Quantum dot cytotoxicity in vitro: An investigation into the cytotoxic effects of a series of different surface chemistries and their core/shell materials

Abstract

The aim of this study was to assess the effects of a series of different surface coated quantum dots (QDs) (organic, carboxylated [COOH] and amino [NH₂] polytethylene glycol [PEG]) on J774.A1 macrophage cell viability and to further determine which part of the QDs cause such toxicity. Cytotoxic examination (MTT assay and LDH release) showed organic QDs to induce significant cytotoxicity up to 48 h, even at a low particle concentration (20 nM), whilst both COOH and NH₂ (PEG) QDs caused reduced cell viability and cell membrane permeability after 24 and 48 h exposure at 80 nM. Subsequent analysis of the elements that constitute the QD core, core/shell and (organic QD) surface coating showed that the surface coating drives QD toxicity. Elemental analysis (ICP-AES) after 48 h, however, also observed a release of Cd from organic QDs. In conclusion, both the specific surface coating and core material can have a significant impact on QD toxicity.

Keywords::

• Quantum dots (QDs)
• cytotoxicity
• surface chemistry/coating
• core/shell
• macrophages

Acknowledgements

The authors would like to thank Dr Helinor Johnston (Edinburgh Napier University) for her constant support and advice throughout this study. The authors would additionally like to thank Stephen Mitchell (The Royal (Dick) Veterinary College, University of Edinburgh, Edinburgh, UK) for preparing the samples for SEM, as well as Andrew Cameron, Jeanie Forbes, David Todd, Carolyn McGonagle and Dr Alison Searl (all Institute of Occupational Medicine) for their technical assistance with the ICP-AES analysis.

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.