Next-Generation Magnetic Nanocomposites: Cytotoxic and Genotoxic Effects of Coated and Uncoated Ferric Cobalt Boron (FeCoB) Nanoparticles In Vitro

: Metal nanoparticles (NPs) have unique physicochemical properties and a widespread application scope depending on their composition and surface characteristics. Potential biomedical applications and the growing diversity of novel nanocomposites highlight the need for toxicological hazard assessment of next-generation magnetic nanomaterials. Our study aimed to evaluate the cytotoxic and genotoxic properties of coated and uncoated ferric cobalt boron (FeCoB) NPs (5-15 nm particle size) in cultured normal human dermal fibroblasts. Cell proliferation was assessed via ATP bioluminescence kit, and DNA breakage and chromosomal damage were measured by alkaline comet assay and micronucleus test. Polyacryl acid-coated FeCoB NPs [polyacrylic acid (PAA)-FeCoB NPs) and uncoated FeCoB NPs inhibited cell proliferation at 10 μg/ml. DNA strand breaks were significantly increased by PAA-coated FeCoB NPs, uncoated FeCoB NPs and l-cysteine-coated FeCoB NPs (Cys-FeCoB NPs), although high concentrations (10 μg/ml) of coated NPs (Cys- and PAA-FeCoB NPs) showed significantly more DNA breakage when compared to uncoated ones. Uncoated FeCoB NPs and coated NPs (PAA-FeCoB NPs) also induced the formation of micronuclei. Additionally, PAA-coated NPs and uncoated FeCoB NPs showed a negative correlation between cell proliferation and DNA strand breaks, suggesting a common pathomechanism, possibly by oxidation-induced DNA damage. We conclude that uncoated FeCoB NPs are cytotoxic and genotoxic at in vitro conditions. Surface coating of FeCoB NPs with Cys and PAA does not prevent but rather aggravates DNA damage. Further safety assessment and a well-considered choice of surface coating are needed prior to application of FeCoB nanocomposites in biomedicine.