High-precision, pressure-driven pump for sub-picoliter scale quantitative injection

The microinjection is generally performed on commercial microinjection pump using a nitrogen gas-holder as pressure supply. However, the commercial pump has some problems in picoliter-scale injection due to the instability of pressure source, and the success rate varies significantly across different operators. In this paper, a high-precision, pressure-driven pump for sub-picoliter scale quantitative injection is developed. This new pumping system is capable of generating a wide range of positive and negative pressure with high resolution by connecting a buffer tank to the gas passage structure. It is able to generate pressure between −30 kPa and +150 kPa with a resolution less than 1 Pa. Compared to the commercial pump, the new pumping system has high stability and resolution (less than 1 Pa versus 68.9 Pa). The injection accuracy of the system was further proved by applying it to quantitative injection experiment. The results demonstrate that the injection accuracy of the injection volume is 0.0022 pL.