Single-Cell/Particle Sample Introduction Device for Mass Cytometry Based on Gas-Driven Flow Focusing

Mass cytometry is considered the second generation of flow cytometry technology, which uses metal-labeled antibodies instead of traditional fluorescent antibodies and can measure much more markers from a single cell simultaneously. However, due to frequent clogging of the capillary and nebulizer, it is still a complicated task to perform the sample introduction smoothly for a long-term determination. Herein, a plug-and-play sample introduction device for mass cytometry analysis was developed based on a gas-driven flow focusing protocol. The device is integrated with a virtual hole to generate liquid jet and omit a conventional nebulizer. Single-cell monodispersion can be achieved by liquid jet breakup instead of the commonly used nebulization by the Venturi effect, thus avoiding clogging of thin central capillary. The device has high universality and compatibility and can be plug-and-play on a mass cytometry instrument or common inductively coupled plasma mass spectrometry for single-cell or single-particle determination. High-speed microscopy imaging was used to capture and study the dynamic processes of monodispersion on microsphere suspensions achieved by the device. We also compared the analysis capabilities when using the device and a conventional nebulizer in mass cytometry analysis of four element calibration beads and cell samples. The results obtained by using the flow focusing device and the conventional nebulizer show great consistency, which means the device has no negative impact on the detection performance of mass cytometry and single-cell/particle monodispersion can be achieved without clogging.