Borax‐Doped Fe ₂ O ₃ and CeO ₂ Nanoparticles Regulate Dose‐Dependently Inflammation, the Cell Cycle, and Migration in LPS‐Activated THP‐1 Cells

This study examined the biological effects of borax-doped Fe₂O₃ and CeO₂ nanoparticles (NPs) on lipopolysaccharide (LPS)-activated THP-1 cells. The morphology and composition of the nanocomposites were confirmed via scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX). Cell viability (resazurin and crystal violet assays), apoptosis/necrosis (annexin V/propidium iodide [PI]), cell cycle (flow cytometry), migration (scratch assay), and inflammatory response (Iba1 immunofluorescence staining, inducible nitric oxide synthase [iNOS] activity, and RT-PCR) were evaluated. The particle sizes ranged from 21.34 to 33.47 nm (Fe₂O₃-B-NPs) and 31.07 to 36.62 nm (CeO₂-B-NPs). The IC₁₀ and IC₅₀ dose ranges were defined for each nanocomposite and applied across different cell lines to evaluate dose-dependent biological effects. Fe₂O₃-B-NPs altered cell cycle progression, increasing the number of S phase cells. Both nanocomposites promoted migration at low doses but inhibited it at high doses. CeO₂-B-NPs reduced Iba1 levels, whereas Fe₂O₃-B-NPs increased inflammatory marker levels at higher concentrations. CeO₂-B-NPs suppressed TNF-α and IL-1β gene expression at the IC₅₀ dose, while both nanocomposites reduced iNOS activity. These results indicate that the dose-dependent effects of nanocomposites should be carefully evaluated.