Establishing a tube foam scaffold for tracheal cartilage tissue engineering by using solvent casting/particulate leaching method / 中国组织工程研究

ABSTRACT

BACKGROUND: Both aperture and porosity are mainly evaluating markers for three-dimensional poly materials. The higher the porosity is, the easier the growth and proliferation of cartilage cells are. However, with the successive increasing of porosity, compressive strength of scaffolds decreases and utility of aperture also decreases. Therefore, it is extremely significant for tracheal cartilage tissue engineering to establish three-dimensional poly scaffolds which have suitable aperture and porosity.OBJECTIVE: To establish tube foam scaffolds by using solvent casting/particulate leaching method so as to find out practical and ideal scaffolds for tracheal cartilage tissue engineering.DESIGN: Observational study.SETTING: Department of Otolaryngology, Taihe Hospital, Yunyang Medical College; Department of Otolaryngology, West China Hospital, Sichuan University.MATERIALS The experiment was carried out in Chemical Institute, Chengdu Sub-college of Chinese Academy of Sciences from March to May 2002. Poly-D, L-lactic acid (PDLLA, Mr= 4.23×104) and sodium chloride granules (50-200 μm in diameter) were used as porogenic agent.METHODS: PDLLA was dissolved in chloroform in spherical-shape glass container to dispend 100 g/L solution and then add with sodium chloride granules (50-200 μm) based on various mass fractions of 800, 850, 900, 920, 940 and 960 g/L. Sodium chloride granules were regarded as porogenic agent (scaffolds numbered from 1 to 6) to stir and make paste suspension. Continuously, suspension was cast into tube models, heated at 90 ℃, compressed,and maintained in ventilation cabinet for 48 hours for solvent volatilization. And the resting solvent was drawn out.Form-fitting drying tube foam scaffolds were taken out and dipped in double distilled water for 48 hours so as to remove sodium chloride. The double distilled water was changed every 8 hours. Then, all tube materials were dried in vacuum drying oven for 24-48 hours. While, three-dimensional PDLLA scaffolds were successfully established.Form and intensity of scaffolds were observed with gross and scanning electron microscope; meanwhile, pore parameter was measured and analyzed.MAIN OUTCOME MEASURES: ①Gross observation of tube foam scaffolds;② measurement of pore parameters.RESULTS: ①Scaffolds were appeared as white tube foam with 8 mm in internal diameter and 12 mm in outside diameter.Scaffolds with 80-250 μm in bore and 90.6% in porosity had defined strength and ductility. ②Scanning electron microscope demonstrated that there were many holes distributed in PDLLA scaffolds in various sizes. Otherwise, hole of scaffolds was connected to each other, while big hole also contained numerous small holes. ③Porosity of scaffolds increased with the increasing mass fraction of sodium chloride; but effective porosity did not increase with the increasing mass fraction of sodium chloride. There were different effective porosities of bore (80-250 μm). Effective bore of number 4 sample was 76% and relative porosity was 90.6%. Therefore, number 4 sample was an ideal scaffold for tracheal cartilage tissue engineering.CONCLUSION: Tube foam scaffold fabricated by solvent casting/particulate leaching method is suitable for tracheal cartilage tissue engineering.