Surface functionalities of gold nanoparticles impact embryonic gene expression responses

Abstract

Incorporation of gold nanoparticles (AuNPs) into consumer products is increasing; however, there is a gap in available toxicological data to determine the safety of AuNPs. In this study, we utilised the embryonic zebrafish to investigate how surface functionalisation and charge influence molecular responses. Precisely engineered AuNPs with 1.5 nm cores were synthesised and functionalized with three ligands: 2-mercaptoethanesulfonic acid (MES), N,N,N-trimethylammoniumethanethiol (TMAT), or 2-(2-(2-mercaptoethoxy)ethoxy)ethanol. Developmental assessments revealed differential biological responses when embryos were exposed to the functionalised AuNPs at the same concentration. Using inductively coupled plasma–mass spectrometry, AuNP uptake was confirmed in exposed embryos. Following exposure to MES- and TMAT-AuNPs from 6 to 24 or 6 to 48 h post fertilisation, pathways involved in inflammation and immune response were perturbed. Additionally, transport mechanisms were misregulated after exposure to TMAT and MES-AuNPs, demonstrating that surface functionalisation influences many molecular pathways.

Keywords::

• Gold nanoparticles
• toxicity
• zebrafish
• nanoparticle–biological interactions

Acknowledgements

The authors would like to thank the staff of the Sinnhuber Aquatic Research Laboratory for the embryos, Dr. Michael Simonich for manuscript assistance, and John Miller for his assistance in preparation of the materials. These studies were partially supported by National Institute of Environmental Health Sciences (NIEHS), R01 ES016896, P30 ES000210, P42 ES016465, F31 ES019445-02, NIEHS Superfund Basic Research Program Grant P42 ES016465 to RLT and KMW, the Air Force Research Laboratory (AFRL) under agreement number FA8650-05-1-5041, and Environmental Protection Agency (EPA) RD-833320. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of NIEHS, AFRL, EPA, or the US Government. Further support was provided by the W.M Keck Foundation.