(114d) Peptide Self-Assembly From the Molecular to the Macroscopic Scale at Standard Conditions
AIChE Annual Meeting
2009 Annual Meeting
Materials Engineering and Sciences Division
Monday, November 9, 2009 - 1:45pm to 2:10pm
We have prepared nanocomposites in one step by hydrolyzing wheat gluten (WG) with trypsin and then drying the solution. Some tryptic peptides from WG self-assembled into fibrous structures under benign conditions (37 °C, 6-8 pH) to form a reinforcing phase while the balance did not to form the matrix phase. Here we describe the characterization of the self-assembled fibers, which were hierarchically structured and showed organization from the nanometer to the micrometer scale. The basic building block of the fiber was a stack of β?sheets. Scanning and transmission electron micrographs showed large fibers about 10 - 15 µm in diameter and appeared to be bundles of 10 - 20 nm diameter fibrils. Fourier transform infrared spectroscopy, X-ray diffraction, and thioflavin-T binding assay indicated that the framework of the fibrils was composed of cross-β structures, where β-strands ran perpendicular to the fiber axis. Preliminary investigation suggested that the elastic modulus of the WG-based fibers was 0.16 ± 0.03 GPa, consistent with reported values for natural protein fibers. A scaling argument is offered for how modulus arises from interaction energy described by fiber helical pitch.