Unrestricted molecular motions enable mild photothermy for recurrence-resistant FLASH antitumor radiotherapy

Organic Radiosensitizer with Aggregation-Induced Emission Characteristics for Tumor Ablation through Synergistic Apoptosis and Immunogenic Cell Death

Inspired by the clinical application of thermotherapy to promote the efficacy of radiotherapy, this study demonstrates the multimodal diagnostic application of pure organic nanoparticles in the combined treatment of tumors through imaging and photothermal properties. The nanoparticles developed in this study demonstrated unique properties and multiple functionalities, including excellent photostability and thermostability, strong fluorescence emission in the near-infrared-II (NIR-II) region, extremely high photothermal conversion efficiency, good biocompatibility, significant radiosensitizing properties, and effective tumor site accumulation. In vitro and in vivo evaluations demonstrated that these nanoparticles are ideal candidates for synergistic photothermal radiotherapy guided by NIR-II fluorescence, NIR-I photoacoustic, and photothermal trimodal imaging. They act as radiosensitizers by alleviating the hypoxic tumor microenvironment, modulating the cell cycle, and inducing apoptosis and immunogenic cell death during radiotherapy, which may provide a potential approach for the clinical treatment of tumors.

A Bright Organic Fluorophore for Accurate Measurement of the Relative Quantum Yield in the NIR-II Window

Organic dyes with photoluminescence in the second near-infrared window (NIR-II, 1000-1700 nm) are promising for bioimaging and optoelectronic devices. Photoluminescence quantum yield (PLQY) is a direct measure of their performance. Integrating sphere technology is effective in determining the absolute PLQY. However, the low PLQY values of most NIR-II organic fluorophores lead to significant measurement errors. Therefore, the most common method for PLQY determination is a relative approach using a photoluminescence spectrometer and a standard reference like IR-26. Although the relative method enables precise calculation of the PLQY ratio between the sample and the reference, the specific PLQY value of IR-26 is not clearly defined and is reported to range from 0.05% to 0.50%. Such a deviation can cause significant errors in relative PLQY measurements. In this study, it is reported that a bright organic fluorophore called TPE-BBT exhibits a high PLQY of 3.94% in THF, which can be accurately measured using a commercially available integrating sphere. Using TPE-BBT as a standard, the PLQY values of IR-26 in 1,2-dichloroethane and IR-1061 in dichloromethane are accurately determined to be 0.0284% and 0.182%, respectively. It is hoped that using this reliable standard will unify the evaluation criteria for NIR-II organic fluorophores.

FLASH radiotherapy: mechanisms, nanotherapeutic strategy and future development

Ultra-high dose-rate (FLASH) radiotherapy serves as an ideal procedure to treat tumors efficiently without harming normal tissues and has demonstrated satisfactory antitumor effects in multiple animal tumor models. However, the biological mechanisms of FLASH radiotherapy have not yet been fully elucidated, and the small number of devices delivering FLASH dose rate has limited its wide application. This review summarizes the possible biological mechanisms and antitumor effects of FLASH radiotherapy, its application in nanotherapeutic strategy, as well as its challenges and future development. Furthermore, some valuable guidance for promoting the progress of FLASH radiotherapy in nanotherapeutic strategies are provided.

Supramolecular Gels With Controllable Degradation for Suppressing Tumor Recurrence and Relieving Postoperative Pain

Postoperative pain and tumor recurrence are critical challenges following malignant tumor resection. To address these issues, we developed a supramolecular gel delivery system loaded with ropivacaine microcrystals (RopC Gel). Using PEG400 as the solvent, we successfully screened and identified matrix materials capable of forming supramolecular hydrogels through a heating–cooling process. By strategically leveraging the hydrophilic and hydrophobic properties of the gel matrix, we controlled its mechanical strength and degradation rate by adjusting the ratio of hydrophilic to hydrophobic components, resulting in a degradable, injectable, and self‐healing gel delivery system. In both rat plantar incision and mouse tumor resection pain models, RopC Gel provided long‐lasting analgesia for up to 5 days. Notably, tumor‐resected mice treated with RopC Gel demonstrated extended survival and slower tumor progression. Further in vitro and in vivo experiments revealed that RopC Gel affects mitochondrial function by promoting the accumulation of reactive oxygen species in tumor cells, inducing pyroptosis, stimulating immunogenic cell death (ICD), and activating anti‐tumor immune responses. This work offers an innovative solution for postoperative tumor resection management. Additionally, the controllable degradation properties outlined in this study provide an efficient strategy for the controlled release of multiple drugs, with the potential for widespread clinical applications.

Hydrogel local drug delivery systems for postsurgical management of tumors: Status Quo and perspectives

Surgery is one of the primary treatments for solid tumors. However, the incomplete resection of tumor cells and the immunosuppressive microenvironment make the issue of postsurgical tumor recurrence a great challenge. Furthermore, a wide range of requirements, including ensuring effective hemostasis, implementing prophylactic measures against infection, and promoting wound healing, were also raised in the postsurgical management of tumors. To fulfill these demands, multiple hydrogel local drug delivery systems (HLDDS) were developed recently. These HLDDS are expected to offer numerous advantages in the postsurgical management of tumors, such as achieving high local drug concentrations at the lesion, efficient delivery to surgical microcavities, mitigating systemic side effects, and addressing the diverse demand. Thus, in this review, a detailed discussion of the diverse demands of postsurgical management of tumors is provided. And the current publication trend on HLDDS in the postsurgical management of tumors is analyzed and discussed. Then, the applications of different types of HLDDS, in-situ HLDDS and non-in-situ HLDDS, in postsurgical management of tumors were introduced and summarized. Besides, the current problems and future perspectives are discussed. The review is expected to provide an overview of HLDDS in postsurgical management of tumors and promote their clinical application.

Reengineering of Donor-Acceptor-Donor Structured Near-Infrared II Aggregation-Induced Emission Luminogens for Starving-Photothermal Antitumor and Inhibition of Lung Metastasis

Electron acceptor possessing strong electron-withdrawing ability and exceptional stability is crucial for developing donor-acceptor-donor (D-A-D) structured aggregation-induced emission luminogens (AIEgens) with second near-infrared (NIR-II) emission. Although 6,7-diphenyl-[1,2,5] thiadiazolo [3,4-g] quinoxaline (PTQ) and benzobisthiadiazole (BBT) are widely employed as NIR-II building blocks, they still suffer from limited electron-withdrawing capacity or inadequate chemo-stability under alkaline conditions. Herein, a boron difluoride formazanate (BFF) acceptor is utilized to construct NIR-II AIEgen, which exhibits a better overall performance in terms of NIR-II emission and chemo-stability compared to the PTQ- and BBT-derived fluorophores. With finely tuned intramolecular motions and strong D-A interaction strength, TPE-BFF simultaneously exhibits high molar extinction coefficient (ε= 4.31 × 104 M-1cm-1), strong NIR-II emission (Φ = 0.49%) and photothermal effect (η = 58.5%), as well as high stability. Thanks to these merits, the thermosensitive nanoparticles constructed by integrating TPE-BFF and the antiglycolytic agent 2-deoxy-d-glucose (2DG) are successfully utilized for imaging-guided photothermal antitumor lung metastasis by regulating glycolysis and reducing ATP-dependent heat shock proteins. Combining experimental results and theoretical calculations, BFF proves to be an outstanding electron acceptor for the design of versatile NIR-II AIEgens. Overall, this study offers a promising alternative for developing multifunctional NIR-II AIEgens in biomedical applications.