RESUMO
The effects of cetyltrimethylammonium bromide ( CTAB) , ascorbic acid, NaBH4 and AgNO3 , as well as the stirring time and reaction time on the preparation of gold nanorods synthesized with seedless growth method were studied. The optimum preparation conditions were obtained in the process of growth of gold nanorods. The gold nanorods prepared under different conditions were characterized by visible absorption spectroscopy and transmission electron microscopy ( TEM ) . Under the optimum conditions such as room temperature, 0. 1 mol/L CTAB, 96 μmol/L AgNO3 , 0. 97 mmol/L ascorbic acid, 1. 5 μmol/L NaBH4 and stirring for 25 s, micro-sized gold nanorods with uniform morphology, good dispersibility, small shaft width and high aspect ratio were prepared within 6 h. The gold nanorods were expected to be applied to the detection of mercury ion in water environment.
RESUMO
The effects of cetyltrimethylammonium bromide ( CTAB) , ascorbic acid, NaBH4 and AgNO3 , as well as the stirring time and reaction time on the preparation of gold nanorods synthesized with seedless growth method were studied. The optimum preparation conditions were obtained in the process of growth of gold nanorods. The gold nanorods prepared under different conditions were characterized by visible absorption spectroscopy and transmission electron microscopy ( TEM ) . Under the optimum conditions such as room temperature, 0. 1 mol/L CTAB, 96 μmol/L AgNO3 , 0. 97 mmol/L ascorbic acid, 1. 5 μmol/L NaBH4 and stirring for 25 s, micro-sized gold nanorods with uniform morphology, good dispersibility, small shaft width and high aspect ratio were prepared within 6 h. The gold nanorods were expected to be applied to the detection of mercury ion in water environment.
RESUMO
The increasing uses of zinc oxide nanoparticles (nZnO) in industrial and personal care products raise possible danger of using nZnO in human. To determine whether ZnO induces size-dependent anomalies during embryonic organogenesis, mouse embryos on embryonic day 8.5 were cultured for 2 days under 50, 100, and 150 microg of nZnO (< 100 nm) or micro-sized ZnO (mZnO; 80 +/- 25 microm), after which the morphological changes, cumulative quantity of Zn particles, and expressions of antioxidant and apoptotic genes were investigated. Although embryos exposed to 50 microg of ZnO exhibited no defects on organogenesis, embryos exposed to over 100 microg of ZnO showed increasing anomalies. Embryos treated with 150 microg of nZnO revealed significant changes in Zn absorption level and morphological parameters including yolk sac diameter, head length, flexion, hindbrain, forebrain, branchial bars, maxillary process, mandibular process, forelimb, and total score compared to the same dose of mZnO-treated embryos. Furthermore, CuZn-superoxide dismutase, cytoplasmic glutathione peroxidase (GPx) and phospholipid hydroperoxidase GPx mRNA levels were significantly decreased, but caspase-3 mRNA level was greatly increased in nZnO-treated embryos as compared to normal control embryos. These findings indicate that nZnO has severer teratogenic effects than mZnO in developing embryos.