A new framework for characterization of poroelastic materials using indentation

Area of Science:

• Biomaterials Science
• Soft Matter Physics
• Mechanical Engineering

Background:

• Poroelastic materials, such as hydrogels and biological tissues, consist of a porous elastic matrix saturated with interstitial fluid.
• Mechanical stimulation of these materials leads to fluid redistribution, influencing their deformation and relaxation behavior.
• Traditional characterization methods often assume instantaneous indentation, which is experimentally unfeasible and can lead to inaccurate poroelastic property estimations.

Purpose of the Study:

• To develop a novel framework for characterizing poroelastic materials that accounts for the finite indentation approach velocity.
• To investigate the influence of indentation velocity on the mechanical response and relaxation time of poroelastic materials.
• To provide a more accurate and experimentally practical method for extracting poroelastic properties.

Main Methods:

• Extensive finite element simulations were performed to study the effect of indentation velocity.
• A new theoretical framework was developed, incorporating a master curve that accounts for the finite rise time of indentation.
• The framework was experimentally validated using macro and micro-scale indentation tests on agarose and polyacrylamide hydrogels.

Main Results:

• The finite approach velocity significantly impacts the poroelastic relaxation time and overall mechanical response.
• The developed master curve framework effectively incorporates the finite rise time, improving characterization accuracy.
• Experimental validation confirmed the framework's ability to provide more precise poroelastic property measurements.

Conclusions:

• The novel framework offers a more accurate and experimentally accessible method for characterizing poroelastic materials by considering the finite indentation approach velocity.
• This approach is crucial for understanding the mechanical behavior of hydrogels, tissues, and other biological materials under physiological loading conditions.
• The study provides a valuable tool for researchers in biomaterials, biomechanics, and tissue engineering.