Mechanical properties of soft tissue

We focus our description of the mechanical properties of soft tissue on muscle, tendon, ligament, and cartilage. The structure and properties of bone are treated elsewhere in this volume. 

Some hydrogels, due to their water content, provide a more flexible structure that is similar to soft tissue. Therefore, by combining the pol5uners that lack certain required mechanical properties such as a suitable modulus of rigidity or modulus of elasticity with hydrogels, suitable degradation and drug delivery properties are obtainable and an exterior is achieved that has mechanical properties similar to the mechanical properties of soft tissue. 

Krouskop, T.A., Dougherty. D.R. and Vonson, F.S. (1987) A pulsed Doppler ultrasonic system for making noninvasive measurements of the mechanical properties of soft tissue. J. Rehab. Res. Dev., 24(1), 1-8. 

Ziegert, J.C. and Lewis, J.L. (1978) In-vivo mechanical properties of soft tissue covering bony prominence, Trans ASME (J. Biomech. Eng.), 100, 194-201. 

Ahmad CS, Gardner TR, Groh M et al (2004) Mechanical properties of soft tissue femoral fixation devices for anterior cruciate ligament reconstruction. Am J Sprats Med 32 635-640... 

Alexander, D. E., K. L. Ratzlaff, R. J. Roggero, and J. S. Hsieh. 1999. Inexpensive, semi-automated system for measuring mechanical properties of soft tissues. fExp Zoo 284 374-78. 

Furthermore, the addition of a small amount of bacterial cellulose nanofibrUs to anisotropic polyvinyl alcohol produces the nanocomposite material PVA-BC. This material possesses a broad range of mechanical properties, including anisotropy by controlling material and processing parameters. A PVA-BC nanocomposite with a controlled degree of anisotropy that matches the mechanical properties of soft tissue can be created. 

In contrast to soft biologies, whose mechanical properties primarily depend upon the orientation of collagen fibers, the mechanical properties of mineralized tissues, or hard biologies, are more complicated. Factors such as density, mineral content, fat content, water content, and sample preservation and preparation play important roles in mechanical property determination. Specimen orientation also plays a key role, since most hard biologies such as bone are composite structures. For the most part, we will concentrate on the average properties of these materials and will relate these values to those of important, man-made replacement materials. 

Silver FH. Mechanical properties of connective tissue. In Biological Materials Structure, Mechanical Properties, and Modeling of Soft Tissues, New York NYU Press 1987 Chapter 6. 

Q.Z. Chen, A. Bismarck, U. Hansen, S. Junaid, M.Q. Tran, S.E. Harding, N.N. Ah, A.R. Boccaccini, Characterization of a soft elastomer poly(glycerol sebacate) designed to match the mechanical properties of myocardial tissue. Biomaterials 29 (2008) 47-57. 

Ho, E., Lowman, A. Marcolongo, M. (2006) Synthesis and characterization of an injectable hydrogel with tunable mechanical properties for soft tissue repair. 

Because natural tissues have anisotropic mechanical properties, in order to better replicate the properties of soft tissue, specifically cardiovascular tissues such as heart valve leaflet and vascular conduits, these anisotropic mechanical properties should be incorporated into the design of PVA-C. PVA-C prepared by the standard freeze-thaw cycling process is isotropic, with mechanical properties independent of sample orientation. MiUon et al. [59] produced anisotropic PVA-C by subjecting the hydrogel to an initial controlled unidirectional strain after the PVA solution... 

The PGS obtained by Wang and coworkers was a kind of thermoset elastomer with the Young s modulus of 0.282 0.025 MPa, a tensile strain of at least 267 zE 59.4%, and a tensUe strength was at least 0.5 MPa. The mechanical properties of PGS were well consisted with that of some common soft tissues. Although PGS is a thermoset polymer, its prepolymer can be processed into various shapes by solving it in common organic solvents such as 1,3-dioxolane, tetrahydrofuran, isopropanol, ethanol, and iV,M-dimethylformamide. Porous scaffolds can be fabricated by salt leaching. 

Silver, F.H. (1987). Biological Materials Structure, Mechanical Properties and Modeling of Soft Tissue. New York University Press, New York, NY. 

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