We describe a comprehensive optimization study culminating in a standardized and validated approach for the preparation of titanium dioxide (TiO2) nanoparticle dispersions in relevant biological media (PBS and DMEM-FBS). This study utilizes a candidate TiO2 reference nanomaterial based on a commercially relevant powder that has been widely applied in both acute and chronic toxicity studies. The dispersion approach as presented here satisfies four key harmonization requirements not previously addressed: 1) method transferability, based in part on the use of a sonication energy calibration method that allows for power measurement and reporting in a device-independent manner; 2) optimization of sonication parameters and thorough method validation in terms of particle size distribution, pH, isoelectric point, concentration range and powder batch variability; 3) minimization of sonolysis side effects by elimination of organics during sonication, and 4) characterization of nanoparticle agglomeration under various dispersion conditions by use of laser diffraction spectrometry, an in situ size characterization technique that provides advantages over techniques more commonly employed within the context of nanotoxicology (e.g., dynamic light scattering). The described procedure yields monomodal, nanoscale, protein-stabilized nanoparticle dispersions in biological media that remain stable for at least 48 h (acute testing timeframe) under relevant incubation conditions.
Pub Type: Journals
nanomaterial, agglomerate, aggregate, bovine serum albumin, toxicology, suspension, colloidal stability