Fe3O4/Au composite particles with core/shell structure were prepared by reduction of Au3+ with hydroxylamine in the presence of an excess of Fe3O4 as seeds.The resultant col-loids,with an average diameter of less than...Fe3O4/Au composite particles with core/shell structure were prepared by reduction of Au3+ with hydroxylamine in the presence of an excess of Fe3O4 as seeds.The resultant col-loids,with an average diameter of less than 100 nm,were obtained;the remaining non-reacted Fe3O4 seeds can be removed by treatment with diluted HCl solution.The Fe3O4/Au colloids ex-hibit a characteristic peak of UV-visible spectra,which largely depend on the size of the particle and the suspension medium.The localized surface plasmon resonance peaks red shift and broaden with increased nanoparticle diameter or increased solvent ionic strength.The optical property is very important in the establishment of means for the detection of biomolecules.展开更多
Using Fe3O4 nano-particles as seeds, a new type of Fe3O4/Au composite particles with core/shell structure and diameter of about 170 nm was prepared by reduction of Au3+ with hydroxylamine in an aqueous solution. Parti...Using Fe3O4 nano-particles as seeds, a new type of Fe3O4/Au composite particles with core/shell structure and diameter of about 170 nm was prepared by reduction of Au3+ with hydroxylamine in an aqueous solution. Particle size analyzer and transmission electron micro-scope were used to analyze the size distribution and microstructure of the particles in different conditions. The result showed that the magnetically responsive property and suspension stability of Fe3O4 seeds as well as reduction conditions of Au3+ to Au0 are the main factors which are crucial for obtaining a colloid of the Fe3O4/Au composite particles with uniform particle dispersion, excellent stability, homogeneity in particle sizes, and effective response to an external magnet in aqueous suspension solutions. UV-Vis analysis revealed that there is a characteristic peak of Fe3O4/Au fluid. For particles with d(0.5)=168 nm, the lmax is 625 nm.展开更多
Superparamagnetism amination nanocrystals Fe3O4 with 3-aminopropyltriethyloxy silane (APTES) were prepared by modified co-precipitation method. Next, 4―5 nm gold nanoparticles, prepared by classical Frens procedure, ...Superparamagnetism amination nanocrystals Fe3O4 with 3-aminopropyltriethyloxy silane (APTES) were prepared by modified co-precipitation method. Next, 4―5 nm gold nanoparticles, prepared by classical Frens procedure, were coated on the surface of the amination Fe3O4 by self-assembly technology. The prepared Fe3O4@Au nanocomposite particles were investigated by transmission electron microscopy (TEM), UV-vis, infrared spectrum (FT-IR), and vibrating sample magnetometer (VSM) in order to eluci-date the morphology, optics and magnetic properties of the nanocomposites. Their uniform distribution of particle size,which is about 15 nm , and good magnetic responsiveness were observed. In view of the fact that Fe3O4 owns superparamagnetism and that nano-gold can readily combine with biological molecules, glucose oxidase (GOx) was chosen as a model to penetrate the condition of immobilizing enzyme, and enzymatic properties of resultant immobilized enzyme were studied as well. By systematic optimization, we established that at 28℃, and pH (5.5) and when mole ratio of Fe3O4:HAuCl4 was 0.5:1, the immobilization provided the best results. Finally, we are glad to find that the immobilized enzyme exhibits excellent thermostability in addition to its better stability than free enzyme. Thus, herein described immobilized enzyme could be used repeatedly with the assistance of an external magnetic field.展开更多
Enhancement of Fe3O4/Au nanoparticles （Fe3O4/Au NPs） catalyst was observed in the oxidative degradation of methyl orange by employing H2O2 as oxidant. To evaluate the catalytic activity of Fe3O4/Au nanoparticles, di...Enhancement of Fe3O4/Au nanoparticles （Fe3O4/Au NPs） catalyst was observed in the oxidative degradation of methyl orange by employing H2O2 as oxidant. To evaluate the catalytic activity of Fe3O4/Au nanoparticles, different degradation conditions were investigated such as the amounts of catalyst, H2O2 concentration and pH value. Based on our data, methyl orange was degraded completely in a short time. The enhanced catalytic activity and increased oxidation rate constant may be ascribed to synergistic catalyst-activated decomposition of H2O2 to ,OH radical, which was one of the strong oxidizing species. Besides, Fe3O4/Au nanoparticles have exhibited satisfying recycle performance for potential industrial application.展开更多
The development of multifunctional contrast agents contributes significant character in the diagnosis of cancer. However, still efforts are required to design and improve the biocompatibility of contrast agents for ea...The development of multifunctional contrast agents contributes significant character in the diagnosis of cancer. However, still efforts are required to design and improve the biocompatibility of contrast agents for early detection of cancer. Herein, we synthesized splat shape Fe_3O_4/Au nanocomposites for multimode biomedical applications. Transmission electron microscopy(TEM) results showed that the splat-like Fe_3O_4/Au structure was in the range of 130 nm and homogeneously distributed in the aqueous medium. The nanocomposites were incubated with MCF-7 cells to investigate the magnetic resonance imaging(MRI) and surface-enhanced Raman scattering(SERS) activities. The excellent T_2 MRI and enhanced SERS properties were obtained without any cytotoxicity. These results demonstrated that assynthesized splat-shaped Fe_3O_4/Au nanocomposites may be a promising MRI/SERS dual probe for the tumor detection.展开更多
Objective： To establish a method of genomic DNA extraction from whole blood using Fe3O4/Au composite particles as a carrier. Methods： Two crucial conditions （sodium chloride concentration and amount of the magnetic...Objective： To establish a method of genomic DNA extraction from whole blood using Fe3O4/Au composite particles as a carrier. Methods： Two crucial conditions （sodium chloride concentration and amount of the magnetic particles） were optimized and 8 different human whole blood samples were used to purify genomic DNA under the optimal condition. Then agarose gel electrophoresis and polymerase cbain reaction （PCR） were performed. Results： The optimal binding condition was 1.5 mol/L NaC1/10% PEG, and the optimal amount of Fe3O4/Au composite particles was 600μg. The yields of the genomic DNA from 100μl of different whole blood samples were 2-5 μg, and the ratio of A260/A280 was in the range of 1.70-1.90. The size of genomic DNA was about 23 kb and the PCR was valid. Conclusion： The purification system using Fe3O4/Au composite microparticles has advantages in high yield, high purity, ease of operating, time saving and avoiding centrifugation. The purified sample was found to function satisfactorily in PCR amplification.展开更多
基金the National Natural Science Foundation of China(Grant No.20273050) the Nat ional High Technology Research and Development Program of China(Grant Nos.2002AA2Z2031&2003AA2Z2080).
文摘Fe3O4/Au composite particles with core/shell structure were prepared by reduction of Au3+ with hydroxylamine in the presence of an excess of Fe3O4 as seeds.The resultant col-loids,with an average diameter of less than 100 nm,were obtained;the remaining non-reacted Fe3O4 seeds can be removed by treatment with diluted HCl solution.The Fe3O4/Au colloids ex-hibit a characteristic peak of UV-visible spectra,which largely depend on the size of the particle and the suspension medium.The localized surface plasmon resonance peaks red shift and broaden with increased nanoparticle diameter or increased solvent ionic strength.The optical property is very important in the establishment of means for the detection of biomolecules.
基金This work was supported by the National Natural Science Foundation of China(Grant No.20273035)the National High Technology Research and Development Program of China(863 Program)(Grant Nos.2002AA2Z2031 and 2001AA224032)the Science and Technology Program of Xi'an(Grant No.GG200148).
文摘Using Fe3O4 nano-particles as seeds, a new type of Fe3O4/Au composite particles with core/shell structure and diameter of about 170 nm was prepared by reduction of Au3+ with hydroxylamine in an aqueous solution. Particle size analyzer and transmission electron micro-scope were used to analyze the size distribution and microstructure of the particles in different conditions. The result showed that the magnetically responsive property and suspension stability of Fe3O4 seeds as well as reduction conditions of Au3+ to Au0 are the main factors which are crucial for obtaining a colloid of the Fe3O4/Au composite particles with uniform particle dispersion, excellent stability, homogeneity in particle sizes, and effective response to an external magnet in aqueous suspension solutions. UV-Vis analysis revealed that there is a characteristic peak of Fe3O4/Au fluid. For particles with d(0.5)=168 nm, the lmax is 625 nm.
基金Supported by the Science Foundation of Sichuan Province, China (Grant No. 2005A033)Science Foundation of Sichuan Agricultural University for Distinguished Young Teachers (Grant No. 007202)
文摘Superparamagnetism amination nanocrystals Fe3O4 with 3-aminopropyltriethyloxy silane (APTES) were prepared by modified co-precipitation method. Next, 4―5 nm gold nanoparticles, prepared by classical Frens procedure, were coated on the surface of the amination Fe3O4 by self-assembly technology. The prepared Fe3O4@Au nanocomposite particles were investigated by transmission electron microscopy (TEM), UV-vis, infrared spectrum (FT-IR), and vibrating sample magnetometer (VSM) in order to eluci-date the morphology, optics and magnetic properties of the nanocomposites. Their uniform distribution of particle size,which is about 15 nm , and good magnetic responsiveness were observed. In view of the fact that Fe3O4 owns superparamagnetism and that nano-gold can readily combine with biological molecules, glucose oxidase (GOx) was chosen as a model to penetrate the condition of immobilizing enzyme, and enzymatic properties of resultant immobilized enzyme were studied as well. By systematic optimization, we established that at 28℃, and pH (5.5) and when mole ratio of Fe3O4:HAuCl4 was 0.5:1, the immobilization provided the best results. Finally, we are glad to find that the immobilized enzyme exhibits excellent thermostability in addition to its better stability than free enzyme. Thus, herein described immobilized enzyme could be used repeatedly with the assistance of an external magnetic field.
基金This work was supported by the National Natural Science Foundation of China （No. 21303136）.
文摘Enhancement of Fe3O4/Au nanoparticles （Fe3O4/Au NPs） catalyst was observed in the oxidative degradation of methyl orange by employing H2O2 as oxidant. To evaluate the catalytic activity of Fe3O4/Au nanoparticles, different degradation conditions were investigated such as the amounts of catalyst, H2O2 concentration and pH value. Based on our data, methyl orange was degraded completely in a short time. The enhanced catalytic activity and increased oxidation rate constant may be ascribed to synergistic catalyst-activated decomposition of H2O2 to ,OH radical, which was one of the strong oxidizing species. Besides, Fe3O4/Au nanoparticles have exhibited satisfying recycle performance for potential industrial application.
基金financially supported by the National Natural Science Foundation of China (Nos. 21305148, U1732127, U1432114, 51303196)the Ningbo Natural Science Foundation Nos. 2014A610159, 2014B82010, 2015C50004, 2015B11002, 2016A610013, 2017C110022)+2 种基金Zhejiang Province (Nos. Bsh1202031, 2017C33129, 2017C03042,12018KY737 andLY18H180011)Zhejiang Pharmaceutical College (No. ZPCSR2015013)Hundred Talents Program of Chinese Academy of Sciences (No. 2010-735)
文摘The development of multifunctional contrast agents contributes significant character in the diagnosis of cancer. However, still efforts are required to design and improve the biocompatibility of contrast agents for early detection of cancer. Herein, we synthesized splat shape Fe_3O_4/Au nanocomposites for multimode biomedical applications. Transmission electron microscopy(TEM) results showed that the splat-like Fe_3O_4/Au structure was in the range of 130 nm and homogeneously distributed in the aqueous medium. The nanocomposites were incubated with MCF-7 cells to investigate the magnetic resonance imaging(MRI) and surface-enhanced Raman scattering(SERS) activities. The excellent T_2 MRI and enhanced SERS properties were obtained without any cytotoxicity. These results demonstrated that assynthesized splat-shaped Fe_3O_4/Au nanocomposites may be a promising MRI/SERS dual probe for the tumor detection.
基金Supported by the National High Technology Research and Development Program of China (2006AA020705)
文摘Objective： To establish a method of genomic DNA extraction from whole blood using Fe3O4/Au composite particles as a carrier. Methods： Two crucial conditions （sodium chloride concentration and amount of the magnetic particles） were optimized and 8 different human whole blood samples were used to purify genomic DNA under the optimal condition. Then agarose gel electrophoresis and polymerase cbain reaction （PCR） were performed. Results： The optimal binding condition was 1.5 mol/L NaC1/10% PEG, and the optimal amount of Fe3O4/Au composite particles was 600μg. The yields of the genomic DNA from 100μl of different whole blood samples were 2-5 μg, and the ratio of A260/A280 was in the range of 1.70-1.90. The size of genomic DNA was about 23 kb and the PCR was valid. Conclusion： The purification system using Fe3O4/Au composite microparticles has advantages in high yield, high purity, ease of operating, time saving and avoiding centrifugation. The purified sample was found to function satisfactorily in PCR amplification.
