Cytotoxicity of gold nanoparticles to human lymphocytes: a comparison between rod-shaped and spherical nanoparticles

This research was funded by the National Science Center in Poland under project 2021/41/N/ST4/03017 (to P.B.). Introduction: Gold nanoparticles (AuNPs) have unique properties that promise new and improved methods for targeting cancer treatment and diagnosis. However, despite their relatively high biocompatibility, AuNPs can negatively affect cell viability. Research indicates that the interactions with the plasma membrane and cellular uptake of AuNPs depend significantly on size, shape, and surface modifications. Material and methods: We evaluated the use of human lymphocyte primary culture as a model for assessing the toxicity of AuNPs in proliferating cells. We compared the toxicity of rod-shaped, PEGylated AuNPs (gold nanorods, AuNRs) of two different sizes and gold nanospheres (AuNSs). Results: Our results show that at high concentrations, both AuNSs and AuNRs negatively affect the viability of activated human lymphocytes in vitro. The cytotoxic effect varies with size and concentration, with larger AuNRs (approx. 22×50 nm) being more toxic than smaller ones (approx. 20×40 nm) and 15 nm AuNSs exhibiting the lowest toxicity. Conclusions: Our results confirm that the application of AuNPs in cancer therapy and diagnostics must be accompanied by a thorough cytotoxicity assessment. Despite certain limitations, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction test for viability assessment of proliferating cells proves to be a simple and cost-effective method useful in nanoparticle toxicity studies.