My overall research focus is quantification and modeling of the
structure-mechanical properties of native and engineered soft tissues,
with a focus on tissues of the cardiovascular and urological systems.
In particular, my laboratory has focused on the mechanical behavior
and function of the native aortic and mitral heart valves, including
the developement of the first constitutive (stress-strain) models
for these tissues using a structural approach. My laboratory is
also active in the biomechanics of engineered tissues, and in particular
understanding the in-vitro and in-vito remodeling processes from
a functional biomechanical perspective. To acquire the necessary
critical experimental data, my laboratory has developed several
novel methods to quantify tissue structure and multi-axial mechanical
testing techniques. By integrating the resulting experimental data
obtained from both techniques, we have developed structural constitutive
(stress-strain) models that directly integrate information on tissue
composition and structure. These models avoid ambiguities in material
characterization, offering insight into the function, structure,
and mechanics of tissue components.
More recent work includes multi-scale studies of cell/tissue/organ mechanical interactions in heart valves. I am particularly interested in determing the local stress environment for heart valve interstitial cells. Next, we are currently utilizing an integrated experimental/multi-scale finite element approach to determine how hemodynamic loading on the valve translates to altered stress states on the valve interstitial cell function and, in-turn, changes in local extra-cellular structure/composition and valve function.
Specific applications include:
- Structural constitutive (stress-strain) models for native and engineered heart valve tissues, and biologically derived biomaterials used in heart valve bioprostheses. This includes the first model of the native and bioprosthetic aortic heart valve.
- Multi-scale experimental studies and finite element simulations that incorporate structural constitutive models for soft tissue that enable simulation of growth and estimation of cell/matrix stress fields.
- Effects of long-term changes in heart valve structure/composition when subjected to altered stress states using valvular tissue from normal and left ventricular assist device (LVAD)-supported calfs. This unique study allows us study how otherwise normal valvular tissue responds to either increased or decreased dynamic stresses.
- Measurement and computation of the dynamic heart valve tissue strains and stresses from in-vivo and in-vitro dynamic deformation data and in-vitro for the mitral valve.
- Structure-strength relations and constitutive models of tissue engineered materials, including stem-cell seeded intestinal sub-mucosa and cell-seeded polymer biocomposites.
- Development of first quasi-static and viscoelastic constitutive models for active and passive mechanical properties of the urinary bladder. These models are correlated to changes in tissue composition and structure in both the normal and post-spinal cord injured rat bladder.
- Quantification and modeling of the mechanical properties of the normal and aneurysmal abdominal aorta.
In addition to the tissue and cell level work, I have established a research program in organ-level stress-analyses that utilize in-vitro and in-vivo imaging technologies. Specific applications include:
- Development of a novel device to quantify heart valve leaflet motion and shape under physiologic flow conditions using a non-contacting structured light approach. This device is to be used for both native, chemically treated, and tissue engineered valve prostheses.
- Development of novel surface fitting methods to quantify the complete shape and deformation of anatomic structures from spiral CT, MR, and material marker data.
- Development of a thin-shell force-equilibrium model to compute the in-vivo wall tensions in abdominal aortic aneurysms and the urinary bladder directly from in-vivo images.
View recent publications here.
For more details, please click here to review Dr. Sacks' curriculum vitae (PDF Format).
CONTACT INFORMATION
Dr. Michael Sacks
Email: msacks@pitt.edu
Phone: (412) 235-5146
Fax: (412) 235-5160
Office: Research: 100 Technology Drive, Room 250
Teaching: Room 742 Benedum Hall
Lab: Engineered Tissue Mechanics Laboratory