title: pH-responsive biodegradable assemblies containing tunable phenyl-substituted vinyl ethers for use as efficient gene delivery vehicles.
abstract: Novel pH-responsive assemblies (PEG-lipid:DOPE liposomes) containing tunable and bifunctional phenyl-substituted vinyl ether (PIVE) cross-linkers were prepared. The assemblies consisted of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), acid-cleavable poly(ethylene glycol) (PEG)-conjugated lipids, pDNA, and protamine sulfate (PS). The PIVE linkage was designed to hydrolyze under acidic conditions, and the hydrolysis studies of PEG-lipid compounds containing PIVE at pH 4.2, 5.4, and 7.4 indicated that the hydrolysis rates of PIVE linker were influenced by the substitution of electron withdrawing or electron donating groups on the phenyl ring. Acid-catalyzed hydrolysis of PIVE leads to destabilization of the acid labile PEG-PIVE-lipid:DOPE liposomes via dePEGylation, thereby triggering content release. Content release assays showed that dePEGylation was highly pH-dependent and correlated with the PIVE proton affinity of the phenyl group. These results indicated that the dePEGylative triggering based on a new pH-sensitive PIVE linkage can be controlled. In vitro transfection studies on the pH-responsive assemblies containing mPEG-(MeO-PIVE)-conjugated 1,3-dioctadecyl-rac-glycerol lipids (mPEG-(MeO-PIVE])-DOG) showed higher transfection efficiency compared to that of polyethylenimine (PEI), a positive control, on HEK 293 and COS-7 cells. In addition, lower cytotoxicity of PEG-PIVE-lipid:DOPE liposomes/PS/DNA was observed in comparison to PEI. These results suggest that PEG-PIVE-lipid:DOPE liposomes can be considered as nonviral vehicles for drug and gene delivery applications.
authors.affiliation: Division of Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, USA. hkkim717@utexas.edu
authors.forename: Hee-Kwon
authors.initials: HK
authors.lastname: Kim
authors.forename: David H
authors.initials: DH
authors.lastname: Thompson
authors.forename: Ho Seong
authors.initials: HS
authors.lastname: Jang
authors.forename: Yong Jin
authors.initials: YJ
authors.lastname: Chung
authors.forename: Jeroen
authors.initials: J
authors.lastname: Van den Bossche
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000494:pharmacology; D019556:COS Cells; D002470:Cell Survival / Q000187:drug effects; D002522:Chlorocebus aethiops; D004247:DNA / Q000737:chemistry; D057809:HEK293 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008081:Liposomes / Q000737:chemistry* / Q000494:pharmacology; D053758:Nanoparticles / Q000737:chemistry*; D010647:Phenyl Ethers / Q000737:chemistry*; D010957:Plasmids / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011479:Protamines / Q000737:chemistry; D014162:Transfection / Q000379:methods*; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D008081:Liposomes; D010647:Phenyl Ethers; D011479:Protamines; D014753:Vinyl Compounds; D011092:Polyethylene Glycols; C096130:phenyl vinyl ether; D004247:DNA