Dynamic mechanical properties of murine brain tissue using micro-indentation

Area of Science:

• Biomechanics
• Neuroscience
• Materials Science

Background:

• Extensive research exists on macro-scale and nanoscale brain tissue properties.
• Limited data is available on micro-scale brain tissue mechanics at dynamic strain rates.
• Previous studies lacked appropriate indentation methods for regional dynamic analysis.

Purpose of the Study:

• To develop and utilize a novel micro-indentation device for measuring dynamic mechanical properties of brain tissue.
• To characterize regional differences in brain tissue at micro-scale under dynamic loading.
• To investigate the shear modulus of murine cerebellum and cortex at varying strain rates.

Main Methods:

• Development of a novel micro-indentation device capable of high strain rates (up to 30/s).
• Indentation tests performed on murine brain tissue (cerebellum and cortex).
• Measurement of shear modulus at dynamic strain rates (5, 15, and 30/s) up to 14% strain.
• Numerical simulations used to validate experimental force-displacement data.

Main Results:

• The device successfully measured dynamic mechanical properties of brain tissue.
• Significant regional differences in shear modulus were observed between cerebellum and cortex.
• Shear modulus values for cerebellum ranged from 2.11 to 3.71 kPa, and for cortex from 4.06 to 7.05 kPa across tested strain rates.

Conclusions:

• The novel micro-indentation device is effective for characterizing dynamic mechanical properties of brain tissue at the micro-scale.
• The study provides crucial data on regional variations in brain tissue mechanics under dynamic loading.
• Findings contribute to a better understanding of brain tissue biomechanics for applications in injury modeling and neurosurgery.