Biological Properties Of EGF Modified Coaxial Electrospun Polycaprolactone/collagen Nanofiberstracheal Stent

Tracheal trauma,tracheal stenosisand tracheal tumors seriously damage the normal ventilation function,causing arterial hypoxem and endangering life.The resection and reconstruction of tracheal lesions is the most effective therapy for these diseases.However,there is no safe and reliable treatment for long segment trachea defect.Tissue engineered trachea is a possible solution to the long segment trachea defect.Therefore,it is a hot topic in this field to hunt appropriate alternative materials for tissue engineered trachea.Coaxial spinning is a noveltechnology,which is based on the classic spinning,improveselectrospunthrough coaxialneedles.Coaxial nanofibers has not only high superficial area and high porosity,but also a special "core-shell" structure,which coulddeliver drugs,growth facters dissolved in liquid.The biodegradable stent provides a growth space for the cells.The tissue compatibility of scaffolds is particularly important for the graft.Polycaprolactone and collagen were widely usedbiodegradable scaffold materials.They have good tissue compatibility and biodegradability.They can be used as novel materials for tissue engineering scaffolds.EGF can promote the adhesion,proliferation and differentiation of interstitial and epithelial cells.EGF can promote the differentiation of type I alveolar epithelium and increase the alveolar surfactant protein A.Epithelialization of transplantatial graft is critical for the survival of graft.EGF can promote the transformation of bone marrow mesenchymal stem cells to the epithelium.EGF which was unsuitable for classic spinning,could be used in tissue engineered trachea by using the coaxial electrospinning technology.Based on the previous studies of artificial tracheal scaffolds,we applied coaxial electrospinning technology and molecular modification technology in the research of tissue engineering tracheal scaffolds.Through coaxial electrospinning technology,using collagen as the core,polycaprolactone as shell,weprepared with a "core-shell" structure of polycaprolactone/collagen coaxial electrospun nanofibrous scaffolds,and epidermal growth factor modifiedcoaxial electrospun nanofibrous scaffolds.We inspected the mechanical properties,biocompatibility and biodegradabilityof the scaffoldas well as epidermal growth factor modified scaffolds.The main contents include the following aspects.First,the coaxial electrospun polycaprolactone/collagen nanofibers were prepared.The parameters of the preparation of coaxial electrospun polycaprolactone/collagen fiber were as follows: the concentration of collagen solution and polycaprolactone solution were 10%,the propulsion rate was 1ml/h,the voltage was 12.5KV,and the receiving distance was 15 cm.The coaxial electrospun polycaprolactone / collagen nanofiber membrane was tested for water contact angle,porosity and tensile test.It was found that the coaxial electrospun polycaprolactone/collagennanofibrousmembrane had good hydrophilicity and good tensile properties.The coaxial electrospun polycaprolactone/collagen nanofibrous membrane and epidermal growth factor modified coaxial electrospun polycaprolactone/collagen nanofibrous membrane weredegraded in vitro.The degradation degree and weight loss rate of coaxial electrospun polycaprolactone/collagen nanofibrous membranes at various time points were detected by scanning electron microscope and weightlessness rate test.It is found that the coaxial electrospunpolycaprolactone/collagen nanofibrous membranes had good degradation efficiency and weight loss rate.Secondly,polycaprolactone and collagen were degradable materials which were usually used as in tissue engineered scaffolds.Epidermal growth factor modified collagen was degraded with scaffold materials,and epidermal growth factor continued to release steadily,promoting cell proliferation and differentiation.It was found that epidermal growth factor modified scaffolds could play an important role in epidermal growth factor related biological functions.Finally,we detectedthedifferentiation mechanism of epidermal growth factor modified stent.We found that epidermal growth factor modified stent can decrease the human bone marrow mesenchymal stem cells in the phosphorylation level of SMAD3,increase the level of pFAK and UCP2,and the up regulation the expression levels of epithelial like moleculers? 1-Integrin and of E-Cadherin.Conclusion: First,the coaxial electrospun polycaprolactone/collagen nanofibers meet the mechanical requirements of the trachea stents.Second,epidermal growth factor modified coaxial electrospun polycaprolactone/collagen nanofibers can release of epidermal growth factorsteadily.Third,epidermal growth factormodified coaxial electrospinning polycaprolactone/collagen nanofibers can promotehMSCs adhesion and proliferation and diferrantion to epithelium.The last,epidermal growth factor modified coaxial electrospun polycaprolactone/collagennanofibersis expected to be used in vivo studiesin the future.