(265f) Modelling of the Degradation of Poly(ethylene glycol)-Co-(lactic acid)-Dimethacrylate Hydrogels

Authors: 
Lattuada, M., University of Fribourg
Storti, G., ETH Zurich
Diederich, V., ETH Zurich
Due to their similarity with extracellular matrix, hydrogels are ideal substrates for cell growth. Hydrogels made of synthetic polymers are excellent alternatives to natural ones and offer the key advantage of precisely controllable degradation times. In this work, we have prepared hydrogels from modified poly(ethylene glycol) macromonomers, functionalized on both ends first with a few lactic acid units, and then with methacrylate groups. A library of hydrogels has been prepared using free-radical polymerization of the macromonomers, by changing both the macromonomer concentration and their type, i.e., the number of lactic acid units contained in them. The degradation kinetics of these hydrogels, caused by the hydrolysis of the lactic acid units, have been carefully monitored in terms of swelling ratio, mass loss and Young’s modulus. A complete mathematical model, accounting for hydrogel degradation, swelling and reverse gelation has been developed and used to predict all the measured quantities until complete disappearance of the gels. The model has been shown to be capable of accurately predicting the time evolution of all the properties investigated experimentally. To the best of our knowledge, this is the first study where such a systematic comparison between model predictions and experimental data has been presented.