W-doped TiO₂ nanoparticles with strong absorption in the NIR-II window for photoacoustic/CT dual-modal imaging and synergistic thermoradiotherapy of tumors

Abstract

Multifunctional nanomaterials that have integrated diagnostic and therapeutic functions and low toxicity, and can enhance treatment efficacy through combination therapy have drawn tremendous amounts of attention. Herein, a newly developed multifunctional theranostic agent is reported, which is PEGylated W-doped TiO 2 (WTO) nanoparticles (NPs) synthesized via a facile organic route, and the results demonstrated strong absorbance of these WTO NPs in the second near-infrared (NIR-II) window due to successful doping with W. These PEGylated WTO NPs can absorb both NIR-II laser and ionizing radiation, rendering them well suited for dual-modal computed tomography/NIR-II photoacoustic imaging and synergistic NIR-II photothermal/radiotherapy of tumors. In addition, the long-term in vivo studies indicated that these PEGylated WTO NPs had no obvious toxicity on mice in vivo, and they can be cleared after a 30-day period. In summary, this multifunctional theranostic agent can absorb both NIR-II laser and ionizing radiation with negligible toxicity and rapid clearance, therefore it has great promise for applications in imaging and therapeutics in biomedicine.

Promoting reactive oxygen species generation: a key strategy in nanosensitizer-mediated radiotherapy

“…Hence, there is a tendency to combine semiconductors with high-Z elements to achieve a higher level of ROS generation in radiosensitization. Several combined approaches have been explored in recent years, such as the use of TiO 2 nanomaterials doped with lanthanide elements [94,95], Au [96] and tungsten [97] and ZnO nanomaterials doped with lanthanide elements [49,98]. For example, Ghaemi et al doped ZnO NPs with europium and Gd to improve restricted radiation absorption [98].…”

Recent progress of nanotechnology-based theranostic systems in cancer treatments

“…Gao et al 43 developed PEGylated W-doped TiO 2 (WTO) nanoparticles, which served as radiotherapy and PTT agents, as well as contrast agents for computed tomography (CT) and photoacoustic (PA) imaging. PEGylation of nanoparticles resulted in excellent stability and dispersibility, and the optical properties of PEGylated WTO nanoparticles were not affected by extra modifications.…”

Cancer nanotheranostics in the second near‐infrared window

“…Introducing extra dopant not only enables multimodal imaging but is also applicable to include additional therapeutic approaches for synergistic therapies. For instance, Li et al prepared W‐doped TiO 2 (WTO) nanoparticles 60 . In this nanoplatform, the high‐Z element, tungsten, not only serves as the contrast agent for X‐ray computed tomography (CT) but also serves as the radiosensitizers to concentrate X‐ray radiation in the tumor for efficient radiotherapy.…”