TiO_2–x Based Nanoplatform for Bimodal Cancer Imaging and NIR-Triggered Chem/Photodynamic/Photothermal Combination Therapy

Abstract

Integration of cancer diagnosis and treatment, namely theranostics, is an important issue in the biomedical field. Benefiting from an excellent photothermal effect, ROS generation ability, and the desired mesoporous structure of the TiO2–x matrix, we strategically designed and fabricated a TiO2–x based theranostic system for realizing fluorescence/photoacoustic tomography (PAT) bimodal imaging guided triple therapy for photothemal/photodynamic/chemotherapy in this work. Nonstoichiometric TiO2–x nanospheres are excellent near-infrared absorptive material, which takes on both photosensitizer and photothermal agent roles in implementing PDT/PTT combination therapy and PAT imaging. Moreover, the mesoporous structure of TiO2–x also allowed drug loading, and the polydopamine sealing layer enabled it to induce NIR/pH-triggered drug controlled release. Resultantly, both the in vitro and in vivo experiment manifested the remarkable tumor inhibition and tumor imaging effects by the TiO2–x based theranostic system. The antitumor mechanism was attributable to a synergistic therapeutic effect (combination index = 0.318) of DOX-induced DNA damage, and PDT/PTT caused mitochondrial dysfunction and a change in the cell membrane permeability. Innovatively, the B-mode ultrasonography was adopted to monitor the rehabilitation process at the solid tumor site after treatment, which observed a liquefaction necrosis process.

Aggressive Man‐Made Red Blood Cells for Hypoxia‐Resistant Photodynamic Therapy

“…Therefore, the level of generated 1 O 2 could serve as an indicator to reflect the local oxygen tension surrounding photosensitizer, provided that the photosensitizer dosage and irradiation power are fixed identically. It is noted that under the tested condition, the oxidant resistance of PDA is ignored due to the large excess of rapidly generated 1 O 2 over the capacity of PDA . The well‐established N , N ‐dimethyl‐4‐nitrosoaniline (RNO) photobleaching method was carried out to assess the production of 1 O 2 .…”

Advanced Near‐Infrared Light‐Responsive Nanomaterials as Therapeutic Platforms for Cancer Therapy

“…As intrinsic MRI signals gradually weakened due to iron degradation, the stable NIR fluorescence provided long-term signal retention for up to 12 days. [242] Reduction of TiO 2 to TiO 2-x caused a fourfold increase in absorbance at 808 nm, which was further enhanced by conjugation with PDA and Cy5.5. Modification of some metal oxide nanomaterials can introduce new optoelectronic properties which enable NIR-based applications.…”

“…[237] On the other hand, some metal oxide species like copper oxides are considered unusable in biological settings, due to their high toxicity in cells. [242] In particular, an oftenused strategy to modify their chemistry and optical properties is the use of a reducing agent, which has also been shown to affect the size and morphology of resulting metal oxides. [239] Metal oxides from different synthesis methods may also display different shapes, such as spherical versus nanocube iron oxides, [240] molybdenum oxide nanosheets and nanospheres, [241] and porous TiO 2 .…”

Bismuth Ferrite‐Based Nanoplatform Design: An Ablation Mechanism Study of Solid Tumor and NIR‐Triggered Photothermal/Photodynamic Combination Cancer Therapy

“…In recent years, there has been an increasing interest in the phototherapy of PTT and PDT, but most of researchers in this field have tended to focus on (1) the discovery of new photoactive materials, (2) the construction of PTT/PDT synergistic effects, and (3) the targeting and multi‐imaging abilities of a theranostic system . Besides, one of the main challenges in the development of PTT and PDT is to investigate the antitumor mechanism as it plays a key role in designing a cancer definitive therapy.…”