Zhao Peng, Cheng Simin, Feng Yongxiang, Liang Fei, Zhang Xinrong, Ma Xiaoxiao, Wang Wenhui
IEEE Trans Biomed Eng. 2023 Feb;70(2):470-478. doi: 10.1109/TBME.2022.3194255. Epub 2023 Jan 19.
Mass spectrometry has become the method of choice for single cell analysis due to its high sensitivity of detection and capability in analyzing a large number of metabolites simultaneously. For a long time, an automated and miniaturized system capable of extracting cellular contents from single cells at the pico-liter level for pico-ESI analysis has been lacking.
This paper presents a first-of-its-kind automated and miniaturized pico-liter extraction system for single-cell MS. The key modules, including imaging, bus controller, and fluidic driving are customized to achieve satisfactory performance at affordable costs, resulting in a miniaturized system movable on a trolley and connectable with the MS. To enable automation, a single cell trapping device, new image-based one-pixel accuracy positioning methods for cells and micropipette, and a surface-tension-based 1-pL accuracy volume control scheme are developed.
The system is able to control the solvent loading at 1.97 ± 0.05 nL, solvent dispensing at 14-15 pL, and solvent evaporation at 689±48 pL. MS experiments demonstrate a throughput of 20 cells/h.
The system has achieved better performance in consistency (∼21%), sensitivity (∼28%), and success rate (up to 40%) than manual operation.
This automated and miniaturized system lays a solid basis for applying pico-ESI MS analysis in the automated and high-throughput single cell MS analysis, such as single-cell metabolomics and lipidomics.
由于质谱检测灵敏度高且能够同时分析大量代谢物，它已成为单细胞分析的首选方法。长期以来，一直缺乏一种能够从皮升水平的单细胞中提取细胞内容物用于皮升电喷雾电离（pico-ESI）分析的自动化小型系统。
本文介绍了首个用于单细胞质谱分析的自动化小型皮升提取系统。对包括成像、总线控制器和流体驱动在内的关键模块进行了定制，以在可承受的成本下实现令人满意的性能，从而得到一个可在手推车上移动并能与质谱仪连接的小型系统。为实现自动化，开发了单细胞捕获装置、基于图像的细胞和微量移液器单像素精度定位新方法以及基于表面张力的1皮升精度体积控制方案。
该系统能够将溶剂加载控制在1.97±0.05纳升，溶剂分配控制在14 - 15皮升，溶剂蒸发控制在689±48皮升。质谱实验表明通量为每小时20个细胞。
该系统在一致性（约21%）、灵敏度（约28%）和成功率（高达40%）方面比手动操作有更好的表现。
这种自动化小型系统为将皮升电喷雾电离质谱分析应用于自动化高通量单细胞质谱分析，如单细胞代谢组学和脂质组学，奠定了坚实基础。
