Viscosity is an essential microenvironmental parameter, which is related to various diseases such as acute inflammation. So it is necessary to develop a probe to monitor viscosity changes during the inflammatory progression in vivo. Herein, a HPQ (2-(2′-hydroxyphenyl)-4(3H)-quinazolinone)-based fluorescent probe named HPQ-BI-V is prepared for detecting viscosity in biological systems. The introduction of benzindole groups extends the π conjugation of HPQ, resulting in far-red emission wavelength at 610 nm. When the viscosity raises from 3.11 cP to 567.1 cP, the fluorescence signal increases 711 times, indicating the high sensitivity of the probe. Furthermore, this probe displays excellent selectivity for viscosity in comparison with other interfering analytes. Furthermore, the probe has excellent photostability and outstanding response capability in the physiological pH range. Given these advantages, HPQ-BI-V can be applied for detecting viscosity changes in HepG2 cells and zebrafish. In particular, the probe can successfully visualize viscosity changes in acute inflammatory mice induced by LPS and the assessment of anti-inflammatory drug.

粘度是重要的微环境参数，与急性炎症等多种疾病有关。因此，有必要开发一种探针来监测体内炎症进展过程中的粘度变化。在此，制备了一种名为 HPQ-BI-V 的基于 HPQ（2-（2'-羟基苯基）-4（3H）-喹唑啉酮）的荧光探针，用于检测生物系统中的粘度。苯并吲哚基团的引入扩展了 HPQ 的 π 共轭，导致 610 nm 的远红发射波长。当粘度从 3.11 cP 上升到 567.1 cP 时，荧光信号增加了 711 倍，表明探针的高灵敏度。此外，与其他干扰分析物相比，该探针显示出出色的粘度选择性。此外，该探针在生理pH范围内具有优异的光稳定性和出色的响应能力。鉴于这些优势，HPQ-BI-V 可用于检测 HepG2 细胞和斑马鱼的粘度变化。特别是，该探针可以成功地可视化 LPS 诱导的急性炎症小鼠的粘度变化和抗炎药物的评估。