While discovery of new pharmaceutical agents is important, an important requirement for any pharmaceutical agent to be safe and effective is that it is delivered to tissues and cells of interest in a controlled manner. This involves understanding the mass transport and the biomaterial carrier, in addition to the other aspects of the biological response. This is also often a difficult process to bypass the barriers in the body and selectively and controllably target the cells of interest. Thus, there is a lot of research in this area trying to tailor the dose of the drug and find novel ways to activate and release the drug of interest. An important component of this is biomaterial design. These considerations are relevant for a range of diseases and treatments, including both traditional small molecule drugs as well as biological reagents such as growth factors.