Three new reference materials (RMs) have been developed through a multi-division effort at NIST, led by the MML Ceramics Division. RMs 8011, 8012, and 8013 consist of colloidal suspensions of spherical gold nanoparticles having primary particle diameters of nominally 10 nm, 30 nm, and 60 nm, respectively. They are intended mainly for validation of methodology and/or instrument performance related to the dimensional characterization of nanoscale particles used in preclinical biomedical research. They may also be useful for the development and evaluation of in vitro assays to assess the biological response (e.g., cytotoxity, hemolysis) of nanomaterials, and for use in interlaboratory test comparisons. Reference values are provided for a large number of physical parameters, and Information values are given for a number of chemical parameters.
Various types of nanoparticles (e.g., dendrimers, quantum dots, gold nanospheres) are finding utility in advanced medical diagnostics and treatments and in nanotoxicology research. Preclinical nanobiotechnology research and nanotoxicology studies are often hampered by a lack of comprehensive and accurate physical and chemical characterizations of the nanoparticles under study. Comparability of results among laboratories is also compromised, stifling progress. The availability of RMs 8011, 8012, and 8013, which have been very well characterized for a large number of physical and chemical parameters, supports research in nanobiotechnology and nanotoxicology and provides a means of attaining comparability of research results between laboratories, thereby accelerating progress in these important fields.
Additional Technical Details:
For each of the three RMs, the mass fraction of gold bound into nanoparticles, the mass fractions of sodium, chloride ion, and citrate ion, pH, and electrolytic conductivity were measured by staff in the Analytical Chemistry Division. The gold and sodium mass fractions were determined using inductively coupled plasma optical emission spectrometry (ICP-OES) calibrated using the standard additions method. Gold bound into nanoparticles was distinguished from dissolved gold by comparison of the mass fraction of gold present before and after quantitative removal of the nanoparticles using ultracentrifugation. The chloride and citrate ion mass fractions were determined using ion chromatography. Measurements were made on unprocessed samples, and the chloride and citrate levels represent free (unbound) species. The pH values were measured using a thermostated glass electrode, calibrated using NIST pH SRM buffer solutions bracketing the pH of the sample. The electrolytic conductivity values were measured using a thermostated dip cell, calibrated using NIST electrolytic conductivity SRMs having conductivity values similar to those of the samples.
- Developed RMs 8011, 8012, and 8013.
- Performed accurate, traceable measurements of the mass fraction of gold bound into nanoparticles, as well as sodium, chloride ion, and citrate ion mass fractions, pH, and electrolytic conductivity.
January 1, 2007
Lead Organizational Unit:
Therese A. Butler
Kenneth W. Pratt
Lane C. Sander
Michael R. Winchester
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