Abstract: In view of the disadvantages of micropipette movement including low speed and low precision in micro- injection, a novel digital piercing and withdrawing micro-pipette device (DPWMD) based on the alternate action of inertial force and friction force is developed. The working principle of DPWMD is introduced. By means of piezo-ceramic actuators’ low frequency vibration, driven by controllable pulse sequence, impact inertial force is produced. When friction force is overcome by inertial force, the micro-feed is generated. On the basis of dynamical analysis, motion model is established for digital piercing and withdrawing micropipette device. Using computer numerical algorithm, the response relation between input and output is calculated. The model solving results are validated by performance test experiment. The DPWMD is applied in microinjection of mouse oocytes. With the experimental confirmation, digital piercing and withdrawing micropipette device can meet the need of microinjection, and the dynamical model is useable and reasonable.

Key words: Cell microinjection, Mechanism analysis, Piercing and withdrawing micropipette digitally, Piezo-ceramic