Clinically Translatable Solid‐State Dye for NIR‐II Imaging of Medical Devices

Abstract Medical devices are commonly implanted underneath the skin, but how to real‐time noninvasively monitor their migration, integrity, and biodegradation in human body is still a formidable challenge. Here, the study demonstrates that benzyl violet 4B (BV‐4B), a main component in the FDA‐approved surgical suture, is found to produce fluorescence signal in the first near‐infrared window (NIR‐I, 700–900 nm) in polar solutions, whereas BV‐4B self‐assembles into highly crystalline aggregates upon a formation of ultrasmall nanodots and can emit strong fluorescence in the second near‐infrared window (NIR‐II, 1000–1700 nm) with a dramatic bathochromic shift in the absorption spectrum of ≈200 nm. Intriguingly, BV‐4B‐involved suture knots underneath the skin can be facilely monitored during the whole degradation process in vivo, and the rupture of the customized BV‐4B‐coated silicone catheter is noninvasively diagnosed by NIR‐II imaging. Furthermore, BV‐4B suspended in embolization glue achieves hybrid fluorescence‐guided surgery (hybrid FGS) for arteriovenous malformation. As a proof‐of‐concept study, the solid‐state BV‐4B is successfully used for NIR‐II imaging of surgical sutures in operations of patients. Overall, as a clinically translatable solid‐state dye, BV‐4B can be applied for in vivo monitoring the fate of medical devices by NIR‐II imaging.