PVP-Modified Multifunctional Bi₂WO₆ Nanosheets for Enhanced CT Imaging and Cancer Radiotherapy

Abstract

Malignant tumors are one of the main causes of human death. The clinical treatment of malignant tumors is usually surgery, chemotherapy, radiotherapy, and so forth. Radiotherapy, as a traditional and effective treatment method for cancer, is widely used in clinical practice, but the radiation resistance of tumor cells and the toxic side effects to normal cells are still the Achilles heel of radiotherapy. Multifunctional inorganic high-atom nanomaterials are expected to enhance the effect of tumor radiotherapy. Tungsten and bismuth, which contain elements with high atomic coefficients, have strong X-ray energy attenuation capability. We synthesized Bi 2 WO 6 nanosheets (NSs) using a hydrothermal synthesis method and modified polyvinylpyrrolidone (PVP) on their surface to make them more stable. PVP–Bi 2 WO 6 NSs have a variety of effects after absorbing X-rays (such as the photoelectric effect and Compton effect) and release a variety of particles such as photoelectrons, Compton electrons, auger electrons, and so forth, which can react with organic molecules or water in cells, generate a large number of free radicals, and promote cell apoptosis, thereby improving the effect of radiotherapy. We show through γ-H2AX and DCFH-DA probe analysis experiments that PVP–Bi 2 WO 6 NSs can effectively increase cell DNA damage and reactive oxygen species formation under X-ray irradiation. Clone formation analysis showed that PVP–Bi 2 WO 6 NSs can effectively suppress cell colony formation under X-ray irradiation. These versatile functions endow PVP–Bi 2 WO 6 NSs with enhanced radiotherapy efficacy in animal models. In addition, PVP–Bi 2 WO 6 NSs can also be used as contrast agents for X-ray computed tomography (CT) imaging with obvious effects. Therefore, PVP–Bi 2 WO 6 NSs can be used as CT imaging contrast agents and tumor radiotherapy sensitizers and have potential medical applications.

Nanomaterial-based CT contrast agents and their applications in image-guided therapy

“…MnO 2 with a catalase-mimic catalytic activity can catalyze overexpressed H The radiosensitization effect of BiNPs is approximately 1.25-fold higher than AuNPs [152]. Li et al prepared PVP-modified Bi 2 WO 6 NSs by the hydrothermal synthesis method for CT image-guided RT (Figure 9J) [153]. The CT values and the accumulation rate at the tumor site was 809 HU and 6.19%, respectively, 24 h after intravenous injection of PVP-Bi2WO6 NSs (Figure 9K-L); therefore, this time point was identified as the point of initiation of treatment.…”

“…(F-I) Adapted with permission from 151 , Copyright 2022 Ivyspring International Publisher. (J-M) Adapted with permission from 153 , Copyright 2022 American Chemical Society.…”

Bimetallic nanoplatform for synergistic sonodynamic-calcium overload therapy utilizing self-supplied hydrogen peroxide and relieved hypoxia

“…PVP was chosen as a biocompatible ligand to improve the stability of the nanoparticles and facilitate passive targeting by the enhanced permeability and retention (EPR) effect. 52 After cellular internalization, Fe 3 O 4 -TAPP@PVP-CaO 2 decomposed instantaneously under the influence of the two triggers, the acidic intracellular TME and US irradiation. The degradation was concurrently accompanied by H 2 O 2 and O 2 generation and calcium overload in an on-demand manner.…”