Characterization of protein interaction with tunable microfabricated hydrogels

Work was completed to quantify biomolecule diffusion into photopolymerized hydrogels of varying crosslinking densities. Fluorescence recovery after photobleaching (FRAP) and gray-scale fluorescence intensity photographs were used in the analysis. For diffusion rates, three proteins were examined: bovine serum albumin, lysozyme, and IgG1. The diffusion in the hydrogels appears to be linearly related to the swelling ratio of the hydrogel and dependent on the hydrodynamic radius of the diffusant once critical crosslinking density has been reached. Higher swelling ratio gels exhibit a larger degree of protein penetration and "storage" in the gel matrix. We conclude that the use of these methods to characterize engineering materials with biomolecules will contribute to a better understanding and better design of sensors and actuators in a biological environment.