International Journal of Nanomedicine (Nov 2018)

Nitroxide-radicals–modified gold nanorods for in vivo CT/MRI-guided photothermal cancer therapy

  • Xia L,
  • Zhang C,
  • Li M,
  • Wang K,
  • Wang Y,
  • Xu P,
  • Hu Y

Journal volume & issue
Vol. Volume 13
pp. 7123 – 7134

Abstract

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Luyao Xia,1,2 Chao Zhang,1 Min Li,1 Kaiyu Wang,1 Yushan Wang,1 Peipei Xu,1 Yong Hu2 1Department of Hematology, Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu, 210093, People’s Republic of China; 2College of Engineering and Applied Science, Nanjing University, Nanjing, Jiangsu, 210093, People’s Republic of China Purpose: This article presents a report of the synthesis, characterization, and biomedical application of nitroxide-radicals–modified gold nanorods (Au-TEMPO NRs) for imaging-guided photothermal cancer therapy.Patients and methods: Au nanorods were synthesized through seed-mediated growth method, 4-Amino-TEMPO was added and the reaction proceeded under magnetic stirring.Results: With a mean length of 39.2 nm and an average aspect ratio of approximately 3.85, Au-TEMPO NRs showed good photothermal ability when they were irradiated by 808-nm laser. Au-TEMPO NRs could be stored in PBS for more than 1 month, showed no cytotoxicity against both tumor and normal cells at a concentration of up to 3 mg/mL, and functioned as a dual-mode contrast agent for CT/magnetic resonance (MR) imaging in vitro and in vivo, due to their high X-ray attenuation of Au and good r1 relaxivity of nitroxide radicals. Further, they had a long retention time (~4 hours) in the main organs, which enabled a long CT/MR imaging time window for diagnosis. Bio-distribution results revealed that these Au-TEMPO NRs passively aggregated in the liver and spleen. After irradiation by 808-nm laser, Au-TEMPO NRs could ablate the solid tumor in 4T1 tumor-bearing mice, which implied they were a potential theranostic agent for dual-mode imaging and photothermal cancer therapy.Conclusion: This type of Au-TEMPO NRs with the abili­ties of CT/MR imaging and photothermal therapy, can play an active role in imaging-guided photothermal cancer therapy. Keywords: PTT, Au NRs, TEMPO, computed tomography, magnetic resonance imaging

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