Cytoindentation for obtaining cell biomechanical properties

Area of Science:

• Biomedical Engineering
• Cellular Biomechanics
• Materials Science

Background:

• Understanding individual cell mechanical properties is crucial for cellular biomechanics.
• Existing methods may not accurately capture intrinsic material properties of single cells on substrates.
• Cellular mechanical behavior influences cellular functions and responses to stimuli.

Purpose of the Study:

• To develop and validate a novel biomechanical testing methodology for determining intrinsic material properties of individual cells.
• To quantify the aggregate modulus, Poisson's ratio, and permeability of MG63 osteoblast-like cells.
• To provide essential data for understanding cell mechanics and mechanotransduction.

Main Methods:

• Development of a custom cell-indentation apparatus (cytoindenter) for displacement-controlled indentation tests.
• Modeling of MG63 cells using linear elasticity and linear biphasic theory to account for viscoelasticity.
• Curve-fitting experimental force-deformation data with finite element analysis and optimization routines to extract material properties.

Main Results:

• The compressive aggregate modulus of MG63 cells was determined to be 2.05+/-0.89 kPa.
• Permeability was measured at 1.18+/-0.65 (x10^-10) m4/N-s, significantly higher than cartilage.
• Poisson's ratio was found to be 0.37+/-0.03.

Conclusions:

• The novel cytoindenter methodology successfully quantifies intrinsic material properties of individual cells.
• The determined biomechanical properties of MG63 cells offer valuable data for cellular mechanics research.
• This information is vital for quantifying mechanical stimuli on cells and advancing mechanotransduction theories.