ABSTRACT
In many applications utilizing polymeric biomaterials, such as in scaffolds for tissue engineering, investigators can choose from natural materials, such as collagen or fibrin, or synthetic polymers such as poly(lactic-coglycolic acid) (PLGA). Each choice has its unique advantages and disadvantages. For example, the extracellular matrix (ECM) proteins have evolved over billions of years to have specific cellular interactions and activities, to be remodeled by cellular activity, and even to guide tissue formation processes. However, the isolation, purification, and processing of these materials can be difficult, mechanical properties are often poor, and there are some concerns about the possibility for disease transmission. Synthetic polymers, on the other hand, offer easier handling and processing as well as a greater degree of control of material properties. Unfortunately, when using synthetic materials such as PLGA, cellular interactions with the material are mediated by nonspecifically adsorbed proteins and are generally difficult to control. In order to obtain some of the advantages of natural bioactive compounds, such as ECM proteins, while gaining the ease of processing and safety of synthetic materials, a number of researchers have developed hybrid materials that are primarily composed of standard synthetic polymers but are also grafted, tethered to, or copolymerized with biologically functional segments such as peptides. Examples discussed in this article include the development of ECM-mimetic materials for use in tissue engineering applications, as well as the development of pharmacologically active biomaterials.
