The Mechanical Behavior of Engineered Hydrogels

Agarose and poly(ethylene-glycol) (PEG) are commonly used as scaffolds for cell and tissue engineering applications [1]. Agarose is a natural biomaterial that is thought to be inert [2] and permits growing cells and tissues in a three-dimensional suspension [3]. Gels synthesized from photoreactive poly(ethylene glycol) (PEG) macromonomers are well suited as cell carriers because they can be rapidly photopolymerized in vivo by a chain radical polymerization that is not toxic to cells, including chondrocytes. This paper explores the differences in mechanical behavior between agarose, a physically cross-linked hydrogel, and PEG, a chemically cross-linked hydrogel, to set the foundation for choosing hydrogel properties and chemistries for a desired tissue engineering application.