Size‐Dependent Cytotoxicity of Gold Nanoparticles

TLDR

Gold nanoparticles are widely used in biomedical imaging and diagnostics, are chemically stable, yet recent studies report conflicting evidence of their cytotoxicity. This study systematically investigates water‑soluble gold nanoparticles stabilized with triphenylphosphine derivatives across a size range of 0.8 to 15 nm. Cytotoxicity was evaluated in four representative cell lines—connective tissue fibroblasts, epithelial cells, macrophages, and melanoma cells—each reflecting key barrier or phagocytic functions. The results show a pronounced size dependence: 1.4‑nm particles exhibit IC₅₀ values of 30–56 µM and induce rapid necrotic death within 12 h, whereas 15‑nm particles and Tauredon are essentially nontoxic even at 60‑ to 100‑fold higher concentrations, and 1.2‑nm particles trigger apoptosis.

Abstract

Abstract Gold nanoparticles are widely used in biomedical imaging and diagnostic tests. Based on their established use in the laboratory and the chemical stability of Au 0 , gold nanoparticles were expected to be safe. The recent literature, however, contains conflicting data regarding the cytotoxicity of gold nanoparticles. Against this background a systematic study of water‐soluble gold nanoparticles stabilized by triphenylphosphine derivatives ranging in size from 0.8 to 15 nm is made. The cytotoxicity of these particles in four cell lines representing major functional cell types with barrier and phagocyte function are tested. Connective tissue fibroblasts, epithelial cells, macrophages, and melanoma cells prove most sensitive to gold particles 1.4 nm in size, which results in IC 50 values ranging from 30 to 56 μ M depending on the particular 1.4‐nm Au compound–cell line combination. In contrast, gold particles 15 nm in size and Tauredon (gold thiomalate) are nontoxic at up to 60‐fold and 100‐fold higher concentrations, respectively. The cellular response is size dependent, in that 1.4‐nm particles cause predominantly rapid cell death by necrosis within 12 h while closely related particles 1.2 nm in diameter effect predominantly programmed cell death by apoptosis.