Peptides/Amphiphilic Peptides Based Silk Fibroin of Bombxy Mori and Their Self-assembly and Functionalization

Given the unique properties and functions, such as bioactivity and good biocompatibility, the self-assembly of peptide, specially amphipathic peptide, and their applications have become the research focus in the fields of supermolecular chemistry as well as functional polymeric and biomedical materials. Generally, most of peptide building blocks are prepared from chemical synthesis such as solid phase peptide synthesis, or genetic engineering. Those "bottom up" methods may be suffered by time consuming and cost, which limit the practical application of assembly peptides materials. Degradation of natural proteins such as casein, corn protein and so on, provides us a convenient way to obtain the mixed peptides. However, most of researches about these mixtures are focused on their bio-functions or surfactant property. The usage of them as building blocks of assembly peptide is overlooked. Silk fibroin from Bombyx mori silkworm silk is with highly repetitive sequences, such as GAGAGY and GAGAGS, their different assembly properties and the relevant structures not only play an important role in the forming of animal silks and silk fibroin based materials, but also have crucial effect on their excellent comprehensive performance. According to the selectivity of different enzymes, there are enzymes which work on the Tyr-Gly or Ala-Gly peptide bone, respectively. Therefore, it provides us the opportunity to harvest the silk peptides with special sequence economically via degrading silk fibroin by those enzymes. We introduced in this paper the enzymatic degradation, a "top down" method on obtaining peptide with specific sequences from silk fibroin and investigated their assembly properties. In addition, we summarized the construction of functionalization amphiphilic peptides with one of those silk peptides (GAGAGAGY) as building block as well as their assembly and applications like the forming pH responsive peptide hydrogel, flexible thermochromism materials and unique peptide surfactant. Finally, we prospected the application of top down method on obtaining functional peptide building blocks as well as application of the silk peptide obtained by this way on construction functional peptides.