Silk biomaterials

Silk is a versatile protein polymer spun as fibers by silkworms and spiders. Silks have played a major role in the history of textures for thousands of years. Silk proteins are of high molecular weight and have been formulated into many biomedical applications. Previous medical uses of silks focused on sutures, while the newer processed forms of silks are expanding biomedical utility into many areas of tissue repair and regeneration and medical device needs. These applications include ligaments, cartilage and bone, optical and microfluidic devices, nanofiber mats for skin wound healing, microspheres/nanoparticles for drug delivery, and hydrogels, among others. Through processing control of beta-sheet crystalline content of silk biomaterials, biological, mechanical, optical, thermal, and electromagnetic properties can be tailored to specific needs. This control can be achieved in all aqueous systems or in organic solvents, offering further versatility to the materials. This chapter provides a broad review of silk-based biomaterials that have been pursued in recent years.