Topological insulator bismuth selenide as a theranostic platform for simultaneous cancer imaging and therapy

Abstract

Employing theranostic nanoparticles, which combine both therapeutic and diagnostic capabilities in one dose, has promise to propel the biomedical field toward personalized medicine. Here we investigate the theranostic properties of topological insulator bismuth selenide (Bi2Se3) in in vivo and in vitro system for the first time. We show that Bi2Se3 nanoplates can absorb near-infrared (NIR) laser light and effectively convert laser energy into heat. Such photothermal conversion property may be due to the unique physical properties of topological insulators. Furthermore, localized and irreversible photothermal ablation of tumors in the mouse model is successfully achieved by using Bi2Se3 nanoplates and NIR laser irradiation. In addition, we also demonstrate that Bi2Se3 nanoplates exhibit strong X-ray attenuation and can be utilized for enhanced X-ray computed tomography imaging of tumor tissue in vivo. This study highlights Bi2Se3 nanoplates could serve as a promising platform for cancer diagnosis and therapy.

Figure 1. Schematic representation of topological insulator bismuth selenide as a theranostic platform.

Bismuth selenide is able to perform for simultaneous X-ray CT imaging and photothermal therapy.

Figure 2. Characterization of Bi₂Se₃ nanoplates.

(a) TEM image and (b) XRD pattern of Bi₂Se_3.

Figure 3. Cell cytotoxicity and cell internalization of nanoplates.

(a) Cell viability of H22 cells after incubation with increased concentration of Bi₂Se₃ nanoplates. (b) ICP-MS results of H22 cells incubated with Bi₂Se₃ nanoplates at 37°C and 4°C. Error bars correspond to mean ± standard deviations.

Figure 4. Results of X-ray CT imaging in vitro and in vivo.

(a) In vitro CT images of Bi₂Se₃ nanoplates and Iopamidol with different concentrations. Cell analysis: H22 cells incubated without contrast agent (1), with increased concentration of Bi₂Se₃ nanoplates (0.02 and 0.05 mol Bi l^-1 for 2 and 3, respectively). (b) CT value (HU) of Bi₂Se₃ nanoplates () or Iopamidol () as function of the concentration. (c) CT coronal views of a mouse following an intratumoral injection of 100 μl of Bi₂Se₃ nanoplates solution (0.2 mol Bi l⁻¹) (top). The corresponding 3D rendering of in vivo CT images above (bottom). The position of tumor is marked by red circles.

Figure 5. Photothermal therapy in in vitro and in vivo system.

(a) Photothermal effect of pure water and Bi₂Se₃ nanoplates with different concentrations (a–e: 0, 5, 10, 20, 50 μg ml⁻¹) upon the irradiation of 1 W cm⁻² 808 nm laser. (b) H22 cell viabilities cultured with Bi₂Se₃ nanoplates at different concentrations with or without laser irradiation. (c) Growth of H22 tumors in different groups of mice after treatment. The relative tumor volumes were normalized to their initial sizes. (d) Representative photos of a Bi₂Se₃ nanoplates-injected mouse at day 0 before PTT treatment and at day 20 after treatment. Error bars correspond to mean ± standard deviations.