Smart theranostic nanoprobes with the integration of multiple therapeutic modalities are preferred for precise diagnosis and efficient therapy of tumors. However, it remains a big challenge to arrange the imaging and two or more kinds of therapeutic agents without weakening the intended performances. In addition, most existing fluorescence (FL) imaging agents suffer from low spatiotemporal resolution due to the short emission wavelength (<900 nm). Here, novel three-in-one Ag₂S quantum dot (QD)-based smart theranostic nanoprobes were proposed for in situ ratiometric NIR-II FL imaging-guided ion/gas combination therapy of tumors. Under the acidic tumor microenvironment, three-in-one Ag₂S QDs underwent destructive degradation, generating toxic Ag⁺ and H₂S. Meanwhile, their FL emission at 1270 nm was weakened. Upon introduction of a downconversion nanoparticle (DCNP) as the delivery carrier and NIR-II FL reference signal unit, the formed Ag₂S QD-based theranostic nanoprobes could achieve precise diagnosis of tumors through ratiometric NIR-II FL signals. Also, the generated Ag⁺ and H₂S enabled specific ion/gas combination therapy toward tumors. By combining the imaging and therapeutic functions, three-in-one Ag₂S QDs may open a simple yet reliable avenue to design theranostic nanoprobes.

中文翻译：

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用于原位比率测定 NIR-II 荧光成像引导离子/气体组合治疗的三合一 Ag2S 量子点的酸触发降解


集成多种治疗方式的智能治疗诊断纳米探针是肿瘤精准诊断和高效治疗的首选。然而，在不削弱预期性能的情况下安排成像和两种或多种治疗剂仍然是一个巨大的挑战。此外，大多数现有的荧光（FL）成像剂由于发射波长短（<900 nm）而存在时空分辨率低的问题。在此，提出了新型三合一基于Ag ₂ S量子点（QD）的智能治疗诊断纳米探针，用于原位比例NIR-II FL成像引导的肿瘤离子/气体联合治疗。在酸性肿瘤微环境下，三合一的Ag ₂ S量子点发生破坏性降解，产生有毒的Ag ⁺ 和H ₂ S。同时，它们的FL 1270 nm 处的发射减弱。引入下转换纳米粒子（DCNP）作为传递载体和NIR-II FL参考信号单元，形成的基于Ag ₂ S QD的治疗诊断纳米探针可以通过比例NIR-II FL实现肿瘤的精确诊断信号。此外，产生的Ag ⁺ 和H ₂ S使得针对肿瘤的特定离子/气体组合疗法成为可能。通过结合成像和治疗功能，三合一 Ag ₂ S QD 可能为设计治疗诊断纳米探针开辟一条简单而可靠的途径。