Advanced Light Scattering Tools for Nanoparticle Characterization

Daniel Some, Wyatt Technology, Santa Barbara, USA (dsome@wyatt.com)

Technologies for nanoparticle characterization tend to fall into two categories: low-throughput, few-particle, high-detail instruments such as electron microscopy (EM), and moderate-throughput, full-ensemble, low-detail instruments such as dynamic light scattering (DLS), zeta potential (ZP), Coulter counter (CC) or nanoparticle tracking analysis (NTA). I will present two technologies that provide enhanced characterization of full ensembles with higher levels of automation and throughput: high-throughput DLS (HT-DLS) and asymmetric-flow field-flow fractionation coupled to light scattering (AF4-LS). 

HT-DLS instrumentation is similar to standard DLS in terms of the information it provides: size and size distributions covering hydrodynamic radii from 0.5 - 1000 nm. However, it does so in standard microwell plates, enabling 10x to 100x increase in throughput and automation. As a result, it becomes feasible to test hundreds of samples in a day in order to screen buffer conditions, excipients, processing conditions, etc. for their impact on particle size and aggregation. Two case studies will demonstrate how this instrument was applied to process development of acoustically milled drug nanoparticles, and exploration of AuNP behavior in simulated serum.

Field-flow fractionation is a versatile technique for size-based separation of nanoparticles from 1 to 1000 nm. Conceptually it is similar to GPC but operates without a packed stationary phase. Downstream of the separation channel it is possible to apply a variety of in-line detectors, including light scattering for sizing and structure, zeta potential, spectroscopy and even mass spectrometry. Several examples from life, nanomaterial and environmental sciences will be presented along with details of electrical AF4 (EAF4) which separates particles according to both size and zeta potential. AF4-LS and EAF4-LS provide accurate size distributions along with rich information regarding structure, electrical properties, chemical content and more, and are fully automated just like liquid chromatography so the researcher can characterize many samples per day with little hands-on effort.

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Short Biography of Presenting Author

Daniel Some is Principal Scientist at Wyatt Technology Corp., currently responsible for scientific and technical marketing content as well as for identifying areas for development of new applications and instrumentation in the field of analytical light scattering. Previously he served in an R&D and product management capacity at Wyatt, developing hardware, software and applications for characterizing protein-protein interactions, label-free and in-solution, using light scattering.

Prior to Wyatt Technology, Dr. Some was a Member of Technical Staff at Applied Materials Israel. He studied physics at the Technion and obtained his Ph.D. in physics at Brown University, and continued to post-doctoral appointments at Los Alamos National Laboratory and Weizmann Institute. He has published peer-reviewed articles, book chapters and encyclopedic entries as well as patent applications in the areas of ultrafast and terahertz spectroscopy of semiconductor quantum structures, semiconductor wafer inspection and biomolecular interactions.