Extension of the Torsional Wave Experiment (TWE) to enable the Measurement of the Viscoelastic Properties of Biological Tissues
Tong Jiao (Brown University), Sean Teller (Intel Corporation), Rodney Clifton (School of Engineering, Brown University)
Symposium in honor of Rod Clifton on the occasion of his 75th Birthday
Mon 4:20 - 5:40
Salomon 101
In the development of tissue-engineered heart valves based on allograft decellularized ECM scaffolds, the material properties of the implant should ideally be comparable to the native semilunar valves. A TWE developed for measuring the viscoelastic properties of vocal folds has been adopted for measuring the viscoelastic properties of the three functional aortic/pulmonary valve tissues (leaflets, sinus wall, and great vessel wall). Results obtained using the original TWE configuration have been limited to infinitesimal deformations and to interpretation of the experiments using linear viscoelasticity. However, both vocal folds and leaflets undergo finite deformations during their cyclic response. In order to measure viscoelasticity properties soft tissues at finite strains, the TWE has been extended to finite deformations. A thin disk of soft material is sandwiched between two rigid plates. The lower plate is driven by a galvanometer at high frequencies and small rotations. A second stiffer material is placed between the upper plate and a third plate attached to an upper galvanometer that oscillates sinusoidally at low frequency and large rotation. At periodic peak rotations of the upper galvanometer, the lower galvanometer superimposes infinitesimal oscillations at a series of higher frequencies. The magnitude and phase of the rotation of the middle plate yield the viscoelastic properties of the test specimen for infinitesimal deformations at high frequency superimposed on finite deformations at low frequency. Preliminary results show the potential of the new test. Comparisons will be made with small strain results obtained using the original TWE.