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Quantitative Magnetometry of Single Nanoparticles with High Throughput


Magnetic nanoparticles have diverse applications in biomedical analysis and therapy, environmental remediation, and nanoscale and microscale manipulation. However, it is difficult to quantitatively measure the magnetic properties of single nanoparticles with high throughput. This measurement problem limits the ability to perform quality control in manufacturing processes for magnetic nanoparticles, which in turn limits the ability to obtain reproducible and predictable results in commercial applications of magnetic nanoparticles. Through its ongoing inter-OU Nanoparticle Manufacturing Program and recent workshop, Advancing Nanoparticle Manufacturing [1], NIST has clearly identified the need of its stakeholders for new measurement technologies to solve this problem. Because of the widespread use of magnetic nanoparticles, there is a particular need for economical technologies that are commercially available to the many manufacturers and users of magnetic nanoparticles with diverse properties. NIST in general, and the Center for Nanoscale Science and Technology in particular, is interested in enabling innovative commercial research to close this measurement gap and fulfill its mission to support the U.S. nanotechnology enterprise from discovery to production by providing industry, academia, NIST, and other government agencies with access to nanoscale measurement and fabrication methods and technology.


The general goals of this project are to increase private sector commercialization of an innovative measurement technology, to use small business to meet federal research and development needs, and to stimulate small business innovation in technology. The specific goals of this project are to develop an innovative measurement technology that enables quantitative magnetometry of single nanoparticles with diverse properties with high throughput, and to develop a manufacturing process that enables the mass production of this measurement technology.


Nanoparticles require routine characterization for quality control to obtain reproducible and predictable results in research and development, manufacturing, commerce, and standardization. But there are no commercially available technologies to quantitatively measure functionally relevant magnetic properties of single nanoparticles, such as hysteresis loops and magnetic anisotropy, with industrially relevant throughput. Most existing instruments for magnetometry are intended for measurements of macroscopic sample volumes. Application of these instruments to nanoparticle samples requires measurement of many particles in an ensemble, complicating a quantitative interpretation of the data and obscuring the distribution of particle properties. More specialized instruments for magnetometry can resolve single nanoparticles, but the throughput of such measurements is low, limiting the rapid analysis of a large number of single particles to populate a distribution of properties. Measurement of distributions of magnetic properties is essential to characterize sample heterogeneity for quality control in nanoparticle manufacturing.


Commercial development of an innovative and economical measurement technology will benefit manufacturers and users of magnetic nanoparticles, as well as manufacturers of scientific instruments. The widespread availability of this measurement technology will enable nanoparticle manufacturers to improve quality control of magnetic nanoparticles, allowing users to obtain reproducible and predictable results using the samples and potentially implement the measurements themselves. Growth in this overall market will motivate instrument manufactures to further develop the technology to serve the market better.


Phase I expected results:
Demonstrate quantitative magnetometry of nanoparticles with high throughput, as defined by the following performance metrics: measurements of coercivity with a limit of uncertainty of less than 1 mT; measurements of isotropic or anisotropic nanoparticles with at least one critical dimension of less than 100 nm; measurement of more than 100 single ferromagnetic nanoparticles in less than 100 minutes.


Phase II expected results:
Demonstrate broad applicability of the measurement technology to a variety of commercially relevant magnetic nanoparticles with diverse magnetic properties. Demonstrate different forms of magnetometry including vector magnetometry. Increase the precision of the measurement technology by an order of magnitude. Increase the throughput of the measurement technology by an order of magnitude. Develop an economical manufacturing process for the measurement technology that is suitable for production and commercial venture.


NIST staff may be available to work collaboratively to develop the technology.


[1] Advancing Nanoparticle Manufacturing,

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