Emerging demands for handling minute liquid samples and reagents have been constantly growing in a wide variety of medical and biological areas. This calls for low-volume and high-precision liquid handling solutions with ease-of-use and portability. In this article, a new digital droplet pipetting method is introduced for the first time, derived from the microfluidic impact printing principle. Configured as a conventional handheld pipette, the prototype device consists of a plug-and-play and disposable microfluidic pipetting chip, driven by a programmable electromagnetic actuator for on-demand dispensing of nanoliter droplets. In particular, the impact-driven microfluidic pipetting chip, in place of the traditional disposable pipette tips, offers both liquid loading and droplet generation. The printing nozzle has been micro-fabricated using a femtosecond laser with a super-hydrophobic structure, in order to minimize the dispensing residues. As a result of the high-precision droplet dispensing principle, the variations of the dispensed volume have been successfully reduced from 49.5% to 0.6% at 0.1 μL, as compared to its commercial counterparts. A proof-of-concept study for concentration dilution and quantitative analysis of cell drug resistance has been carried out by using the digital droplet pipetting system, demonstrating its potential in a broad range of biomedical applications which require both high precision and low-volume processing.

中文翻译：

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即插即用的微流体移液芯片可实现高精度的数字液滴移液†

在各种医学和生物学领域，对处理微小液体样品和试剂的新兴需求一直在不断增长。这要求具有易于使用和便携性的小批量和高精度液体处理解决方案。在本文中，首次引入了一种新的数字液滴移液方法，该方法源于微流体冲击印刷原理。原型设备配置为传统的手持式移液器，由即插即用和一次性微流体移液芯片组成，由可编程电磁致动器驱动，可按需分配纳升液滴。特别是，冲击驱动的微流控移液芯片代替了传统的一次性移液器吸头，既可以增加液体负荷，又可以产生液滴。为了使分配残留物最小化，已使用具有超疏水结构的飞秒激光对打印喷嘴进行了微加工。由于采用了高精度的液滴分配原理，与市售同类产品相比，在0.1μL时，分配体积的变化已成功地从49.5％降低至0.6％。通过使用数字液滴移液系统进行了浓度稀释和细胞耐药性定量分析的概念验证研究，证明了其在需要高精度和小批量处理的广泛生物医学应用中的潜力。与市售同类产品相比，在0.1μL时，分配量的变化已成功地从49.5％降低至0.6％。通过使用数字液滴移液系统进行了浓度稀释和细胞耐药性定量分析的概念验证研究，证明了其在需要高精度和小批量处理的广泛生物医学应用中的潜力。与市售同类产品相比，在0.1μL时，分配量的变化已成功地从49.5％降低至0.6％。通过使用数字液滴移液系统进行了浓度稀释和细胞耐药性定量分析的概念验证研究，证明了其在需要高精度和小批量处理的广泛生物医学应用中的潜力。