Date

2023-1-18

Author

Haliloğlu, Alper

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Silk Sericin (SS) is one of the two major proteins in silk fiber and it is discarded as a waste in the silk industry. Recently, sericin captured attention in the biomedical field due to its variable amino acid composition and diverse functional groups. The physical and chemical properties of silk sericin can be adjusted via incorporation of different secondary phase additives for biomedical applications. However, brittle nature, low mechanical properties, and inability to avoid bacterial growth by itself limits its use in such areas. In this study, high temperature and pressure method is used to extract sericin from silk cocoons. To fabricate sericin based composite films, extracted sericin is combined with different agents, namely glycerol to overcome the brittle characteristics, as well as Sr and Zn incorporated bioactive glass (BG) particles and graphene oxide (GO) to provide mechanical durability and antibacterial properties. SEM images of the sericin based composite films showed that reinforcements were homogenously distributed throughout the films without any agglomeration. Thermogravimetric analysis showed that nearly 35% of the initial mass of the sericin films were lost during the early stages of degradation, which was correlated with glycerol diffusing out the system. Moreover, approximately 85-105 % swelling was observed upon soaking sericin films in 1xPBS, which indicated their good water retention ability. The Young’s modulus values of silk sericin based films increased from 16.7±0.9 MPa up to 19.3±1.9 MPa and 22.4±0.6 MPa upon 1% GO and 7% BG addition, respectively. When L929 fibroblast cells were treated with extracts of silk sericin films, no toxicity was observed and cellular viability was promoted up to 7 days of culture in vitro. Both reinforcement materials (GO and BG) exhibited antibacterial activity against gram-positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli) strains in a concentration dependent manner. Cumulatively, the obtained results showed that silk sericin based composite films are promising candidates for biomaterial applications.

Subject Keywords

Silk sericin, Composite film, Bioactivity, Antibacterial, Natural polymer

URI

https://hdl.handle.net/11511/102072

Collections

Graduate School of Natural and Applied Sciences, Thesis