ساخت، مشخصه يابي و تحليل مكانيكي داربست‌هاي زيست كامپوزيتي پلي(‌وينيل الكل)/ نانوهيدروكسي آپاتيت تقويت شده با نانوالياف سلولزي جهت كاربرد در مهندسي بافت استخوان

چكيده انگليسي :

Fabrication characterization and mechanical analysis of poly vinyl alcohol nanohydroxy apatite electrospun biocomposite scaffolds reinforced by cellulose nanofibers for bone tissue engineering application Mohammad Saeid Enayati ms enayati@ce iut ac ir Date of Submission 20 09 2016 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree Ph D Language Persian Supervisor Dr Tayebeh Behzad tbehzad@cc iut ac irAbstract Taking into account advantagous properties of nanofibers in tissue engineering fibrousbiocomposites scaffolds of poly vinyl alcohol PVA nanohydroxy apatite nHAp and cellulosenanofibers CNF electrospun and characterized Scanning electron microscopy SEM and filed emissionSEM FE SEM were applied to investigate morphology of spun fibers The 8 wt PVA solution at 15 cmelectrospinning distance resulted in bead free fibers with 238 38 nm average diameter Loading 1 to 15wt nHAp into PVA solution it was shown that at 10 wt of nanoparticles fibrous scaffolds withappropriate mechanical and morphological properties were obtained Then different amounts of CNF wereloaded into PVA nHAp10 By increasing nHAp and also CNF average diameter of fibers decreased tolower than 150 nm Both nanofillers corporation and probable interactions caused emergence of new peaksand also change in position available peak in ATR FTIR patterns respectively Thermal behaviour analysisproved that electrospinning and filler addition led to increase in glass transition temperature T g andcrystalline temperature Tc but reduction ofmelting point T m Wide angle x ray scattering WAXS wasapplied to study supermolecular structure of electrospun fibers PVA powder WAXS pattern displayed fourdistinct crystalline peak however electrospinning and filler addition left only one broad peak at 19 3 which are evidences for PVA crstallinity reduction In the case of electrospinning this effect is observeddue to extremely short time of solvent evaporation during the process resulting in stopping of crystallizationat the early stage In the case of additives the mechanism of PVA crystallinity reduction is most probablydue to the interactions between OH groups in matrix PVA and nanofillers as well as calcium ions innHAp Tensile mechanical characterization of fibrous scaffolds was carried out it was obtained thatPVA nHAp at 10 wt nanoparticles PVA8 nHAp10 had the highest tensile modulus 142 84 7 10 MPa Adding 3 wt of CNF to this sample resulted in a 3 component composite scaffold PVA8 nHAp10 CNF3 with 322 90 20 47 MPa modulus Heat treatment of scaffolds at 180 oC made themstable against water disintegration Hydrophilicity of scaffolds was investigated by contact angle methodwhich was determined that PVA composite fibers were more hydrophil than pure PVA fibers In addition biodegradability in PBS demonstrated that nanofillers nHAp and CNF reduced degradation rate ofscaffolds Biomineralization in SBF also was done which showed higher mineralization of compositescaffolds compared to pure PVA scaffold MTT assay proved that both nHAp and CNF decreasedcytotoxicity of PVA scaffold Furthermore cell attachment characterized by SEM and functionality investigated by alkaline phosphatase ALP and alizarin red proved that nanocomposite scaffolds hadhigher potential in MG 63 osteoblast growth proliferation and osteogenic activity Another aim of currentstudy was to investigate the mechanical properties of electrospun PVA and its nanocomposites Tensile testand AFM nanoindentaion were applied to measure tensile modulus of elecrospun scaffolds and electrospunsingle fibers respectively In addition theoretical models were used to predict stiffness of nanocompositesand verify their accuracy by experimental data In conclusion Generally the obtained results confirm thatthe 3 component fibrous scaffold of PVA nHAp CNF has promising potential in hard tissue engineering Keywords Poly vinyl alcohol Biocomposite Electrospinning Electrospun scaffold Bone tissueengine

عنايتي، محمد سعيد

ساخت، مشخصه يابي و تحليل مكانيكي داربست‌هاي زيست كامپوزيتي پلي(‌وينيل الكل)/ نانوهيدروكسي آپاتيت تقويت شده با نانوالياف سلولزي جهت كاربرد در مهندسي بافت استخوان

پلي (وينيل الكل) , زيست كامپوزيت , الكتروريسي , داربست الكتروريسي شده , مهندسي بافت استخوان