Hydrogels are multifunctional, water-filled, three-dimensional structures made up of cross-linked polymer chains. The biomedical utility of hydrogels is limited due to a lack of control over its physical properties. In this research, we sought to address this issue by utilizing photo-switchable proteins known as opto-proteins to control the density of cross-linking throughout the hydrogel. In order to achieve this, constructs containing the opto-protein, mCherry, and SNAP-tag binding enzyme were expressed, purified, and proven to be photo-switchable. Collagen gels were cast and imaged in order to determine a baseline for the strength and number of cross-links in a regular gel. BG-Maleimide will be used to link the SNAP-tag on the opto-protein to cysteines inthe collagen ultimately creating a light-tunable hydrogel.