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  • Publication
    Mechanical characterization of the P56 mouse brain under large-deformation dynamic indentation
    The brain is a complex organ made up of many different functional and structural regions consisting of different types of cells such as neurons and glia, as well as complex anatomical geometries. It is hypothesized that the different regions of the brain exhibit significantly different mechanical properties, which may be attributed to the diversity of cells and anisotropy of neuronal fibers within individual brain regions. The regional dynamic mechanical properties of P56 mouse brain tissue in vitro and in situ at velocities of 0.71-4.28 mm/s, up to a deformation of 70 μm are presented and discussed in the context of traumatic brain injury. The experimental data obtained from micro-indentation measurements were fit to three hyperelastic material models using the inverse Finite Element method. The cerebral cortex elicited a stiffer response than the cerebellum, thalamus, and medulla oblongata regions for all velocities. The thalamus was found to be the least sensitive to changes in velocity, and the medulla oblongata was most compliant. The results show that different regions of the mouse brain possess significantly different mechanical properties, and a significant difference also exists between the in vitro and in situ brain.
      211Scopus© Citations 32
  • Publication
    Dynamic mechanical properties of murine brain tissue using micro-indentation
    Significant advances have been made in recent decades to determine the macro-scale properties of brain tissue in compression, tension, shear and indentation. There has also been significant work done at the nanoscale using the AFM method to characterise the properties of individual neurons. However, there has been little published work on the micro-scale properties of brain tissue using an appropriate indentation methodology to characterise regional differences at dynamic strain rates. This paper presents a novel micro-indentation device that has been developed and used to measure the dynamic mechanical properties of brain tissue. The device is capable of applying up to 30/s strain rates with a maximum indentation area of 1500μm^2. Indentation tests were carried out to determine the shear modulus of the cerebellum (3.59±1.27 kPa) and cortex (7.05±3.92 kPa) of murine brain tissue at 30/s up to 14% strain. Numerical simulations were carried out to verify the experimentally measured force-displacement results.
      456Scopus© Citations 29