In biological hydrogels, the gel matrix is usually reinforced with micro- or nano-fibers and the resulting composite is tough and strong. In contrast, synthetic hydrogels are weak and brittle, although they are highly elastic. Other than in food, the main structural application of hydrogels is as soft contact lenses. The developing interest in soft tissue engineering has exposed a need for strong synthetic hydrogels to act as scaffolds for tissue growth.
In this work a new class of hydrogels based on fiber reinforced hydrogel composites with a cartilage-like structure is designed. A 3D rapid prototyping technique was used to form crossed “logpiles” of elastic fibers that are then impregnated with an epoxy-based hydrogel in order to form a fiber-reinforced gel structure. The fibrous construct improves the strength, modulus and toughness of the hydrogel and also constrains the swelling. By altering the construct geometry and studying the effect on mechanical properties we will develop the understanding needed to design strong hydrogels for biomedical devices and soft machines.