Implemented by the National Institute of Advanced Industrial Science and Technology<\/p>\n
Final objective: We provide nanomaterial suspensions for hazard testing and characterize the samples. We compile and release a technical instruction manual about methods and points of sample preparation and characterization for intratracheal administration testing.<\/p>\n
Main result: Since we observed that TiO2<\/sub> particles easily agglomerate when the pH of their suspension is approximately 7 (neutral), instead of pure water, we used a solvent containing disodium phosphate (DSP), a dispersing agent that has been considered to be less hazardous to a living body. In addition, it was possible to prepare test materials other than TiO2<\/sub> using pure water without DSP. We prepared a TiO2<\/sub> suspension for hazard testing, using materials of various sizes, shapes and surface conditions, such as particles of 6\u20131,000 nm diameters, particle shapes ranging from spherical (aspect ratio 1) to needle-shaped (aspect ratio 13), and particle surfaces modified and unmodified with Al(OH)3<\/sub>.<\/p>\n As a more hazardous material relative to TiO2<\/sub>, which is a relatively low-hazard material, we selected NiO. We provide NiO suspensions prepared by using spherical particles with diameters ranging from 18 to 300 nm and fibrous particles with an aspect ratio of 1,000.<\/p>\n In the case of SiO2<\/sub>, whose hazard was expected to vary drastically depending on its crystallinity, we prepared samples of amorphous and crystalline materials (a quartz). For the amorphous SiO2<\/sub>, samples with different diameters (10\u201370 nm) and those with their surfaces modified with Al(OH)3<\/sub> or a carboxylic acid were purchased as commercial items. In the case of crystalline materials, however, we prepared them by ball milling and centrifugation because the particle size of the commercially available items was limited. When crystalline SiO2<\/sub> is milled, part of its crystalline structure becomes amorphous due to the mechanical damage; therefore, we decreased the amount of the amorphous component using an alkali solution and performed a quantitative evaluation of the amorphous component by X-ray diffraction analysis.<\/p>\n We also prepared suspension of CeO2 <\/sub>whose hazard is reported in several publications, while it is considered to be a substance of low solubility within a body of test animals.<\/p>\n Table \u2460(b) shows the materials used for preparation of the samples provided for animal testing.<\/p>\n We characterize physicochemical properties of nanoparticles in consideration of the standard characterization requirements recommended by the ISO, OECD, and others. Thus, the characterization includes evaluation of the shape and primary particle size of nanoparticles using a transmission and a scanning electron microscopes (TEM, SEM), measurement of the specific surface area of nanoparticles and calculation of their particle size from the results, evaluation of the zeta potential and isoelectric point of nanoparticles, their crystal structure by X-ray diffraction and measurement of the particle size (secondary particle size) in suspension using the dynamic light scattering method. We move forward with the characterizations of the whole provided samples.<\/p>\n Table\u2460(b) List of materials used for preparation of samples provided for animal testing<\/p>\n Implemented by the National Institute of Advanced Industrial Science and Technology Final objective: We provid […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":74,"menu_order":9,"comment_status":"open","ping_status":"open","template":"","meta":{"_acf_changed":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":"","_links_to":"","_links_to_target":""},"tags":[],"class_list":["post-76","page","type-page","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\n\t\t\n
\nAs a sample to be used for animal testing in order to establish sample preparation techniques for equivalence evaluation\u00a0<\/em>, we selected TiO2<\/sub> from the following viewpoint and established preparation procedure for a standard suspension, which is the base for preparing other nanomaterial for testing:<\/p>\n\n
\n\n
\n Material<\/td>\n Crystal Structure<\/td>\n Particle Shape<\/td>\n Diameter\u00a0(catalog value, nm)<\/td>\n<\/tr>\n \n titanium
\ndioxide<\/td>\nanatase<\/td>\n sphere<\/td>\n 6<\/td>\n<\/tr>\n \n rutile \/ anatase<\/td>\n sphere<\/td>\n 21<\/td>\n<\/tr>\n \n rutile<\/td>\n spindle<\/td>\n long-D. 29, short-D. 8<\/td>\n<\/tr>\n \n rutile<\/td>\n spindle<\/td>\n long-D. 50-100, short-D. 10-20<\/td>\n<\/tr>\n \n rutile<\/td>\n spindle
\n(Al(OH)3<\/sub>coat\uff09<\/td>\nlong-D. 50-100, short-D. 10-20<\/td>\n<\/tr>\n \n rutile<\/td>\n sphere<\/td>\n 1,000<\/td>\n<\/tr>\n \n rutile<\/td>\n needle<\/td>\n long-D. 1,700, short-D. 130<\/td>\n<\/tr>\n \n nickel
\noxide<\/td>\nNaCl<\/td>\n box<\/td>\n 18<\/td>\n<\/tr>\n \n NaCl<\/td>\n irregular<\/td>\n <50<\/td>\n<\/tr>\n \n NaCl<\/td>\n box<\/td>\n 300<\/td>\n<\/tr>\n \n NaCl<\/td>\n wire<\/td>\n long-D. 20,000, short-D. 20<\/td>\n<\/tr>\n \n silicon
\ndioxide<\/td>\namorphous<\/td>\n sphere<\/td>\n 10<\/td>\n<\/tr>\n \n amorphous<\/td>\n sphere<\/td>\n 70<\/td>\n<\/tr>\n \n amorphous<\/td>\n sphere
\n(Al(OH)3<\/sub>coat\uff09<\/td>\n70<\/td>\n<\/tr>\n \n amorphous<\/td>\n sphere
\n(COOH coat)<\/td>\n70<\/td>\n<\/tr>\n \n \u03b1-quartz \/ amorphous<\/td>\n irregular<\/td>\n 80, milled + NaOH dissolution<\/td>\n<\/tr>\n \n \u03b1-quartz \/ amorphous<\/td>\n irregular<\/td>\n 200, milled<\/td>\n<\/tr>\n \n \u03b1-quartz<\/td>\n irregular<\/td>\n 300, (classification from 800 nm)<\/td>\n<\/tr>\n \n \u03b1-quartz<\/td>\n irregular<\/td>\n 300, (classification from 1,400 nm)<\/td>\n<\/tr>\n \n \u03b1-quartz<\/td>\n irregular<\/td>\n 1,400<\/td>\n<\/tr>\n \n cerium
\ndioxide<\/td>\nfluorite<\/td>\n box<\/td>\n 10<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"