Toxicity and Biodistribution Comparison of Functionalized Nanodiamonds, Quantum Dot Nanocarbons and Gold Nanoparticles

Elena Alexander ^* Kam W Leong

• Columbia University, New York City, United States

Nanoscience and nanotechnology are rapidly advancing fields, with nanomaterials being utilized in electronic devices, drug delivery, and disease diagnosis. However, this widespread application has raised concerns about their potential toxicity in humans. The efficacy and toxicity of nanoparticles are influenced by their biodistribution profile and exposure at the site of action.Consequently, this study aimed to evaluate the dose-dependent toxicity and biodistribution patterns of nanoparticles in mice. Unconjugated and nanobody-conjugated nanodiamonds were intravenously administered to 22 female C57BL/6 mice. The results were compared to those of gold nanoparticles, which are well-studied and widely used in the industry, as well as to quantum dot nanocarbons. Nanoparticle solution concentrations of 5, 10, 20, and 40 mg/kg were administered and compared. Samples were collected at 2, 24, and 96 hours and analyzed for tolerability and biodistribution. The findings showed that unconjugated nanodiamonds were well tolerated, eliciting lower inflammatory responses and no significant activation of memory T cells, compared to gold nanoparticles and quantum dot nanocarbons, which induced increased inflammation and memory T cell activation. While nanobody-conjugated nanodiamonds triggered an inflammatory response at 2 hours post-dosing, their overall immunogenic profile was moderate. CD69 expression in CD8⁺ T cells was highest in the gold nanoparticles group (mean: 0.40 ± 0.16, 95% CI: 0.00 to 0.79) and lowest in the nanodiamonds group (mean: 0.12 ± 0.09, 95% CI: -0.11 to 0.35). CD25 expression was most elevated in the quantum dot nanocarbons group (mean: 0.23 ± 0.04, 95% CI: 0.13 to 0.32), while the ND + anti-CD62L group showed the lowest levels (mean: 0.09 ± 0.04, 95% CI: -0.01 to 0.19). Total T cells as a percentage of live cells varied significantly, with the ND + anti-CD62L group exhibiting the highest proportion (mean: 49.10% ± 6.99, 95% CI: 31.74 to 66.46) and the nanodiamonds group the lowest (mean: 40.70% ± 8.10, 95% CI: 20.59 to 60.81). These findings reveal group-specific differences in T cell activation and survival, which may reflect underlying variations in experimental conditions or interventions.