similar condensation capability. The methyl (from AP1) ormethylene (from AP2) species could benefit the gene transfectionefficiency, and the resultant transfection performance mediated byPGAP1is best. DED possesses the tertiary amine group, which could bequaternized to further enhance the surface cationic charge and DNAcondensation ability. No obvious increase in cytotoxicity of QPGDEDwas observed. But both DED and its quaternized species seriouslyaffected buffering capacity, making the DED or its quaternizedcounterpart-containing vectors exhibit poor gene transfection. The currentstudy would provide the useful information for constructing betterPGMA-based delivery systems with good biophysical properties.3. Further improvement in degradability and transfection efficifencyof the PGEA vectors will facilitate their applications in gene therapy.Comb-shaped cationic copolymers have been of interest and importanceas non-viral gene carries. Herein, the degradable high-molecular-weightcomb-shaped PGEA vectors (c-PGEAs) composed of the low molecularweigh PGEA backbone and side chains were prepared by a combinationof atom transfer radical polymerization (ATRP) and ring-openingreactions. The PGEA side chains were linked with the PGEA backbones via hydrolyzable ester bonds. Such comb-shaped c-PGEA vectorspossessed the degradability, good pDNA condensation ability, lowcytotoxicity and good buffering capacity. More importantly, thecomb-shaped c-PGEA vectors could enhance the gene expression levels.Moreover, the PGEA side chains of c-PGEA could also be copolymerizedwith some poly(poly(ethylene glycol)ethyl ether methacrylate) species tofurther improve the gene delivery system.