Preparation And Performance Study Of Wool Keratin/polyvinyl Alcohol (PVA) Composite Film

As a natural protein,wool keratin has good biocompatibility and biological activity,as well as good hydrophilic properties.It is a good medical material.However,pure wool keratin membrane has the characteristics of brittle,hard and fragile under dry conditions,which limits its application in the medical field.Polyvinyl alcohol as a modified material for the modification of wool keratin,using its good adhesion and film forming properties,blending it with keratin to form a skeleton connection,can prepare composite membrane materials for the application of medical dressing and tissue engineering.In this paper,wool keratin was extracted by reduction method and blended with polyvinyl alcohol to prepare wool keratin/PVA blend membrane,glutaraldehyde crosslinked wool keratin/PVA blend membrane and wool keratin/PVA nanofiber membrane.The microstructure,mechanical properties,drug sustained-release were studied,including:(1)By using the casting method,wool keratin and PVA were blended in different ratios to prepare the wool keratin/PVA blend membrane.The properties of the blend membrane were characterized by SEM,ultraviolet spectrophotometer and FTIR.The results showed that some a-helical structures in the wool keratin extracted by the reduction method were destroyed and transformed into ?-sheet and random coil structure.The keratin and PVA in the blend membrane were the physical blend.When the mass ratio of wool keratin to PVA was 1:9,the tensile strength of the keratin/PVA blend membrane reached a peak of 38.56 MPa,the swelling ratio rose to 82%,and with the increase of keratin content,the sustained release ability of the wool keratin/PVA drug-loaded blend membrane was enhanced,and the release time lasted more than 48 hours.(2)Different ratios of glutaraldehyde crosslinked wool keratin/PVA blend membrane were prepared by casting method with 2.5%glutaraldehyde as a crosslinker.It was found that the glutaraldehyde with both keratin and PVA had cross-linking reaction,and there was a strong interaction between the molecules,which changed the crystal state of the molecules in the blend membrane.The mechanical properties of the blended membrane were improved compared to before crosslinking,the tensile strength was increased to 41.27MPa,and the swelling ratio was lowered.The drug release rate of the blend membrane was only 59.8%,which was much lower than that before the cross-linking,indicating that the addition of glutaraldehyde made the drug release more inhibited,and the sustained release ability was greatly enhanced before the cross-linking.(3)Different ratios of wool keratin/PVA nanofiber membrane were prepared by electrospinning.It was found that the viscosity of the spinning solution decreased with the increase of keratin content,when the mass ratio of wool keratin to PVA was 3:7,the average diameter of nanofiber was 342 nm,and the nanofiber distribution was uniform which formed dense three-dimensional network structure.At the same time,the nano fiber membrane had the largest breaking strength of 2.27 MPa,the water contact angle was 25°and the hydrophilic property was good.The test of the drug sustained-release performance showed that the wool keratin/PVA nano fiber membrane had drug sustained release ability.The higher the keratin content,the higher the sustained release ability,and the release time lasted more than 48 hours.