Advances in understanding the properties of spider silk

Spider silk has remarkable mechanical properties that rival many man-made materials, including nylon, Kevlar®, and high-tensile steel. Over the past three decades, scientists have been unraveling its mysterious, unique chemical and physical properties. Much insight into spider silk molecular structure has been driven by technological advances in biochemistry, molecular and structural biology, engineering, and physics. To comprehend its superior qualities and wide range of opportunities for industrial applications, we will review the diversity and chemical composition of different fiber types as well as the biofactories or silk-producing glands that manufacture fibers. We will place an emphasis on highlighting spider silk protein sequences and their relationship to structure and functions and compare the mechanical properties of fibers spun from two different species, specifically the cob weaver black widow spider, Latrodectus hesperus, and the golden orb weaver, Nephila clavipes. We will also explain the challenging nature of spider silk farming, which has resulted in the pursuit of recombinant DNA methodologies to clone spider silk genes for expression in transgenic organisms. Lastly, we will discuss the long-term goal of the scientific community, which includes the expression and purification of vast amounts of recombinant silk proteins as well as development of a spinning methodology to produce synthetic silks for endless applications. These include using the silk proteins and spun fibers for medicine, engineering, athletics, and defense.