(741a) Dynamic and Rheological Properties of Hydrogels/Bioactive Ceramics Based On Degradable Poly(2-hydroxyethyl methacrylate)

Dynamic and rheological properties of hydrogels/bioactive ceramics based on degradable poly(2-hydroxyethyl methacrylate)

Jijun Huang¹, Eduardo Saiz², Antoni P. Tomsia¹

¹Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720

²Center for Advanced Structural Ceramics, Department of Materials, Imperial College London, United Kingdom

Hydrogel-based organic-inorganic bioactive composites have attracted increasingly attention in bone tissue engineering. The hydrogel/bioactive ceramics materials are expected to exhibit cell adhesion, calcium-binding, and mechanical properties as tissue scaffolds. Hydrogels composites based on poly(2-hydroxyethyl methacrylate), pHEMA, have been recently investigated to create elastomeric bonelike materials that may be machined, cut, and bent for low- to medium-load bearing applications. However, the non-degradability of the pHEMA hydrogel limits its applications.

We recently initiate our efforts to create biocompatible, biodegradable pHEMA hydrogels and their biocomposites with hydroxyapatite and bioglass. Our goal was to create a series of biodegradable pHEMA/hydroxyapatite and pHEMA/bioglass materials with various concentrations (30%, 50%, and 70 wt%) of hydroxyapatite and bioglass with tuning mechanical properties. These novel materials have a variety of applications in bone repair, reshaping, and regeneration. We purposely synthesized a hydrolytically cross-linker, N, O-dimethacryloyl hydroxylamine through which degradable pHEMA hydrogels were synthesized. Degradable pHEMA/hydroxyapatite and pHEMA/bioglass biocomposites were formed by pre-dispersing the biocermics into the structural components of the hydrogel prior to cross-linking. In this work, we will show the effect of bioceramics centration on dynamic mechanical properties, rheological properties, stress relaxation, creep behavior, and Payne effect. We will compare hydroxyapatite to bioglass in these properties. All these properties are important to bone regeneration. This work was supported by the National Institutes of Health/National Institute of Dental and Craniofacial Research (NIH/NIDCR) Grant No. 1 R01 DE015633.