| 研究报告 |
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| Study on inner structure controllable large volume 3-D scaffolds formation method |
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Abstract AbstractObjective: To develop a novel method for preparating large volume threedimensional scaffolds, and controlling the pore structure, uniformity, and interconnectivity of the scaffolds to meet the requirement of pore structure for tissue engineering. Methods: Spherical porogen (a pore generating materials made from sodium chlorate) and bonding reagents (developed by our laboratory) were mixed uniformly, the mixture was put in a polypropylene mold (cylindrical vial with microholes on bottom for solution leaving off), the mold containing mixture was centrifuged at a chosen force for 5min to get ride of unwanted solution, then the bonded porogen assembly was cut into halves with a razor blade after completely dried in dessicator at room temperature. The upper, middle and bottom sections of assemblies were observed by optical microscope to detect the bonding uniformity and degree. A chosen polymer (PDLLA) was dissolved in chloroform to prepare a solution of a desired concentration, the polymer solution was cast onto the assembly, and additional casting was repeated after the solvent was evaporated. The dried porogen/polymer discs were removed from the mold, and the top and bottom layers were cut away to obtain flat surfaces. The discs was immersed in distilled water to remove porogen, dried under vacuum, then the scaffolds was harvested for structure characterization. Results: Optical micrographs clearly displayed that the porogen spheres remained spherical appearance and the bonding areas between spherical particles were homogeneous in large dimensional bonded assembly, and there was no statistical difference in bonding extent. In addition, the bonding extent could be controlled by variety of bonding reagent concentration as well as centrifugal force. For instance, the bonding extent was 33.78±5.56 (134) μm and 42.89±5.87 (132) μm respectively, when reagent concentration was 20% and 40% with centrifugal force of 161g and porogen size range of 100~220μm. SEM imagines revealed that the pore size and the diameter of interconnected openings of the scaffolds equaled separately to porogen size and bonding extent in bonded assembly. For example, the diameter of openings was 33.34±5.21(12)μm, when the bonding degree was 33.78±5.56 (134)μm in bonded assembly. Conclusion: With the newly developed bonding reagent and bonding technique, large dimensional biodegradable polymer scaffolds with high porosity as well as with controllable and homogeneous innerstructure can be formed, the pore size of scaffolds as well as diameter of openings between pores can be controlled by adjusting the porogen size and bonding degree in bonded porogen assembly. In addition, the resulting completely interconnected scaffolds have implications for facilitating cell migration, nutrients or waste exchange, abundant cellcell interaction, and potentially improved neural and vascular growth within tissue engineering scaffolds.
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Received: 25 January 2006
Published: 25 January 2006
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