【摘要】 血管内皮生长因子(VEGF)是生理性和病理性血管生成的重要调节因子。尽管单细胞分析技术最近取得了进展，但用于跟踪单细胞外泌因子的能力仍然有限。该研究报道了一个用于单细胞外泌因子的微液滴-荧光成像分析平台，该平台集微液滴分隔单细胞与荧光成像追踪分泌细胞因子的单细胞的双功能于一体，提高了液滴的有效率。采用两种免疫二氧化硅纳米粒子为探针(分别为捕获探针和检测探针),首先将捕获探针锚定在细胞膜表面，使其捕获更多的细胞分泌因子；其次是染料掺杂的荧光检测探针实现信号报告功能，在VEGF存在下可形成免疫夹心构型，实现了检测探针在细胞表面富集，提高了检测VEGF的灵敏度。应用该平台在单细胞水平上研究了三种细胞系(MCF-7, HeLa, H8)分泌VEGF的能力，实现了基于外泌因子含量的细胞异质性分析。更多还原

【Abstract】 It is increasingly recognized that vascular endothelial growth factor(VEGF) is an important regulator of physiological and pathological angiogenesis. Despite recent advances in single-cell analysis techniques, the ability to track single-cell exocrine factors remains limited. Here, we report an analytical platform for microdroplet-fluorescence imaging of single-cell secreted cytokines that combines the dual functions of microdroplet separation of single cells and fluorescence imaging to track cytokine-secreting single cells, addressing the difficulty of manipulating single cells and individual sensing elements(e. g., magnetic beads) simultaneously encapsulated in a single droplet in previous studies, while improving the efficiency of the droplet. In this study, two types of immunosilica nanoparticles were introduced into the microfluidic droplet. Firstly, the capture probe(CP) was anchored on the cell membrane surface to capture more secreted cytokines, and secondly, the dye-doped fluorescent detection probe(RP), so that an immune sandwich conformation could be formed in the presence of VEGF, which realized the amplification effect of enriching the fluorescent detection probe 2 on the cell surface and greatly improved the sensitivity of detecting VEGF. We applied this platform to study the ability of three cell lines(MCF-7, HeLa, H8) to secrete VEGF at the single cell level, and to realize the analysis of cell heterogeneity based on the content of extracellular factors.更多还原