Dragonfly-Like Micro Sampling Device for Extracting Nano-Liter Sample from Plants

In this paper, a dragonfly-like micro sampling device is introduced, which shows potential to continuously and low-invasively extract nanoliter volume sample from plants' stem for monitoring nutrient content inside. The micro sampling device is based on a micro metal needle (diameter: 500 μm) with an inner gap (volume: ~50 nL) for drawing in liquid. Experimental data indicate good stability and prove the feasibility of this sampling device. A final integrated system containing the sampling device, flowing tube, pump, control board and analyzer is also introduced.