SWELLING AND VISCOELASTIC PROPERTIES OF OSMOTICALLY STRESSED ELASTIN

The swelling and viscoelastic properties of purified elastin were stud ied in aqueous solutions of superswelling agents or osmotic deswelling agents to develop models to study the behavior of elastin at frequenc ies not easily accessible by direct measurement. Increasing the concen tration of any of the deswelling solutes (glucose, sucrose, sodium chl oride ammonium sulphate, dextran, and polyethylene glycol) increased t he tensile storage and loss moduli. The viscoelastic behavior was inde pendent of solute when compared on the basis of swelling behavior. The data collected at various solute concentrations at 37 degrees C could be reduced to one master curve, and the master curves for elastin in each of the deswelling solutes were themselves superposable. The abili ty to reduce the data indicates that dehydration can be used to model elastin's viscoelastic behavior at high frequencies or over short time s. The viscoelastic behavior of elastin in the superswelling agents [p otassium thiocyanate (KSCN), dimethyl sulfoxide (DMSO), and ethylene g lycol (EG)] depended on the solute and was independent of swelling beh avior. In KSCN the behavior of elastin seemed to be a continuation of the pattern established by the deswelling agents in that an increase i n swelling was accompanied by a decrease in both moduli, and the visco elastic spectra were reducible to one master curve. In high concentrat ions of DMSO and EG the spectra were not reducible. KSCN appears a sui table superswelling solute to model elastin's viscoelastic behavior at low frequencies or over long times. (C) 1996 John Wiley & Sons, Inc.