A near-infrared fluorescence probe for selective detection of butyrylcholinesterase and its application in colitis and colorectal cancer diagnosis and therapeutic evaluation

Abstract

Colitis is a known risk factor for the development and progression of colorectal cancer. Excessive inflammation is a key feature of inflammatory bowel disease (IBD), which is closely linked to colorectal cancer onset. Early and accurate diagnosis of colitis and colorectal cancer is therefore essential for effective intervention. This study presents a novel fluorescence probe, NR-BChE, for the detection of butyrylcholinesterase (BChE) activity. NR-BChE is composed of a hydroxyl Nile Red fluorophore and a BChE-recognition group, cyclopropyl formyl chloride. The probe functions through an intramolecular charge transfer (ICT) mechanism. Upon hydrolysis by BChE, a strong electron donor hydroxyl group is released, the ICT is enhanced and the fluorescence intensity is increased, leading to the emission of red light (λ_em = 690 nm). The probe has several advantageous properties, including a large Stokes shift (110 nm), low detection limit (0.024 U/L), high selectivity and sensitivity, and excellent biocompatibility. Cellular imaging demonstrated that NR-BChE could effectively detect the elevated BChE levels in colorectal cancer and colitis cells. In vivo imaging further revealed that NR-BChE could differentiate normal mouse model from colitis and colorectal cancer mouse models, and evaluate the therapeutic efficacy of four colitis treatment methods. NR-BChE is a new molecular tool for the early diagnosis of colitis and colorectal cancer. It has high potential in the monitoring of disease progression and the evaluation of therapeutic outcomes in clinical settings.