Here lanthanide‐doped luminescent nanoparticles (LNPs) NaYF₄:Er conjugated to the indocyanine green dye (ICG) are introduced for theranostics applications in trimodal imaging as well as in photothermal therapy. ICG as a donor with high absorption cross‐section at 808 nm increases excitation efficiency of Er³⁺ through the energy transfer mechanism and, therefore, significantly enhances both upconverted and Stokes emissions from Er³⁺ ions in LNPs. Enhanced Stokes emission is used at 1.5 µm for bioimaging in the second near‐infrared wavelength window, which allows deeper penetration in biological media due to reduced scattering. A part of the ICG excitation decays by the competing nonradiating relaxation to produce local heating, which is utilized for photoacoustic imaging as well as for local thermal imaging. All these modalities are demonstrated by in vivo imaging of subcutaneous pancreatic tumor‐bearing nude mice. Furthermore, in the thermal imaging as well as in vitro photocytotoxicity studies, it is shown that the local temperature rise is high enough to be used for highly effective photothermal therapy. Cytotoxicity study on cells using the MTT assay shows the biocompatibility feature of this nanoconstruct. The obtained results demonstrate the potential of ICG‐NaYF₄:Er nanoconjugates for multimodal theranostics.

中文翻译：

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ICG认可的用于治疗学的NaYF4：Er纳米结构

在此介绍了掺有吲哚菁绿色染料（ICG）的掺镧掺杂的发光纳米粒子（LNP）NaYF ₄：Er在三峰成像以及光热疗法中的诊断学应用。ICG作为在808 nm具有高吸收截面的供体，通过能量转移机制提高了Er ^3+的激发效率，因此，显着增强了Er ^3+的上转换和斯托克斯发射LNP中的离子。在第二个近红外波长窗口中，用于生物成像的Stokes发射增强为1.5 µm，由于减少了散射，因此可以更深地穿透生物介质。ICG激发的一部分会因竞争性非辐射弛豫而衰减，从而产生局部加热，该局部加热可用于光声成像以及局部热成像。所有这些方式均通过体内对皮下胰腺癌裸鼠的成像来证明。此外，在热成像以及体外光细胞毒性研究中，显示出局部温升足够高以用于高效的光热疗法。使用MTT测定法对细胞的细胞毒性研究显示了这种纳米结构的生物相容性特征。获得的结果证明了ICG‐NaYF的潜力₄：Er纳米共轭物，用于多峰理论。