Excessive production of reactive oxygen species such as H₂O₂ is the pathological basis of chronic inflammatory diseases, as well as bacterial infection‐induced inflammation. Therefore, the in situ H₂O₂ level is a reliable biomarker of inflammatory responses, and its real‐time measurement can monitor disease progression and improve therapeutic outcomes in inflammation‐linked diseases. However, the currently used strategies for the diagnosis of inflammation is mainly through routine blood test, which are limited in determining the inflammation status and cannot provide comprehensive quantitative information. In this work, a novel H₂O₂‐responsive theranostic nanoplatform comprising Ag shell coated Pd‐tipped gold nanorods (Au–Pd@Ag NR) is developed. The etching and oxidation of the Ag shell by H₂O₂ release the Ag ions, which effectively kill bacteria in vivo and trigger their absorption variation at 700 and 1260 nm. The ratiometric photoacoustic (PA) imaging at 1260 and 700 nm (PA₁₂₆₀/PA₇₀₀) accurately quantifies H₂O₂ in a mice model of bacterial infection and abdomen inflammation, even in a rabbit model of osteoarthritis. The H₂O₂ activated second near‐infrared (NIR‐II) PA images of the probe can further precisely differentiate the inflammation region and normal tissue. This nanoplatform not only can quantify H₂O₂ during inflammation but also act as a potent antibacterial agent.

中文翻译：

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可激活的治疗性纳米探针对体内炎症的定量光声诊断和精确治疗

H ₂ O ₂等活性氧的过量产生是慢性炎性疾病以及细菌感染引起的炎症的病理基础。因此，原位H ₂ O ₂水平是炎症反应的可靠生物标志物，其实时测量可以监测疾病进展并改善炎症相关疾病的治疗效果。然而，目前用于诊断炎症的策略主要是通过常规血液检查，其在确定炎症状态方面受到限制并且不能提供全面的定量信息。在这项工作中，一部新颖的H ₂ O ₂开发了包括银壳包被的Pd尖端金纳米棒（Au–Pd @ Ag NR）的响应型治疗学纳米平台。H ₂ O ₂对银壳的腐蚀和氧化释放出银离子，从而有效杀死体内细菌并触发其在700和1260 nm处的吸收变化。在细菌感染和腹部炎症的小鼠模型中，甚至在骨关节炎的兔子模型中，在1260和700 nm的比例光声（PA）成像（PA ₁₂₆₀ / PA ₇₀₀）都能准确定量H ₂ O ₂。H ₂ O ₂探头的第二次激活的近红外（NIR-II）PA图像可以进一步精确地区分炎症区域和正常组织。这种纳米平台不仅可以量化炎症过程中的H ₂ O ₂，还可以作为有效的抗菌剂。