Prepared Techniques and Characteristic of the Porous Calcium Phosphate Cement Composite Reinforced by Fiber and Coating Method

• Main Authors: Chang, Yung-Yu, 張詠裕
• Other Authors: Lou, Ching-Wen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/92682591762130867559

碩士 === 中臺科技大學 === 醫學工程暨材料研究所 === 103 === Calcium phosphate bone cement (CPC) is one material for artificial bone scaffolds, and has desirable biocompatibility. However, CPC is brittle and does not have a porous structure, which is disadvantageous for cell growth. This study aims to create CPC with a porous structure for cell growth via the addition of porogen that have different particle sizes and blending ratios. Moreover, fibers that are used in the biomedical field are also incorporated in order to improve the toughness and brittle fracture of CPC. The porous fiber-embedded bone scaffolds are then coated with polymer solutions, and then freeze dried. This process gives the bone scaffolds with a porous layer of a freeze-dried sponge. The composite bone scaffolds are thus featured by having desired mechanical strength and biocompatibility. This study consists of four parts. In the first part, saturated vapor pressures at different temperatures are used in a hydration reaction. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) are used to analyze the presence of a crystalline phase and functional groups in order to yield the optimal manufacturing temperature. In the second part, two biomedical fibers are alkali treated, followed by being tested with a tensile strength, surface observation, and biocompatibility. This process is to examine the influence of alkali treatment on the fibers’ structure, after which fibers are trimmed into small pieces for the subsequent experiment. In the third part, two fiber types and a porogen are added to CPC in order to form porous fiber-embedded bone scaffolds. The compression test, biocompatibility tests, and surface observation are used to evaluate how the addition of fibers affects the bone scaffolds. Afterwards, porogen with different particle sizes and different ratios is incorporated with the manufacturing. The bone scaffolds are tested for compression, biocompatibility, and are observed for surface structure in order to determine the optimal manufacturing parameters. In the fourth part, the optimal porous fiber-embedded bone scaffolds are coated with natural polymer solution and freeze-dried, which allows for a porous layer of freeze-dried sponge, and yields the composite bone scaffolds that are determined by a compression test as well as surficial and structural observations. The test results indicate that the hydroxyapatite is induced via the hydration reaction at different temperatures, and XRD and FTIR patterns show that a high temperature results in a significant peak of hydroxyapatite and the presence of phosphate groups. A tensile test and cell co-culture are conducted to evaluate the PVA and PET fibers before and after the alkali treatment. The mechanical properties and biocompatibility of the fibers are not subjected to the alkali treatment. Moreover, the SEM observation shows that the fiber-embedded bone scaffolds, made with a porogen with different particle sizes and blending ratios, exhibit significant variations in their porous structure and have interconnected pores. These results suggest that the bone scaffolds are good option for bone repair. The Alkaline phosphatase (ALP) results show that the bone scaffolds that undergo cell co-culture exhibit a great deal of cell differentiation and induce mineralization. The SEM observation also indicates that cell growth surrounding the pores of bone scaffolds, and a long-term co-culture also engenders crystalline structure of cells and causes multilayers of cell growth. The cell co-culture results indicate that regardless of the addition of fibers, the bone scaffolds all have satisfactory cell activity and mechanical properties that meet the requirements through bone repair. Moreover, the SEM observation shows that the fibers are found embedded or dispersed in the bone scaffolds, and thereby can disperse the stress to strengthen the bone scaffolds and defer their facture. The ALP and SEM results also indicate that the addition of staple fibers to the bone scaffold is conducive to the cell differentiation, growth, and attachment onto the fiber-embedded bone scaffolds. Finally, the composite bone scaffolds with gelatin coating and freeze-drying processing are wrapped with a sponge layer that benefits the mechanical properties and biocompatibility, as indicated in SEM observation. In addition, these composite bone scaffolds also have improved compressive strength and modulus, which qualifying their use for bone repair. Keywords: calcium phosphate cement (CPC), freeze drying, hydroxyapatite, biocompatibility, polymer