Nanoparticles in ambient air. measurement methods

Methods for the measurement of the parameters of aerosol particles with the use of an analyzer based on the differential mobility of nanoparticles and with a diffusion aerosol spectrometer are described and tested. A comparison of the results of measurements of the diameters of nanoparticles by the two methods is performed. Results of inter-laboratory comparisons of the analyzers based on the differential mobility of nanoparticles and studies of the electric motors of household appliances which are generators of the aerosols of nanoparticles with dimensions in the range 6–50 nm are presented.     

纳米颗粒的应用

纳米颗粒具有传统尺度颗粒所没有的独特性能,从而得到人们的重视,并被广泛应用。就纳米颗粒的力学、磁学、电学、光学、敏感、催化性能等方面的特性和应用进行归纳总结,并分析概述了在生物医学、工业填料等方面的应用。     

Antibacterial Characterization of Silver Nanoparticles against E. Coli ATCC-15224

Silver nanoparticles of mean size 16 nm were synthesized by inert gas condensation （IGC） method. Crystalline structure, morphology and nanoparticles size estimation were conducted by X-ray diffraction （XRD） and transmission electron microscopy （TEM）. Antibacterial activity of these silver nanoparticles as a function of particles concentration against gram-negative bacterium Escherichia coli （E. coli） was carried out in liquid as well as solid growth media. Scanning electron microscopy （SEM） and TEM studies showed that silver nanoparticles after interaction with E.coli have adhered to and penetrated into the bacterial cells. Antibacterial properties of silver nanoparticles are attributed to their total surface area, as a larger surface to volume ratio of nanoparticles provides more efficient means for enhanced antibacterial activity.     

Flexible Nanoparticles Reach Sterically Obscured Endothelial Targets Inaccessible to Rigid Nanoparticles

Molecular targeting of nanoparticle drug carriers promises maximized therapeutic impact to sites of disease or injury with minimized systemic effects. Precise targeting demands addressing to subcellular features. Caveolae, invaginations in cell membranes implicated in transcytosis and inflammatory signaling, are appealing subcellular targets. Caveolar geometry has been reported to impose a ≈50 nm size cutoff on nanocarrier access to plasmalemma vesicle associated protein (PLVAP), a marker found in caveolae in the lungs. The use of deformable nanocarriers to overcome that size cutoff is explored in this study. Lysozyme‐dextran nanogels (NGs) are synthesized with ≈150 or ≈300 nm mean diameter. Atomic force microscopy indicates the NGs deform on complementary surfaces. Quartz crystal microbalance data indicate that NGs form softer monolayers (≈60 kPa) than polystyrene particles (≈8 MPa). NGs deform during flow through microfluidic channels, and modeling of NG extrusion through porous filters yields sieving diameters less than 25 nm for NGs with 150 and 300 nm hydrodynamic diameters. NGs of 150 and 300 nm diameter target PLVAP in mouse lungs while counterpart rigid polystyrene particles do not. The data in this study indicate a role for mechanical deformability in targeting large high‐payload drug‐delivery vehicles to sterically obscured targets like PLVAP.     

以CeO2纳米颗粒可控合成CeOCl纳米颗粒

以水热法合成的粒径7nm左右的CeO2纳米立方体颗粒为合成CeOCl的原料,在2种不同的反应系统中分别得到了22nm的CeOCl立方体和144nm的CeOCl花形纳米颗粒.十四烷基三甲基氯化铵为反应提供氯源,在油胺作保护剂条件下,CeO2纳米颗粒转化为CeOCl纳米立方体;在1,2-十六烷二醇作还原剂、油胺和癸酸作保护剂条件下,CeO2转化为花状CeOCl纳米颗粒.CeOCl的最终形貌取决于还原剂与保护剂.