Characterizing the micro-scale elastic modulus of hydrogels for use in regenerative medicine

Our objective was to characterize the elasticity of hydrogel formulations intended to mimic physical properties that cells and tissues experience in vivo. Using atomic force microscopy (AFM), we tested a variety of concentrations in a variety of biomaterials, including agarose, alginate, the collagens, fibrin, hyaluronic acid, kerateine, laminin, Matrigel, polyacrylamide, polyethylene glycol diacrylate (PEGDA) and silicone elastomer (polydimethylsiloxane). Manipulations of the concentration of biomaterials were detectable in AFM measurements of elasticity (Young's modulus, E), and E tended to increase with increased concentration. Depending on the biomaterials chosen, and their concentrations, generation of tunable biocompatible hydrogels in the physiologic range is possible.