Carbon monoxide (CO) is considered as the second gasotransmitter involved in a series of physiological and pathological processes. Although a number of organic fluorescent probes have been developed for imaging CO, these probes display excitation within the ultraviolet or visible range, which restrict their applications in the complex biosystems. In the present work, a strategy is developed to construct an upconversion nanoparticles-based nanosystem for upconversion luminescent (UCL) sensing CO. This nanosystem exhibits a fast response to CO with high sensitivity and selectivity in aqueous solution by a near-infrared-excited ratiometric UCL detection method. Meanwhile, laser scanning upconversion luminescence microscope experiments demonstrate that this nanosystem can visualize the endogenous CO bio-signaling in living cells, deep tissues, zebrafish, and living mice by ratiometric UCL imaging. In particular, this nanosystem has been successfully employed in visualization of the endogenous CO bio-signaling through up-regulation of heme oxygenase-1 (HO-1) in the progression of hypoxia, acute inflammation, or ischemic injury. This work demonstrates that the outstanding performance of the nanosystem not only can provide an effective tool for further understanding the role of CO in the physiological and pathological environment, but also may have great potential ability for tracking the expression of HO-1 in living systems.

中文翻译：

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一种半花青组装的上转换纳米系统，用于近红外激发体内一氧化碳生物信号的可视化

一氧化碳（CO）被认为是参与一系列生理和病理过程的第二种气体递质。尽管已经开发了许多用于 CO 成像的有机荧光探针，但这些探针在紫外或可见光范围内显示激发，这限制了它们在复杂生物系统中的应用。在目前的工作中，开发了一种策略来构建基于上转换纳米粒子的纳米系统，用于上转换发光 (UCL) 传感 CO。该纳米系统通过近红外-激发比率法在水溶液中表现出对 CO 的快速响应，具有高灵敏度和选择性UCL检测方法。同时，激光扫描上转换发光显微镜实验表明，该纳米系统可以可视化活细胞、深层组织、斑马鱼和活鼠通过比率 UCL 成像。特别是，该纳米系统已通过在缺氧、急性炎症或缺血性损伤的进展中上调血红素加氧酶-1 (HO-1) 成功地用于内源性 CO 生物信号的可视化。这项工作表明，纳米系统的优异性能不仅可以为进一步了解CO在生理和病理环境中的作用提供有效工具，而且可能具有跟踪生命系统中HO-1表达的巨大潜力。或缺血性损伤。这项工作表明，纳米系统的优异性能不仅可以为进一步了解CO在生理和病理环境中的作用提供有效工具，而且可能具有跟踪生命系统中HO-1表达的巨大潜力。或缺血性损伤。这项工作表明，纳米系统的优异性能不仅可以为进一步了解CO在生理和病理环境中的作用提供有效工具，而且可能具有跟踪生命系统中HO-1表达的巨大潜力。