Viscosity is an indispensable micro-environmental parameter that affects the diffusion of matter and molecular activity in biological systems. Abnormal changes in viscosity levels are strongly associated with various human diseases, such as thrombosis, Alzheimer's disease, and the formation of malignant tumors. This paper reports a highly biocompatible xylan-based viscosity fluorescent probe (Xyl-V) for cell-level viscosity measurement. Xyl-V is constructed using non-toxic and biodegradable xylan (Xyl) in plant resources, combined with mitochondrial targeting and a near-infrared emission luminescent group. Under viscous conditions, the fluorescence of Xyl-V at 580 nm and 820 nm is very sensitive to viscosity changes, and the fluorescence intensity increases by 16 and 32 times with the increase in viscosity level, respectively. As the first xylan-based probe for viscosity detection, it has excellent selectivity, low toxicity, high biocompatibility, and superior detection performance in the living cell environment.

粘度是影响生物系统中物质扩散和分子活动的不可或缺的微环境参数。粘度水平的异常变化与多种人类疾病密切相关，例如血栓形成、阿尔茨海默病和恶性肿瘤的形成。本文报道了一种高度生物相容性的基于木聚糖的粘度荧光探针（Xyl-V），用于细胞水平粘度测量。Xyl-V是利用植物资源中无毒且可生物降解的木聚糖（Xyl ），结合线粒体靶向和近红外发射发光基团构建的。在粘稠条件下， Xyl-V在580 nm和820 nm处的荧光对粘度变化非常敏感，随着粘度水平的增加，荧光强度分别增加16和32倍。作为首款用于粘度检测的木聚糖探针，它具有优异的选择性、低毒性、高生物相容性以及在活细胞环境中的优越检测性能。