Human fibroblasts are cells that provide the structure of many tissues. In this image, these cells can be seen spreading within a semi-interpenetrating network (semi-IPN) made of a polymer called polyethylene glycol diacrylate-hyaluronic acid (Pegda-HA). This material is mechanically similar to soft tissues in the human body, such as vocal folds. Such a material could be used as a base material for reconstructing missing or damaged tissue. Because the cells are not only growing but also organizing themselves within the material, semi-IPN materials could be used to restore normal tissue function once implanted into the human body. These materials may be used for a variety of other soft tissue replacements applications.