Accurate detection of butyrylcholinesterase (BChE) activity is imperative to understand its biological function and diagnose related disease. Far-red (FR)/Near-Infrared (NIR) fluorescent probe with large Stokes shift for BChE detection is extremely important. In this study, we reported a new “off-on” FR/NIR fluorescent probe (DX-2) with large Stokes shift (110 nm). DX-2 was constructed through cyclopropionate to pull-push the optical tuable hydroxyl group of chloro-substituted dicyanoisophorone fluorophore. DX-2 (λ_ex/λ_em = 555/665 nm) featured high sensitivity (LOD∼0.08 U/mL) and selectivity, good pH practicability, low toxicity and good cell membrane permeability with a bright emission triggered by BChE. Furthermore, DX-2 exhibited good optical performance to image BChE activity in living cells. More importantly, the FR/NIR probe DX-2 was successfully applied to real-time monitor BChE in live tumor-bearing mouse model. These studies suggest that probe DX-2 has potential applicable value for detecting BChE in living biological systems and diagnosing BChE-related diseases.

准确检测丁酰胆碱酯酶 (BChE) 活性对于了解其生物学功能和诊断相关疾病至关重要。具有大斯托克斯位移的远红外 (FR)/近红外 (NIR) 荧光探针对于 BChE 检测极为重要。在这项研究中，我们报道了一种新的“关断”FR/NIR 荧光探针(DX-2 )，具有大斯托克斯位移 (110 nm)。DX-2是通过环丙酸酯拉-推氯代二氰基异佛尔酮荧光团的光导羟基而构建的。DX-2 (λ _ex /λ _em = 555/665 nm) 具有高灵敏度 (LOD~0.08 U/mL) 和选择性、良好的 pH 实用性、低毒性和良好的细胞膜通透性以及 BChE 触发的明亮发射。此外，DX-2在对活细胞中的 BChE 活性成像方面表现出良好的光学性能。更重要的是，FR/NIR 探针DX-2成功应用于活体荷瘤小鼠模型中 BChE 的实时监测。这些研究表明，探针DX-2在检测活体生物系统中的BChE和诊断BChE相关疾病方面具有潜在的应用价值。