Chen Zhenna, Chen Beibei, He Man, Hu Bin
Department of Chemistry, Wuhan University, Wuhan 430072, China.
Anal Chem. 2022 May 10;94(18):6649-6656. doi: 10.1021/acs.analchem.1c04216. Epub 2022 Apr 28.
High-throughput single-cell analysis is critical to elucidate the cell heterogeneity. Recently, droplet microchips using oil/gas phases to generate single-cell encapsulated droplets have been combined with inductively coupled plasma-mass spectrometry (ICP-MS) for determination of trace elements in single cells with a throughput of dozens of cells per min. To improve the sample throughput and avoid the oil phase introduced into ICP-MS, herein, a negative magnetophoresis focusing microchip was established and online-coupled to ICP-MS for single-cell analysis. MCF-7 cells in the paramagnetic salt solution were introduced into the designed focusing microchannel, in which they were focused into a single stream under both the magnetic repulsion force and inertial lift force, and then were introduced into ICP-MS for online single-cell analysis. The important parameters including the chip design, the concentration of the paramagnetic salt solution, flow rate, cell density, and dwell time were optimized. Under the optimal conditions, a high sample throughput of 1390 cells min was obtained. The established online analytical system was applied to study the uptake behaviors of MCF-7 cells for Zn and ZnO nanoparticles (NPs) at a single-cell level. The single-cell analysis results indicate that MCF-7 cells displayed more remarkable heterogeneity when they were treated with ZnO NPs, and the uptake content of ZnO NPs by MCF-7 cells was less than that of Zn. Compared with other droplet microdevice-ICP-MS analysis systems, the developed system has the advantages of simple design and fabrication, no organic phase, a high throughput, and a low sample consumption (only 5 μL).
高通量单细胞分析对于阐明细胞异质性至关重要。最近，利用油/气相生成单细胞包封液滴的液滴微芯片已与电感耦合等离子体质谱（ICP-MS）相结合，用于测定单细胞中的微量元素，通量可达每分钟数十个细胞。为了提高样品通量并避免油相引入ICP-MS，本文建立了一种负磁泳聚焦微芯片，并将其与ICP-MS在线联用进行单细胞分析。将顺磁盐溶液中的MCF-7细胞引入设计的聚焦微通道，在该通道中，细胞在磁排斥力和惯性升力的作用下被聚焦成单一流，然后引入ICP-MS进行在线单细胞分析。对芯片设计、顺磁盐溶液浓度、流速、细胞密度和停留时间等重要参数进行了优化。在最佳条件下，获得了1390个细胞/分钟的高样品通量。所建立的在线分析系统用于在单细胞水平研究MCF-7细胞对锌和氧化锌纳米颗粒（NPs）的摄取行为。单细胞分析结果表明，用氧化锌纳米颗粒处理时，MCF-7细胞表现出更显著的异质性，且MCF-7细胞对氧化锌纳米颗粒的摄取量低于对锌的摄取量。与其他液滴微器件-ICP-MS分析系统相比，所开发的系统具有设计和制造简单、无有机相、高通量和低样品消耗（仅5 μL）的优点。
