REGULAR ARTICLE Potential of 2D crosslinked sericin membranes with improved biostability for skin tissue engineering Sunita Nayak & Sarmistha Talukdar & Subhas C. Kundu Received: 18 May 2011 / Accepted: 20 October 2011 / Published online: 12 February 2012 # Springer-Verlag 2012 Abstract 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, antimicro- bial, 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 biopoly- mer in biomedical applications. Crosslinked sericin mem- branes, 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. Keywords Sericin . Membrane . Cell culture . Wound healing Introduction Silks of commercial importance are obtained from Lepidopteran silkworm larvae of the families Bomb- ycidae and Saturniidae (Jolly et al. 1968). Domesticated silkworms of the Bombycidae family (Bombyx mori) feed on mulberry leaves whereas members of the Saturniidae family are wild or semi-domesticated and feed on non- mulberry leaves (Mahendran et al. 2006). The silk fiber consists in two major proteins, the central core fibroin and the surrounding layer of glue protein sericin (Shaw and Smith 1951; Magoshi et al. 1985; Dash et al. 2007). Fibroin is a hydrophobic, structural protein secreted in the lumen of the posterior silk gland of silkworms. Sericin is a hydrophilic, hot water soluble macromolec- ular glycoprotein (Gamo et al. 1977) and contributes to about 20–30% of the total cocoon weight. Molecular weight of this protein ranges from 24–400 kDa, the predominant amino acid groups being serine (40%), glycine (16%), glutamic acid, aspartic acid, threonine and tyrosine (Gamo et al. 1977; Takasu et al. 2002; Tokutake 1980). These amino acids consist in hydroxyl, carboxyl and amino groups that provide high hydro- philicity (Voegeli et al. 1993). The physical association of sericin with fibroin in improperly degummed fibers has been reported to elicit immune responses (Panilaitis et al. 2003; Zaoming et al. 1996). In vivo studies showed sericin peptides with lower immunogenicity (Zhang et al. 2006a; Zhang et al. 2006b) promoting wound healing (Nagai et al. 2009) without generating significant levels of inflammatory mediators in studies conducted on rats (Aramwit et al. 2010a, b). Sericin is antibacterial, resists S. Nayak : S. Talukdar : S. C. Kundu (*) Department of Biotechnology, Indian Institute of Technology, Kharagpur 7213-02, India e-mail: kundu@hijili.iitkgp.ernet.in Cell Tissue Res (2012) 347:783–794 DOI 10.1007/s00441-011-1269-4