سنتز و بررسي خواص فيزيكي - مكانيكي و تخريب پذيري داربست هاي پلي ﴿گليسيرول-سباسات﴾ ﴿PGS﴾ براي كاشت سلول هاي بنيادي شبكيه چشم به روش الكتروريسي

چكيده انگليسي :

Synthesis and Investigating Physico Mechanical Properties and Degradation Behavior of Poly glycerol sebacate PGS Scaffold for Retinal Stem Cell Using Electerospining Technique Narges Mazaheri n mazahery@yahoo com Date of Submission 2012 10 3 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Saied Nouri Khorasani saied@cc iut ac ir AbstractThese days nanofibrous materials are gaining great application in biomedical fields including drug releasedevice tissue regeneration matrices and tissue engineering For tissue regeneration composite nanofibers arefavored due to their mechanical and biological properties Moreover use of biopolymer as a compositematrix allows easy fabrication and provides a level of mechanical felexibility A bio scaffold can bebroadly defined as a structure used to repair and regenerate of damaged tissue through the cell migrationinto the defect site The scaffold can be made from natural or synthetic materials Many types ofpolymers natural and synthetic are widely used in research associated with human retinal eye disease The main advantages of scaffolds made from composites or synthetic polymers are extensive structure various properties in comparison with natural polymers capability of choosing undegradable polymer ordegradable polymer under specific condition Poly glycerol sebacate PGS is a degradable polyesterwhich is synthesized through a polycondensation reaction of glycerol and sebacic acid under hightemperature and vacuum Its degradation products of hydrolysis are nontoxic and undugous naturalmetabolites These properties make PGS a good candidate for cornea and retina tissues repair In this thesis the PGS prepolymer was synthesized by polycondensation of equimolar glycerol and sebacic acid at 120 Cunder nitrogen atmosphere for 24 h Then synthesized prepolymer was dried at 50 oC under vacuum 200mbar Therefore a viscous and transparent prepolymer was obtained which can be dissolved in differentsolvents Thereafter polymer characterization was carried out using FTIR X ray and DSC The resultsshowed that the synthesized polymer has the properties similar to PGS that was synthesized in previouslypublished literature In the next step prepolymer solutions were prepared using different ratios ofpolycaprolactone in various solvents such as tetrahydrofurane THF ethanol EtOH chloroform ClF dimethylformamide DMF and dichloromethane DCM All solutions were electrospun under differentconditions of spinning distance applied electric voltage and flow rate SEM and optical microscope imagesof electrospun fibers showed that spinning distance of 15 cm electric voltage of 10 kV and flow rate of 0 3ml min are the optimal conditions to obtain free bead fibers Then PGS PCL 1 1 were dissolved in DCM toprepare 30 wt v solution Electrospinning of this solution was performed under the mentioned optimalcondition and led to fibers without any bead In the next step mechanical and degradation properties ofnanofiber webs were measured Degradation analysis showed that after 28 days the weight loss of thesamples immersed in phosphate buffer solution at 37 C and pH 7 4 was only 40 The reason of this lowrate of degradation of PGS PCL nanofibers is higher crystallinity of PCL component The mechanicalmeasurements indicated that tensile modulus of nanofiber web is 0 1 MPa approximately equal to that of theretina tissue Key WordsCondensation polymerization scaffold nanofiber poly glycerol sebacate electerospinning retina tissueengineering

مظاهري، نرگس

سنتز و بررسي خواص فيزيكي - مكانيكي و تخريب پذيري داربست هاي پلي ﴿گليسيرول-سباسات﴾ ﴿PGS﴾ براي كاشت سلول هاي بنيادي شبكيه چشم به روش الكتروريسي

پليمريزاسيون تراكمي , نانو الياف , الكتروريسي , مهندسي بافت