Preparation And Characterization Of Rana Chensinensis Skin Collagen/Poly(L-lactide) Nanofibrous Membrane

Wound healing is a complicated biomedical process. For promoting the woundsrepair, Biologic Dressings were widely used. The ideal wound dressing should stopbleeding, keep wounds moist, permeate air and water, it also should promoteepithelial tissue formation. The nanofibrous membrane which is prepared byelectrospinning have a better function in coverage and protection for wounds becauseof its nanofibrous elasticity, high specific surface area, high porosity, and the propertywhich can mimic the ECM to promote the cells migration and proliferation.Collagen is an important protein of human body, which has goodbiocompatibility and biodegradability, and it is an ideal raw material for preparingmedical wound dressings. Due to its weak mechanical properties, the application ofcollagen is restricted. Rana chensinensis skin contains a wealth of bioactivator, whichhas special molecular structures and complicated functions. In this subject, collagenwas extracted from recycled Rana chensinensis skin, then nanofibrous membrane wasprepared via electrospinning. The aim of this project is to provide a kind ofnanofibrous material, which has a good mechanical property, a certain bioactivity andcan be used to repair wounds.Rana chensinensis skin collagen was extracted through acid enzyme extraction,after freeze-drying, light yellow flocculent collagen powder was received. Thencollagen/PLLA composite nanofibrous membranes were prepared. Under certain massfraction, through optimize electrospinning process parameters: Spinning voltage, pushspeed, diameter of the needle, receiving distance, prepare a set of nanofibrousmembranes, which have uniform fiber morphology and good effect of fiber-forming.In the composite nanofibrous membrane, with PLLA content increased, themechanical properties of collagen/PLLA films subsequently improved, at the sametime, The addition of PLLA make the shape of the fiber become cylindrical, and thecollagen surface texture was deepened, which is benefit for cell adhesion. After FTIRtesting, the existence of hydrogen bonding interactions between collagen and Poly(L-lactide) was proved, which make the composite fibers possess a finer diametercompared to the pure collagen fiber and pure PLLA fiber. Contact angle tests haveshown that when Poly(L-lactide) content is not less than50%, collagen/PLLAmembrane exhibits hydrophobic property which consistent with PLLA nanofibermembrane. It has an important significance for the application of collagen/PLLAnanofibrous membrane in wet environment.By thermal annealing, PLLA recrystallized. Through tensile test, DSC, XRD,nano indentation test, the mechanical properties of collagen/PLLA membranes wereevaluated; it shows that the mechanical characteristics of different components ofcollagen/PLLA nanofibrous membrane change regularly. This rule is mainly comesfrom the crystallization behavior of PLLA. Through the nano indentation test, withthe increase of PLLA content, the longitudinal elastic modulus of film increasegradually. Therefore, PLLA can be added to improve the transverse and longitudinalmechanical properties of the material. It makes the Rana chensinensis skin collagennanofibrous membranes satisfy the required mechanical properties of clinicalapplication.