(646a) Hydrophobically-Modified Alginate Gels with Improved Mechanical and Drug Release Characteristics

Alginate-based biomaterials have been widely investigated as biomaterials, with applications in delivery, wound healing, and cell encapsulation. However, the mechanical strength and ability to solubilize hydrophobic active agents in these materials is limited. Hydrophobic modification of alginate (HMA) was found to yield a significant improvement in the mechanical properties and drug release characteristics of hydrogels. Even at a relatively low concentration of 2wt%, chemical crosslinking of HMA with calcium ions yielded storage moduli close to 100 kPa. Ability to alter the degree of substitution along with hydrophobic tail itself gives an extra handle to tweak the mechanical and physical properties of hydrogels. Our initial drug release studies suggest that the mechanical strength of our gels is directly correlated with extended release of a model hydrophobic drug, and these are likely both to a denser microstructure that is formed upon hydrophobic modification. In order to fully understand the structure-property-activity relationship, we will also present detailed scattering data and complementary imaging results from confocal and electron microscopy. There is a clear evidence of drug-polymer interaction in the release profile of our hydrogels. Possible drug release mechanisms and the effect of critical material characteristics will be evaluated in future work. In addition, it will be shown that a hybrid assembly of alginate and HMA can be used to generate ?microfluidic?-like channels embedded inside HMA hydrogels. Our technique can be used to form an tubular structures that mimic vasculature.