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Imaging tools are crucial for studying the vascular network and its barrier function in various physiopathological conditions. Shortwave infrared (SWIR) window optical imaging allows noninvasive, in-depth exploration. We applied SWIR imaging, combined with vessel segmentation and deep learning analyses, to study real-time dextran probe extravasation in mice experiencing intermittent hypoxia (IH)—a characteristic of obstructive sleep apnea associated with potential cardiovascular alterations due to early vascular permeability. Evidence for permeability in this context is limited, making our investigation significant. C57Bl/6 mice were exposed to normoxia or intermittent hypoxia for 14 days. Then SWIR imaging between 1,250 and 1,700 nm was performed on the saphenous artery and vein and on the surrounding tissue after intravenous injection of labeled dextrans of two different sizes (10 or 70 kDa). Postprocessing and segmentation of the SWIR images were conducted using deep learning treatment. We monitored high-resolution signals, distinguishing arteries, veins, and surrounding tissues. In the saphenous artery and vein, after 70-kD dextran injection, tissue/vessel ratio was higher after intermittent hypoxia (IH) than normoxia (N) over 500 seconds (P < 0.05). However, the ratio was similar in N and IH after 10-kD dextran injection. The SWIR imaging technique allows noninvasive, real-time monitoring of dextran extravasation in vivo. Dextran 70 extravasation is increased after exposure to IH, suggesting an increased vessel permeability in this mice model of obstructive sleep apnea. NEW & NOTEWORTHY: We demonstrate that SWIR imaging technique is a useful tool to monitor real-time dextran extravasation from vessels in vivo, with a high resolution. We report for the first time an increased real-time dextran (70 kD) extravasation in mice exposed to intermittent hypoxia for 14 days compared with normoxic controls. [ABSTRACT FROM AUTHOR]

Efficient type II photodynamic therapy (PDT) requires stable and biocompatible photosensitizers (PS) that present low dark cytotoxicity, are photo‐excitable in deep tissue regions, and can efficiently penetrate and kill cells via in situ singlet oxygen production. Here, heavy‐metal‐free organic PS are combined with near‐infrared (NIR)‐excitable small (<20 nm) upconversion nanoparticles (UCNPs) into UCNP‐PS nanohybrids for accomplishing such advanced PDT conditions. UCNP‐to‐PS energy transfer efficiencies between 11% and 42% and 1O2 generation quantum yields between 74% and 86% resulted in efficient NIR‐sensitized PDT. HeLa cells incubated with UCNP‐PS can be efficiently destroyed via 808 nm laser irradiance at 140 mW cm−2 for 3 min (<30% cell viability) or 3.2 W cm−2 for 6 min (<10% cell viability). Theranostic functionality of UCNP‐PS is demonstrated via live cell in situ imaging of intracellular UCNP‐PS‐mediated 1O2 production, which resulted in cell death, most probably via apoptosis. Preliminary in vivo experiments are also performed and the consequences for a detailed in vivo study toward clinical translation are discussed. The combined PDT and deep‐tissue imaging properties of the nanomolecular PS present a large potential for future implementation into advanced in vivo photodynamic theranostics. [ABSTRACT FROM AUTHOR]

Chemoradiation therapy is on the forefront of pancreatic cancer care, and there is a continued effort to improve its safety and efficacy. Liposomes are widely used to improve chemotherapy safety, and may accurately deliver high-Z element- radiocatalytic nanomaterials to cancer tissues. In this study, the interaction between X-rays and long-circulating nanoliposome formulations loaded with gold nanoclusters is explored in the context of oxaliplatin chemotherapy for desmoplastic pancreatic cancer. Hydrophobic gold nanoclusters stabilized with dodecanethiol (AuDDT) are efficiently incorporated in nanoliposomal bilayers. AuDDT-nanoliposomes significantly augmented radiation-induced • OH production, which is most effective with monochromatic X-rays at energies that exceed the K-shell electron binding energy of Au (81.7 keV). Cargo release assays reveal that AuDDT-nanoliposomes can permeabilize lipid bilayers in an X-ray dose- and formulation-dependent manner. The radiocatalytic effect of AuDDT-nanoliposomes significantly augments radiotherapy and oxaliplatin-chemoradiotherapy outcomes in 3D pancreatic microtumors. The PEGylated AuDDT-nanoliposomes display high tumor accumulation in an orthotopic mouse model of pancreatic cancer, showing promise for nanoliposomes as carriers for radiocatalytic nanomaterials. Altogether, compelling proof for chemo-radiation dose-enhancement using AuDDT-nanoliposomes is presented. Further improving the nanoliposomal loading of high-Z elements will advance the safety, efficacy, and translatability of such chemoradiation dose-enhancement approaches., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

Imaging tools are crucial for studying the vascular network and its barrier function in various physiopathological conditions. Shortwave infrared (SWIR) window optical imaging allows noninvasive, in-depth exploration. We applied SWIR imaging, combined with vessel segmentation and deep learning analyses, to study real-time dextran probe extravasation in mice experiencing intermittent hypoxia (IH)-a characteristic of obstructive sleep apnea associated with potential cardiovascular alterations due to early vascular permeability. Evidence for permeability in this context is limited, making our investigation significant. C57Bl/6 mice were exposed to normoxia or intermittent hypoxia for 14 days. Then SWIR imaging between 1,250 and 1,700 nm was performed on the saphenous artery and vein and on the surrounding tissue after intravenous injection of labeled dextrans of two different sizes (10 or 70 kDa). Postprocessing and segmentation of the SWIR images were conducted using deep learning treatment. We monitored high-resolution signals, distinguishing arteries, veins, and surrounding tissues. In the saphenous artery and vein, after 70-kD dextran injection, tissue/vessel ratio was higher after intermittent hypoxia (IH) than normoxia (N) over 500 seconds ( P < 0.05). However, the ratio was similar in N and IH after 10-kD dextran injection. The SWIR imaging technique allows noninvasive, real-time monitoring of dextran extravasation in vivo. Dextran 70 extravasation is increased after exposure to IH, suggesting an increased vessel permeability in this mice model of obstructive sleep apnea. NEW & NOTEWORTHY We demonstrate that SWIR imaging technique is a useful tool to monitor real-time dextran extravasation from vessels in vivo, with a high resolution. We report for the first time an increased real-time dextran (70 kD) extravasation in mice exposed to intermittent hypoxia for 14 days compared with normoxic controls.