Autofluorescence arising from normal tissues can compromise the sensitivity and specificity of in vivo fluorescence imaging by lowering the target-to-background signal ratio. Since bioluminescence resonance energy transfer quantum dot (BRET-QDot) nano-particles can self-illuminate in near-infrared in the presence of the substrate, coelenterazine, without irradiating excitation lights, imaging using BRET-QDots does not produce any autofluorescence. In this study, we applied this BRET-QDot nano-particle to the in vivo lymphatic imaging in mice in order to compare with BRET, fluorescence or bioluminescence lymphatic imaging. BRET-QDot655, in which QDot655 is contained as a core, was injected at different sites (e.g. chin, ear, forepaws and hind paws) in mice followed by the intravenous coelenterazine injection, and then bioluminescence and fluorescence imaging were serially performed. In all mice, each lymphatic basin was clearly visualized in the BRET imaging with minimal background signals. The BRET signal in the lymph nodes lasted at least 30 min after coelenterazine injections. Furthermore, the BRET signal demonstrated better quantification than the fluorescence signal emitting from QDot655, the core of this BRET particle. These advantages of BRET-QDot allowed us to perform real-time, quantitative lymphatic imaging without image processing. BRET-Qdots have the potential to be a robust nano-material platform for developing optical molecular imaging probes.

中文翻译：

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使用生物发光共振能量转移量子点纳米粒子的自发光体内淋巴成像。

正常组织产生的自发荧光会降低目标与背景信号的比率，从而影响体内荧光成像的灵敏度和特异性。由于生物发光共振能量转移量子点 (BRET-QDot) 纳米粒子可以在基底腔肠素存在的情况下在近红外光下自发光，而无需照射激发光，因此使用 BRET-QDots 成像不会产生任何自发荧光。在这项研究中，我们将这种 BRET-QDot 纳米颗粒应用于小鼠体内淋巴成像，以与 BRET、荧光或生物发光淋巴成像进行比较。BRET-QDot655，其中包含 QDot655 作为核心，在小鼠的不同部位（例如下巴、耳朵、前爪和后爪）注射，然后静脉注射腔肠素，然后依次进行生物发光和荧光成像。在所有小鼠中，每个淋巴盆在 BRET 成像中清晰可见，背景信号最小。注射腔肠素后，淋巴结中的 BRET 信号持续至少 30 分钟。此外，BRET 信号表现出比 QDot655（该 BRET 粒子的核心）发出的荧光信号更好的量化。BRET-QDot 的这些优势使我们能够在没有图像处理的情况下进行实时、定量的淋巴成像。BRET-Qdots 有可能成为开发光学分子成像探针的强大纳米材料平台。注射腔肠素后，淋巴结中的 BRET 信号持续至少 30 分钟。此外，BRET 信号表现出比 QDot655（该 BRET 粒子的核心）发出的荧光信号更好的量化。BRET-QDot 的这些优势使我们能够在没有图像处理的情况下进行实时、定量的淋巴成像。BRET-Qdots 有可能成为开发光学分子成像探针的强大纳米材料平台。注射腔肠素后，淋巴结中的 BRET 信号持续至少 30 分钟。此外，BRET 信号表现出比 QDot655（该 BRET 粒子的核心）发出的荧光信号更好的量化。BRET-QDot 的这些优势使我们能够在没有图像处理的情况下进行实时、定量的淋巴成像。BRET-Qdots 有可能成为开发光学分子成像探针的强大纳米材料平台。