Electrospinning is one of the most effective methods for making high porous scaffolds with good mechanical properties. The most important features of soft tissues is high elasticity structure and ability of tolerate the tensions during the tissue regeneration. Hence an elastomeric biodegradable polymer such as poly(glycerol sebacate) (PGS) is a good substitute for soft tissue Engineering. Poly caprolactone and gelatin are two polymers with high mechanical properties and biocompatibility that improves properties of scaffold, respectively. In this research the prepolymer of PGS was synthesized by polycondensation of equimolar ratio glycerol and sebacic acid. Thereafter prepolymer characterization was carried out using FTIR, X-ray, and DSC. At the next step, ratio and concentration of PGS:PCL in chloroform (as solvent) and optimum condition for electrospinning were obtained by try and error. As similar, optimum condition for electrospinning of gelatin in acetic acid and coaxial electrospinning of PGS/PCL/gelatin with PGS/PCL as core and gelatin (Gt) as shell, were obtained. Samples containing gelatin were crosslinked by glutaraldehyde . Physico-mechanical properties and morphological analysis of electrospun samples was carried out using tensile test, SEM and TEM. Biodegradation, drug delivery, biocompatibility and cellular response of PGS/PCL/Gt core/shell nanofibers was carried out using mass loss in solution, spectrophotometry, contact angle and MTT test. Porosity of PGS/PCL/Gt core/shell nanofiber was obtained to be 79%. According to the mechanical tests, PGS/PCL/Gt nanofiber has lower elastic modulus, tensile strength in break and maximum strain in break compared with PGS/PCL nanofiber that is more close to natural mechanical properties of soft tissue. On the other hand, lower contact angle improved the biocompatibility of scaffold. Three step of drug release was observed by spectrophotometry analysis. After seventh day the drug release rate get constant. MTT observations demonstrate that there is no evidence of toxicity in sample polymer scaffold containing dexamethasone and without dexamethasone. That for the first time a porous scaffold of PGS/PCL/Gt core/shell nanofiber is obtained using coaxial electrospinning method, witch has proper specifications for soft tissue Engineering substitute and drug delivery system. Keywords: Electrospinning, PCL, PGS,Gelatin, core-shell fibers, soft tissue Engineering
