Elastin is a versatile elastic protein that dominates flexible tissues capable of recoil, and facilitates commensurate cell interactions in these tissues in all higher vertebrates. Elastin's persistence and insolubility hampered early efforts to construct versatile biomaterials. Subsequently the field has progressed substantially through the adapted use of solubilized elastin, elastin-based peptides and the increasing availability of recombinant forms of the natural soluble elastin precursor, tropoelastin. These interactions allow for the formation of a sophisticated range of biomaterial constructs and composites that benefit from elastin's physical properties of innate assembly and elasticity, and cell interactive properties as discussed in this tutorial review.

A structural protein blend system based on silkworm silk fibroin and recombinant human tropoelastin is described. Silk fibroin, a semicrystalline fibrous protein with beta-sheet crystals provides mechanical strength and controllable biodegradation, while tropoelastin, a noncrystallizable elastic protein provides elasticity. Differential scanning calorimetry (DSC) and temperature modulated DSC (TMDSC) indicated that silk becomes miscible with tropoelastin at different blend ratios, without macrophase separation. Fourier transform infrared spectroscopy (FTIR) revealed secondary structural changes of the blend system (beta-sheet content) before and after methanol treatment. Atomic Force Microscopy (AFM) nano-indentation demonstrated that blending silk and tropoelastin at different ratios resulted in modification of mechanical features, with resilience from ~68% to ~97%, and elastic modulus between 2~9Mpa, depending on the ratio of the two polymers. Some of these values are close to those of native aortic elastin or elastin-like polypeptides. Significantly, during blending and drying silk-tropoelastin form micro- and nano-scale porous morphologies which promote human mesenchymal stem cell attachment and proliferation. These blends offer a new protein biomaterial system for cell support and tailored biomaterial properties to match mechanical needs.

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Severe burn injuries are a major health problem as they can compromise whole body function and result in extensive emotional trauma exacerbated by prolonged hospital stay. Burn injury treatment has improved dramatically to increase the probability of survival, but burn survivors still suffer from excessive scarring and skin contractures, which substantially compromise their health and quality of life. Elastin is historically underrepresented in commercial dermal substitutes, yet deserves consideration because of its fundamental role in skin structure and function. Dermal elastic network is a strong determinant of skin resilience, texture, and quality but is not sufficiently regenerated following burn injury. In addition to its structural and mechanical roles, elastin has inherent cell signaling properties that promote a diverse range of cellular responses including chemotaxis, cell attachment, proliferation, and differentiation. Scaffold elasticity and regeneration of the elastic fiber system is now recognized as integral to the development of functional dermal substitutes. Dermal substitutes are intended to replace damaged dermal tissue in severe burn injuries. Elastin-based dermal substitutes have the potential to decrease wound contraction, improve scar appearance and functionality, and contribute to wound healing outcomes through a combination of elastin's mechanical and cell signaling properties.

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