Immunoregulatory Effect Of Esterified Glucan/Collagen Fibrous Membrane And It's Application As Skin Dressing

Seeking biomaterials with biomedical function is becoming a hotspot in biomaterial research.Particularly,it needs more for biomaterials or their degradations to partake some biomedical processes instead of just acting as physical scaffold during tissue repair.The present skin dressing is designed to absorb wound exudate,moisturize,have antibacteria and gas permeability,but rarely to the have biological modulating function.?-glucan as a biomacromolecule-has a significant immunomodulatory function,but it has special molecular structure leading to a very poor solubility and poor process properties,which limits it's application in biomedicine.In this study,the esterified glucan/collagen composite nanofiber membrane was fabricated by electrospinning after ?-glucan was esterified,and the biological properties of the composite fiber membrane for skin dressing were evaluated.Firstly,?-glucan was esterified with trifluoroacetic anhydride and analyzed by FT-IR spectroscopy.The esterified glucan and type I collagen were mixed in different ratios(10:0,8:2,5:5)and dissolved in hexafluoroisopropanol,and then the esterified glucan/collagen(10:0,8:2,5:5)composite nanofiber membrane were prepared by electrospinning.The structural and physical properties of the fiber membranes were analyzed by scanning electron microscopy,water absorption,contact angle test and tensile test.The proliferation of RAW264.7 and NIH-3T3 cells on the membrane was characterized by cell proliferation assay(CCK-8).The adhesion of RAW264.7 and NIH-3T3 cells on fibrous membrane was observed under scanning electron microscopy and confocal laser scanning microscopy.The NO secretion in RAW264.7 cells was detected by Griess method and the secretion of IL-6,IL-10 and TGF-? from RAW264.7 cells cultured on fibrous membrane at 1,3,7,14 d by fluorescence quantitative PCR for the detection of immunomodulating activities of the fibrous membrane.The effect of cytokines secreted from RAW264.7 cells on the proliferation of NIH-3T3 cells was detected by the method of CCK-8.Finally,the model of whole skin defect of mouse was established,and the effect of fibrous membrane on skin wound was analyzed by gross observation,H & E staining and Masson staining.The results showed that the ?-glucan was successfully esterified,and the composite membranes with ratios of the esterified glucan/collagen being 10:0,8:2,5:5 were fabricated by electrospinning.The diameter of the fiber in the composite membrane was ranged from 100 nm to 200 nm,and with the increase of type I collagen content,the diameter of the fiber was decreased.The composite membranes were non-toxic to RAW264.7 and NIH-3T3 cells,and had good biocompatibility.The composite membrane with the ratio of esterified glucan/collagen being 5:5(abbr:5:5 membrane)has better hydrophilicity and higher tensile strength.RAW264.7 and NIH-3T3 cells adhered better on the 5:5 membrane.The 5:5 membrane could stimulate RAW264.7 cells to secrete inflammatory factors IL-6 during 1~3d,which warrants the membrane stimulating the inflammatory reaction of macrophages;and secrete IL-10 and TGF-? during 3~7d,which does the membrane stimulating macrophages for tissue regeneration.RAW264.7 cells cultured on 5:5 membrane could promote the proliferation of NIH-3T3 cells.The results of gross examination of the repaired full-thickness skin defects in mice showed that 5:5 membrane could be better for skin wound repair by both of promoting collagen deposition and epithelial formation.These studies have shown that the 5:5 membrane has a biological modulating function and has a promise to be used as a biologically functional dressing for skin repair.