Tungsten Oxide Nanorods: An Efficient Nanoplatform for Tumor CT Imaging and Photothermal Therapy

Zhiguo Zhou,Hong Yang,Shiping Yang,Mingwei Wang,Xiangyang Shi,Yanan Sun,Wei Liu,Chao Yu,Yingjian Zhang,Bin Kong

doi:10.1038/srep03653

Abstract

We report here a facile thermal decomposition approach to creating tungsten oxide nanorods (WO2.9 NRs) with a length of 13.1 ± 3.6 nm and a diameter of 4.4 ± 1.5 nm for tumor theranostic applications. The formed WO2.9 NRs were modified with methoxypoly(ethylene glycol) (PEG) carboxyl acid via ligand exchange to have good water dispersability and biocompatibility. With the high photothermal conversion efficiency irradiated by a 980 nm laser and the better X-ray attenuation property than clinically used computed tomography (CT) contrast agent Iohexol, the formed PEGylated WO2.9 NRs are able to inhibit the growth of the model cancer cells in vitro and the corresponding tumor model in vivo, and enable effective CT imaging of the tumor model in vivo. Our “killing two birds with one stone” strategy could be extended for fabricating other nanoplatforms for efficient tumor theranostic applications.

Highlights

We report here a facile thermal decomposition approach to creating tungsten oxide nanorods (WO2.9 NRs) with a length of 13.1 6 3.6 nm and a diameter of 4.4 6 1.5 nm for tumor theranostic applications
With the high photothermal conversion efficiency irradiated by a 980 nm laser and the better X-ray attenuation property than clinically used computed tomography (CT) contrast agent Iohexol, the formed PEGylated WO2.9 NRs are able to inhibit the growth of the model cancer cells in vitro and the corresponding tumor model in vivo, and enable effective CT
We demonstrated the first use of tungsten oxide nanorods (WO2.9 NRs) modified with polyethylene glycol (PEG) for simultaneous CT imaging and NIR photothermal therapy of tumors in vivo

Summary

Results

Synthesis and characterization of PEGylated WO2.9 NRs. WO2.9 NRs were synthesized by a modified high-temperature pyrolysis of a cheap and air-stable precursor of tungstic acid in a mixture solvent of oleyl alcohol and diphenyl ether at 260uC under nitrogen atmosphere (Fig. 1a). Motivated by the obvious photothermal property of PEGylated WO2.9 NRs in vitro under the 980 nm laser irradiation, we investigated the potential to use them to photothermally ablate HeLa tumor model in vivo. A high damage level was observed in the tumor tissue treated with a 980 nm laser and PEGylated WO2.9 NRs. The photothermal therapy for tumor tissue was further quantitatively confirmed by TUNEL staining after various treatments. Tumor growth in the group injected with PEGylated WO2.9 NPs and exposed the NIR laser irradiation were completely inhibited (Fig. S10) These results further demonstrate that the combination of PEGylated WO2.9 NRs and NIR irradiation is essential for effective photothermal therapy of tumors

Discussion

Methods

Additional information