We have prepared nanocomposites in one step by hydrolyzing wheat gluten (WG) with trypsin and then drying the solution. Some tryptic peptides from WG can self-assemble into fibrous structures under benign conditions (37 °C, pH 8) to form a reinforcing phase while the balance do 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 beta–sheets. Scanning and transmission electron micrographs showed large fibers about 10–15 μm in diameter with left-handed helical configuration and appeared to be bundles of 10–20 nm diameter fibrils. 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. Fourier transform infrared spectroscopy, X-ray diffraction, and thioflavin-T binding assay indicated that the framework of the fibrils was composed of cross-beta structures, where beta-strands ran perpendicular to the fiber axis.

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