Comparison of Oxidative Stresses Mediated by Different Crystalline Forms and Surface Modification of Titanium Dioxide Nanoparticles

Karim Samy El-Said,Koki Kanehira,Akiyoshi Taniguchi,Ehab Mostafa Ali

doi:10.1155/2015/703632

Abstract

Titanium dioxide nanoparticles (TiO2NPs) are manufactured worldwide for use in a wide range of applications. There are two common crystalline forms of TiO2anatase and rutile with different physical and chemical characteristics. We previously demonstrated that an increased DNA damage response is mediated by anatase crystalline form compared to rutile. In the present study, we conjugated TiO2NPs with polyethylene glycol (PEG) in order to reduce the genotoxicity and we evaluated some oxidative stress parameters to obtain information on the cellular mechanisms of DNA damage that operate in response to TiO2NPs different crystalline forms exposure in hepatocarcinoma cell lines (HepG2). Our results indicated a significant increase in oxidative stress mediated by the anatase form of TiO2NPs compared to rutile form. On the other hand, PEG modified TiO2NPs showed a significant decrease in oxidative stress as compared to TiO2NPs. These data suggested that the genotoxic potential of TiO2NPs varies with crystalline form and surface modification.

Highlights

With the development of nanotechnology, there has been a tremendous growth in the application of nanoparticles (NPs) for drug delivery systems, antibacterial materials, cosmetics, sunscreens, and electronics [1, 2]
We demonstrated that an increased DNA damage response is mediated by the anatase crystalline form compared to rutile and mixed forms [20] and that PEG-modified TiO2 NPs (PEGTiO2) NPs showed a reduction in DNA damage responses compared to TiO2 NPs [21]
The present results showed that ROS generation was reduced following polyethylene glycol (PEG) modification, as evidenced by reduced levels of H2O2, preservation of Glutathione Peroxidase (GPX) and GSH levels, and decreased caspase-3 activation, confirming the decreased DNA damage and oxidative stressinduced apoptosis in HepG2 cells exposed to PEG-TiO2 NPs compared to cells exposed to TiO2 NPs

Summary

Introduction

With the development of nanotechnology, there has been a tremendous growth in the application of nanoparticles (NPs) for drug delivery systems, antibacterial materials, cosmetics, sunscreens, and electronics [1, 2]. The increased generation, use, and disposal of nanomaterial-containing products have led to an increase in the potential exposure risk to nanomaterials for both humans and the environment [3]. Titanium dioxide (TiO2) NPs rank among the top five NPs used in consumer products [4]. TiO2 NPs are produced abundantly and used widely because of their high stability and anticorrosive and photocatalytic properties [5]. TiO2 is believed to be chemically inert. When the particles become progressively smaller, their surface areas, in turn, become progressively larger. Researchers have expressed concerns about the harmful effects of TiO2 NPs on human health, which are associated with this decrease in particle size [6, 7]

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Conclusion