Biomaterials are substances, natural or manmade, that are used in medicine to interact with the human body for various purposes, such as wound healing and tissue regeneration. Previous work on biomaterials has shown that they can affect cells in many ways, including how they grow, move, and the type of cell they develop into. Scientists have recently begun investigating biomaterials with properties that can be fine-tuned to optimize their use in regenerative medicine. Now, researchers at Tokyo Medical and Dental University (TMDU) have identified a polymer with tunable mobility properties that can alter the immune activity of specific liver cells.