Fig. 1

A Schematic description of BFE NPs preparation. The particle size and zeta potential of BFE NPs at different molar ratios of EGCG (B) and Fe³⁺ (C). The particle size, PDI (D) and photograph (E) of BFE NPs in various media. F The long-term stability of BFE NPs. G Schematic description of BFE@BSA NPs preparation. H The particle size and PDI of nanoparticles at different BSA concentrations. I The long-term stability of BFE@BSA NPs. J The summary of the four types of nanoparticles. The TEM images of BFE NPs (K) and BFE@BSA NPs (L). Scale bars were 200 nm