Neurotoxicity of Zero-Valent Iron Nanoparticles in Primary Zebrafish Brain Cell Cultures

Keyla Soto Hidalgo*, Laura Tirado Mena, Beatriz Zayas Rivera and Karoline Rios Rodriguez

Zero-valent iron nanoparticles (nZVI) are increasingly used in environmental remediation and explored for biomedical applications; however, their potential neurotoxic effects and underlying cellular mechanisms remain incompletely understood. In this study, newly synthesized nZVI were physicochemically characterized and evaluated for cytotoxic effects using primary brain cell cultures derived from adult zebrafish (Danio rerio) as an in vitro model of neurotoxicity. Nanoparticles were characterized by scanning electron microscopy (SEM), which revealed spherical morphologies with aggregate chain formation, and by X-ray photoelectron spectroscopy (XPS), confirming the presence of mixed metallic and oxidized iron states at the surface. Primary zebrafish brain cells were exposed to increasing concentrations of nZVI for 48 hours to assess cell viability, apoptotic cell death, and mitochondrial membrane integrity. Cell viability assays demonstrated a concentration-dependent decrease in metabolic activity, with a 50% growth inhibition (GI₅₀) observed at approximately 220 ng/mL. Apoptosis analysis using Annexin V/propidium iodide staining showed limited and non-significant activation of apoptotic pathways across the tested concentrations. In contrast, mitochondrial membrane damage assays revealed significant, dose-dependent mitochondrial dysfunction beginning at 188 ng/mL. Together, these findings indicate that nZVI induces cytotoxic effects in primary zebrafish brain cells that are closely associated with mitochondrial dysfunction and occur largely independent of classical apoptotic cell death. This in vitro model informs the risk assessment and safe development of iron-based nanomaterials for environmental and biomedical research contexts.

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Published on: Oct 27, 2026 Pages: 41-48

Full Text PDF Full Text HTML DOI: 10.17352/aest.000095
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