Gd₂O₃/b‐TiO₂ composite nanoprobes with ultra‐high photoconversion efficiency for MR image‐guided NIR‐II photothermal therapy

Abstract

Photothermal therapy (PTT), as an important noninvasive and effective tumor treatment method, has been extensively developed into a powerful cancer therapeutic technique. Nevertheless, the low photothermal conversion efficiency and the limited tissue penetration of typical photothermal therapeutic agents in the first near-infrared (NIR-I) region (700-950 nm) are still the major barriers for further clinical application. Here, we proposed an organic/inorganic dual-PTT agent of synergistic property driven by polydopamine-modified black-titanium dioxide (b-TiO 2 @PDA) with excellent photoconversion efficiency in the second NIR (NIR-II) region (1000-1500 nm). More specifically, the b-TiO 2 treated with sodium borohydride produced excessive oxygen vacancies resulting in oxygen vacancy band that narrowed the b-TiO 2 band gap, and the small band gap led to NIR-II region wavelength (1064 nm) absorbance. Furthermore, the combination of defect energy level trapping carrier recombination heat generation and conjugate heat generation mechanism, significantly improved the photothermal performance of the PTT agent based on b-TiO 2 . The photothermal properties characterization indicated that the proposed dual-PTT agent possesses excellent photothermal performance and ultra-high photoconversion efficiency of 64.9% under 1064 nm laser irradiation, which can completely kill esophageal squamous cells. Meanwhile, Gd 2 O 3 nanoparticles, an excellent magnetic resonance imaging (MRI) agent, were introduced into the nanosystem with similar dotted core-shell structure to enable the nanosystem achieve real-time MRI-monitored cancer therapeutic performance. We believe that this integrated nanotherapeutic system can not only solve the application of PTT in the NIR-II region, but also provide certain theoretical guidance for the clinical diagnosis and treatment of esophageal cancer.

In situ assembled titanium carbide-based heterojunctions for the synergistic enhancement of NIR-II photothermal/photodynamic therapy against breast cancer

“…Generally, TiO 2 has been considered to be an excellent photo-agent with good biocompatibility; 27 however, its nearultraviolet absorption edge limits its application in tumor phototherapy due to the relatively wide bandgap and limited surface area. [28][29][30] To expand the application of TiO 2 in cancer treatment, strategies for upconverting nanoparticles loaded with titanium dioxide have been proposed and studied. 31,32 In recent years, 2D MXene materials have risen in popularity by enhancing the photocatalysis capacity of TiO 2 in industrial and biomedical fields by facilitating electron-hole pair separation.…”

Carbon dots-mediated synthesis of gold nanodendrites with extended absorption into NIR-II window for in vivo photothermal therapy

“…For example, by tuning the gap between the Au nanorod and the Au/Ag nanoshell, Yeh et al prepared a rod-in-shell gold structure with two NIR SPR bands beyond 1000 nm [ 13 ]. However, the laser power density (3 W cm −2 ) is not suitable for the in vivo applications since the larger MPE for skin exposure is 1 W cm −2 at 1064 nm (American National Standard for Safe Use of Lasers, ANSI Z136.1-2007) [ 14 , 15 ]. Therefore, it is necessary to develop a new synthetic approach to regulate the absorption of gold nanostructures in NIR-II for PTT.…”

Reprogramming of the tumor microenvironment using a PCN-224@IrNCs/d-Arg nanoplatform for the synergistic PDT, NO, and radiosensitization therapy of breast cancer and improving anti-tumor immunity

“…A series of nanomaterial-mediated RT sensitization strategies have been proposed to improve the efficacy of RT. 15 These strategies include the use of high-Z elements at the tumor site, which enhance the radiotherapy effect by increasing the X-ray attenuation coefficient as well as enhancing the production of secondary electrons and ROS, 16 for example, Pt, 17,18 Au, 19,20 Bi, 21 and Gd, 22,23 the combination of RT with other therapeutic modalities, including chemotherapy, 24 chemodynamic therapy (CDT), 25 photothermal therapy (PTT), 26 photodynamic therapy (PDT), 27 and immunotherapy, 28 and the reprogramming of the hypoxic TME (such as downregulation of HIF-1α at the tumor site 29 or in situ oxygen production). 30,31 Some reactive nitrogen/oxygen species, 32 such as nitric oxide (NO), could alleviate tumor hypoxia by downregulating HIF-1α.…”