Composition tunability of semiconductor radiosensitizers for low-dose X-ray induced photodynamic therapy

Abstract

Radiation therapy is one of the most commonly used methods in clinical cancer treatment, and radiosensitizers could achieve enhanced therapeutic efficacy by incorporating heavy elements into structures. However, the secondary excitation of these high-Z elements-doped nanosensitizers still imply intrinsic defects of low efficiency. Herein, we designed Bi-doped titanium dioxide nanosensitizers in which high-Z Bi ions with adjustable valence state (Bi3+ or Bi4+) replaced some positions of Ti4+ of anatase TiO2, increasing both X-rays absorption and oxygen vacancies. The as-prepared TiO2:Bi nanosensitizers indicated high ionizing radiation energy-transfer efficiency and photocatalytic activity, resulting in efficient electron–hole pair separation and reactive oxygen species production. After further modification with cancer cell targeting peptide, the obtained nanoplatform demonstrated good performance in U87MG cell uptakes and intracellular radicals-generation, severely damaging the vital subcellular organs of U87MG cells, such as mitochondrion, membrane lipid, and nuclei etc. These combined therapeutic actions mediated by the composition-tunable nanosensitizers significantly inhibited the U87MG tumor growth, providing a refreshing strategy for X-ray induced dynamic therapy of malignant tumors.

Radio- and Photosensitizing Os(II)-Based Nanocage for Combined Radio-/Chemo-/X-ray-Induced Photodynamic Therapies, NIR Imaging, and Drug Delivery

“…To probe the dual X-ray sensitization capability of CMNPs inherent in the Os-elements as radiosensitizers and OsL 3 2+ metalloligands as photosensitizers, as well as the intramolecular energy conversion from the high-energy X-ray photons into the light photons suitable for intersystem crossing (ISC) between the excited singlet state (S1) and triplet state (T1) for photosensitization of oxygen, 9,10-anthracenediyl-bis­(methylene) dimalonic acid (ABDA) and singlet oxygen sensor green (SOSG) are used as the detection probe and reference to evaluate the amounts of singlet 1 O 2 produced by MOC-43 and CMNPs under X-ray irradiation (Figures S21 and S22). After exposure to 6 Gy X-radiation, the 1 O 2 amount rapidly increased to 310.5% in 9 min as compared with the blank control without CMNPs, – a similar result by using the SOSG probe to observe the 1 O 2 amount, indicating excellent ROS production ability of CMNPs under X-ray irradiation that benefits a synergistic X-PDT against cancer. A tentative energy-transfer process is illustrated in Figure f to show the conversion of X-ray photons to photoelectrons for the generation of 1 O 2 .…”

Remote Control of Energy Transformation‐Based Cancer Imaging and Therapy

“…In order to minimize the side effects caused by prolonged exposure to high levels of radiation, Chen et al prepared Bi-doped TiO 2 NPs (TBR) to enhance Xray absorption (Figure 10). [96] Even under low-dose X-ray irradiation, the high-Z element Bi doping enabled the NPs to produce [94] Copyright 2023, Wiley-VCH. b) Schematic illustration of H 2 production under X-ray excitation.…”

Mechanical stimuli-driven cancer therapeutics

“…External energy source-mediated cancer therapy has drawn considerable attention due to its paramount significance in enhancing treatment efficacy. Indeed, therapies involving various fundamental stimuli, including light in phototherapy (photodynamic therapy [PDT] and photothermal therapy [PTT]), 1,2 heat in thermal therapy, 3 electricity in electrodynamic therapy, 4 radiation in X-ray/Cherenkov PDT, 5 and microwaves in microwave dynamic/thermal therapy, 6 have been established in basic research or preclinical fields as novel cancer therapeutic strategies. Nevertheless, many clinical situations require the limitations of these therapies to be overcome such as (1) tissue scattering, (2) poor tissue penetration, and (3) low targeting capabilities.…”