Finite Element Analysis of Single Cell Wall Cutting by Piezoelectric-Actuated Vibrating Rigid Nanoneedle

We proposed a piezoelectric-actuated rigid nanoneedle for single cell wall cutting. A fabricated Tungsten (W) nanoneedle was assembled with a commercial piezoelectric actuator laterally and perpendicularly. The body of the nanoneedle is cylindrical while the shape of the tip is conical. Calibration of the assembled device was conducted using both experimental and numerical approaches. Experimentally, we have obtained a 4.5 μm displacement of the nanoneedle from an input potential of 100 V toward the Y axis. Results also showed that, at lateral configuration, nanoneedle tip is more stable than at perpendicular configuration. For the perpendicular configuration, we observed a fractional displacement of 1.2 pm, but in the lateral configuration we did not experience any fractional displacement. As a result, for a precise cell wall cutting we choose the lateral configuration of the nanoneedle tip. W303 yeast cell model was used as a sample for single cell wall cutting. Yeast cell wall is more likely to behave as a Mooney-Rivlin hyperelastic material. Two different frequencies of vibrating nanoneedle were used for cell wall cutting operation; 1 and 10 Hz. For a constant penetration depth of 1.2 μm, penetration velocity was 7 and 24 μm/s, respectively. Investigated results showed that the faster nanoneedle causes less damage to the cell wall during cutting operation. Additionally, further finite element (FE) analysis was performed to observe the effect of tip edge angle for cell wall cutting. Three different edge angles, 10°, 15°, and 20° were used to perform cell wall cutting. Single cell wall penetration force increases with the increasing of tip edge angle and the diameters of the nanoneedle.