FY2010 - Oak Ridge National Laboratory

Seed Money Fund—
Neutron Scattering Science Division
that it will be possible to measure the kinetics of a drug at lower concentrations in carriers. This
investigation demonstrates that a combination of QENS and SANS can be employed for characterization
of drug delivery systems. In particular, it highlights how QENS can be used to calculate the diffusion
coefficients of individual components in a complex environment. A manuscript is currently being
prepared on this work.
The assembly and organization of a sol-gel material formed via an in vitro biomineralization reaction was
investigated using a combination of electron microscopy and SANS. Lysozyme-templated precipitation of
silica synthesized by sol-gel chemistry produces a composite material with antimicrobial properties. The
aim of this study was to investigate the structural properties of the composite material that allow for
retention of the native antimicrobial activity of lysozyme. Electron microscopy, both scanning (SEM) and
transmission (TEM), revealed that the composite has a hierarchical structure composed of quasi-spherical
structures, approximately 450 nm in diameter, which are in turn composed of closely packed spherical
structures of approximately 8–10 nm in diameter. Using SANS with contrast variation, it was possible to
separate the scattering signatures of the lysozyme and silica within the composite. It was determined that
the lysozyme molecules are spatially correlated in the material and form clusters with colloidal silica
particles. The size of the clusters determined by SANS agrees well with the structural architecture
observed by TEM. BET analysis revealed that the surface area of the composite is relatively low
(4.73 m 2 /g). However, after removal of the protein by heating to 200°C, the surface area is increased by
~20%. In addition to demonstrating a well-organized sol-gel synthesis that generates a functional material
with antimicrobial applications, the analysis and modeling approaches described herein can be used for
characterizing a wide range of mesoporous and ultrastructural materials. This work was selected as the
cover image for the September 23, 2010, issue of Advanced Functional Materials.
Information Shared
Cardoso, M. B., H. R. Luckarift, V. S. Urban, H. O’Neill, and G. R. Johnson. 2010. “Protein Localization
in Silica Nanospheres Derived via Biomimetic Mineralization.” Adv. Functional Mater. 18(20),
3031–3038.
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