State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
Department of Pulmonary and Critical Care Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
Biosens Bioelectron. 2022 May 15;204:113879. doi: 10.1016/j.bios.2021.113879. Epub 2021 Dec 21.
Exosomes are lipid-bilayered nanovesicles secreted by cells to mediate intercellular communication. Various kinds of biomolecules involved in exosomes offer non-invasive approaches for detecting or monitoring disease and developing targeted therapeutics. Here, we present an integrated microfluidic exosome isolation and detection system (EXID system) to analyze the abundance of the exosomal PD-L1 protein marker, which is a transmembrane protein expressed by tumors to suppress immune activation of T cells. By incorporating exosome isolation and biomarker labelling and quantification within a single microfluidic chip, our system reduced the total analysis time below 2 h. Using the EXID system, 7 categories of cell lines including cancer cell lines and control samples were profiled, where significant differences in the fluorescence intensity were observed with the limit of detection (LOD) down to 10.76 per microliter. Such noticeable variations in PD-L1 abundance among cancer cell lines highlighted the need of personalized treatments. Furthermore, 16 clinical samples from 7 post-treated cancer patients, 3 prior-treatment patients and 6 healthy controls, are tested, among which differences in sensitivity toward immune response were subsistent. Because the abundance of PD-L1 reflects the sensibility for immune response, our results provide useful guides to design immunotherapy strategies for different types of tumors.
外泌体是由细胞分泌的双层脂质纳米囊泡，可介导细胞间通讯。外泌体中涉及的各种生物分子为疾病的检测或监测以及靶向治疗的发展提供了非侵入性的方法。在这里，我们提出了一种集成的微流控外泌体分离和检测系统（EXID 系统）来分析外泌体 PD-L1 蛋白标志物的丰度，PD-L1 是一种由肿瘤表达的跨膜蛋白，可抑制 T 细胞的免疫激活。通过在单个微流控芯片内整合外泌体分离和生物标志物标记和定量，我们的系统将总分析时间缩短到 2 小时以下。使用 EXID 系统，对包括癌细胞系和对照样本在内的 7 种细胞系进行了分析，其中观察到荧光强度存在显著差异，检测限（LOD）低至 10.76 皮升。癌细胞系中 PD-L1 丰度的显著差异突出了个性化治疗的必要性。此外，还对来自 7 名经治疗后的癌症患者、3 名未经治疗的患者和 6 名健康对照者的 16 份临床样本进行了测试，其中对免疫反应的敏感性存在差异。因为 PD-L1 的丰度反映了对免疫反应的敏感性，所以我们的结果为设计针对不同类型肿瘤的免疫治疗策略提供了有用的指导。
