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A Novel Methodology for Exposing Tissue Cultures to Blast Overpressure for Determining Injury Criteria
VETERANS ADMINISTRATION HOSPITAL DURHAM NC
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Introduction A growing number of clinicians and scientists acknowledge that there exists some level of primary blast exposure that can disrupt or damage neuronal tissue resulting in traumatic brain injury. This injury may be associated with persistent and progressive sequelae. While the groundwork for identifying the brain s tolerance to primary blast has been created using animal and computational models, the mode volumetric or deviatoric and threshold of tissue-level deformation associated with brain tissue injury remains unknown. We report here a new test methodology to apply overpressure conditions to brain tissue preparations in vitro similar to those created from blast. We hypothesize this method would replicate the physical characteristics of blast, allowing measurements of tissue mechanical response and ultimately cell and tissue injury response. Materials and Methods Blast waves were generated by a helium-driven shock tube 76 mm diameter tube with a 25 mm driver and a 1220 mm driven section. The blast wave impacts a fluid-filled apparatus that contains living brain tissue, creating a single overpressure pulse that propagates through the suspended tissue. Downstream, the apparatus was designed to mitigate returning shock reflections. An axisymmetric numerical model of the apparatus and tissue was developed in LS-DYNA to assess the response of the tissue that could not be measured experimentally. Experimental and modeled results were compared. Results and Discussion The apparatus was able to generate blast overpressure waves at the tissue culture that were characteristic of Friedlander blast waves with minimal amount of reflected overpressure, but with slightly longer rise times Figure 1A. Peak reflected overpressures generated using the shock tube ranged from 500 to 1500 kPa with durations from 0.5 to 1.0 ms.
APPROVED FOR PUBLIC RELEASE