3D Alginate Hydrogels with Controlled Mechanical Properties for Mammalian Cell Encapsulation

Alginate is one of the most attractive biomaterials for the design of hydrogels for biological and biomedical applications. This biomaterial is composed of varying amounts of two monomers, αL-guluronic acid (G) and β-D-mannuronic acid (M). Recent reports have suggested that depending on the monomeric composition of the hydrogel, stability, mechanical resistance, biodegradability, permeability and gelation might vary significantly. Even though different alginate-based hydrogels have been explored for encapsulation of cells, a correlation between composition and mechanical properties is still missing. Closing this important knowledge gap has been considered crucial for the development of next generation 3D materials capable of resembling the features of extracellular matrices. The purpose of this study was therefore to correlate rheological and mechanical properties of two alginatebased hydrogel formulations. Alginate 1 (Low G 20%-30% of G) and alginate 2 (High G 65%-75% of G) hydrogels were prepared by the diffusion of Calcium ions from a two-layer agarose matrix. The prepared hydrogels were characterized by determining the elastic and Loss moduli at a time sweep of 1Hz. Also, stiffness was determined via AFM. The rheological tests suggest that Low G hydrogels, exhibit higher Storage moduli than High G hydrogels. In line with this result, stiffness is significantly higher for High G hydrogels.