| Objective:To search for a novel technique on fabricating poly(lactide-co-glycolide) copolymer foamy scaffolds that have better three-dimensional microstructure and suit for tissue engineering usage as matrix material. Study the degradation properties of scaffolds,and ethanol disinfection effects on its physical properties. Modify the material surface function and improve the hydrophilic ability. Construct cytokine control-release system in foamy scaffolds that sustained release growth factors. Join the conductive and inductive approaches together,thus the utilized basic of tissue engineering scaffolds put into use prepared for orthopaedics in future. Methods:Solid scaffolds were fabricated by lower-heating and compressive method,particles of polymer and sodium chloride(NaCl) were ground and sieved to a diameter of 200-250 u m,mixed ratio to 1:16 and 1:20(W/W). Studies were done in such ways:1.Three-dimensional microstructure study. Calculated the open pore rate,porosity and average leaching time. Photomicrograph of representative porous microstructure of matrix were taken by scanning electron microscope (SEM).2 Jn vitro degradation study. Mass loss,intrinsic viscosity,volume,acidity and compressive strength changes during storage at 37C in saline forl-8 weeks was determined for the two groups of scaffolds.3.Modification study. Scaffolds were modified with alginate calcium and alcohol,24-hours hydrophilic test were taken in the treated between two groupscaffolds with each contrasts. Microstructure scanning and significant statistics were done after that.4.Ethanol sterilization effects on scaffolds. Measured physical and mass changes of each group every set time for 24 hours,calculated the volume and mass loss.S.Control-release dynamic study. Two group scaffolds modified with alginate calcium containing BMP or VEGF respectively were incubated in liquid in triplicate at 37 C. At set times,samples of media were collected,and the remove volume was replaced with fresh media. The amount of factor released from alginate calcium was determined (n=3) in Western blotting. Results:l.The two group of scaffolds with PLGA/NaCl(W/W) 1:16 and 1:20 all reach the expect results,porosity was 90.8+ 1.2% and 92.2+ 0.9%,and open pore rate up to 98.8 +0.3% and 99.0 +0.2% respectively,average leaching time was 12.7+ 0.7h. Photomicrograph representing of varying pore size of 200-250 u m,revealing a highly porous structure with largely open and interconnected pore.2.There were statistically differences between the groups in acidity and compressive strength changing at the first 6 weeks after degradation test,mass loss and intrinsic viscosity changed significantly in whole period,volume contract happened after the 2nd week (p<0.05).3.After modified with alginate calcium,the scaffolds have the much higher hydrophilic ability,water uptake reached 50-60% (V/V) from 0.5 to 24 hours,no significant difference found between the inner groups. Ethanol also has the ability to modify the foams and scaffolds with higher porosity could be treated and have the more affinity to water than the lower one.4.Foams immersed in ethanol for 2.5 and 17.5 hours,mass loss happened but notable in the one with lower porosity. Volume shrink happened from 7.5th hour and decreased to 70-75% at 25th hour respectively and significantly (p<0.05).5.The control-release ability was related to the porosity of scaffolds. Polymer matrix modified and contained BMP or VEGF were subsequently rehydration,little factors released within the first 3 days,at the 7 day reach the peak point and sustained release for 28 days. Factors released last to more than 49 days.Conclusions:1. It's a useful novel method on fabricating polymer scaffolds by lower-heating and compressive method and the three-dimensional porous microstructure under control. PLGA particles expand around NaCl particles create the well-distributed foamy disc and PLGA/NaCl particles ratio effects the porosity and open pore rate,the diameter of NaCl particles determined the pore s...
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