Theranostics 2014; 4(1):1-11. doi:10.7150/thno.7101

Research Paper

ROS-Responsive Activatable Photosensitizing Agent for Imaging and Photodynamic Therapy of Activated Macrophages

Hyunjin Kim1, Youngmi Kim2, In-Hoo Kim1, Kyungtae Kim3✉, Yongdoo Choi1✉

1. Molecular Imaging & Therapy Branch, Division of Convergence Technology, National Cancer Center, 111 Jungbalsan-ro, Ilsandong-gu, Goyang, Gyeonggi-do 410-769, Republic of Korea;
2. Department of Chemistry, Institute of Nanosensor and Biotechnology, Dankook University, 126 Jukjeon-dong, Yongin-si, Gyeonggi-do 448-701, Republic of Korea;
3. Molecular Epidemiology Branch, Division of Cancer Epidemiology and Prevention, National Cancer Center, 111 Jungbalsan-ro, Ilsandong-gu, Goyang, Gyeonggi-do 410-769, Republic of Korea.

Abstract

The optical properties of macrophage-targeted theranostic nanoparticles (MacTNP) prepared from a Chlorin e6 (Ce6)-hyaluronic acid (HA) conjugate can be activated by reactive oxygen species (ROS) in macrophage cells. MacTNP are nonfluorescent and nonphototoxic in their native state. However, when treated with ROS, especially peroxynitrite, they become highly fluorescent and phototoxic. In vitro cell studies show that MacTNP emit near-infrared (NIR) fluorescence inside activated macrophages. The NIR fluorescence is quenched in the extracellular environment. MacTNP are nontoxic in macrophages up to a Ce6 concentration of 10 μM in the absence of light. However, MacTNP become phototoxic upon illumination in a light dose-dependent manner. In particular, significantly higher phototoxic effect is observed in the activated macrophage cells compared to human dermal fibroblasts and non-activated macrophages. The ROS-responsive MacTNP, with their high target-to-background ratio, may have a significant potential in selective NIR fluorescence imaging and in subsequent photodynamic therapy of atherosclerosis with minimum side effects.

Keywords: Reactive oxygen species, macrophage, theranostics, activatable, photodynamic therapy.

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How to cite this article:
Kim H, Kim Y, Kim IH, Kim K, Choi Y. ROS-Responsive Activatable Photosensitizing Agent for Imaging and Photodynamic Therapy of Activated Macrophages. Theranostics 2014; 4(1):1-11. doi:10.7150/thno.7101. Available from http://www.thno.org/v04p0001.htm