Mechanical testing of hydrogels

Understanding the mechanical properties of hydrogels is important when deciding on their suitability for different applications. Here, a number of different mechanical characterization techniques are discussed. Tensile and compression testing are the most commonly used techniques and can be used to obtain elastic and viscoelastic material properties of the hydrogels. Several different type of indentation are described including freestanding spherical indentation which allow cell seeded hydrogels to be monitored nondestructively over several weeks. Finally, three imaging-based mechanical testing techniques with differing resolutions—ultrasound, optical coherence elastography, and Brillion microscopy—are described.