中文摘要：

叶酸受体（FR）在肿瘤细胞中都有过度表达，而在正常组织中保守表达，利用叶酸受体与叶酸及其类似物高亲合力结合的特性，将叶酸偶联荧光探针输送到肿瘤组织，从而实现肿瘤组织的特异性靶向光学成像。本文阐述了叶酸荧光探针的结构及其用于标记肿瘤细胞的作用机制，介绍了近十年来叶酸受体介导的肿瘤靶向光学成像技术，例如有机荧光染料，染料掺杂纳米颗粒，量子点，磁性纳米微粒以及多功能纳米粒子等在肿瘤靶向成像中的研究及应用进展，指出了当前研究中的主要发展方向和仍需解决的问题。

英文摘要：

Folate receptor （FR） are up regulated in a broad spectrum of malignant tumors, including cancers of breast, ovary, endometrium, lung, kidney, colon, brain and myeloid cells of hematopoietic origin, while limited expression on normal cells. This over-expression of folate receptors on cancer tissues can be exploited to target folate-linked imaging agents specifically to FR-expressing tumor cells to realize the specific targeted optical imaging by linking folate to fluorescent probes using FR＇ s character of binding folate and folate conjugate with very high affinity . In this review,the schematic of folate fluorescence probe and its mechanism on the marking of tumor cells are introduced. Research and development of FR-mediated tumor targeting optical imaging technology in recent ten years such as the use of organic fluorescent dye, dye-doped nanoparticles, quantum dots （QDs）, magnetic nanoparticles and multifunctional particles are summarized. The future prospects and challenges of the current tumor targeted optical imaging research are also proposed in this review. Some FR-mediated tumor targeting optical imaging technologies are shown to be very effective for sensitive cancer imaging with greater success in the cellular level, but most of the experiments are in vitro. There are several challenges in developing fluorescent probes for in vivo cancer imaging applications, such as, to develop NIR fluorescent agents and improve surface modifying technology.