Mechanical behavior of cells in microinjection: a minimum potential energy study

Area of Science:

• Biophysics
• Cell Biology
• Mechanical Engineering

Background:

• Microinjection is crucial for delivering substances into cells.
• Understanding cell mechanics during this process is vital for successful application.
• Existing models may not fully capture the complex interplay of forces and cell deformation.

Purpose of the Study:

• To develop a mathematical model for analyzing cell mechanical behavior during microinjection.
• To investigate the influence of microinjector radius on injection force, pressure, and membrane stress.
• To predict potential cell rupture locations based on microinjector geometry.

Main Methods:

• Modeling the cell as a hyperelastic membrane with interior cytoplasm.
• Analyzing the potential energy function during microinjection.
• Employing Lagrange multiplier and Rayleigh-Ritz techniques to find equilibrium configurations.
• Conducting experimental verification using zebrafish egg cells.

Main Results:

• The microinjector radius significantly affects injection force and internal cell pressure.
• Larger microinjector radii lead to higher injection forces and pressures.
• The microinjector radius dictates the location of maximum membrane stress and potential rupture.
• Rupture is likely at the contact edge for fine injectors (<20% cell radius) and shifts inward for larger injectors.

Conclusions:

• The developed mathematical model accurately predicts cell behavior during microinjection.
• Microinjector size is a critical parameter influencing both the injection process and cell integrity.
• The findings provide valuable insights for optimizing microinjection protocols and minimizing cell damage.