Peroxynitrite-activated near-infrared fluorescence sensing platform for early non-invasive IBD diagnosis, herbal formula efficacy evaluation and anti-enteritis bioactive components screening.

Inflammatory bowel disease (IBD) severely impairs patients' quality of life and elevates colorectal cancer risk, where early diagnosis and timely intervention are vital to control disease remission. Peroxynitrite (ONOO-), a critical reactive nitrogen species closely involved in IBD pathogenesis, is an attractive biomarker for biological detection. Herein, we rationally constructed a turn-on near-infrared fluorescent probe HCY-PO targeting ONOO-. Upon ONOO--triggered cleavage of the diphenylphosphinamide recognition group, HCY-PO exhibited a distinct fluorescence enhancement at 750 nm within 60 s, with a detection limit of 90 nM and strong anti-interference capability in complex biological systems. Using HCY-PO, we achieved real-time tracking of endogenous ONOO- fluctuations in inflamed NCM460 cells, zebrafish enteritis models, and early diagnosis of ulcerative colitis in mouse models. Importantly, the probe's fluorescent signal intensity was positively correlated with IBD severity. Moreover, HCY-PO achieved the sensitive detection of ONOO- in mouse feces, enabling non-invasive monitoring of IBD progression. Based on this superior analytical performance, an integrated fluorescence sensing platform was first established to semi-quantitatively evaluate the therapeutic efficacy of the traditional Chinese medicine formula Bu-Zhong-Yi-Qi-Tang. Consistent results among fluorescence, pathology and inflammatory factor tests verified the method reliability, and five anti-enteritis bioactive constituents from the formula were efficiently screened via this platform. Collectively, this work provides a powerful analytical tool for non-invasive early IBD diagnosis, drug efficacy evaluation, and rapid screening of anti-enteritis bioactive components.