Polyplex Micelles with Double-Protective Compartments of Hydrophilic Shell and Thermoswitchable Palisade of Poly(oxazoline)-Based Block Copolymers for Promoted Gene Transfection

Abstract

Improving the stability of polyplex micelles under physiological conditions is a critical issue for promoting gene transfection efficiencies. To this end, hydrophobic palisade was installed between the inner core of packaged plasmid DNA (pDNA) and the hydrophilic shell of polyplex micelles using a triblock copolymer consisting of hydrophilic poly(2-ethyl-2-oxazoline), thermoswitchable amphiphilic poly(2-n-propyl-2-oxazoline) (PnPrOx) and cationic poly(L-lysine). The two-step preparation procedure, mixing the triblock copolymer with pDNA below the lower critical solution temperature (LCST) of PnPrOx, followed by incubation above the LCST to form a hydrophobic palisade of the collapsed PnPrOx segment, induced the formation of spatially aligned hydrophilic-hydrophobic double-protected polyplex micelles. The prepared polyplex micelles exhibited significant tolerance against attacks from nuclease and polyanions compared to those without hydrophobic palisades, thereby promoting gene transfection. These results corroborated the utility of amphiphilic poly(oxazoline) as a molecular thermal switch to improve the stability of polyplex gene carriers relevant for physiological applications.

Cyclodextrin‐Based Star‐Like Amphiphilic Cationic Polymer as a Potential Pharmaceutical Carrier in Macrophages

“…Biological safety is an important aspect in the design of gene delivery carrier, as the cytotoxicity of polymer against normal cells not only led to heavily side effect, but also had strong impact on the transfection efficiency . Figure A showed the in vitro cytotoxicity of β‐CD‐ g ‐(PCL‐ b ‐PDMAEMA) x of different concentrations in comparison with its counterparty without PCL segments.…”

Design concepts of polyplex micelles for in vivo therapeutic delivery of plasmid DNA and messenger RNA

“…We constructed hydrophobic physical barriers between the hydrophilic shell and core containing nucleic acids in polyplex micelles by the use of triblock copolymer with thermoswitchable segment, poly‐(2‐ n ‐propyl‐2‐oxazoline) (PnPrOx), placing between the hydrophilic and cationic segments of the block copolymer (Fig. ) . Polyplex micelle was prepared by mixing this triblock copolymer with pDNA below the lower critical solution temperature (LCST) of PnPrOx, followed by raising the temperature above the LCST to form protective hydrophobic barrier on the surface of the polyplex core.…”

“…1). 45 Polyplex micelle was prepared by mixing this triblock copolymer with pDNA below the lower critical solution temperature (LCST) of PnPrOx, followed by raising the temperature above the LCST to form protective hydrophobic barrier on the surface of the polyplex core. Eventually, the hydrophobic barriers were shown to drastically increase the tolerability of the polyplex micelles to both of nucleases (DNase I) and polyanions (chondroitin sulfate [CS]) attack.…”

Polyplex Particles Based on Comb‐Like Polyethylenimine/Poly(2‐ethyl‐2‐oxazoline) Copolymers: Relating Biological Performance with Morphology and Structure

“…Owing to a number of advantages, the nonviral vectors have gained significance and attracted the attention of the researchers from various disciplines in the past years: they are less hazardous, less pathogenic, less immunogenic, and cheaper compared to the viral ones and can be considered as a safe and inexpensive alternative of the latter. The class of nonviral vector systems include cationic lipids (lipoplexes), polymers (polyplexes), polymer micelles (micelleplexes), inorganic particles, etc. Among them, the polymer‐based vectors have many of the necessary prerequisites to fulfill the challenges associated with gene therapy.…”