Study On Preparation And Properties Of Silk Fibroin/keratin Composite

As a big country of textile industry and animal husbandry,every year,there are huge number of solid wastes like feather,short animal fiber,leather and so on,which are valuable keratin resources.These wastes are often not properly utilized and directly discarded into environment,giving rise to great pollution and causing serious pollution.Keratin extracted from these solid wastes has excellent biocompatibility,natural degradability and other properties,so it has broad application prospects in tissue engineering,biology and other fields.Thus,research on utilization of those solid wastes have great values on both of academics and industry.However,low mechanical properties of keratin materials have always been an obstacle for the further wide application of keratin materials.It is reported that secondary structure of the regenerated protein materials is important for their mechanical property.Therefore,secondary structure induced transformation method was adopted to improve the mechanical property of keratin material.In this research,keratin and silk fibroin were extracted from animal feathers and silk fabrics by swelling reduction method and lithium bromide dissolution method respectively.Taking ?-sheet structure of silk fibroin as template,random coil structure of keratin was combined with ?-sheet chain of silk fibroin under the action of hydrogen bond,and then induced to transform into ?-sheet structure,so as to improve the mechanical properties of keratin material.It was found that the ?-sheet structure in the composite membrane increased with the addition of silk fibroin,and the tensile strength,crystallinity,water solubility,degradation rate and glass transition temperature increased with the increase of ?-sheet content.In addition,the relationship between the mechanical properties and the secondary structure of the composite membrane is studied and compared.Silk fibroin/keratin hydrogel was prepared from silk fibroin/keratin mixture by adding crosslinking agent.Keratin contains a large number of amino,carboxyl and other functional groups,these functional groups can be used as adsorption sites for dye and heavy metal ions.Therefore,we studied the application of silk fibroin/keratin hydrogel as adsorbent material.It was found that the hydrogel has a larger adsorption capacity for reactive brilliant blue KN-R and Cu2+and Pb2+,which are 482.43 mg/g,483.15 mg/g and 525.80 mg/g respectively.In the last part of this paper,the porous membrane was prepared by freeze-drying method,and the modified natural macromolecular aldehyde cellulose microcrystalline(DCNC)was used for further mechanical strengthening.The performance of porous membrane as drug carrier was studied.Aspirin and indomethacin were used as two kinds of drug carriers.It was found that the porous membrane was pH sensitive to the sustained release of the drug.At pH 1.2,the release of aspirin and indomethacin was very slow.In the first 450 minutes,the release of aspirin and indomethacin was only about 44.94%and 42.84%,respectively.In the pH value of 7.4,the release behavior of aspirin and indomethacin was obvious,and the release amount of aspirin and indomethacin reached 86.56%and 94.91%respectively in the initial 450 minutes.