Fig. 2: Characterization of the OatNF-SA-Fe hybrids.
a,b, The XPS spectrum of the representative Fe 2p region (a) for the OatNF-SA-Fe hybrid. Multicomponent fitting was performed according to previous literature25. The XPS spectrum of the O 1s region (b) comparing the OatNF-SA-Fe and OatNF-NaOH-Fe hybrids. The Fe–O feature is clearly visible in OatNF-NaOH-Fe hybrid but is absent in the OatNF-SA-Fe hybrid. c, Background-subtracted EELS spectrum of the OatNF-SA-Fe hybrid at the FeL2,3 edges. d, HAADF-TEM image of aligned iron particles on the nanofibril surface in the OatNF-SA-Fe hybrid. Scale bars, 50 nm. e, OatNF-SA-Fe dispersion at different concentrations of FeCl3 and SA. f, The fraction of ferrous iron in freshly prepared OatNF-SA-Fe hybrid (n = 3) and after exposure to air for 1 month (n = 2), demonstrating the stability of the ferrous state. Plot is shown as mean ± s.d. g, Illustration of chelation, binding, reduction, stabilization and preservation of iron particles (green) on the OatNF surface. The X-ray crystallographic structure of the amyloid-forming fragment (Ala–Val–Try–Val–Phe–Asp) of oat protein reveals that surface amino acids (AAs), including aspartic acid and tyrosine, in OatNF may serve as specific sites for iron binding and reduction, respectively. Panel g created with PyMOL 3.1.
