The influence of size and surface chemistry on the bioavailability, tissue distribution and toxicity of gold nanoparticles in zebrafish (Danio rerio)

• Published in: Ecotoxicology and environmental safety Vol. 260; p. 115019
• Main Authors: Windell, Dylan L., Mourabit, Sulayman, Moger, Julian, Owen, Stewart F., Winter, Matthew J., Tyler, Charles R.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 15-07-2023; Elsevier
• Subjects: Gold nanoparticles; Light sheet microscopy; Nanotoxicology; SPIM; Zebrafish; Zebrafish; Light sheet microscopy; Nanotoxicology; Gold nanoparticles; SPIM
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2023.115019

Gold nanoparticles (AuNPs) are widely used in biomedicine and their specific properties including, size, geometrics, and surface coating, will affect their fate and behaviour in biological systems. These properties are well studied for their intended biological targets, but there is a lack of understanding on the mechanisms by which AuNPs interact in non-target organisms when they enter the environment. We investigated the effects of size and surface chemistry of AuNPs on their bioavailability, tissue distribution and potential toxicity using zebrafish (Danio rerio) as an experimental model. Larval zebrafish were exposed to fluorescently tagged AuNPs of different sizes (10–100 nm) and surface modifications (TNFα, NHS/PAMAM and PEG), and uptake, tissue distribution and depuration rates were measured using selective-plane illumination microscopy (SPIM). The gut and pronephric tubules were found to contain detectable levels of AuNPs, and the concentration-dependent accumulation was related to the particle size. Surface addition of PEG and TNFα appeared to enhance particle accumulation in the pronephric tubules compared to uncoated particles. Depuration studies showed a gradual removal of particles from the gut and pronephric tubules, although fluorescence indicating the presence of the AuNPs remained in the pronephros 96 h after exposure. Toxicity assessment using two transgenic zebrafish reporter lines, however, revealed no AuNP-related renal injury or cellular oxidative stress. Collectively, our data show that AuNPs used in medical applications across the size range 40–80 nm, are bioavailable to larval zebrafish and some may persist in renal tissue, although their presence did not result in measurable toxicity with respect to pronephric organ function or cellular oxidative stress for short term exposures.
•Light sheet microscopy was used to assess gold nanoparticle uptake in zebrafish.•Uptake of gold nanoparticles is size-dependant and affected by surface coating.•Uptake of gold nanoparticles is most pronounced in the pronephros.•Accumulation in the pronephros is mostly eliminated after depuration.•Multi-size/modified gold nanoparticles cause no clear renal injury/oxidative stress.