Spider silk fibers: Synthesis, characterization, and related biomedical applications

Abstract

Compared to silkworm silks, spider silks (SS) are considered stronger, most elastic, and tougher biomaterials. Web-weaving spiders use impressive silks where the proteins in the silks can be described as virtually nondiverged. In the last three decades, several research papers have studied the physical, mechanical, and chemical properties of SS, as promising biomaterials for a variety of applications. However, the study of their optical and electrical properties is, for the most part, still lacking. The mechanical and frictional forces align the protein molecules to form nanofibers. The mechanical properties of natural SS are illustrated by their absorption of the energy of insects without breaking and whilst also avoiding insect bouncing away from the web. Different parameters affect the formed protein silk, including temperature, hydration state, protein concentration, and extension rate. Major ampullate silk is a two-protein composition in every orb-weaving spider. MaSp proteins are composed of GGX and poly-alanine repeats with no substitutions in a certain position. Recent research has also revealed a hierarchical structure of the silk fibers that led to a better understanding of their promising mechanical performance, but there is a lack of studies into the formation of its nanofibers by the electrospinning process with both electrical and optical characterizations. This chapter introduces the concept, synthesis, most important characteristics, and biomedical applications of SS fibers. Recent research updates about the generation of SS nanofibers are presented, especially through the electrospinning process. In addition, a literature survey about the mechanical, structural, and electrical characteristics of SS nanofibers is discussed in different environmental conditions. In addition, related biomedical applications, such as drug delivery and neural system regrowth, are presented.