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Journal of Nanomaterials
Volume 2015 (2015), Article ID 704789, 8 pages
http://dx.doi.org/10.1155/2015/704789
Research Article

Autophagy in RAW264.7 Cells Treated with Surface-Functionalized Graphene Oxides

1Department of Internal Medicine, Chung-Ang University College of Medicine, 221 Heukseok-dong, Dongjak-gu, Seoul 156-756, Republic of Korea
2School of Chemical Engineering and Materials Science, Chung-Ang University, 221 Heukseok-dong, Dongjak-gu, Seoul 156-756, Republic of Korea

Received 19 May 2015; Accepted 21 July 2015

Academic Editor: Jin W. Seo

Copyright © 2015 Chang Seok Park et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study investigated cytotoxicity, particularly autophagy, in RAW264.7 cells exposed to graphene oxide (GO) and its derivatives (dodecylamine-GO (DA-GO), reduced GO (rGO), and sodium dodecyl sulfate-rGO (SDS-rGO)). Appearance of amine stretching bands, out-of-plane C-H stretching vibrations, and S=O stretching bands in infrared spectra indicated the formation of DA-GO, rGO, and SDS-rGO, respectively. Light microscopy and microculture tetrazolium assay showed that all the GO types exerted cytotoxic effects on RAW264.7 cells in a concentration-dependent manner. Higher concentrations of the GO types downregulated the expression of PU.1, a unique transcription factor in monocytes and macrophages, and decreased the conversion of LC3A/B-I to LC3A/B-II, suggesting that PU.1 was associated with autophagy in RAW264.7 cells. These results suggested that surface-functionalized GOs exerted cytotoxic effects in a concentration-dependent manner by changing the expression of critical genes and inducing autophagy in macrophages.