Prospects of the practical use of silk sericins

In Lepidoptera and Trichoptera, a blend of sericin proteins seals the pair of fibroin filaments into the silk fiber that is coated by additional layers of adhesive sericins. The structure and function, and even the number of sericin proteins, are poorly known. Most sericin applications to date employ mixtures of proteins extracted by hot alkaline water during the cocoon processing in the reeling mills. The extracts were shown to have antioxidant, moistening, UV-shielding and also moderate antibiotic properties. They are used as additives to various cosmetic products and in some countries also as remedies in human medicine. Sericins were reported to suppress tumor promotion, provide protection against ulcers and exert other health supporting effects. They also support proliferation and can provide a basic matrix for the differentiation of the cells cultured in vitro. Commercial production of sericin hydrolyzates as components of the tissue culture media will probably expand with the use of stem cells for the tissue repair. Sericins can polymerize to fibers, films and 3-D structures that provide scaffolds for complex tissue reconstructions. The use of recombinant sericin-type proteins for these applications is in the phase of basic investigations.