ساخت و بررسي مشخصات داربست هاي آلياژي پلي ﴿هيدروكسي بوتيرات﴾ /كيتوزان به منظور استفاده در مهندسي بافت

چكيده انگليسي :

Preparation and Characterization of Poly hydroxy butyrate Chitosan Blend Scaffold for Tissue Engineering Application Somayeh Ebrahimi Ebrahimi1985@gmail com Date of Submission 9 05 2011 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors S Nouri Khorasani saied@cc iut ac ir S Karbasi karbasi@med mui ac irAbstract Tissue engineering is continually being developed to meet the increasing demand for human tissue andorgan substitutes It is very important to choose the proper scaffold as the template for including cell andtissue growth Microbial poly hydroxy butyrate PHB is a natural biodegradable polymer withbiocompatibility and good mechanical properties However PHB has several inherent deficiencies in use including brittleness thermal instability in molten slow rate of degradation and acidic degradationproducts Chitosan is a linear biopolymer and has been of enormous interest because of many advantagesincluding biocompatibility biodegradability hydrophilicity non toxity and anti microbial activity However mechanically inferior feature of Chitosan in the wet state has limited its usage On the basis ofabove mentioned characteristics it can be seen that Chitosan and PHB have mutually complementarypotentials Therefore it is reasonable to expect that their individual deficiencies would be overcome if PHBand Chitosan could be well blended together But some difficulties have been frequently encountered aboutblending PHB with Chitosan due to tow main problems 1 melting processing technique cannot be appliedsince chitosan has high melting point and PHB will start to decompose before melting Chitosan 2 thereare very few common solvents available for Chitosan and PHB In the present work PHB Chitosan blendscaffolds where prepared using trifluoro acetic acid as a new co solvent combined with salt leachingtechnique Fabricating PHB Chitosan blend scaffolds according to a Taguchi experimental design thematerial parameters as the PHB concentration Chitosan and salt content were investigated The scaffoldswere analyzed by scanning electron microscopy SEM Fourier transform infrared FT IR contact angle water absorption and degradation measurements FT IR band intensity of the carbonyl stretching absorptionfrom PHB revealed that the crystallization of PHB in these blends is suppressed when the concentration ofChitosan was increase SEM images showed a thin and rough top layer with a nodular structure supportedwith a porous sub layer in blend scaffolds According to SEM images there were two kinds of pore in theblend scaffold cubic pores that arise from salt leaching and spherical small pores that arise from immersionprecipitation The contact angle of blend scaffolds where influenced by salt content and chitosanconcentration with increasing the salt content the top layer became rougher and the contact angleincreased but with increasing the Chitosan concentration the contact angle decreased As well as waterabsorption measurements showed that the water absorption of blend scaffolds increase with increasing theChitosan concentration degradation of blend scaffolds in phosphate buffer solution PBS has been studiedby measuring weight of samples and measurement of PBS pH for 14 weeks In vitro degradabilityinvestigation indicated that the degradation rate of blend scaffold was higher than pure PHB scaffolds andthe dissolution of chitosan could neutralize the acidity of PHB degradation products Maximum degradationrate has been seen for prepared scaffold with 90wt NaCl and 40wt Chitosan The Obtained resultssuggest these newly developed PHB Chitosan blend scaffolds may serve as a three dimensional substrate incartilage tissue engineering Keywords Scaffold Blend Poly hydroxy butyrate Chitosan Tissue Engineering SaltLeaching Immersion Precipitation

ابراهيمي، سميه

ساخت و بررسي مشخصات داربست هاي آلياژي پلي ﴿هيدروكسي بوتيرات﴾ /كيتوزان به منظور استفاده در مهندسي بافت

PHB