Fig. 2

Characterizations and multiple ROS scavenging ability of Pd@insulin clusters. A Scheme illustration of Pd@insulin synthesis via the protein biomimetic method. B HRTEM images of Pd@insulin (Scale bar: 10 nm left, 1 nm right). C Superoxide anion E hydroxyl radical, and G H₂O₂ scavenging ability of Pd@insulin (n = 4). Time depended D superoxide anion and F hydroxyl radical scavenging ability of Pd@insulin by EPR spectrum. Comparison of H superoxide anion I hydroxyl radical J H₂O₂ scavenging ability between Pd@insulin cluster, insulin, and Pd²⁺ (n = 5). K Adsorption energies profiles of catalytic process of the SOD and CAT processes for Pd, and L geometry structures of the intermediate states (red and white dots represent oxygen and hydrogen atoms respectively; * represents absorption state). M Intracellular ROS scavenging ability evaluation via N2a, BV2, and A172 cells (Rosup is positive control, green fluorescence represents ROS positive) (Scale bar 200 μm), and N corresponded quantitative results (n = 3). Data are all shown as mean ± SD. Statistical analysis of (C, E, G, H, I, J, and N) was performed by one-way ANOVA with a Tukey post hoc test