Several bacterial strains of Actinomycetes belonging to Streptomyces and Arthrobacter genera for the first time were used to study the biotechnology of synthesis of gold and silver nanoparticles. The experimental cond...Several bacterial strains of Actinomycetes belonging to Streptomyces and Arthrobacter genera for the first time were used to study the biotechnology of synthesis of gold and silver nanoparticles. The experimental conditions of gold and silver nanoparticles production by the cells of studied strains in aqueous chloroauric acid （HAuCIq） and in silver nitrate （AgNO3） solutions, respectively, were determined. Concentration and time-dependences of nanoparticle formation were investigated. The complex of optical and analytical methods was used for testing the gold and silver nanoparticles in the bacterial biomass. The TEM （Transmission Electron Microscopy） and XRD （X-ray Diffraction） data in all cases demonstrated the presence of crystals with fcc （face centered cubic） structure. The results obtained show that the Actinomycetes are capable of producing gold and silver nanoparticles of spherical shape extracellularly when exposed to suitable compounds. The particle size distribution shows that the sizes of nanoparticles are in the range of 5 nm to 80 nm. The biomass obtained may be used for industrial as well as medical and pharmaceutical purposes.展开更多
Spirulina platensis were chosen as templates to produce microscopic helical soft-core magnetic particles by way of depositing ferromagnetic alloy onto their surface using electroplating technique,and the process of el...Spirulina platensis were chosen as templates to produce microscopic helical soft-core magnetic particles by way of depositing ferromagnetic alloy onto their surface using electroplating technique,and the process of electroplating ferromagnetic alloy onto microorganism cells was studied.The morphology and appearance of the coated Spirulina platensis were analyzed with optical microscopy and scanning electron microscopy,respectively,and the ingredients and phase structure of the alloy coating were analyzed with energy dispersive X-ray detector(EDX) and X-ray diffractive analysis(XRD),respectively.The result showed that the particles were successfully coated with uniform metal coating and their initial helical shape was perfectly replicated.The coating was NiFe alloy,and its phase structure was face-centered cubic structure.The magnetic properties of the coated particles were tested with vibrating sample magnetometer(VSM),and the result showed that the particles were ferro-magnetic,which means the magnetic electroplating of the microorganism cells was successfully achieved.The electrochemical reaction mechanism of the magnetic plating process was also analyzed;the result showed that the deposition of NiFe on the microorganism cells was anomalous codeposition,and that Fe2+ ion was preferential deposited when magnetic stirring was applied.展开更多
With the development of science and technology,ordered microstructures with special functions have aroused intense research interest.These functional microstructures have been widely used in fields of microelectronic ...With the development of science and technology,ordered microstructures with special functions have aroused intense research interest.These functional microstructures have been widely used in fields of microelectronic devices,micro-reactors,biochemical sensors and optical devices,etc.This paper summaries our work on preparation and application of microscopic patterned surfaces with ordered microstructures,and looks into the future development of this field.展开更多
文摘Several bacterial strains of Actinomycetes belonging to Streptomyces and Arthrobacter genera for the first time were used to study the biotechnology of synthesis of gold and silver nanoparticles. The experimental conditions of gold and silver nanoparticles production by the cells of studied strains in aqueous chloroauric acid （HAuCIq） and in silver nitrate （AgNO3） solutions, respectively, were determined. Concentration and time-dependences of nanoparticle formation were investigated. The complex of optical and analytical methods was used for testing the gold and silver nanoparticles in the bacterial biomass. The TEM （Transmission Electron Microscopy） and XRD （X-ray Diffraction） data in all cases demonstrated the presence of crystals with fcc （face centered cubic） structure. The results obtained show that the Actinomycetes are capable of producing gold and silver nanoparticles of spherical shape extracellularly when exposed to suitable compounds. The particle size distribution shows that the sizes of nanoparticles are in the range of 5 nm to 80 nm. The biomass obtained may be used for industrial as well as medical and pharmaceutical purposes.
基金supported by the National High Technology Research and Development Program of China (Grant No 2009AA043804)Foundation for the Author of National Excellent Doctoral Dissertation of PR China (Grant No 2007B32)
文摘Spirulina platensis were chosen as templates to produce microscopic helical soft-core magnetic particles by way of depositing ferromagnetic alloy onto their surface using electroplating technique,and the process of electroplating ferromagnetic alloy onto microorganism cells was studied.The morphology and appearance of the coated Spirulina platensis were analyzed with optical microscopy and scanning electron microscopy,respectively,and the ingredients and phase structure of the alloy coating were analyzed with energy dispersive X-ray detector(EDX) and X-ray diffractive analysis(XRD),respectively.The result showed that the particles were successfully coated with uniform metal coating and their initial helical shape was perfectly replicated.The coating was NiFe alloy,and its phase structure was face-centered cubic structure.The magnetic properties of the coated particles were tested with vibrating sample magnetometer(VSM),and the result showed that the particles were ferro-magnetic,which means the magnetic electroplating of the microorganism cells was successfully achieved.The electrochemical reaction mechanism of the magnetic plating process was also analyzed;the result showed that the deposition of NiFe on the microorganism cells was anomalous codeposition,and that Fe2+ ion was preferential deposited when magnetic stirring was applied.
基金supported by the National Natural Science Foundation of China (20921003,20534040 & 20874039)the National Basic Research Program of China (2007CB936402)
文摘With the development of science and technology,ordered microstructures with special functions have aroused intense research interest.These functional microstructures have been widely used in fields of microelectronic devices,micro-reactors,biochemical sensors and optical devices,etc.This paper summaries our work on preparation and application of microscopic patterned surfaces with ordered microstructures,and looks into the future development of this field.
