Dendritic poly(amidoamine)-b-poly(L-glutamate)(PAMAM-b-PLG) biohybrids were synthesized by the ring-opening polymerization ofγ-benzyl-L-glutamate N-carboxyanhydride monomer,followed by the deprotection of benzyl grou...Dendritic poly(amidoamine)-b-poly(L-glutamate)(PAMAM-b-PLG) biohybrids were synthesized by the ring-opening polymerization ofγ-benzyl-L-glutamate N-carboxyanhydride monomer,followed by the deprotection of benzyl groups on poly(benzyl-L-glutamate),and were characterized by ~1H-NMR,FT-IR and gel permeation chromatography.The self-assembly behavior of the PAMAM-b-PLG biohybrid was investigated by means of UV-Vis,dynamic light scattering (DLS),transmission electronic microscopy(TEM) and ~1H-NMR.UV-Vis analysis ...展开更多
Design and development of efficient non-viral gene delivery systems is critical to overcome various barriers for effective intracellular gene delivery.Eight new spermine-based protonatable surfactants were designed,sy...Design and development of efficient non-viral gene delivery systems is critical to overcome various barriers for effective intracellular gene delivery.Eight new spermine-based protonatable surfactants were designed,synthesized and evaluated as non-viral pH-sensitive gene carriers.These carriers formed stable complexes with plasmid DNA at an N/P ratio as low as 2.The sizes of the carrier/pDNA nanoparticles (N/P = 12) were in the range of 90–130 nm,smaller than that of Lipofectamine2000/pDNA nanoparticles.The pDNA nanoparticles of the carriers exhibited substantially increased hemolysis when pH decreased from 7.4 to 5.5.The DNA nanoparticles had low cytotocixity,similar to that of Lipofectamine-2000/pDNA nanoparticles.The pH-sensitive gene carriers with no helper lipids resulted in much higher intracellular transfection and gene expression in U87 cells than Lipofectamine-2000.[N,N′-Bis(oleoylcysteinyl)(β-alanyl-α-lysyl)]-spermine monoamide (SKACO) resulted in the highest luciferase transfection efficiency,more than 400 times higher than that of Lipofectamine-2000,and GFP expression in 71% of transfected U87 cells.SKACO was identified as a promising lead carrier for efficient gene delivery.These spermine-based pH-sensitive amphiphilic carriers have a potential to be further developed as efficient non-viral multifunctional gene delivery systems.展开更多
To increase the in vivo stability of polycation gene carriers,a pH-sensitive shielding system,γ-benzyl L-glutamate-co-glutamate acid polymer(PGA(60)(60 refers to the molar ratio of glutamate acid in the polymer)),was...To increase the in vivo stability of polycation gene carriers,a pH-sensitive shielding system,γ-benzyl L-glutamate-co-glutamate acid polymer(PGA(60)(60 refers to the molar ratio of glutamate acid in the polymer)),was synthesized and characterized.PGA(60) showed pH sensitivity at about pH 6.0.PGA(60) shielded the positive charge of DNA/PEI(1:1) complexes.Gel retardation assay showed that no DNA-strand exchange with PGA(60) occurred after PGA(60) was added to DNA/PEI complexes at different proportions.MTT cytotoxicity tests demonstrated that neither PGA(60) nor DNA/PEI/PGA(60) ternary complexes had cytotoxicity at the test concentration.The transfection efficiency was improved when the positive charge was partly shielded by PGA(60).Because of the charge repulsion between the surface of cells and ternary complex particles,there was almost no transfection efficiency when the zeta potential of ternary complexes turned to negative.Because of the suitable pH sensitive range,PGA(60) may be a potential shielding system for polycation gene carriers to be used in vivo.展开更多
For the purpose of increasing the in vivo stability of polycation gene carriers, we prepared a kind of p H-sensitive poly（ethylene glycol）-poly（γ-benzyl-L-glutamate-co-glutamic acid）（PEG-PGA（65）, 65 denotes th...For the purpose of increasing the in vivo stability of polycation gene carriers, we prepared a kind of p H-sensitive poly（ethylene glycol）-poly（γ-benzyl-L-glutamate-co-glutamic acid）（PEG-PGA（65）, 65 denotes the molar ratio of glutamic acid in poly（γ-benzyl-L-glutamate-co-glutamic acid））. PEG-PGA（65） showed low cytotoxicity and could shield the positive charge of DNA/PEI（1：1） polyplexes efficiently. The transfection was enhanced due to the partially charge shielding in He La cell line at pH of 7.4. There was almost no transfection efficiency when the surface charge of the ternary particles turned to negative at p H of 7.4. However, the transfection efficiency recovered a lot by culturing at p H of 6.0 at the beginning of transfection. Confocal microscopic observation and flow cytometry results showed DNA/PEI polyplexes should be efficiently released and endocytosized at p H 6.0, because of the p H triggered deshielding action of PEG-PGA（65）. Due to the good biocompatibility and suitable p H triggered shielding/deshielding property, PEG-PGA（65） could be a potential shielding system for polycationic gene carriers used in vivo.展开更多
基金supported by the National Natural Science Foundation of China(No.20674050)Shanghai Leading Academic Discipline Project(No.B202)
文摘Dendritic poly(amidoamine)-b-poly(L-glutamate)(PAMAM-b-PLG) biohybrids were synthesized by the ring-opening polymerization ofγ-benzyl-L-glutamate N-carboxyanhydride monomer,followed by the deprotection of benzyl groups on poly(benzyl-L-glutamate),and were characterized by ~1H-NMR,FT-IR and gel permeation chromatography.The self-assembly behavior of the PAMAM-b-PLG biohybrid was investigated by means of UV-Vis,dynamic light scattering (DLS),transmission electronic microscopy(TEM) and ~1H-NMR.UV-Vis analysis ...
文摘Design and development of efficient non-viral gene delivery systems is critical to overcome various barriers for effective intracellular gene delivery.Eight new spermine-based protonatable surfactants were designed,synthesized and evaluated as non-viral pH-sensitive gene carriers.These carriers formed stable complexes with plasmid DNA at an N/P ratio as low as 2.The sizes of the carrier/pDNA nanoparticles (N/P = 12) were in the range of 90–130 nm,smaller than that of Lipofectamine2000/pDNA nanoparticles.The pDNA nanoparticles of the carriers exhibited substantially increased hemolysis when pH decreased from 7.4 to 5.5.The DNA nanoparticles had low cytotocixity,similar to that of Lipofectamine-2000/pDNA nanoparticles.The pH-sensitive gene carriers with no helper lipids resulted in much higher intracellular transfection and gene expression in U87 cells than Lipofectamine-2000.[N,N′-Bis(oleoylcysteinyl)(β-alanyl-α-lysyl)]-spermine monoamide (SKACO) resulted in the highest luciferase transfection efficiency,more than 400 times higher than that of Lipofectamine-2000,and GFP expression in 71% of transfected U87 cells.SKACO was identified as a promising lead carrier for efficient gene delivery.These spermine-based pH-sensitive amphiphilic carriers have a potential to be further developed as efficient non-viral multifunctional gene delivery systems.
基金supported by the National Natural Science Foundation of China (Grant Nos 20604028,50873102,50733003,A3 Foresight Program 20621140369)Ministry of Science and Technology of China (Grant No 2007DFR5020)
文摘To increase the in vivo stability of polycation gene carriers,a pH-sensitive shielding system,γ-benzyl L-glutamate-co-glutamate acid polymer(PGA(60)(60 refers to the molar ratio of glutamate acid in the polymer)),was synthesized and characterized.PGA(60) showed pH sensitivity at about pH 6.0.PGA(60) shielded the positive charge of DNA/PEI(1:1) complexes.Gel retardation assay showed that no DNA-strand exchange with PGA(60) occurred after PGA(60) was added to DNA/PEI complexes at different proportions.MTT cytotoxicity tests demonstrated that neither PGA(60) nor DNA/PEI/PGA(60) ternary complexes had cytotoxicity at the test concentration.The transfection efficiency was improved when the positive charge was partly shielded by PGA(60).Because of the charge repulsion between the surface of cells and ternary complex particles,there was almost no transfection efficiency when the zeta potential of ternary complexes turned to negative.Because of the suitable pH sensitive range,PGA(60) may be a potential shielding system for polycation gene carriers to be used in vivo.
基金financially supported by the National Natural Science Foundation of China(Nos.51203132,51222307,51303173,51390484,21474104 and 51403205)Natural Science Foundation of Guangdong Province,China(S2012040008070)Foundation for Distinguished Young Talents in Higher Education of Guangdong,China(2012LYM_0093)
文摘For the purpose of increasing the in vivo stability of polycation gene carriers, we prepared a kind of p H-sensitive poly（ethylene glycol）-poly（γ-benzyl-L-glutamate-co-glutamic acid）（PEG-PGA（65）, 65 denotes the molar ratio of glutamic acid in poly（γ-benzyl-L-glutamate-co-glutamic acid））. PEG-PGA（65） showed low cytotoxicity and could shield the positive charge of DNA/PEI（1：1） polyplexes efficiently. The transfection was enhanced due to the partially charge shielding in He La cell line at pH of 7.4. There was almost no transfection efficiency when the surface charge of the ternary particles turned to negative at p H of 7.4. However, the transfection efficiency recovered a lot by culturing at p H of 6.0 at the beginning of transfection. Confocal microscopic observation and flow cytometry results showed DNA/PEI polyplexes should be efficiently released and endocytosized at p H 6.0, because of the p H triggered deshielding action of PEG-PGA（65）. Due to the good biocompatibility and suitable p H triggered shielding/deshielding property, PEG-PGA（65） could be a potential shielding system for polycationic gene carriers used in vivo.
