Research Center for Analytical Sciences, Department of Chemistry, College of Sciences , Northeastern University , Shenyang 110819 , China.
Anal Chem. 2018 Dec 18;90(24):14543-14550. doi: 10.1021/acs.analchem.8b04471. Epub 2018 Dec 6.
In single-cell analysis with ICP-MS it is highly important to ensure precise single-cell sampling into ICP. For this purpose, a simple configured pressure-resistant MicroCross interface is developed for high-throughput/high-precision microdroplet generation and single-cell encapsulation. Aqueous cell suspension is ejected and sheared into droplets by tangent-flowing hexanol-continuous phases in the flow-focusing geometry of MicroCross, wherein to precisely trap a single cell into a droplet, with an extremely low probability of <0.005% for a single droplet encapsulating two cells. MicroCross interface is coupled with time-resolved ICP-MS (TRA-ICP-MS) for quantifying nanoparticles in single MCF-7 cells. At the optimal conditions, sufficient temporal-spatial resolution of the microdroplets is achieved facilitating high-throughput sampling of single cells into ICP. For solving the serious carbon deposition on the sampling cone and the unstable plasma torch caused by incomplete oxidation of hexanol phase in ICP, dimethyl carbonate (DMC) is for the first time used as a superb oxygen compensation reagent, which ensures adequate oxidation of hexanol, effectively eliminates the carbon deposition, and maintains a stable plasma. The single-cell analysis results indicated a remarkable discrepancy of the number of nanoparticles among the individual cells, falling into a range of 130-584 per MCF-7 cell in the case of AuNPs.
在 ICP-MS 的单细胞分析中，确保精确的单细胞采样进入 ICP 非常重要。为此，开发了一种简单配置的耐高压 MicroCross 接口，用于高通量/高精度微滴生成和单细胞封装。水相细胞悬浮液通过 MicroCross 的流聚焦几何形状中的切向流动正己醇连续相被喷出并剪切为液滴，其中通过极低的概率<0.005%将单个细胞精确捕获到液滴中，对于单个液滴封装两个细胞的情况。MicroCross 接口与时间分辨 ICP-MS（TRA-ICP-MS）耦合，用于定量单个 MCF-7 细胞中的纳米颗粒。在最佳条件下，实现了足够的微滴时空分辨率，从而能够高通量地将单细胞采样进入 ICP。为了解决 ICP 中由于正己醇相不完全氧化而导致采样锥上严重积碳和等离子体炬不稳定的问题，首次将碳酸二甲酯（DMC）用作卓越的氧补偿试剂，它确保了正己醇的充分氧化，有效地消除了积碳，并维持了稳定的等离子体。单细胞分析结果表明，单个细胞之间的纳米颗粒数量存在显著差异，在 AuNPs 的情况下，每个 MCF-7 细胞的纳米颗粒数量范围为 130-584。
