A quantitative fluorescence intensity method to measure sub-picogram injection amount for tiny cell injection

We present a method for characterizing injection volume of the robotic cell injection system through measuring fluorescence intensity of the injected cell. The relationship of the concentration of the fluorescence dye and the fluorescence intensity was found to be linear, which was confirmed by measuring the cell-morphology-like droplets. The droplet was generated by dispensing in a mineral oil filled microfluidic cell holder. Human foreskin fibroblast (HFF) was injected with known concentration of fluorescence dye. The injection amount was determined by relating the fluorescence intensity of the injected cell and that of the droplet in mineral oil. The measured injection amount was compared with the volumetric change of the droplet to verify the accuracy of the proposed method.