New bioartificial hydrogels: Characterization and physical properties

Physical properties of a bioartificial hydrogel prepared by cross-linking activated poly(ethylene glycol) of molecular mass of 8000 with bovine serum albumin (BSA) are described. This hydrogel shows a great swelling capacity and a high equilibrium water content (EWC > 95%). The volume expansion factor of a BSA-PEG 8000 hydrogel during swelling was a function of its initial thickness. This hydrogel shows a high elasticity since it was reversibly deformable until a level of compression of 60% and it broke only when this level reached 80%. DSC heating scans demonstrated that differentiation of two kinds of water in the hydrogel is possible : the free (bulk) and the bound water. There was evidence that bound water is in the form of a trihydrate complex with ethylene oxide units of the PEG in the network. This hydrogel was suitable for controlled drug release systems, as demonstrated with release experiments.