单颗粒示踪（Single particle tracking，SPT）技术是应用显微镜系统对细胞内单个特定荧光或散射颗粒的定位和追踪。由于SPT能够实时监控活细胞内复杂、高度动态的组织结构的变化并提供结构—功能间的动力学关系，因此在细胞生物学上有重要的应用。本文总结了SPT的机理以及在细胞上的应用，首先介绍了SPT的动力学原理，包括单颗粒定位，轨道重建以及轨道分析，然后总结了SPT技术现阶段重点发展的光学材料及仪器，最后阐述了SPT在细胞膜、细胞内信号通路、分子转运机制、遗传信息表达以及病毒感染机制的应用。此外，本文还对SPT技术未来的发展进行了展望。

Single particle tracking(SPT) technology can be used to locate and track each microscale and nanoscale particles in living cells. Typically a fluorescence microscope is used to real time detect fluorescence or scattering signals. SPT provides a more quantitative view of the highly dynamic interactions in the complex of intracellular organisms within living cells in real time. In this review we focus on the tutorial of SPT and their biological applications. We first illustrate the basics of particle localization, trajectory reconstruction and data analysis. The availability of luminescent nanoparticles and their new implementations in SPT technology are then discussed. This review further showcases several practical applications of SPT technology in living cells, including cell membranes, signal pathway, molecular transport, nucleus and virus. We conclude this review by discussing the future development of new SPT technologies.