This article celebrating Arthur von Hippel's career considers the expanding frontiers in the field of biomaterials, a subject that intrigued him given his interests in the molecular engineering of materials. The interface of materials science and biology started to develop decades ago when synthetic materials were first used to repair parts of the human body. An exciting transformation is now occurring in the field, as advances in biology are used to engineer bioactive materials at the molecular level. The transformation is going further to other frontiers that include the use of sophisticated materials to obtain biological information and learn biology, the creation of materials that imitate biological microstructures and functions, and the manipulation of organisms to create artificial materials.