Biochip as a new research field has enjoyed its rapid development in the past 10 years. Using microfabrication technology, thousands or hundred thousands of biological molecules can be assembled on a centimeter square...Biochip as a new research field has enjoyed its rapid development in the past 10 years. Using microfabrication technology, thousands or hundred thousands of biological molecules can be assembled on a centimeter square microchip. Those chip-based devices can be used to analyze mutations, antigens, cells, etc. Compared with the traditional analytical instruments, chip-based micro total analytical systems have many advantages, such as reduced size, lower consumption of both reagents and energy contamination-free, etc. Biochip technology is believed to revolutionize the future research in life sciences, disease diagnosis, drug discovery forensic sciences and outer space exploitation in the coming展开更多
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.Particle...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
Micrometer-sized Fe3O4 particles and nano-sized gold particles were first synthesized by methods of self-aggregation of surface-chemically modified Fe3O4 nanoparticles and citrate reduction of the Au3+to Au0,respectiv...Micrometer-sized Fe3O4 particles and nano-sized gold particles were first synthesized by methods of self-aggregation of surface-chemically modified Fe3O4 nanoparticles and citrate reduction of the Au3+to Au0,respectively.Interaction between these two types of particles resulted in the assembly of nano-sized gold particles on the surface of the micrometer-sized Fe3O4 particles,forming an assembled structure with the Fe3O4 core particles around which are attached nano-sized gold parti-cles.The Fe3O4/Au structure is named GoldMag particles with assembled structure.The synthetic process,structure,and magnetic property of the GoldMag particles were analyzed.GoldMag particles with assembled structure have an irregular shape,rough surface with a diameter of 2―3μm.These particles exhibit the superparamagnetic property with saturated magnetization of 41 A·m2/kg.In a single step,antibodies could be readily immobilized onto the surface of the particles with a high binding capacity.The GoldMag particles can be used as a novel carrier in immunoassays.The maximum quantity of human IgG immobilized onto GoldMag particles was 330μg/mg.In order to validate the quality of the GoldMag particles as immunoassay carriers,an immunoassay system was used.The relative amount of immobilized human IgG was measured by HRP-labeled anti human IgG.The coefficient of variation within parallel samples of each group was below 6%and the coefficient of variation of means between five groups carried out separately was below 7%.Based on the sandwich method,the Hepatitis B surface antigen(HBsAg)and interleukin-8(IL-8)were also analyzed by qualitative and quantitative detection,respectively.The result indicated that the GoldMag particles with assembled structure were an ideal carrier in immunoassay.展开更多
Two kinds of streptavidin magnetic particles,namely streptavidin GoldMag particles and streptavidin amino terminal particles were prepared by the methods of physical adsorption and covalent interaction respectively.Th...Two kinds of streptavidin magnetic particles,namely streptavidin GoldMag particles and streptavidin amino terminal particles were prepared by the methods of physical adsorption and covalent interaction respectively.The streptavidin coated on magnetic particle surface,crucial to many applications,was greatly influenced by the choice of the different buffer.Compared with DynalbeadsM-270 streptavidin, the binding capacity for biotin of different streptavidin magnetic particles was determined by enzyme inhibition method,and the coupling capacity and activity of biotinylated oligonucleotide on their sur- face were also analyzed.The results indicated that the streptavidin GoldMag particle prepared by physical adsorption was stable in STE(NaCl-Tris-EDTA)buffer that was frequently used in nucleic acid hybridization and detection.The streptavidin amino terminal particles prepared by covalent interaction could be used both in STE buffer and PBS(phosphate buffered saline)buffer.The biotin binding ca- pacity for 1 mg of streptavidin GoldMag particles and streptavidin amino terminal particles was 4950 and 5115 pmol respectively.The capacity of biotinylated oligonucleotide(24 bp)coupled on 1 mg of GoldMag and amino terminal magnetic particles was 2839 and 2978 pmol separately.These data were about 6-7 times higher than those of DynabeadsM-270 streptavidin.The hybridization results with FITC-labeled complementary probe on magnetic particle surface demonstrated that the oligonucleotide coupled on streptavidin magnetic particles had high biological activity.展开更多
文摘Biochip as a new research field has enjoyed its rapid development in the past 10 years. Using microfabrication technology, thousands or hundred thousands of biological molecules can be assembled on a centimeter square microchip. Those chip-based devices can be used to analyze mutations, antigens, cells, etc. Compared with the traditional analytical instruments, chip-based micro total analytical systems have many advantages, such as reduced size, lower consumption of both reagents and energy contamination-free, etc. Biochip technology is believed to revolutionize the future research in life sciences, disease diagnosis, drug discovery forensic sciences and outer space exploitation in the coming
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 National Natural Science Foundation of China(Grant No.20273050)the National High Technology Research and Development Program of China(Grant Nos.2003AA2Z2031 and 2005AA205220)
文摘Micrometer-sized Fe3O4 particles and nano-sized gold particles were first synthesized by methods of self-aggregation of surface-chemically modified Fe3O4 nanoparticles and citrate reduction of the Au3+to Au0,respectively.Interaction between these two types of particles resulted in the assembly of nano-sized gold particles on the surface of the micrometer-sized Fe3O4 particles,forming an assembled structure with the Fe3O4 core particles around which are attached nano-sized gold parti-cles.The Fe3O4/Au structure is named GoldMag particles with assembled structure.The synthetic process,structure,and magnetic property of the GoldMag particles were analyzed.GoldMag particles with assembled structure have an irregular shape,rough surface with a diameter of 2―3μm.These particles exhibit the superparamagnetic property with saturated magnetization of 41 A·m2/kg.In a single step,antibodies could be readily immobilized onto the surface of the particles with a high binding capacity.The GoldMag particles can be used as a novel carrier in immunoassays.The maximum quantity of human IgG immobilized onto GoldMag particles was 330μg/mg.In order to validate the quality of the GoldMag particles as immunoassay carriers,an immunoassay system was used.The relative amount of immobilized human IgG was measured by HRP-labeled anti human IgG.The coefficient of variation within parallel samples of each group was below 6%and the coefficient of variation of means between five groups carried out separately was below 7%.Based on the sandwich method,the Hepatitis B surface antigen(HBsAg)and interleukin-8(IL-8)were also analyzed by qualitative and quantitative detection,respectively.The result indicated that the GoldMag particles with assembled structure were an ideal carrier in immunoassay.
基金the National Natural Science Foundation of China(Grant No.20273050)the National High Technology Research and Development Programof China(Grant No.2005AA205220)
文摘Two kinds of streptavidin magnetic particles,namely streptavidin GoldMag particles and streptavidin amino terminal particles were prepared by the methods of physical adsorption and covalent interaction respectively.The streptavidin coated on magnetic particle surface,crucial to many applications,was greatly influenced by the choice of the different buffer.Compared with DynalbeadsM-270 streptavidin, the binding capacity for biotin of different streptavidin magnetic particles was determined by enzyme inhibition method,and the coupling capacity and activity of biotinylated oligonucleotide on their sur- face were also analyzed.The results indicated that the streptavidin GoldMag particle prepared by physical adsorption was stable in STE(NaCl-Tris-EDTA)buffer that was frequently used in nucleic acid hybridization and detection.The streptavidin amino terminal particles prepared by covalent interaction could be used both in STE buffer and PBS(phosphate buffered saline)buffer.The biotin binding ca- pacity for 1 mg of streptavidin GoldMag particles and streptavidin amino terminal particles was 4950 and 5115 pmol respectively.The capacity of biotinylated oligonucleotide(24 bp)coupled on 1 mg of GoldMag and amino terminal magnetic particles was 2839 and 2978 pmol separately.These data were about 6-7 times higher than those of DynabeadsM-270 streptavidin.The hybridization results with FITC-labeled complementary probe on magnetic particle surface demonstrated that the oligonucleotide coupled on streptavidin magnetic particles had high biological activity.
