Mechanical characterization of the P56 mouse brain under large-deformation dynamic indentation

MacManus, David B.; Pierrat, Baptiste; Murphy, Jeremiah G.; Gilchrist, Michael D.

doi:10.1038/srep21569

Cited by 44 publications

(44 citation statements)

References 41 publications

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“…S2). This suggests that over the range of the wire diameters studied, bulk brain tissue mechanics are generally homogeneous, consistent with previous studies on indentation into brain tissue 17,22 .…”

Section: Influence Of Microwire Diametersupporting

confidence: 89%

Ultra-sensitive measurement of brain penetration mechanics and blood vessel rupture with microscale probes

Obaid

Hanna

et al. 2020

Preprint

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Microscale electrodes, on the order of 10-100 μm, are rapidly becoming critical tools for neuroscience and brain-machine interfaces (BMIs) for their high channel counts and spatial resolution, yet the mechanical details of how probes at this scale insert into brain tissue are largely unknown. Here, we performed quantitative measurements of the force and compression mechanics together with real-time microscopy for in vivo insertion of a systematic series of microelectrode probes as a function of diameter (7.5-100 μm and rectangular Neuropixels) and tip geometry (flat, angled, and electrochemically sharpened). Results elucidated the role of tip geometry, surface forces, and mechanical scaling with diameter. Surprisingly, the insertion force post-pia penetration was constant with distance and did not depend on tip shape. Real-time microscopy revealed that at small enough lengthscales (<25 μm), blood vessel rupture and bleeding during implantation could be entirely avoided. This appears to occur via vessel displacement, avoiding capture on the probe surface which led to elongation and tearing for larger probes. We propose a new, three-zone model to account for the probe size dependence of bleeding, and provide mechanistic guidance for probe design.

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Section: Influence Of Microwire Diametersupporting

confidence: 89%

Ultra-sensitive measurement of brain penetration mechanics and blood vessel rupture with microscale probes

Obaid

Hanna

et al. 2020

Preprint

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“…2). This suggests that over the range of the wire diameters studied, bulk brain tissue mechanics are generally homogeneous, consistent with previous studies on indentation into brain tissue 20,32 .…”

Section: Influence Of Microwire Diametersupporting

confidence: 89%

Ultra-sensitive measurement of brain penetration with microscale probes for brain machine interface considerations

Obaid

Hanna

et al. 2018

Preprint

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Microscale electrodes are rapidly becoming critical tools for neuroscience and brain-machine interfaces (BMIs) for their high spatial and temporal resolution. However, the mechanics of how devices on this scale insert into brain tissue is unknown, making it difficult to balance between larger probes with higher stiffness, or smaller probes with lower damage. Measurements have been experimentally challenging due to the large deformations, rapid events, and small forces involved. Here we modified a nanoindentation force measurement system to provide the first ultra-high resolution force, distance, and temporal recordings of brain penetration as a function of microwire diameter (7.5 µm to 100 µm) and tip geometry (flat, angled, and electrosharpened).Surprisingly, both penetration force and tissue compression scaled linearly with wire diameter, rather than cross-sectional area. Linear brain compression with wire diameter strongly suggest smaller probes will cause less tissue damage upon insertion, though unexpectedly no statistical difference was observed between angled and flat tipped probes. These first of their kind measurements provide a mechanical framework for designing effective microprobe geometries while limiting mechanical damage.

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“…In the absence of appropriate human tissue, animal tissue is used instead, and a porcine or rodent model is typically employed in these investigations 50 . Like human tissue, previous results in the literature have demonstrated that the mechanical properties of animal brain tissue are regionally dependent in the rat, mouse, and pig brains 13 – 16 , 21 . However, the answer as to which animal model is the most suitable surrogate remains moot.…”

Section: Discussionmentioning

confidence: 92%

Region and species dependent mechanical properties of adolescent and young adult brain tissue

MacManus

Pierrat

Murphy

et al. 2017

Sci Rep

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Traumatic brain injuries, the leading cause of death and disability in children and young adults, are the result of a rapid acceleration or impact of the head. In recent years, a global effort to better understand the biomechanics of TBI has been undertaken, with many laboratories creating detailed computational models of the head and brain. For these models to produce realistic results they require accurate regional constitutive data for brain tissue. However, there are large differences in the mechanical properties reported in the literature. These differences are likely due to experimental parameters such as specimen age, brain region, species, test protocols, and fiber direction which are often not reported. Furthermore, there is a dearth of reported viscoelastic properties for brain tissue at large-strain and high rates. Mouse, rat, and pig brains are impacted at 10/s to a strain of ~36% using a custom-built micro-indenter with a 125 μm radius. It is shown that the resultant mechanical properties are dependent on specimen-age, species, and region, under identical experimental parameters.

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Mechanical characterization of the P56 mouse brain under large-deformation dynamic indentation

Cited by 44 publications

References 41 publications

Ultra-sensitive measurement of brain penetration mechanics and blood vessel rupture with microscale probes

Ultra-sensitive measurement of brain penetration mechanics and blood vessel rupture with microscale probes

Ultra-sensitive measurement of brain penetration with microscale probes for brain machine interface considerations

Region and species dependent mechanical properties of adolescent and young adult brain tissue

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