Computational biomechanics: A materials science of tissue
The essential question of materials science is this: How does the underlying makeup of a material determine its macroscopic-scale behavior? We are interested in precisely that question, but within the specific concept of mechanically functioning tissues.
As such, we focus on mechanical properties and on the transmission of mechanical information between the large and the small scale. Specific examples of our research interests follow.
Multiscale mechanics of engineered tissues
Tissue engineering emerged a few decades ago as a novel field in which one attempts to create replacement tissues de novo. Working with my PhD thesis advisor and long-time collaborator Bob Tranquillo, we have endeavored to develop an understanding of how the arrangement of an engineered tissue’s components, especially collagen fibers, determine the tissue behavior.
We have developed a two-scale modeling scheme that accounts macroscopically for the continuous nature of the tissue as a whole and microscopically for individual components. The application to this approach to progressively more complex systems is an important part of our research.
Multiscale mechanics of native tissues
We have also extended the ideas to apply to native tissues. Notably, we are studying the biomechanics of the ascending thoracic aorta and of ascending thoracic aortic aneurysm (aTAA).
An aTAA is a troubling and confounding condition because it is largely harmless unless the vessel fails, in which case the consequences are dire. On the other hand, surgery can be quite dangerous, so it is important to assess how at risk a specific aTAA is. We are working to use a combination of novel experiments and multiscale mechanical models to understand aTAA mechanics.
We are also using a similar approach to study the biomechanics of the facet capsular ligament (FCL), the capsular ligament that surrounds each of the facet joints of the spine (each adjacent pair of vertebrae has one facet joint on each side).
This work has focused on understanding the mechanical behavior of the tissue. It has also focused on exploring how tissue deformation is related to neuronal deformation, which may be important in the development of pain from traumatic or repeated-use injury in the spine.
We work on a wide range of other soft tissues also. Please feel free to visit our webpage or contact me if you have further interest.
Biomechanics of the Pacinian corpuscle
The Pacinian corpuscle (PC) is an end organ associated with the sensation of vibrational stimuli by the skin of the hands and feet, being particularly sensitive to vibrations in the 100-400 Hz range.
Our group has developed a computer model that accounts for the distinctive structure of the PC and predicts the neural signal generated in response to a vibratory stimulus. Work continues on trying to understand the function and role of individual PCs and how the population of a few hundred PCs in the hand can provide more information than a single PC could.
Claeson, A.A. and V.H. Barocas, “Planar Biaxial Extension of the Lumbar Facet Capsular Ligament Reveals Significant In-Plane Shear Forces,” Journal of Mechanical Behavior of Biomedical Materials, 65(1):127-136, 2017.
Vanderheiden, S.M., Hadi, M.F., and V.H. Barocas, “Crack Propagation vs. Fiber Alignment in Collagen Gels: Experiments and Multi-Scale Simulation,” ASME Journal of Biomechanical Engineering, 137(12):121002, 2015.
Lai, V.K., Nedrelow, D.S., Lake, S.P., Kim, B., Weiss, E.M., Tranquillo, R.T., and V.H. Barocas, “Swelling of collagen-hyaluronic acid co-gels: An in vitro residual stress model,” Annals BME, 44(10):2984-2993, 2016.
Quindlen, J.C., Stolarski, H.K., Johnson, M.D., and V.H. Barocas, “A Multiphysics Model of the Pacinian Corpuscle,” Integrative Biology, 8:1111-1125, 2016.
Witzenburg, C.M., Dhume, R.Y., Shah, S.B., Korenczuk, C.E., Wagner, H.P., Alford, P.W., and V.H. Barocas, “Failure of the porcine ascending aorta: Multidirectional experiments and a unifying structural model,” Journal of Biomechanical Engineering, accepted.
Shah, S., Witzenburg, C., Hadi, M.F., Wagner, H., Goodrich, J., Alford, P.W., and V.H. Barocas, “Prefailure and Failure Mechanics of the Porcine Ascending Thoracic Aorta: Experiments and a Multiscale Model,” J. Biomechanical Engineering, 136(2):021028, 2014.