Dissertation
Dissertation > Medicine, health > Basic Medical > Medical science in general > Biomedical Engineering > General issues > Biomaterial

Preparing PLGA Three-dimensional Scaffolds of Tissue Engineer by Electro-spinning

Author MaZuo
Tutor ZhangWeiGuo
School Dalian Medical University
Course Surgery
Keywords tissue engineering three-dimensional scaffolds electrospinning PLGA gelatin
CLC R318.08
Type Master's thesis
Year 2013
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Objective: To explore the effect of electro-spinning parameters (concentration,solvent ratio, output voltage) on PLGA electro-spun fiber morphology, fiber diameter,porosity; to look for the best electro-spinning parameters and prepare PLGAthree-dimensional scaffold and PLGA/(Gt) composite fiber three-dimensional scaffold,which can simulate the thickness(3-4mm) of the meniscus; to prove the preparedelectro-spinning scaffolds with good biological safety and histocompatibility.Methods:1) According to the concentration of PLGA electro-spinning solution, the PLGAelectro-spinning solution divided into group A0.5g/ml, group B1.0g/ml, group C1.5g/ml. Each group was grouped into nine subgroups by different solvent proportion(DMF:THF=1:1,2:1,3:1) and output voltage (20kv,10kv and15kv), respectively.There are27sets of electro-spinning solution in total. Then, the morphology ofelectro-spinning fibers was observed by SEM and the average diameter of fiber wascalculated.2) Select the optimal electro-spinning parameters. To improve electro-spinningdevice, firstly,20×20×1.5cm~3of pure copper used as receiving plate instead of theprevious aluminum membrane. Secondly, two pieces of electrode plates were placedrespectively on two sides of the receiving plate. Thirdly, the aluminum membrane wassurrounded at the nozzle. After that, PLGA three-dimensional scaffold and PLGA/(Gt)composite fiber three-dimensional scaffold were prepared.3) Animal model were used to detect the biological safety and histocompatibility.Firstly, PLGA scaffolds and PLGA/Gt scaffolds were implanted into the subcutaneousof12rats on both sides of the spine as group A and group B, respectively. Three ratswere selected randomly at2,4,6,8weeks. We removed scaffolds from subcutaneousfor overall observation and histological examination and compared the degradation rateof two kinds of scaffolds. Secondly, the hemolysis test was carried out by PLGAscaffolds and PLGA/Gt scaffolds’ extracts, respectively. Results:1) When the solvent ratio was DMF:THF=1:1, the electrospun solutionconcentration was greater than1.5g/ml and the solvent ratio was DMF:THF=3:1, theelectrospun solution concentration was less than0.5g/ml, we can not gain electrospunfibers. In the spinning range, keeping concentration and voltage constant, with theincrease in the proportion of high-volatile solvents, the average fiber diameter will bethinner; remain solvent and voltage constant, with the increase of the concentration ofthe solution, the average fiber diameter will be thinner; keeping concentration andsolvent constant, as the output voltage increases, the average fiber diameter will bethinner. There was a negative correlation between electrospinning fiber porosity andaverage diameter (R~2=0.797, P <0.01).2) The PLGA scaffolds of3.52mm and PLGA/Gt scaffolds of3.64mm weregained successfully by improving device.3) The hemolysis test of PLGA and PLGA/Gt scaffolds’ extracts was negative. Insubcutaneous-implanted experiment, there was no visible adverse reactions and necrotictissue in the surrounding tissue of two scaffolds at histological examination.Distribution of inflammatory cells decreased gradually with the time changing. Thedensity of inflammatory cells and fibrous capsule thickness in PLGA/Gt scaffolds weresignificantly lower than PLGA scaffolds (12.47±3.62v5.16±4.38, P=0.012;178.54±51.54v234.89±67.81, P=0.001).Conclusion:1) When the PLGA (50:50, Mw=120,000) electro-spinning solution in spinningrange, along with the concentration of the solution reduced, the high proportion ofvolatile solvent and the output voltage increased, the average diameter of theelectrospun fibers will be thinner. It was the best parameters for preparation of PLGAscaffolds that the concentration was1.0g/ml, solvent ratio was DMF: THF=1:1andvoltage was15kv.2) The PLGA and PLGA/Gt three-dimensional scaffolds simulating the meniscusthickness were gained by improving device (using20×20×1.5cm~3of pure copper as areceiving plate, placing two pieces of electrode plates on two sides receiving plate,surrounding the aluminum film on the nozzle).3) PLGA and PLGA/Gt three-dimensional scaffolds were prepared throughelectro-spinning technology with stable degradation, non-toxic, non-irritating, both of them possess good biological safety and tissue compatibility.

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