Design and control of a piezoactuated microfeed mechanism for cell injection

A novel microfeed mechanism for cell injection driven by a piezoelectric actuator (PEA) was developed in this study to fulfill the requirement of a precise cell membrane puncture. A bridge-type displacement amplification mechanism was designed based on a compliant mechanism principle and the micrometric displacement characteristic of the PEA to realize the zero-clearance precision motion of the microfeed mechanism using a flexure hinge as a supporting member. Static and modal analyses and structural optimization specific to the bridge-type amplification mechanism were performed to acquire a high inherent frequency and a large displacement amplification coefficient. A simulation verification of the mechanism’s mechanical performance was implemented. A sliding-mode control strategy was proposed, considering that the complicated nonlinear hysteresis effect of PEA might cause low system precision. Cell puncturing experiments were performed on zebrafish embryos to demonstrate the performance of the proposed methodology. In comparison with existing studies, the manipulation precision of the proposed technique was less than 1.1 μm with a strong robustness. Thus, this new approach could be beneficial for the progress of cell puncture technology.