Hong-Wei Lu

Sun Yat-Sen University, Guangzhou, Guangdong Sheng, China

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Publications (4)0 Total impact

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    ABSTRACT: Hydrophilic amylopectin was modified by grafting hydrophobic poly (lactic acid) chains. The 13C NMR and X-ray diffraction (XRD) analyses confirmed the modification reaction. For the resultant amphiphilic derivatives with various grafting yields, their self-association behavior and micellar aggregates were investigated by fluorometry, transmission electron microscopy and dynamic light scattering. The critical aggregation concentration (cac) was found to be in the range from 0.038 to 0.190 mg/L and the mean diameter (MD) was observed to be in the range from 20.7 to 77.2 nm in aqueous solutions at 25 °C. With the increase of the grafting yield, the cac value decreased while the MD value increased. For the resultant micellar aggregates, their drug loading and in vitro drug release characteristics were studied using indomethacin as the model drug. It was found that such micellar aggregates could be used as potential nanocarriers for drug delivery.
    Carbohydrate Polymers. 01/2011;
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    ABSTRACT: To investigate the inhibitory effect of nanoparticle-mediated endostatin gene therapy on hepatocellular carcinoma xenografts combined with local hyperthermia utilizing heat-inducible promoter. Heat-inducible HSP70B promoter and fusion gene of Endo/EGFP were cloned into pcDNA3.1 (+) plasmid, thus obtaining recombinant plasmid of pcDNA3.1 (+)/HSP70-Endo/EGFP using restriction endonucleases BglII/HindIII and EcoRI/SalI. The nanoparticles polylactide-grafted dextran copolymer (DEX-g-PLA) encapsulating the recombinant plasmid DNA were prepared by the method of emulsification and evaporation of organic solvent, and the surface shape of nanoparticles was observed by transmission electron microscope. Human hepatocellular cells of the lines HepG2 and ECV304 were cultured and transfected with the recombinant plasmid utilizing the nanoparticles. Following thermal induction at 37 degrees C, 39 degrees C, 41 degrees C, 43 degrees C, and 45 degrees C for 30 min, the expression of enhanced green fluorescent protein (EGFP) was detected by fluorescence microscope and flow cytometry. The concentration of endostatin protein in the supernatant was tested by ELISA, and the growth inhibition on the HepG2 and ECV304 cells was tested by MTT method. Balb/c nude mice were inoculated with HeG2 cells and then randomly divided into 2 groups to undergo intra-tumor injection of nanoparticles (heated or not heated), Lipofectamine 2000. Mice were used as controls without intra-tumor injection. Four weeks the mice were killed to observe the tumor inhibition rate. The nanoparticles encapsulating recombinant plasmid were of round or elliptical shape 90 approximately 120 nm in diameter. The efficiency of gene transfection mediated by nanoparticles was about 30.65%. The expression of Endo/EGFP gene in the HepG2 cells was up-regulated along with the increase of temperature, peaked at 43 degrees C (with the EGFP expression level 3.3 times as that at 37 degrees C). The concentration of endostatin protein in the supernatant of the 43 degrees C group was (177 +/- 28) microg/L, significantly higher than that of the 37 degrees C group [(41 +/- 10) microg/L]. MTT results indicated that endostatin inhibited the growth of ECV304 cells with a inhibition rate of 96.3% at the time point of 72 h in the 43 degrees C group, however, it did not show influence on HepG2 cells no matter what was the temperature The tumor inhibition rate in the mice of endostatin with thermal induction group was 58.5%, significantly higher than that of the 37 degrees C group (34.9%, P < 0.05). Low temperature thermal induction enhances the expression and secretion of endostatin in hepatocellular cells transfected by nanoparticles, and inhibits the growth of hepatocellular carcinoma xenografts.
    Zhonghua yi xue za zhi 03/2009; 89(12):795-9.
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    ABSTRACT: A new route for the synthesis of novel amphiphilic polysaccharides was developed, in which a synthetic biodegradable poly(ε-caprolactone) was capped with a phenylalanine group (PCL-phenylalanine). The ring-opening polymerization of ε-caprolactone (ε-CL) was carried out in the absence of a metal catalyst with L-phenylalanine as the initiator; this was followed by a coupling reaction with biodegradable dextran in the presence of carbonyldimidazole. The FTIR and 1H NMR analyses confirm the coupling reaction. Fluorescence, transmission electron microscopy (TEM), and dynamic light scattering (DLS) confirm that in aqueous solution the amphiphilic polysaccharides self-assemble into the nanoscale spherical micelles with good stability. The in vitro drug release behavior of the nonsteroidal indomethacin drug exhibits sustained drug release profile as described by the Higuchi model without a burst effect.
    Journal of Bioactive and Compatible Polymers - J BIOACT COMPAT POLYM. 01/2008; 23(2):154-170.
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    ABSTRACT: Biodegradable colloidal nano-micelles is a novel targeting drug delivery and controlled release system, which could prolong the biological half-life and lighten the toxicity of chemotherapeutant, meanwhile, present fine biocompatibility. This study was to prepare the biodegradable 5-fluorouracil (5-FU)/DEX-g-PLA nano-micelles, and investigate their killing effect on hepatocarcinoma cell line HepG2 in vitro and in vivo. 5-FU/DEX-g-PLA nano-micelles were prepared by 'self-assembly'. Its morphology was observed by transmission electron microscopy. The encapsulating efficiency of 5-FU was determined by ultraviolet spectrophotometry. The in vivo releasing of 5-FU from nano-micelles was investigated by high-performance liquid chromatography (HPLC). The inhibitory effect of 5-FU/DEX-g-PLA on HepG2 cells in vitro was measured by MTT assay. 5-FU/DEX-g-PLA nano-micelles were round or elliptical; the diameter was about 50 nm. The encapsulating efficiency was about 9.3%. The concentration of 5-FU released from 5-FU/DEX-g-PLA nano-micelles was sustained for longer time than that of the naked drug. The in vitro inhibition rate of cell growth was similar in 5-FU/DEX-g-PLA group and naked 5-FU group (58.8% vs. 58.0%, P>0.05); the in vivo inhibition rate of tumor growth was significantly higher in 5-FU/DEX-g-PLA group than in naked 5-FU group (73.1% vs. 57.5%, P<0.05). 5-FU/DEX-g-PLA nano-micelles can effectively inhibit the growth of HepG2 cells.
    Ai zheng = Aizheng = Chinese journal of cancer 01/2007; 25(12):1459-63.