Potential of 2D crosslinked sericin membranes with improved biostability for skin tissue engineering

Silk sericin protein is a natural, hydrophilic, macromolecular glycoprotein mainly synthesized in the middle silk gland of the silkworm. It constitutes 25-30% of the silk cocoon. Sericin proteins have antioxidant, antimicrobial, UV-resistant properties, promote wound healing and support cell proliferation even in serum-free media. Most of the sericin is discarded as waste in silk processing industries. This study aims at improving the mechanical strength and stability of sericin extracted from the silk cocoons during processing and utilize it as a biocompatible natural biopolymer in biomedical applications. Crosslinked sericin membranes, from the cocoon of non-mulberry tropical silkworm, Antheraea mylitta, were prepared using gluteraldehyde as the crosslinking agent. Physical and structural characteristics of the membranes were analyzed using scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy and X-ray diffraction along with swelling and degradation studies. The secondary structure of the membrane indicates that crosslinking provides a more integrated structure that significantly improves the stability and mechanical strength of the membranes. In vitro cytocompatibility of the membranes was evaluated by MTT assay and cell cycle analysis of feline fibroblast cells. The adherence, growth and proliferation patterns of cells on membranes were assessed by confocal microscopy, which demonstrated that the latter is non-toxic and supports cell growth. Cell cycle analyses indicate cytocompatibility with normal cell cycle pattern. This study reveals that silk sericin protein can be used as a biocompatible natural biopolymer for various applications in the biomedical field.