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Journal of Nanomaterials
Volume 2015, Article ID 583456, 7 pages
http://dx.doi.org/10.1155/2015/583456
Research Article

UV Photocatalysis of Bone Marrow-Derived Macrophages on TiO2 Nanotubes Mediates Intracellular Ca2+ Influx via Voltage-Gated Ca2+ Channels

1Department of Dental Biomaterials and Institute of Biomaterials-Implant, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
2Department of Oral and Maxillofacial Surgery, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
3Department of Oral Physiology and Institute of Biomaterial-Implant, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea

Received 1 April 2015; Revised 18 May 2015; Accepted 18 May 2015

Academic Editor: Ramaswamy Narayanan

Copyright © 2015 Seunghan Oh 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

Titanium (Ti) possesses excellent properties for use in dental implants but has low osteogenic surface properties that result in limiting rapid osseointegration. The physiological interaction between the surface of the implant material and bone cells, especially osteoclasts, is a crucial factor in determining successful osseointegration. However, the details of such an interaction remain elusive. Here, we demonstrated that nanotopography on the Ti surface is a crucial factor for modulating intracellular signal transduction in bone marrow-derived macrophages (BMMs). To define this, intracellular Ca2+ and ROS were simultaneously measured in BMMs that were seeded on polished Ti and TiO2 nanotubes. We found that UV photocatalysis of TiO2 immediately elicits intracellular calcium concentration ([Ca2+]i) increase and intracellular reactive oxygen species concentration ([ROS]i) reduction in cells on TiO2 nanotubes. UV photocatalysis-mediated [Ca2+]i increase is dependent on extracellular and intracellular ROS generation. Furthermore, extracellular Ca2+ influx through voltage-gated calcium channels (VGCCs) is critical for the UV photocatalysis-mediated [Ca2+]i increase, while phospholipase C (PLC) activation is not required. Considering the physiological roles of Ca2+ signaling in BMMs and osteoclastogenesis, nanotopography on the Ti surface should be considered an important factor that can influence successful dental implantation.