Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University , Wuhan 430072, China.
Anal Chem. 2017 May 2;89(9):4931-4938. doi: 10.1021/acs.analchem.7b00134. Epub 2017 Apr 17.
Single cell analysis is a significant research field in recent years reflecting the heterogeneity of cells in a biological system. In this work, a facile droplet chip was fabricated and online combined with time-resolved inductively coupled plasma mass spectrometry (ICPMS) via a microflow nebulizer for the determination of zinc in single HepG2 cells. On the focusing geometric designed PDMS microfluidic chip, the aqueous cell suspension was ejected and divided by hexanol to generate droplets. The droplets encapsulated single cells remain intact during the transportation into ICP for subsequent detection. Under the optimized conditions, the frequency of droplet generation is 3-6 × 10 min, and the injected cell number is 2500 min, which can ensure the single cell encapsulation. ZnO nanoparticles (NPs) were used for the quantification of zinc in single cells, and the accuracy was validated by conventional acid digestion-ICPMS method. The ZnO NPs incubated HepG2 cells were analyzed as model samples, and the results exhibit the heterogeneity of HepG2 cells in the uptake/adsorption of ZnO NPs. The developed online droplet-chip-ICPMS analysis system achieves stable single cell encapsulation and has high throughput for single cell analysis. It has the potential in monitoring the content as well as distribution of trace elements/NPs at the single cell level.
单细胞分析是近年来一个重要的研究领域，反映了生物系统中细胞的异质性。在这项工作中，通过微流雾化器在线制备了一种简单的液滴芯片，并与时间分辨电感耦合等离子体质谱（ICPMS）结合，用于测定单个 HepG2 细胞中的锌。在聚焦几何设计的 PDMS 微流控芯片上，水相细胞悬浮液被喷射并与正己醇分离以产生液滴。在运输到 ICP 进行后续检测过程中，包裹单个细胞的液滴保持完整。在优化条件下，液滴的生成频率为 3-6×10 min，注入的细胞数为 2500 min，可以确保单细胞的封装。氧化锌纳米粒子（NPs）用于定量单个细胞中的锌，通过常规酸消解-ICPMS 方法验证了准确性。以 ZnO NPs 孵育的 HepG2 细胞作为模型样品进行分析，结果表明 HepG2 细胞在摄取/吸附 ZnO NPs 方面存在异质性。所开发的在线液滴芯片-ICPMS 分析系统实现了稳定的单细胞封装和高通量的单细胞分析。它具有在单细胞水平监测痕量元素/NPs 含量和分布的潜力。
