Tumour metastasis is a main barrier in fully recovery of cancer, in most cases, metastasis has already occurred before the detection of cancer. Until now, the detection limit of tumour sizes is still ~1 mm in mouse models, thus, it is difficult to track tumour metastasis in the early stage by current imaging techniques and related others. Herein, we demonstrated a novel way to detect early tumour metastasis by utilizing background-negligible phosphorescence imaging at room-temperature, putting the detection limits ahead to the stage of tumour metastatic niches. Ultra-bright phosphorescence nanoparticles (NPs) with good biocompatibility and long lifetime (49 ms) were prepared by the simply enveloping process, which achieved high signal to background ratio (SBR) of 2278 ± 242 in subcutaneous imaging. This is the highest one among phosphorescent nanoparticles of organic molecules reported, partially assuring the detection of early metastases from orthotopic liver tumours to lungs with high sensitivity. Finally, the metastatic niches in lungs before the formation of secondary tumours, as confirmed by immunohistochemistry, which appeared after tumour implantation in liver for three days, can be detected by phosphorescent NPs with SBR of 62 ± 23, far ahead of other reported imaging methods under the same conditions, thus providing an efficient approach to early diagnosis of cancer.

中文翻译：

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通过磷光成像照亮早期转移灶

肿瘤转移是癌症完全康复的主要障碍，在大多数情况下，在发现癌症之前就已经发生了转移。到目前为止，在小鼠模型中肿瘤大小的检测限仍为~1 mm，因此，目前的成像技术和相关技术很难在早期跟踪肿瘤转移。在这里，我们展示了一种通过在室温下利用背景可忽略的磷光成像检测早期肿瘤转移的新方法，将检测限提前到肿瘤转移生态位阶段。通过简单的包络工艺制备了具有良好生物相容性和长寿命（49 ms）的超亮磷光纳米粒子（NPs），在皮下成像中实现了2278±242的高信噪比（SBR）。这是已报道的有机分子磷光纳米粒子中最高的一种，部分保证了以高灵敏度检测从原位肝肿瘤到肺的早期转移。最后，通过免疫组织化学证实，在肿瘤植入肝脏三天后出现的继发性肿瘤形成之前肺部的转移性微环境，可以通过 SBR 为 62 ± 23 的磷光 NPs 检测到，远远领先于其他报道的成像方法在相同的条件下，从而为癌症的早期诊断提供了一种有效的方法。