荧光/磁性纳米球用于循环肿瘤细胞的高灵敏检测

The detection and investigation of circulating tumor cells (CTCs) are of great significance to early diagnosis of tumors, treatment monitoring, prognosis, and metastasis diagnosis, in which isolation and enrichment of CTCs are key steps due to their extremely low concentration in peripheral blood. In this proposal, fluorescent/magnetic nanospheres will be modified with multiple kinds of targeting molecules which can specifically recognize CTCs to fabricate multi-targeting fluorescent/magnetic nanoprobes. The obtained nanoprobes will be then applied to the rapid, sensitive, and reliable detection of tumor cells. Compared with using a single kind of targeting molecule, combination of multiple molecules will be able to associate with the multiple antigens on the cells, which will enhance the binding between the tumor cells and the bioprobes. This will ameliorate the “CTC miss” problem arising from the heterogeneity of tumor cell antigen expression and evolving changes, which will improve the capture efficiency of tumor cells. On the other hand, fluorescent/magnetic nanospheres will facilitate the one-step detection of CTCs, in which the magnetic capture and the fluorescence identification can be accomplished simultaneously. Compared with the two-step detection strategy, which includes capture and a subsequent identification process, the one-step strategy will simplify the detection process, save labor and time, and reduce the CTC loss caused by washing steps. Thus, this research will greatly benefit the sensitive and reliable CTC detection, which is of important medical significance.

循环肿瘤细胞（CTCs）的检测对肿瘤的早期诊断、治疗过程监测、预后、转移复发的早期监测等具有重要的意义。由于CTCs存在于复杂的外周血中，且浓度极低，所以CTCs的分离和富集是检测的关键步骤。本项目拟通过在荧光/磁性纳米球表面修饰多种能特异性识别CTCs的靶向分子，构建针对CTCs多种靶标的荧光/磁性纳米探针，进而基于该探针建立快速、灵敏、可靠检测肿瘤细胞的方法。在该法中，一方面，多种靶向分子的联用相比于使用单一靶向分子，能更充分地利用细胞表面的多种抗原，从而改善由于肿瘤细胞异质性或表面抗原丢失造成的“漏捕”问题，提高肿瘤细胞的捕获率；另一方面，利用纳米球的磁性功能和荧光功能同时完成CTCs的捕获和鉴定，相比于目前常用的先捕获后鉴定的方法，简化了操作步骤，节省了人力和时间，同时洗涤次数的减少降低了CTCs的损失率。因此，本项目能够在很大程度上促进CTCs的灵敏可靠检测，具有重要的医学意义。

近年来，恶性肿瘤已经成为一类严重威胁人类生命健康的疾病。循环肿瘤细胞的检测对肿瘤的早期诊断、治疗和预后等具有重要的意义。由于循环肿瘤细胞存在于复杂的外周血中，且浓度极低，造成目前检测技术存在灵敏度和准确度都比较差的问题。基于此，本项目完成了如下工作：（1）通过将量子点和磁性纳米粒子负载到聚合物球上制得性能优良的荧光/磁性纳米球，进一步对纳米球进行生物修饰赋予其相应的生物靶向功能，为其生物应用奠定了材料基础；（2）基于磁性纳米球建立了高效快速富集方法，以结构简单的细菌为模式目标物，实现了复杂体系中超低浓度细菌的捕获，并直接与荧光检测、聚合酶链式反应、培养等技术联用完成了细菌的鉴定和分析，为实现处于复杂环境中的超低浓度循环肿瘤细胞的检测提供了必要的工作经验；（3）基于磁性纳米球和荧光纳米球，实现了肿瘤标志物的一步灵敏检测，进一步基于兼具有磁性和荧光的纳米球，同时完成了肿瘤细胞的捕获和鉴定。相比于目前常用的先捕获后鉴定的方法，简化了操作步骤，节省了人力和时间，同时洗涤次数的减少降低了目标物的损失率，从而在很大程度上提高了检测的灵敏度和可靠性。