Pushing the
Envelope of In-Situ Synchrotron Scattering Technique
for
Characterization of Biocomposites
Benjamin S. Hsiao
Chemistry Department, Stony Brook University, Stony Brook, NY 11794-3400
The lecture focuses on the current status and future trends of the simultaneous small-angle X-ray scattering (SAXS) and wide angle X-ray diffraction (WAXD) technique1 to characterize the nanostructure of biomaterials. By nature, SAXS probes relatively large-scale structures, in contrast to WAXD that deals mainly with the atomic structure of ordered phase. SAXS includes not only the diffraction of large lattice spacing, of the order of tens, hundreds or even thousands of inter-atomic distances, but also the scattering by perturbed or non-periodic structures of amorphous and semi-crystalline materials. The state-of-the-art visualization technique for extraction of the superstructure information in reciprocal spacing from supramolecular systems will be described. The superstructure of materials organized on a nanoscopic length scale often determines the functionality of such systems. In one example study, the biocomposite material from native fish bone, consisting of inorganic mineral crystals reinforcing an organic nanofibrous matrix, will be considered in detail2.
The future direction for the simultaneous SAXS/WAXD study will move toward the characterization of very small and specimen-specific biological samples in either ex-vivo or in-situ conditions. Two challenges needs to be resolved in order to fully implement this technique: (1) the use of microfocus beam (less than 1 mm) while retaining very high spatial resolution for SAXS (i.e., larger than 100 nm); (2) the development of an integrated SAXS and WAXD detectors with full 2D views and minimal dead space. The proposed Energy Recovery Linacs facility at CHESS may readily resolve the first challenge.
References:
1. B. Chu and B. S. Hsiao; "Small Angle X-ray Scattering of Polymers", Chemical Reviews, 101(6), 1727-1761 (2001)
2. This is a collaborative project with Benjamin Chu, Christian Burger (Stony Brook), and Melvin Glimcher (Harvard Medical School).
