Although microliter-scale liquid handling with a handheld pipette is a routine task, pipetting nanoliter-scale volumes is challenging due to several technical difficulties including surface tension, adhesion and evaporation effects. We developed a fully automated piezoelectric micropipette with a precision of < 1 nanoliter, improving the efficiency of imaging-based single-cell isolation to above 90%. This improvement is crucial when sorting rare or precious cells, especially in medical applications. The compact piezoelectric micropipette can be integrated into various (bio)chemical workflows. It eliminates plastic tubes, valves, syringes, and pressure tanks. For high-quality phase-contrast illumination of the sample, e.g., cells or tiny droplets, we constructed rings of LEDs arranged concentrically to the micropipette. The same device can be readily used for single-cell printing and nanoliter-scale droplet printing of reagents using either fluorescent or transparent illumination on a microscope. We envision that this new technology will shortly become a standard tool for single-cell manipulations in medical diagnostics, e.g., circulating tumor cell isolation.

尽管使用手持式移液器进行微升级液体处理是一项常规任务，但由于若干技术难题（包括表面张力，附着力和蒸发效果），对纳升级体积进行移液仍具有挑战性。我们开发了精度小于1纳升的全自动压电微量移液器，将基于成像的单细胞分离效率提高到90％以上。当分选稀有或珍贵的细胞时，尤其是在医疗应用中，这一改进至关重要。紧凑的压电微量移液器可以集成到各种（生物）化学工作流程中。它消除了塑料管，阀门，注射器和压力罐。为了对样品（例如细胞或微小液滴）进行高质量的相衬照明，我们构建了与微移液管同心排列的LED环。使用显微镜上的荧光或透明照明，同一设备可轻松用于试剂的单细胞打印和纳升级液滴打印。我们设想，这项新技术将很快成为医学诊断（例如循环肿瘤细胞分离）中单细胞操作的标准工具。