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Fabrication and Cytocompatibility Evaluation of Surface Functionalization for PLA Film

Author: TianYe
Tutor: ZhouChangRen
School: Jinan University
Course: Biomedical Engineering
Keywords: Tissue Engineering Polylactic acid Surface functionalization Cytocompatibility Induced differentiation
CLC: R318.08
Type: PhD thesis
Year: 2008
Downloads: 311
Quote: 2
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Abstract

One of the core content of the tissue engineering is to build a complex of cells and scaffold materials, cell adhesion on the material, proliferation, differentiation is mainly dependent on the surface of the physical and chemical properties of the material, different surface properties of materials preparation and become a hot research at home and abroad with the interaction between the cells. Due to the limitations of the material preparation and surface modification technologies, the most affected by the material surface properties on cell behavior research is still relatively easier to achieve functional, but not a wide range of applications in the field of tissue engineering materials as the base, such as polystyrene (PS), quartz, etc., in commonly used biological material, for example, polylactic acid (PLA), the research conducted for the substrate is less reported, which is precisely more practical significance of the research and development of tissue engineering. In order to investigate the interaction of the surface cells of common tissue engineering scaffolds, commonly used in the field of tissue engineering PLA matrix surface with different physical and chemical properties of PLA film on the performance of the cell biology for the future development of biological The good compatibility PLA material composite scaffold of the cell to explore some of the theoretical basis and practical skills. To the interaction between the more systematic study material surface and the cells, the present study was to construct a series of surface morphology and chemical composition of functionalized PLA film. The first is in the single mode microwave in Organic Synthesis, using Unlike traditional vacuum sealed tube thermal polymerization of the microwave polymerization method, a molecular weight of approximately 4.86 × 10 ~ 4 and 10.47 × 10 ~ 4 was synthesized under the protection of the atmospheric nitrogen PLA. Secondly, as the raw materials, using SNS (Solvent-Non-Solvent) constructed PLA film and PS membrane pore size between 1μm-20μm, and porous PS film as a template, to prepare a surface having a micro-island structure PLA film, the size of the pore size and pore density can be provided by changing the concentration of the solution, of a non-solvent, methods such as the ambient temperature and the rate of evaporation of the solvent control. Finally Photooxidation graft, to hydrogen peroxide as the photo-oxidant in the UV irradiation under the success of the acrylic acid (AA), propylene amide (AAM), hydroxyethyl acrylate (HEA) and other hydrophilic monomers ground sticks to the surface of the PLA film, which introduces a carboxyl group, an amide group and hydroxyl group in the PLA film surface, the contact angle measurements show improved PLA film of the hydrophilic polar groups introduced, increase the surface free energy of the material . As bone tissue engineering scaffolds, not only material and bone cell interactions are very important, and the surface of the material nature of the mineralization performance and collagen adsorption is also very critical, this thesis research material surface properties of biological mine of collagen protein adsorption performance. PLA film induced mineralization performance results show that pure PLA film to the surface of the lack of nucleation sites without conducive to the formation of mineralized product, a small molecular weight PLA due to its surface carboxyl density is greater than the molecular weight of PLA and mineral apposition a product of relatively high; For the physical morphology functionalized surface, having the 1μm micro island structure of PLA film crystalline mineralization, the display surface of this structure is conducive to promoting the deposition of mineralized product, while the other three the three kinds of morphology of the surface were not seen the formation of the crystallinity of the mineralized product, among which the the 20μm surface of the microporous structure of the deposition of calcium phosphate salts least; compare different groups of functional surfaces, introduced pole group carries a negative charge and therefore is capable of inducing a large number of crystalline calcium and phosphorus product formed, the X-ray diffraction (XRD) shows this product to have a certain crystalline hydroxy apatite (HA). The quartz crystal microbalance (QCM) technology to explore the molecular weight of the PLA film surface groups of collagen protein adsorption. The results showed that the adsorption of collagen in line with the Langmuir isotherm equation, the surface of the collagen in the introduction of the functionalized groups can be faster to reach equilibrium, and has a strong absorption edge; comparison of three functional groups surface, collagen Protein in the maximum amount of adsorption of the carboxyl surface PLA film; atomic force microscope (AFM) observation showed that the adsorption of collagen in the small molecular weight PLA less curved shape, while on the adsorbed amount of collagen in the larger molecular weight PLA is relatively more, some collagen morphology linear shape; group functional surfaces, collagen in the the carboxyl surface showed dense mesh distribution, the display The carboxylated surface facilitates adsorption of collagen. Osteoblasts in the Evaluation of the compatibility of the different PLA film surface, a low molecular weight PLA is high molecular weight PLA is more conducive to cell adhesion, but the former rapid degradation rate, detrimental to the long-term growth of cells; surface having a micro PLA film of the hole and the micro-island structure conducive to cell adhesion and spreading, but the contribution of cell proliferation performance. Although the cells adherent properties, but are not attached along the hole wall and island walls growth of smaller diameter than the micropores of 20 μm and micro-island structure, cell pseudopodia, but in the pores and micro island side spreadability; PLA film for different surface groups, whether the adhesion and spreading of cells or cell proliferation performance have been improved to some extent, among which the introduction of the the amide PLA film cells the best compatibility. Finally, this study also innovative discusses the impact of the different nature of PLA film performance of induced differentiation of bone marrow mesenchymal stem cells (BMSCs). The results show that in the presence of the inducing agent, BMSCs are able pure PLA film normal to osteoblast differentiation, and for the different morphologies PLA film of 1μm micro-island structure of the surface on BMSCs differentiation performance membrane with pure PLA similar, while three additional morphologies different degrees toward on BMSCs into osteoblasts inhibition; more noteworthy is the introduction of an amide group in the surface of the PLA film can not only promote the BMSCs induced differentiation, even in non-inducing agent under the action of its own also has some inducing BMSCs to differentiate into osteoblasts function.

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