M S Sacks

Summary

Affiliation: University of Pittsburgh
Country: USA

Publications

  1. ncbi Multiaxial mechanical behavior of biological materials
    Michael S Sacks
    Engineered Tissue Mechanics Laboratory, McGowan Institute for Regenerative Medicine and the Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
    Annu Rev Biomed Eng 5:251-84. 2003
  2. pmc Heart valve function: a biomechanical perspective
    Michael S Sacks
    Engineered Tissue Mechanics and Mechanobiology Laboratory, Department of Bioengineering and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Philos Trans R Soc Lond B Biol Sci 362:1369-91. 2007
  3. ncbi Incorporation of experimentally-derived fiber orientation into a structural constitutive model for planar collagenous tissues
    Michael S Sacks
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, Room 749 Benedum Hall, 3700 Ohara St, University of Pittsburgh, Pittsburgh, PA 15261, USA
    J Biomech Eng 125:280-7. 2003
  4. ncbi A structural model for the flexural mechanics of nonwoven tissue engineering scaffolds
    George C Engelmayr
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering and McGowan Institute for Regenerative Medicine, University of Pittsburgh, 100 Technology Drive, Suite 200, Pittsburgh, PA 15219, USA
    J Biomech Eng 128:610-22. 2006
  5. ncbi Surface strains in the anterior leaflet of the functioning mitral valve
    M S Sacks
    Engineered Tissue Mechanics Laboratory, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Ann Biomed Eng 30:1281-90. 2002
  6. pmc In vivo biomechanical assessment of triglycidylamine crosslinked pericardium
    Michael S Sacks
    Department of Bioengineering, Engineered Tissue Mechanics Laboratory, McGowan Institute for Regenerative Medicine, 100 Technology Drive, Room 234, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Biomaterials 28:5390-8. 2007
  7. ncbi Bioprosthetic heart valve heterograft biomaterials: structure, mechanical behavior and computational simulation
    Michael S Sacks
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
    Expert Rev Med Devices 3:817-34. 2006
  8. ncbi In-vivo dynamic deformation of the mitral valve anterior leaflet
    Michael S Sacks
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
    Ann Thorac Surg 82:1369-77. 2006
  9. doi Bioengineering challenges for heart valve tissue engineering
    Michael S Sacks
    Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pennsylvania 15219, USA
    Annu Rev Biomed Eng 11:289-313. 2009
  10. pmc On the biomechanics of heart valve function
    Michael S Sacks
    Department of Bioengineering, Engineered Tissue Mechanics and Mechanobiology Laboratory, The McGowan Institute, University of Pittsburgh, Pittsburgh, PA, United States
    J Biomech 42:1804-24. 2009

Collaborators

Detail Information

Publications83

  1. ncbi Multiaxial mechanical behavior of biological materials
    Michael S Sacks
    Engineered Tissue Mechanics Laboratory, McGowan Institute for Regenerative Medicine and the Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
    Annu Rev Biomed Eng 5:251-84. 2003
    ..The focus of this review is to describe the application of multiaxial testing techniques to soft tissues and their relation to modern biomechanical constitutive theories...
  2. pmc Heart valve function: a biomechanical perspective
    Michael S Sacks
    Engineered Tissue Mechanics and Mechanobiology Laboratory, Department of Bioengineering and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Philos Trans R Soc Lond B Biol Sci 362:1369-91. 2007
    ..While we focus on the work from the authors' respective laboratories, the works of most investigators known to the authors have been included whenever appropriate. We conclude with a summary and underscore important future trends...
  3. ncbi Incorporation of experimentally-derived fiber orientation into a structural constitutive model for planar collagenous tissues
    Michael S Sacks
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, Room 749 Benedum Hall, 3700 Ohara St, University of Pittsburgh, Pittsburgh, PA 15261, USA
    J Biomech Eng 125:280-7. 2003
    ..This result supports the assumption of affine strain to estimate the fiber strains. However, future evaluations will have to be performed for tissue subjected to a wider range of strain to more fully validate the current approach...
  4. ncbi A structural model for the flexural mechanics of nonwoven tissue engineering scaffolds
    George C Engelmayr
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering and McGowan Institute for Regenerative Medicine, University of Pittsburgh, 100 Technology Drive, Suite 200, Pittsburgh, PA 15219, USA
    J Biomech Eng 128:610-22. 2006
    ..These important results underscore the need for structural approaches in modeling the effects of engineered tissue formation on nonwoven scaffolds, and their potential utility in scaffold design...
  5. ncbi Surface strains in the anterior leaflet of the functioning mitral valve
    M S Sacks
    Engineered Tissue Mechanics Laboratory, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Ann Biomed Eng 30:1281-90. 2002
    ..These studies represent a first step in improving our understanding of normal MV function and to help establish the principles for repair and replacement...
  6. pmc In vivo biomechanical assessment of triglycidylamine crosslinked pericardium
    Michael S Sacks
    Department of Bioengineering, Engineered Tissue Mechanics Laboratory, McGowan Institute for Regenerative Medicine, 100 Technology Drive, Room 234, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Biomaterials 28:5390-8. 2007
    ..We conclude that TGA-MABP crosslinked bovine pericardium, when subjected to in vivo BHV stress levels in a blood-contacting environment, maintains stable functionality...
  7. ncbi Bioprosthetic heart valve heterograft biomaterials: structure, mechanical behavior and computational simulation
    Michael S Sacks
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
    Expert Rev Med Devices 3:817-34. 2006
    ....
  8. ncbi In-vivo dynamic deformation of the mitral valve anterior leaflet
    Michael S Sacks
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
    Ann Thorac Surg 82:1369-77. 2006
    ..However, these data do not presently exist. In the present study, a sheep model and sonomicrometry were used to compute the in-surface Eulerian strain tensor of the anterior leaflet over the cardiac cycle at varying afterloads...
  9. doi Bioengineering challenges for heart valve tissue engineering
    Michael S Sacks
    Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pennsylvania 15219, USA
    Annu Rev Biomed Eng 11:289-313. 2009
    ..Overall, such approaches need to be structured to address these fundamental issues to lay the basis for TEHVs that can be developed and designed according to truly sound scientific and engineering principles...
  10. pmc On the biomechanics of heart valve function
    Michael S Sacks
    Department of Bioengineering, Engineered Tissue Mechanics and Mechanobiology Laboratory, The McGowan Institute, University of Pittsburgh, Pittsburgh, PA, United States
    J Biomech 42:1804-24. 2009
    ..While we focus on the work from the author's laboratories, relevant works of other investigators have been included whenever appropriate. We conclude with a summary of important future trends...
  11. ncbi Simulated bioprosthetic heart valve deformation under quasi-static loading
    Wei Sun
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15219, USA
    J Biomech Eng 127:905-14. 2005
    ..The present study also underscores the need for rigorous experimentation and accurate constitutive models in simulating BHV function and design...
  12. ncbi Biaxial mechanical response of bioprosthetic heart valve biomaterials to high in-plane shear
    Wei Sun
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
    J Biomech Eng 125:372-80. 2003
    ..The results of this study underscore the limited predictive ability of current soft tissue models, and the need to collect experimental data for soft tissue simulations over the complete functional range...
  13. ncbi The effects of collagen fiber orientation on the flexural properties of pericardial heterograft biomaterials
    Ali Mirnajafi
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, McGowan Institute for Regenerative Medicine, Room 234, 100 Technology Drive, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Biomaterials 26:795-804. 2005
    ..These findings can be used to guide the development of novel chemical treatment methods that seek to optimize biomechanical properties of heterograft biomaterials...
  14. ncbi The relation between collagen fibril kinematics and mechanical properties in the mitral valve anterior leaflet
    Jun Liao
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
    J Biomech Eng 129:78-87. 2007
    ..These unique mechanical characteristics are likely necessary for normal valvular function...
  15. ncbi A method for planar biaxial mechanical testing that includes in-plane shear
    M S Sacks
    Department of Bioengineering, University of Pittsburgh, PA 15261, USA
    J Biomech Eng 121:551-5. 1999
    ..Further, the method is very general and can be applied to any anisotropic planar tissue that has identifiable material axes...
  16. ncbi Prediction of extracellular matrix stiffness in engineered heart valve tissues based on nonwoven scaffolds
    George C Engelmayr
    Engineered Tissue Mechanics Laboratory ETML, Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, 100 Technology Drive, Suite 200, Pittsburgh, PA 15219, USA
    Biomech Model Mechanobiol 7:309-21. 2008
    ....
  17. ncbi Fiber kinematics of small intestinal submucosa under biaxial and uniaxial stretch
    Thomas W Gilbert
    Department of Bioengineering, McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
    J Biomech Eng 128:890-8. 2006
    ..Nonaffine structural models will be necessary to fully predict the fiber kinematics under large uniaxial strains in SIS...
  18. ncbi On the biaxial mechanical properties of the layers of the aortic valve leaflet
    John A Stella
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15219, USA
    J Biomech Eng 129:757-66. 2007
    ....
  19. ncbi Cyclic flexure and laminar flow synergistically accelerate mesenchymal stem cell-mediated engineered tissue formation: Implications for engineered heart valve tissues
    George C Engelmayr
    Engineering Tissue Mechanics Laboratory, Department of Bioengineering and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, 100 Technology Drive, Suite 200, Pittsburgh, PA 15219, USA
    Biomaterials 27:6083-95. 2006
    ..We thus demonstrated that cyclic flexure and laminar flow can synergistically accelerate BMSC-mediated tissue formation, providing a basis for the rational design of in vitro conditioning regimens for BMSC-seeded TEHV...
  20. pmc A novel flex-stretch-flow bioreactor for the study of engineered heart valve tissue mechanobiology
    George C Engelmayr
    Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, 100 Technology Drive, Suite 200, Pittsburgh, PA 15219, USA
    Ann Biomed Eng 36:700-12. 2008
    ..We conclude that the present design provides a robust tool for the study of mechanical stimuli on in vitro engineered heart valve tissue formation...
  21. ncbi Age dependency of the biaxial biomechanical behavior of human abdominal aorta
    Jonathan P Vande Geest
    Department of Surgery, Division of Vascular Surgery, University of Pittfsburgh, Pittsburgh, PA 15219, USA
    J Biomech Eng 126:815-22. 2004
    ..Response functions fit to experimental data were used as a tool to guide the appropriate choice of the strain energy function W...
  22. ncbi In-situ deformation of the aortic valve interstitial cell nucleus under diastolic loading
    Hsiao Ying Shadow Huang
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15219, USA
    J Biomech Eng 129:880-89. 2007
    ....
  23. ncbi Effects of boundary conditions on the estimation of the planar biaxial mechanical properties of soft tissues
    Wei Sun
    Engineered Tissue Mechanics Laboratory, Department of Bioengineerirng, University of Pittsburgh, Pittsburgh, PA, USA
    J Biomech Eng 127:709-15. 2005
    ....
  24. ncbi Effects of collagen fiber orientation on the response of biologically derived soft tissue biomaterials to cyclic loading
    Tiffany L Sellaro
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
    J Biomed Mater Res A 80:194-205. 2007
    ..Taken as a whole, the results of this study suggest that initial collagen orientation plays a critical role in bioprosthetic heart valve biomaterial fatigue response...
  25. ncbi Planar biaxial creep and stress relaxation of the mitral valve anterior leaflet
    Jonathan S Grashow
    Department of Bioengineering, Engineered Tissue Mechanics Laboratory, University of Pittsburgh, 100 Technology Drive, Room 234, PA 15219, USA
    Ann Biomed Eng 34:1509-18. 2006
    ..Moreover, insight into these specialized characteristics can help guide and inform efforts directed toward surgical repair and engineered valvular tissue replacements...
  26. ncbi The effects of aneurysm on the biaxial mechanical behavior of human abdominal aorta
    Jonathan P Vande Geest
    Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, USA
    J Biomech 39:1324-34. 2006
    ..It was concluded that aneurysmal degeneration of the abdominal aorta is associated with an increase in mechanical anisotropy, with preferential stiffening in the circumferential direction...
  27. ncbi Molecular orientation of collagen in intact planar connective tissues under biaxial stretch
    Jun Liao
    Department of Bioengineering and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Acta Biomater 1:45-54. 2005
    ..The results of this first study suggest that collagen fiber/molecular kinematics under biaxial stretch are more complex than under uniaxial deformation, and warrant future studies...
  28. ncbi The independent role of cyclic flexure in the early in vitro development of an engineered heart valve tissue
    George C Engelmayr
    Engineered Tissue Mechanics Laboratory, McGowan Institute for Regenerative Medicine and the Department of Bioengineering, University of Pittsburgh, 100 Technology Drive, Suite 200, Pittsburgh, PA 15219, USA
    Biomaterials 26:175-87. 2005
    ..These results show that cyclic flexure can have independent effects on TEHV cell and ECM development, and may be useful in predicting the mechanical properties of TEHV constructed using novel scaffold materials...
  29. ncbi Cyclic loading response of bioprosthetic heart valves: effects of fixation stress state on the collagen fiber architecture
    Sarah M Wells
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, 100 Technology Drive, Room 234, Pittsburgh, PA 15219, USA
    Biomaterials 26:2611-9. 2005
    ..Our findings also suggest that without in vivo remodeling, any collagenous tissue used to fabricate BHV may undergo similar degenerative, irreversible changes in vivo...
  30. pmc Effects of cyclic flexural fatigue on porcine bioprosthetic heart valve heterograft biomaterials
    Ali Mirnajafi
    Cardiovascular Biomechanics Laboratory, Department of Bioengineering and the McGowan Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
    J Biomed Mater Res A 94:205-13. 2010
    ..c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010...
  31. ncbi A novel bioreactor for the dynamic flexural stimulation of tissue engineered heart valve biomaterials
    George C Engelmayr
    Engineered Tissue Mechanics Laboratory, McGowan Institute for Regenerative Medicine, Department of Bioengineering, University of Pittsburgh, 100 Technology Drive, Room 250, Pittsburgh, PA 15219, USA
    Biomaterials 24:2523-32. 2003
    ....
  32. ncbi Effects of fixation pressure on the biaxial mechanical behavior of porcine bioprosthetic heart valves with long-term cyclic loading
    Sarah M Wells
    Department of Bioengineering, University of Pittsburgh, PA 15261, USA
    Biomaterials 23:2389-99. 2002
    ..This study further underscores that chemically treated collagen fibers can undergo conformational changes under long-term cyclic loading not associated with damage...
  33. pmc Effects of decellularization on the mechanical and structural properties of the porcine aortic valve leaflet
    Jun Liao
    Engineered Tissue Mechanics and Mechanobiology Laboratory, Department of Bioengineering and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Biomaterials 29:1065-74. 2008
    ..In conclusion, changes in mechanical and structural properties of decellularized leaflets were likely associated with disruption of the ECM, which may impact the durability of the leaflets...
  34. ncbi Design and analysis of tissue engineering scaffolds that mimic soft tissue mechanical anisotropy
    Todd Courtney
    Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Biomaterials 27:3631-8. 2006
    ..The results of this study will help to provide the basis for rationally designed mechanically anisotropic soft tissue engineered implants...
  35. ncbi Biaixal stress-stretch behavior of the mitral valve anterior leaflet at physiologic strain rates
    Jonathan S Grashow
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Ann Biomed Eng 34:315-25. 2006
    ..The mechanisms underlying this quasi-elastic behavior are as yet unknown, but are likely an important functional aspect of native mitral valve tissues and clearly warrant further study...
  36. pmc The role of organ level conditioning on the promotion of engineered heart valve tissue development in-vitro using mesenchymal stem cells
    Sharan Ramaswamy
    Cardiovascular Biomechanics Laboratory, Department of Bioengineering, Swanson School of Engineering, The McGowan Institute, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Biomaterials 31:1114-25. 2010
    ....
  37. pmc Viscoelastic properties of the aortic valve interstitial cell
    W David Merryman
    Engineered Tissue Mechanics and Mechanobiology Laboratory, Department of Bioengineering, and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219
    J Biomech Eng 131:041005. 2009
    ..92% and 7.35%, respectively). We conclude that while AVIC viscoelastic effects are negligible during valve closure, they likely contribute to the deformation time-history of AVIC deformation during diastole...
  38. ncbi Correlation between heart valve interstitial cell stiffness and transvalvular pressure: implications for collagen biosynthesis
    W David Merryman
    Dept of Bioengineering, Univ of Pittsburgh, Pittsburgh, PA 15219, USA
    Am J Physiol Heart Circ Physiol 290:H224-31. 2006
    ..This functional VIC stress-dependent biosynthetic relation may be crucial in maintaining valvular tissue homeostasis and also prove useful in understanding valvular pathologies...
  39. ncbi Biaxial mechanical properties of muscle-derived cell seeded small intestinal submucosa for bladder wall reconstitution
    Shing Hwa Lu
    Department of Urology, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Biomaterials 26:443-9. 2005
    ..These results suggest that MDC growth was supported by SIS and that initial remodeling of the SIS ECM had occurred within the first 10 days of incubation, but may have slowed once the MDC had grown to confluence within the SIS...
  40. ncbi Changes in the biaxial viscoelastic response of the urinary bladder following spinal cord injury
    Jiro Nagatomi
    Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
    Ann Biomed Eng 32:1409-19. 2004
    ....
  41. ncbi Finite element implementation of a generalized Fung-elastic constitutive model for planar soft tissues
    Wei Sun
    Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Biomech Model Mechanobiol 4:190-9. 2005
    ..Moreover, since our approach is formulated within a general FE code, it can be straightforwardly adopted across multiple software platforms...
  42. ncbi Orthotropic mechanical properties of chemically treated bovine pericardium
    M S Sacks
    Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
    Ann Biomed Eng 26:892-902. 1998
    ..Thus, structural control leads to an improved understanding of chemically treated BP mechanical properties. Judicious use of this knowledge can facilitate the design and enhanced long-term performance of bioprosthetic heart valves...
  43. ncbi Local mechanical anisotropy in human cranial dura mater allografts
    M S Sacks
    Department of Biomedical Engineering, University of Miami, Coral Gables, FL 33124 0621, USA
    J Biomech Eng 120:541-4. 1998
    ..The testing methods established in this study can be used in the evaluation of new CDM processing methods and post-implant allograft mechanical integrity...
  44. ncbi Collagen fiber disruption occurs independent of calcification in clinically explanted bioprosthetic heart valves
    Michael S Sacks
    Tissue Mechanics Laboratory, Department of Bioengineering, Room 749 Benedum Hall, 3500 Ohara St, University of Pittsburgh, Pittsburgh, Pennsyvlania 15261, USA
    J Biomed Mater Res 62:359-71. 2002
    ..Our results suggest a mechanism of noncalcific degradation dependent on cuspal mechanics that could contribute to porcine aortic BHV failure...
  45. pmc Preparation and characterization of highly porous, biodegradable polyurethane scaffolds for soft tissue applications
    Jianjun Guan
    McGowan Institute for Regenerative Medicine, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA 15219, USA
    Biomaterials 26:3961-71. 2005
    ..These biodegradable and flexible scaffolds demonstrate potential for future application as cell scaffolds in cardiovascular tissue engineering or other soft tissue applications...
  46. ncbi On the mechanical role of de novo synthesized elastin in the urinary bladder wall
    Silvia Wognum
    Department of Bioengineering, McGowan Institute, University of Pittsburgh, PA 15219, USA
    J Biomech Eng 131:101018. 2009
    ..In conclusion, our results suggest that the urinary bladder responds to prolonged periods of high strain by increasing its effective compliance through the interaction between collagen and de novo synthesized elastic fibers...
  47. ncbi The collagen fibers of the anteroinferior capsulolabrum have multiaxial orientation to resist shoulder dislocation
    Richard E Debski
    Musculoskeletal Research Center, Department of Orthopaedic Surgery, University of Pittsburgh, PO Box 71199, Pittsburgh, PA 15213, USA
    J Shoulder Elbow Surg 12:247-52. 2003
    ..Moreover, a biomechanical evaluation of the anteroinferior capsulolabrum that investigates the possibility that the mechanical properties may be directionally independent should be conducted...
  48. ncbi The flexural rigidity of the aortic valve leaflet in the commissural region
    Ali Mirnajafi
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, University of Pittsburgh, 100 Technology Drive, Room 234, Pittsburgh, PA 15219, USA
    J Biomech 39:2966-73. 2006
    ..From a valve design perspective, these findings can be used as design criteria in fabricating prosthetic devices AV resulting in better functional performance...
  49. ncbi The biomechanical effects of fatigue on the porcine bioprosthetic heart valve
    M S Sacks
    Tissue Mechanics Laboratory, Department of Bioengineering, University of Pittsburgh, Room 749 Benedum Hall, 3700 Ohara St, Pittsburgh, PA 15261, USA
    J Long Term Eff Med Implants 11:231-47. 2001
    ..We discuss the implications of these results that point toward the development of chemical-treatment methods that seek to maintain the integrity of the amorphous extracellular matrix to ultimately extend BHV long-term durability...
  50. ncbi In vivo three-dimensional surface geometry of abdominal aortic aneurysms
    M S Sacks
    Department of Bioengineering, University of Pittsburgh, PA 15261, USA
    Ann Biomed Eng 27:469-79. 1999
    ..Our results indicate that AAA surface geometry is highly complex and cannot be simulated by simple axisymmetric models, and suggests an equally complex wall stress distribution...
  51. pmc Synergistic effects of cyclic tension and transforming growth factor-beta1 on the aortic valve myofibroblast
    W David Merryman
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Cardiovasc Pathol 16:268-76. 2007
    ..Therefore, we hypothesized that isolated and combined treatments of cyclic tension and transforming growth factor-beta1 would alter the phenotype and subsequent collagen biosynthesis of aortic valve interstitial cells in situ...
  52. pmc Time-dependent biaxial mechanical behavior of the aortic heart valve leaflet
    John A Stella
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
    J Biomech 40:3169-77. 2007
    ..These mechanisms are an important functional aspect of native valvular tissues, and are likely critical to improve our understanding of valvular disease and help guide the development of valvular tissue engineering and surgical repair...
  53. pmc Tissue-to-cellular level deformation coupling in cell micro-integrated elastomeric scaffolds
    John A Stella
    Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Biomaterials 29:3228-36. 2008
    ..This result has fundamental implications when attempting to elucidate the events of de-novo tissue development and remodeling in engineered tissues, which are thought to depend substantially on cellular deformations...
  54. ncbi Design and hydrodynamic evaluation of a novel pulsatile bioreactor for biologically active heart valves
    Daniel K Hildebrand
    Engineered Tissue Mechanics Laboratory, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
    Ann Biomed Eng 32:1039-49. 2004
    ..Extensive testing and evaluation demonstrated the device's ability to subject a biologically active heart valve to highly controlled pulsatile waveforms that can be modulated during the course of sterile incubation...
  55. pmc Generating elastin-rich small intestinal submucosa-based smooth muscle constructs utilizing exogenous growth factors and cyclic mechanical stimulation
    Rebecca Long Heise
    Engineered Tissue Mechanics and Mechanobiology Laboratory, Department of Bioengineering and McGowan Institute, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
    Tissue Eng Part A 15:3951-60. 2009
    ..Moreover, our results suggest that a strategy involving growth factors and controlled mechanical stimulation may be used to engineer functional, elastin-rich tissue replacements using decellularized biologically derived scaffolds...
  56. pmc On the biomechanical function of scaffolds for engineering load-bearing soft tissues
    John A Stella
    Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Acta Biomater 6:2365-81. 2010
    ....
  57. ncbi The role of MMP-I up-regulation in the increased compliance in muscle-derived stem cell-seeded small intestinal submucosa
    Rebecca A Long
    Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Biomaterials 27:2398-404. 2006
    ..These findings suggest that the release of MMP-I in response to initial seeding on SIS and subsequent breakdown of collagen fibers is the mechanism responsible for an increase in mechanical compliance...
  58. pmc Stability and function of glycosaminoglycans in porcine bioprosthetic heart valves
    Joshua J Lovekamp
    Cardiovascular Implant Research Laboratory, Department of Bioengineering, Clemson University, 501 Rhodes Engineering Research Center, Clemson, SC 29634, USA
    Biomaterials 27:1507-18. 2006
    ..Controlling the extent of pre-implantation GAG degradation in BHVs and development of improved GAG crosslinking techniques are expected to improve the mechanical durability of future cardiovascular bioprostheses...
  59. ncbi Biodegradable poly(ether ester urethane)urea elastomers based on poly(ether ester) triblock copolymers and putrescine: synthesis, characterization and cytocompatibility
    Jianjun Guan
    McGowan Institute for Regenerative Medicine, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA 15219, USA
    Biomaterials 25:85-96. 2004
    ....
  60. pmc Biomechanics of the fetal membrane prior to mechanical failure: review and implications
    Erinn M Joyce
    The Swanson School of Engineering, Department of Bioengineering, and the McGowan Institute, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Eur J Obstet Gynecol Reprod Biol 144:S121-7. 2009
    ..This integrated approach will further the understanding of this unique physiological event and thereby provide insight into how to anticipate and when appropriate, intervene to prevent preterm FM rupture...
  61. pmc Functional collagen fiber architecture of the pulmonary heart valve cusp
    Erinn M Joyce
    Department of Bioengineering and the McGowan Institute, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
    Ann Thorac Surg 87:1240-9. 2009
    ..This necessity is especially the case for novel tissue-engineered PV, which rely on extensive in-vivo remodeling for long-term function...
  62. pmc Effects of cell seeding and cyclic stretch on the fiber remodeling in an extracellular matrix-derived bioscaffold
    Tan D Nguyen
    Department of Bioengineering, Musculoskeletal Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
    Tissue Eng Part A 15:957-63. 2009
    ..The better-aligned ECM-SIS has the prospect of eliciting improved effects on enhancing the healing of ligaments and tendons...
  63. pmc Scale-dependent fiber kinematics of elastomeric electrospun scaffolds for soft tissue engineering
    John A Stella
    Department of Bioengineering, Swanson School of Engineering and the McGowan Institute, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
    J Biomed Mater Res A 93:1032-42. 2010
    ....
  64. ncbi Synthesis, characterization, and cytocompatibility of elastomeric, biodegradable poly(ester-urethane)ureas based on poly(caprolactone) and putrescine
    Jianjun Guan
    McGowan Institute for Regenerative Medicine, University of Pittsburgh, 300 Technology Drive, Pennsylvania 15219, USA
    J Biomed Mater Res 61:493-503. 2002
    ..01) and >160% (p < 0.001) of polystyrene on RGDS-modified PEUUs. These biodegradable PEUUs demonstrate potential for future application as cell scaffolds in cardiovascular tissue-engineering or other soft-tissue applications...
  65. pmc Collagen fiber alignment and biaxial mechanical behavior of porcine urinary bladder derived extracellular matrix
    Thomas W Gilbert
    McGowan Institute for Regenerative Medicine, Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Biomaterials 29:4775-82. 2008
    ..There are distinct differences in the mechanical behavior of different layers of ECM from the porcine urinary bladder, and the processing methods can substantially alter the mechanical behavior observed...
  66. ncbi Contribution of the extracellular matrix to the viscoelastic behavior of the urinary bladder wall
    Jiro Nagatomi
    Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15219, USA
    Biomech Model Mechanobiol 7:395-404. 2008
    ..e., smooth muscle hypertrophy and altered ECM synthesis) under various pathological conditions...
  67. pmc In vivo dynamic deformation of the mitral valve annulus
    Chad E Eckert
    Engineered Tissue Mechanics and Mechanobiology Laboratory, Department of Bioengineering, Swanson School of Engineering, The McGowan Institute, School of Medicine, University of Pittsburgh, 100 Technology Drive, Room 234, Pittsburgh, PA 15219, USA
    Ann Biomed Eng 37:1757-71. 2009
    ....
  68. ncbi Passive biaxial mechanical properties of the rat bladder wall after spinal cord injury
    D Claire Gloeckner
    Department of Bioengineering Tissue Mechanics Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
    J Urol 167:2247-52. 2002
    ..To our knowledge we report the first application of biaxial mechanical testing to the normal bladder wall and demonstrate how these properties change after spinal cord injury...
  69. ncbi Experimentally tractable, pseudo-elastic constitutive law for biomembranes: II. Application
    John C Criscione
    Dept of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
    J Biomech Eng 125:100-5. 2003
    ..This paper illustrates the experimental advantages of this novel constitutive theory via analysis of biaxial test data obtained from chemically treated bovine pericardium...
  70. ncbi The material properties of the native porcine mitral valve chordae tendineae: an in vitro investigation
    Jennifer Ritchie
    Wallace H Coulter, Department of Biomedical Engineering, Cardiovascular Fluid Mechanics Laboratory, Georgia Institute of Technology, Emory University, 313 Ferst Drive, Room 2119, Atlanta, GA 30332, USA
    J Biomech 39:1129-35. 2006
    ..In conclusion, a non-destructive technique was developed to measure in vitro chordal strain in the mitral valve. This technique allows the investigation of the behavior of biological tissues under physiologic loading conditions...
  71. ncbi An experimentally derived stress resultant shell model for heart valve dynamic simulations
    Hyunggun Kim
    Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
    Ann Biomed Eng 35:30-44. 2007
    ....
  72. ncbi In vitro dynamic strain behavior of the mitral valve posterior leaflet
    Zhaoming He
    Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 315 Ferst Drive, Atlanta, GA 30332 0535, USA
    J Biomech Eng 127:504-11. 2005
    ..We conclude that PM positions may influence the posterior strain in a different way as compared to the anterior leaflet...
  73. ncbi Dynamic simulation pericardial bioprosthetic heart valve function
    Hyunggun Kim
    Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
    J Biomech Eng 128:717-24. 2006
    ..Dynamic simulations with experimentally determined leaflet material specification can be potentially used to modify the valve towards an optimal design to minimize regions of stress concentration and structural failure...
  74. ncbi Transforming growth factor-beta1 modulates extracellular matrix production, proliferation, and apoptosis of endothelial progenitor cells in tissue-engineering scaffolds
    Virna L Sales
    Department of Cardiac Surgery, Children s Hospital Boston, 300 Longwood Ave, Boston, Massachusetts 02115, USA
    Circulation 114:I193-9. 2006
    ..In the 15-day experiments, TGF-beta1-stimulated scaffolds revealed dramatically enhanced collagen production (types I and III) and incorporated more 5-bromodeoxyuridine and TUNEL staining compared with unstimulated controls...
  75. ncbi From stem cells to viable autologous semilunar heart valve
    Fraser W H Sutherland
    Department of Cardiothoracic Surgery, Children s Hospital, Boston, Mass, USA
    Circulation 111:2783-91. 2005
    ..Recent advances in tissue engineering and our understanding of stem cell biology may provide a lifelong solution to these problems...
  76. ncbi Effect of length of the engineered tendon construct on its structure-function relationships in culture
    Victor S Nirmalanandhan
    Department of Biomedical Engineering, University of Cincinnati, 2901 Woodside Drive, 827 Engineering Research Center, Cincinnati, OH 45221 0048, USA
    J Biomech 40:2523-9. 2007
    ..0404). We now plan to use principles of functional tissue engineering to determine if repairs containing central regions of longer MSC-collagen constructs improve defect repair biomechanics after implantation at surgery...
  77. ncbi Experimentally tractable, pseudo-elastic constitutive law for biomembranes: I. Theory
    John C Criscione
    Dept of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
    J Biomech Eng 125:94-9. 2003
    ..This paper is part 1 of 2 with "I. Theory" and "II. Application."..
  78. ncbi Effects of papillary muscle position on in-vitro dynamic strain on the porcine mitral valve
    Zhaoming He
    Cardiovascular Fluid Mechanics Laboratory, Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332 0535, USA
    J Heart Valve Dis 12:488-94. 2003
    ..Initially, the dynamic deformation of the central region of the porcine MV anterior leaflet was quantified under simulated physiological conditions to explore the effects of varying papillary muscle (PM) position...
  79. ncbi Protein precoating of elastomeric tissue-engineering scaffolds increased cellularity, enhanced extracellular matrix protein production, and differentially regulated the phenotypes of circulating endothelial progenitor cells
    Virna L Sales
    Department of Cardiac Surgery, Children s Hospital Boston, 300 Longwood Ave, Boston, MA 02115, USA
    Circulation 116:I55-63. 2007
    ..We assessed the effect of different protein precoatings on a single scaffold type (elastomeric poly (glycerol sebacate)) with a single cell source (endothelial progenitor cells)...
  80. ncbi Prevention of polyurethane valve cusp calcification with covalently attached bisphosphonate diethylamino moieties
    Ivan Alferiev
    Division of Cardiology, The Children s Hospital of Philadelphia, Abramson Research Bldg, 3516 Civic Center Blvd, Philadelphia, Pennsylvania 19104 4318, USA
    J Biomed Mater Res A 66:385-95. 2003
    ..Thus we evaluated the mechanical and in vivo anticalcification properties of heart-valve leaflets composed of this modified polymer...
  81. pmc The effects of anisotropy on the stress analyses of patient-specific abdominal aortic aneurysms
    Jonathan P Vande Geest
    Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, AZ 85721, USA
    Ann Biomed Eng 36:921-32. 2008
    ..non-ruptured AAAs, the lower p-value when using the anisotropic model suggests including it into patient-specific AAAs may help better identify AAAs at high risk...
  82. ncbi Dynamic simulation of bioprosthetic heart valves using a stress resultant shell model
    Hyunggun Kim
    Department of Biomedical Engineering, College of Engineering, University of Iowa, 1402 SC, Iowa City, IA 52242, USA
    Ann Biomed Eng 36:262-75. 2008
    ..It is expected that the developed experimental and computational methodology will aid in the understanding of the complex dynamic behavior of native and bioprosthetic valves and in the development of tissue engineered valve substitutes...
  83. ncbi Biomechanics of engineered heart valve tissues
    Michael S Sacks
    Conf Proc IEEE Eng Med Biol Soc 1:853-4. 2006
    ..The purpose of this paper is to present a review of the structure-strength relationships for native and engineered heart valve tissues...

Research Grants17

  1. ENHANCED DURABILITY OF BIOPROSTHETIC HEART VALVES
    Michael Sacks; Fiscal Year: 2001
    ..Determine how chemical treatment alters cuspal layer micromechanics. 2. Quantify PBHV cuspal deformation during the cardiac cycle. 3. Determine how long-term cyclic fatigue alters PBHV later structure and mechanical properties. ..
  2. Biomechanical optimization of TE heart valves
    Michael S Sacks; Fiscal Year: 2010
    ..Specific Aim 3 - Evaluate the EPC-seeded ES-PEUU scaffold's ability to perform in-vivo using a single leaflet model. ..
  3. Mechanisms of In-Vivo Remodeling in Tissue Engineered Heart Valves
    Michael Sacks; Fiscal Year: 2009
    ..Relevance to public health includes the develop of valved pulmonary conduits for the pediatric population that can grow with the patient, minimizing the need for continued re-operations to bring the patient to adulthood. ..
  4. Biomechanical optimization of TE heart valves
    Michael Sacks; Fiscal Year: 2009
    ..Specific Aim 3 - Evaluate the EPC-seeded ES-PEUU scaffold's ability to perform in-vivo using a single leaflet model. ..
  5. Training in Biomechanics in Regenerative Medicine
    Michael Sacks; Fiscal Year: 2008
    ..Coursework includes intensive life science, and biomechanics is utilized to provide the students with a thorough grounding in both areas. Skills acquired in these courses are combined in later courses and the trainees' research. ..
  6. Mechanisms of In-Vivo Remodeling in Tissue Engineered Heart Valves
    Michael Sacks; Fiscal Year: 2008
    ..Relevance to public health includes the develop of valved pulmonary conduits for the pediatric population that can grow with the patient, minimizing the need for continued re-operations to bring the patient to adulthood. ..
  7. Biomechanical optimization of TE heart valves
    Michael Sacks; Fiscal Year: 2008
    ..Specific Aim 3 - Evaluate the EPC-seeded ES-PEUU scaffold's ability to perform in-vivo using a single leaflet model. ..
  8. Mechanisms of In-Vivo Remodeling in Tissue Engineered Heart Valves
    Michael Sacks; Fiscal Year: 2007
    ..Relevance to public health includes the develop of valved pulmonary conduits for the pediatric population that can grow with the patient, minimizing the need for continued re-operations to bring the patient to adulthood. ..
  9. Training in Biomechanics in Regenerative Medicine
    Michael Sacks; Fiscal Year: 2007
    ..Coursework includes intensive life science, and biomechanics is utilized to provide the students with a thorough grounding in both areas. Skills acquired in these courses are combined in later courses and the trainees' research. ..
  10. Biomechanical optimization of TE heart valves
    Michael Sacks; Fiscal Year: 2007
    ..Specific Aim 3 - Evaluate the EPC-seeded ES-PEUU scaffold's ability to perform in-vivo using a single leaflet model. ..
  11. Biomechanical optimization of TE heart valves
    Michael Sacks; Fiscal Year: 2004
    ..3) Perform in-vitro evaluation of TEHV fabricated using optimal scaffold designs and 3D guided RV outflow track geometry using novel bioreactor loop imaging system. ..
  12. ENHANCED DURABILITY OF BIOPROSTHETIC HEART VALVES
    Michael Sacks; Fiscal Year: 2004
    ..Determine how chemical treatment alters cuspal layer micromechanics. 2. Quantify PBHV cuspal deformation during the cardiac cycle. 3. Determine how long-term cyclic fatigue alters PBHV later structure and mechanical properties. ..
  13. ENHANCED DURABILITY OF BIOPROSTHETIC HEART VALVES
    Michael Sacks; Fiscal Year: 2003
    ..Determine how chemical treatment alters cuspal layer micromechanics. 2. Quantify PBHV cuspal deformation during the cardiac cycle. 3. Determine how long-term cyclic fatigue alters PBHV later structure and mechanical properties. ..
  14. Biomechanical optimization of TE heart valves
    Michael Sacks; Fiscal Year: 2003
    ..3) Perform in-vitro evaluation of TEHV fabricated using optimal scaffold designs and 3D guided RV outflow track geometry using novel bioreactor loop imaging system. ..
  15. ENHANCED DURABILITY OF BIOPROSTHETIC HEART VALVES
    Michael Sacks; Fiscal Year: 2002
    ..Determine how chemical treatment alters cuspal layer micromechanics. 2. Quantify PBHV cuspal deformation during the cardiac cycle. 3. Determine how long-term cyclic fatigue alters PBHV later structure and mechanical properties. ..
  16. Biomechanical optimization of TE heart valves
    Michael Sacks; Fiscal Year: 2002
    ..3) Perform in-vitro evaluation of TEHV fabricated using optimal scaffold designs and 3D guided RV outflow track geometry using novel bioreactor loop imaging system. ..
  17. Mechanisms of In-Vivo Remodeling in Tissue Engineered Heart Valves
    Michael S Sacks; Fiscal Year: 2010
    ..Relevance to public health includes the develop of valved pulmonary conduits for the pediatric population that can grow with the patient, minimizing the need for continued re-operations to bring the patient to adulthood. ..