Protein-based composite materials

Natural structural proteins display critical structural and bioactive properties that have evolved in nature for millions of years. However, depending on the specific protein, there may be useful functions, such as mechanical toughness, while other critical features may be more limiting, such as cell compatibility or a broader range of mechanical properties. Nature has evolved strategies to resolve this problem by generating multifunctional composite materials in vivo. For example, collagen and elastin are often found together in the body to provide the combination of strength and toughness required for specific tissue functions(1). Blending (mixing) proteins is a technological approach to generate protein-based biomaterials with a more complete set of specific properties. Blending can also benefit materials engineering through improved processability and material uniformity. As an alternative to blending, genetic engineering strategies have been exploited to generate combinations or hybrids of structural proteins to achieve control of functional features. However, at present this process remains limited due to the costs of scale up for these biotechnologically driven processes. Therefore, generating multifunctional, biodegradable structural protein composite biomaterials is emerging as a useful direction in the field to tailor properties to specific medical needs in vitro and in vivo, or as a strategy to generate a broader range of functional properties with which to conduct more systematic studies of the impact of the biomaterials on cell and tissue functions.