Cytotoxicity of multi-walled carbon nanotubes in three skin cellular models: Effects of sonication, dispersive agents and corneous layer of reconstructed epidermis

Abstract

The effects of multi-walled carbon nanotubes were investigated in SZ95 sebocytes, IHK keratinocytes and reconstructed human epidermises. Carbon nanotubes were subjected to dispersion protocols leading to different agglomeration states. Toxicological methods were chosen and adapted in order to ensure compatibility with nanotubes. Results show that: (i) Water-suspended nanotubes, as micrometric agglomerates, were not harmful to skin cells, except minor effects in keratinocytes, (ii) mild sonication slightly decreased nanotube agglomeration but increased cytotoxicity on keratinocytes, (iii) addition of hydroxypropylcellulose or Pluronic F108, which improved nanotube dispersion, masked the harmful effects of sonicated nanotubes. Altogether, these results indicate that carbon nanotubes induced cytotoxicity in human keratinocytes after a short exposure (24–48 h), particularly when they were sonicated before cell incubations. However, the cytotoxic effects of raw and sonicated nanotubes could be prevented in presence of dispersive agents. No cytotoxic effects were observed in SZ95 sebocytes or in stratified epidermises reconstructed in vitro.

Keywords::

• Epidermis
• keratinocyte
• sebocyte
• carbon nanotube
• sonication
• dispersive agent

Acknowledgements

This work was supported by the “Direction Générale des Technologies de la Recherche et de l’Energie” (DGTRE) of the Walloon Region of Belgium (Nanotoxico Pole of Excellence, RW/FUNDP research convention No. 516252). Dr O. Toussaint is a Senior Research Associate of the Belgian FNRS. SZ95 and IHK cell lines were kind gifts respectively from Prof. C.C. Zouboulis (Departments of Dermatology, Venereology, Allergology and Immunology, Dessau Medical Center) and from J.G. Rheinwald (Department of Medicine and Harvard Skin Disease Research Center). We also thank the Walloon Region Research Programme FIRST-DEI “COSMET-X”, research convention No. 516141.

Declaration of Interest: The authors would like to report no conflict of interests. The authors are entirely responsible for the content and writing of the manuscript.