Robotic Improved Micropipette Aspiration Method for Accurate Measurement of Cellular Mechanical Properties

For the first time, an improved robotic micropipette aspiration (MA) method considering the effects of the intra-cellular pressure, friction between cell and micropipette, and the micropipette opening size was proposed for improving the measurement accuracy of the cell elasticity properties in this paper. First, an elastic energy model of the aspirated cell was established to analyze the effects of intracellular pressure on MA results. Then a force analysis of MA process was conducted to evaluate the influences of the friction force between the cell surface and micropipette opening as well as the inner diameter of the micropipette opening to MA results. Based on the above work, an improved robotic MA process was developed for reducing the cell elasticity measurement errors through automated release of intracellular pressure, micropipette opening polishing and inner diameter control of the micropipette. The effectiveness of the above work was validated by both finite elemental model (FEM) and MA experiments. The MA results on porcine oocytes demonstrate that our proposed MA method can rectify the 20.11%, 35.08% and 6.80% measure errors of cell Young’s modulus caused by the above three factors, respectively. Our research may provide a more objective evaluation of cell mechanical properties in the related research.