Effects of fabrication parameters on viscoelastic shear modulus of 2,3-dialdehydecellulose membranes--potential...

Porous 2,3-dialdehydecellulose (2,3-DAC) membranes were investigated for use as a synthetic scaffold for engineering vocal fold-like tissues. Two criteria of this application are (i) the viscoelastic shear properties of the scaffold should be controllable in the range of vocal fold tissues and (ii) scaffolds should remain biomechanically stable to withstand vibrational stresses in a bioreactor. Porous 2,3-DAC membranes were fabricated from methylolcellulose by water-induced cellulose regeneration, with or without sodium chloride leaching, followed by periodate oxidation. They were freeze-dried and ethylene oxide-sterilized. Different degrees of oxidation were obtained on reacting with sodium metaperiodate for different time points. Rheological studies were performed to investigate the effect of freeze-drying, porosity, degree of oxidation, sterilization, and incubation time on elastic and viscous shear moduli, G' and G'', respectively, for frequencies 0.01-10 Hz. Freeze drying increased G' and G'', while increased porosity and degree of oxidation reduced G' and G''. Sterilization had no effect on viscoelasticity. When incubated in Dulbecco's minimum essential medium at 37 degrees C, membranes with 6-7% and 19-20% oxidation disintegrated after 7 and 3 days, respectively, while membranes with 3-4% oxidation showed little viscoelastic change over a period of 42 days. The upper frequency limit of rheologic measurement was a limitation of the study and should be addressed in future investigations.