Femtoliter Scale Quantitative Injection Control by Experimental and Theoretical Modeling

Abstract

Purpose Injection is a useful technology for delivery the solution like drug in medical science, because injection amount can be simply controlled by adjusting the injection duration and pressure. With advances in fabrication technology, the small size of syringe can be made from cm to nm scale. Therefore, its application model has been also decreased to a single cell. However, in femto-scale, the precise volume measurement and the theoretical estimation by the time and the pressure becomes very challengeable, because of the dramatic change of inertial forces. In order to estimate the quantitative value of injected volume in femtoliter scale, empirical equation was established as injection pressure, duration and viscosity. Methods We observed the experimental results of the injected volume in femtoliter scale as a function of viscosity, duration, and pressure. Based on these results, we design and experimentally verify a theoretical equation for the quantitative control of the volume in femto-scale. The quantitative deliveries of the injection solution in a living cell were investigated. Results When the external material has viscosity between 80 to 12 mPa.s, injection volume is observed to vary between 22 to 46 fL. At same conditions, it was observed similarities between theoretical values and experimental results. Furthermore, fluorescent material was quantitatively injected into a living single cell. The fluorescent intensity is linearly increased with the injection volume. Conclusions It is possible to quantitatively control the injection volume using the empirical equation in the scale of femtoliter without any process on coating an injection solution.