Alternative tissue scaffolds for wound dressing: in vitro studies

In this study, nanofibrous polycaprolactone (PCL) and PCL/gelatin scaffolds were prepared in order to support and enhance the wound healing mechanism. Over the entire studies of this thesis; characterizations of produced tissue scaffolds were carried out and in vitro interactions were observed by cell culture studies.Fabrication of tissue scaffolds achieved by electrospinning method. PCL which has molecular weight of 80000 Da and pig skin originated gelatin of type A were used as components of scaffolds. N,N-dimethylformamide (DMF) and dichloromethane (DCM) mixture (25:75), and hexafluoroisopropanol (HFIP) were used as solvents for PCL and PCL/gelatin mixture, respectively. The parameters that affect the electrospinning process were optimized and nanofiber-based tissue scaffolds were achieved. SEM analysis showed the fiber diameters are 488±114 nm and 663±107 nm for PCL and PCL/gelatin scaffolds, respectively. Furthermore, according to results of the porosity analysis; the values of the porosities were calculated as 79% for PCL and 68% for PCL/gelatin scaffolds.Biodegradability studies for PCL and PCL/gelatin tissue scaffolds have been carried out in Dulbecco?s Modified Eagle?s Medium (DMEM) for 14 days under 37?C in CO2 incubator. Samples that were taken after 3rd, 5th, 7th and 14th days of the experiment were examined by SEM and ATR-FTIR analysis. Results showed that chemical structure of PCL tissue scaffolds did not change during 14 days incubation, on the other hand, PCL/gelatin scaffolds degraded by means of surface erosion.Immobilization of epidermal growth factor (EGF) to the nano-fibrous tissue scaffolds was realized by covalent bonding to enhance the wound healing mechanism by increasing the biological activities of the tissue scaffolds. EGF immobilization were evaluated qualitatively and quantitatively. Furthermore, the MTT analysis were held on during the cell culture and taken SEM images showed that, EGF immobilized tissue scaffolds affect the cellular proliferation and morphology positively.In the light of these experimental studies, it has been understood that, nanofibrous tissue scaffolds that were produced by the electrospinning method and immobilized EGF to the surfaces, are found to have suitable attribution for the wound dressing applications.Keywords: Electrospinning, nanofibrous tissue scaffolds, polycaprolactone, gelatin, epidermal growth factor (EGF), wound dressing, skin tissue engineering.