A Near-Infrared Fluorogenic Spray Probe for Rapid and Wash-Free Intraoperative Nerve Imaging

Intraoperative nerve injury remains a major surgical challenge. Rapid, wash-free nerve visualization is highly desirable for fluorescence image-guided surgery (FIGS), yet existing probes lack spray compatibility and sufficient fluorogenicity. Here we introduce N4, a near-infrared fluorogenic spray probe that enables ∼10 s, wash-free visualization of peripheral nerves. N4 is engineered to remain nonfluorescent in its spirocyclic form under physiological conditions but undergoes MBP-triggered spiro-opening to a bright zwitterionic state, yielding a 6.3-fold turn-on. Topical spraying of N4 produces clear sciatic and vagus nerve imaging with nerve-to-muscle contrast up to 6.4 and allows visualization of branches as small as 0.12 mm, even under blood-contaminated fields. N4 provides a robust platform for real-time FIGS nerve mapping and advances the development of next-generation fluorogenic surgical probes.术中神经损伤仍是外科领域的重大挑战。荧光影像引导手术（fluorescence image-guided surgery, FIGS）亟需快速、无需洗脱的神经可视化方案，但现有探针均不具备喷雾适配性，且荧光生成能力不足。本研究报道了一款近红外荧光生成喷雾探针N4，可实现约10秒内无需洗脱的外周神经可视化。该探针经过工程化设计，在生理条件下以螺环构型保持无荧光状态，可在髓鞘碱性蛋白（myelin basic protein, MBP）触发下发生螺环开环，转变为明亮的两性离子状态，荧光开启倍率达6.3倍。对N4进行局部喷雾后，可获得清晰的坐骨神经与迷走神经影像，神经与肌肉对比度最高可达6.4，即便在血液污染的视野中，也能可视化直径仅0.12 mm的神经分支。N4为实时荧光影像引导手术的神经定位提供了稳定可靠的技术平台，推动了下一代荧光生成型手术探针的研发进展。