Near-Infrared Fluorescent Probes and NIR-Responsive Nanomaterials for Inflammatory Bowel Disease: Advances in Imaging and Therapy

Inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, is a chronic inflammatory disorder of the gastrointestinal tract that requires accurate diagnosis, continuous disease monitoring, and effective treatment. Conventional approaches are often limited by invasiveness, insufficient sensitivity, and limited capacity for real-time disease monitoring. Near-infrared (NIR)-based theranostic technologies have emerged as a promising strategy for IBD management owing to their deep tissue penetration, low autofluorescence, high spatial resolution, and ability to integrate diagnosis and therapy on a single platform. This review summarizes the recent advances in NIR technologies for IBD diagnosis and treatment. It first introduces the fundamentals of NIR-I and NIR-II optical windows, the optical properties of intestinal tissues, and the design principles of NIR-responsive nanoplatforms. Recent advances in NIR fluorescence imaging for disease detection and monitoring, including small-molecule dyes, activatable probes, and nanoparticle-based imaging agents, are highlighted. NIR-responsive therapeutic systems, including photothermal therapy (PTT), photodynamic therapy (PDT), triggered drug delivery, and nanozyme-integrated catalytic therapy, are also reviewed in this article. In addition, multimodal imaging methods and imaging-guided therapeutic approaches are discussed, along with evolving combination therapies, including antioxidant nanozymes, immunomodulation, and microbiota-guided strategies. Finally, we outline the major challenges and future directions associated with clinical translation. Overall, NIR-based theranostic technologies hold considerable potential for precise diagnosis, real-time monitoring, and personalized treatment of IBD.