Low sensitivity, photobleaching, high-power excitation and long acquisition times constrain the utility of afterglow luminescence. Here we report the design and imaging performance of nanoparticles made of electron-rich trianthracene derivatives that, on excitation by room light at ultralow power (58 μW cm^–2), emit afterglow luminescence at ~500 times those of commonly used organic afterglow nanoparticles. The nanoparticles’ ultrabright afterglow allowed for deep-tissue imaging (up to 6 cm), for ultrafast afterglow imaging (at short acquisition times down to 0.01 s) of naturally behaving mice with negligible photobleaching, even after re-excitation for over 15 cycles, and for the accurate visualization of subcutaneous and orthotopic tumours and of plaque in carotid arteries. We also show that an afterglow nanoparticle that is activated only in the presence of granzyme B allowed for the tracking of granzyme-B activity in the context of therapeutic monitoring. The high sensitivity and negligible photobleaching of the organic afterglow nanoparticles offer advantages for real-time in vivo monitoring of physiopathological processes.

低灵敏度、光漂白、高功率激发和长采集时间限制了余辉发光的实用性。在这里，我们报告了由富电子三杂草烷衍生物制成的纳米颗粒的设计和成像性能，这些纳米颗粒在室内光以超低功率 （58 μW cm^–2） 激发时，发出的余辉发光是常用有机余辉纳米颗粒的 ~500 倍。纳米颗粒的超亮余辉允许对自然行为的小鼠进行深层组织成像（长达 6 cm），进行超快余辉成像（采集时间低至 0.01 s），光漂白可以忽略不计，即使在重新激发超过 15 个周期后，以及皮下和原位肿瘤以及颈动脉斑块的准确可视化。我们还表明，仅在颗粒酶 B 存在下被激活的余辉纳米颗粒允许在治疗监测的背景下跟踪颗粒酶-B 活性。有机余辉纳米颗粒的高灵敏度和可忽略不计的光漂白为生理病理过程的实时体内监测提供了优势。