Our goal is to develop certified reference materials, standard test methods, measurements, and critical data for the physicochemical characterization of engineered and multifunctional nanoparticles. This body of information will enable widespread acceptance and adoption of nanotechnologies for the diagnosis, treatment, and prevention of human disease, as well as enable evaluation of the environmental, health, and safety (EHS) risks of nanomaterials.
Taking nanoparticle therapeutic and diagnostic platforms from the laboratory to the clinic requires a well-defined pre-clinical route for FDA approval that must include widely adopted and standardized procedures for assessing the efficacy and toxicity/health risk of new nanomaterials. Certified reference materials underpin the approval procedures and enable interlaboratory comparison and benchmarking. To this end, we are working to develop measurement protocols (assays), consensus standard test methods, and computational tools for the physicochemical characterization of different nanoparticle classes under physiologically and environmentally relevant conditions. Particle properties characterized include size and size distribution, surface area, surface charge, zeta potential, crystallinity, aggregation, stability, transport characteristics, chemical composition, purity, and photothermal/plasmonic behavior.
Impact and Customers:
Engineered nanoparticles hold great promise for the detection and treatment of disease. Advanced applications in cancer management, for instance, could result in precise in situ imaging and localization of tumors and targeted application of therapeutic agents directly to tumor cells. To bring these technologies to the clinical stage, and enable assessment of the EHS aspects of nanoparticles, we are partnering with FDA and NCI, and working with NIOSH, NTP and others, to develop a nanoparticle measurement infrastructure.
Developing a viable measurement approach for quantifying the dispersion quality of nanoparticles such as carbon nanotubes within a liquid medium or solid matrix remains a challenge due to the variety and complexity of aggregative morphologies that can result. Working with industry and academic partners, we have applied quantitative ultra small-angle X-ray scattering (USAXS) methods to a range of single- and multi-wall carbon nanotube (SWCNT and MWCNT) dispersions and composites. A three-component morphology model has been applied to interrogate CNT structures in dispersions. The relative prominence of these components, together with their respective characteristic sizes or persistence lengths, can be related to the observed scattering. When combined with constraints such as the known C mass loading, the model can be used to infer the degree of filling of the tube interiors. The information obtained has implications for the application of CNTs in biomedical and other applications.
USAXS data from a SWCNT dispersion with 3-component model fit decomposition
We have also developed different flow-cell configurations to augment the USAXS and SAXS instrumentation located at the Advanced Photon Source (APS, Argonne, Illinois), a 3rd generation synchrotron source. Working with collaborators at the University of Maryland, Columbia University and APS, we have utilized these flow-cells to study the nucleation, growth, dispersion, and structure of technologically important nanoscale materials. Examples include quantitative correlation of the diameter and aspect ratio of solution-suspended gold nanowires with their agglomeration and flow characteristics, and interrogation of the homogeneous solution-phase precipitation of nanocrystalline cerium oxide particles in the 2 nm to 12 nm size range.
Start Date:October 27, 2008
Lead Organizational Unit:mml