Showing papers by "Yao Fu published in 2007"

Randomly 50% N-acetylated low molecular weight chitosan as a novel renal targeting carrier.

Abstract: Selective targeting of drugs to kidneys may improve renal effectiveness and reduce extrarenal toxicity. Using fluorescence imaging, we found for the first time that randomly 50% N-acetylated low molecular weight chitosan (LMWC) selectively accumulated in the kidneys, especially in the renal tubules after i.v. injection in mice. To develop and evaluate the novel renal drug carrier, prednisolone, used as a model drug, was covalently coupled with various molecular weight LMWCs via a succinic acid spacer. The mean residence time (MRT) in plasma of prednisolone conjugates increased as the molecular weight increased. The conjugate with molecular weight 19 kD (conjugate-19k) displayed the highest accumulation rate in the kidneys, which was 14.06 ± 2.81% of the administered dose 15 min after i.v. injection. The total amount of the conjugate-19k in the kidneys was 13-fold higher than that of controlled prednisolone group. Both conjugate-19k and conjugate-31k had higher retention and about 10% of injected dose was ...

Characterization of transferrin-modified procationic-liposome protamine-DNA complexes

Abstract: We developed a novel transferrin modied non-viral gene delivery system, transferrin-modied procationic- liposome-protamine-DNA complexes (Tf-PLPD) and investigated its characteristics. Blank procationic liposomes were prepared using thelm dispersionlter method. Protamine was used to condense plasmid DNA to form protamine-D- NA complexes and the complexes were further incubated with blank procationic liposomes to form PLPD. Transferrin was adsorbed onto the surface of PLPD via an electrostatic interaction, and thus Tf-PLPD was produced. Characteris- tics such as stability in rat serum, morphology, average particle size, zeta potential, and transfection e‹ciency in HepG2 cells were further investigated. The results indicated that the procationic liposomes remained stable in rat serum for 24 h. Tf-PLPD protected plasmid DNA from enzymatic degradation even after lyophilization. The size distribution of Tf- PLPD was in the range of 240±12 nm and the zeta potential was-24.10±2.5 mV (n=3), respectively. The transfec- tion e‹ciencies of Tf-PLPD were 24.26±2.6 mU b-galactosidase/mg protein. Lyophilization and the presence of serum did not aSect the transfectivity of Tf-PLPD and the procationic liposomes also had low cytotoxicity to cells. Key words―procationic liposomes; transferrin; transfection e‹ciency; stability

Investigation on characterization and transfection of a novel multi-polyplex gene delivery system

Abstract: pDNA was condensed by polycationic peptide polylysine (PLL) to form a core, and then encapsulated in biodegradable monomethoxy (poly ethylene glycol)-poly(lactide-co-glycolide)-monomethoxy (poly ethylene glycol) (PELGE) to form core-shell nanoparticles (NPs) as a novel multi-polyplex gene delivery system—PPD(PELGE-PLL-DNA). NPs were prepared by a double emulsification-solvent evaporation technique, using F68 (Pluronic F68, namely Poloxamer 188) as surfactant (not traditional stabilizer PVA), and characterized by morphology, particle size, zeta potential, nuclease, and sonication protection ability, as well as transfection efficiency. Results showed that PPD had a regular spherical shape, with an average diameter of 155 ± 2.97 nm and a zeta potential of −25.6 ± 1.35 mV. PPD could protect plasmid DNA from nuclease degradation and sonication during preparation, while the transfection efficiencies in HepG2 cells and Hela cells were much higher than that of NPs without PLL. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007