DDAO (1,3-Dichloro-7-hydroxy-9,9-dimethyl-2(9H)-acridone) is a near-infrared (NIR) fluorophore that has received increasing attention in recent years, exhibiting near-infrared emission at 658 nm, low pKa (∼5.0), good water solubility and high quantum yield (Φ = 0.39). The reported DDAO-based fluorescent probes can be applied to biological imaging ofenzymes and other substances in vivo with high sensitivity and selectivity. Herein, using –OCN as the detection group, a novel NIR H₂S fluorescent probe DDAO-CN based on DDAO was designed and synthesized. In PBS buffer (10 mM, pH 7.4), probe DDAO-CN displayed specific selection, short response time (within 10 s) and low detection limit (4.3 nM) towards to H₂S under the catalysis of CTAB. At the same time, the probe is able to sense H₂S gas produced by food spoilage via the fluorescent test strip loaded with DDAO-CN. Moreover, since the probe has optimal pH range (6.0–9.0), it has been successfully used for bioimaging H₂S in the HeLa cells with low cytotoxicity.

DDAO (1,3-Dichloro-7-hydroxy-9,9-dimethyl-2(9 H )-acridone) 是一种近红外 (NIR) 荧光团，近年来受到越来越多的关注，在658 nm，低 pKa (~5.0)，良好的水溶性和高量子产率 (Φ = 0.39)。所报道的基于DDAO的荧光探针可应用于体内酶和其他物质的生物成像，具有高灵敏度和选择性。本文以-OCN为检测基团，设计合成了一种基于DDAO的新型NIR H ₂ S荧光探针DDAO-CN 。在 PBS 缓冲液（10 mM，pH 7.4）中，探针DDAO-CN显示出对 H 2 的特异性选择、短响应时间（10 秒内）和低检测限（4.3 nM _）S 在 CTAB 的催化下。同时，探针能够通过载有DDAO-CN的荧光试纸检测食物腐败变质产生的H ₂ S气体。此外，由于该探针具有最佳 pH 范围 (6.0–9.0)，它已成功用于低细胞毒性的 HeLa 细胞中的H _{2 S 生物成像。}