I-motif作为一种新型pH敏感元件,因其在不同pH条件下可以进行快速的构象转变,以及具有自动化合成、优异的生物相容性和灵活的功能化整合等优点,在生物医学领域引起了广泛的关注和研究热潮.该文介绍了i-motif的基本性能,综述了基于i-motif的纳米系统在细胞pH成像、pH控制的药物释放和pH响应型肿瘤诊疗一体化等生物医学领域的应用研究进展,总结了基于i-motif的纳米系统在生物医学应用中面临的挑战,并展望了基于i-motif的纳米系统在精准医学中的应用前景.“,”I-motif,as a novel pH-sensitive element,has attracted extensive attention and research upsurge in the field of biomedicine due to its ability of fast conformation alteration at different pH conditions,as well as the advantages of au?tomatic synthesis,excellent biocompatibility and flexible functional integration.In this review,the basic performances of i-motif are firstly described. Then, the applications of i-motif-based nanosystems in biomedical field are reviewed from three aspects of cellular pH imaging, pH-controlled drugs release and pH-responsive tumor theranostics applica?tions.Finally,some of the current challenges of the i-motif-based nanosystems for the biomedical applications are point?ed out,and an insight into the future prospects of i-motif-based nanosystems for precision medicine is provided .