Nanotechnology Characterization Laboratory Frederick United States
As part of an Interagency Agreement between the US Armys Center for Environmental Health Research CEHR and the National Cancer Institutes Nanotechnology Characterization Laboratory NCL, the NCL evaluated 21 nanomaterials supplied by CEHR. The overall goal was to align nanomaterial physicochemical properties to toxicities determined by CEHR using a zebrafish model. All of the materials were aqueous suspensions, and all but one nanocrystalline cellulose were metal or metal oxide materials. Some additional nanomaterials were supplied but could not be evaluated due to their insolubility. The NCL evaluated sterility, endotoxin contamination, sizesize distribution, shape, metal concentrations, purity, surface chemistry, and stability. Size and polydispersity were evaluated using transmission electron microscopy TEM, dynamic light scattering DLS, and asymmetric flow field-flow fractionation AF4 coupled with DLS detection. Nanoparticle concentrations were measured using inductively coupled plasma mass spectrometry ICP-MS and thermogravimetric analysis TGA. ICP-MS was also used to assess purity by detection of trace metal impurities, and stability by monitoring the level of free metal ions released in solution over time. Surface chemistry was evaluated by TGA to detect the presence of a surface coating or other excipient, and surface charge was indirectly evaluated by measuring the zeta potential.