Effects of aqueous-organic solvents on peroxidase mimetic activity of Fe3O4 magnetic nanoparticles / 生物工程学报

We prepared Fe3O4 magnetic nanoparticles (MNPs) with the size of 10 nm by chemical coprecipitation. The effects of six aqueous-organic solvents, including tetrahydrofuran, dioxane, acetone, N, N-Dimethylformamide, methylalcohol, and Dimethyl Sulfoxide, on peroxidase mimetic activity of Fe3O4 MNPs were studied and compared with that of horseradish peroxidase (HRP). The relative activity of Fe3O4 MNPs droped sharply as the elevation of organic solvent concentration increased from 30% to 75% (V/V). In 15% organic solutions, the optimum activity of Fe3O4 MNPs was observed around 50 degrees C, under pH 3.6. After being treated at different temperatures and pH in 15% organic solutions, even under 75% concentration, Fe3O4 MNPs still preserved most of the activity when reacting in aqueous phase. The catalytic performances of Fe3O4 MNPs under given conditions were generally more superior to that of HRP. For it costs lower and it is easy to be prepared and segregated magnetically for recycle, to use the magnetic nanoparticles as a substitution for HRP has potential to be applied into organic catalysis.

Effect of nanometer magnetic interferon-?_2b liposome on expression of VEGF and Caspase-3 in the process of targeting therapy Human Hepatocelluar carcinoma Implants of Nude Mice / 中国药理学通报

Aim To evaluate the effect and mechanism of vascular endothelial growth factor(VEGF) and Cysteine protease aspartic acid-3(Caspase-3) inhibition of human hepatocellular carcinoma(HCC)implants in nude mice by nanometer magnetic interferon-?2b liposome targeting therapy.Methods Thirty nude mices bearing human HCC were divided into 5 groups of 6 mice:group 1,saline(NS);group 2,free interferon-?2b group(IFN);group 3,interfe-ron-?2b liposome group(IL);group 4,magnetic liposome group(ML);group 5,nanometer magnetic interferon-?2b liposome group(MIL).Above dosage of 200 ?l/nude mice was respectively injected through the caudal vein in these 6 groups.Meantime,magnetic field with the strength of 5000 GS was added to the tumor surface about 30 min,and this therapy was done three times.After 30 days,the mices were killed and the tumors were taken out.The difference at the mRNA expression level of VEGF and Caspase-3 was observed by RT-PCR between the experimental group and control group.The protein expression level of VEGF and Caspase-3 was detected by western blot between the experimental group and control group.Results Targeting therapy study in nude mice bearing human HCC displayed that the growth speed of tumor in the MIL group significantly slowed down than other groups.The tumor inhibition rate of MIL group was 62.50%,which was remarkably higher than those of the IFN group(27.61%) and IL group(28.17%).RT-PCR showed that the mRNA expression of VEGF of MIL group is the lowest of all groups(P