*2.3. Cell Culture and Processing*

The KG1a and HL60 cells were cultured in DMEM supplemented with 10% fetal bovine serum (FBS), 100 units/mL penicillin, and 100 μg/mL streptomycin. All iron nanoparticles were filtered through a 0.22-μm membrane. The KG1a and HL60 cells were exposed to 50 μg/mL of PBNPs or FeNPs for 72 h. To detect cell viability, the KG1a and HL60 cells were seeded in 96-well microplate (10<sup>4</sup> cells/well). After incubation with iron nanoparticles for 72 h, 10 μL of CCK-8 solution was dropped to each well and incubated in cell culture incubator for 2 h. Finally, the absorbance at 450 nm was measured.
