Hydrogels are commonly used as biomaterials for applications in biomedicine due to their biocompatibility. However, the relationship between biological cells and the hydrogel surface is still unclear and the existing parameters to explain the interactions are not sophisticated enough. In a recent study, Jooyoung Lee, Boa Song and co-workers at the Center for Biomaterials and the Department of Polymer Engineering in the Republic of Korea studied the impact of polymer chain flexibility on cell adhesion, with a variety of hydrogel constructs composed of the natural polymers collagen and fibrin.