低温快速成型个性化组织工程活性支架的制备及性能分析

Manufacture and property analysis of individual active tissue engineering scaffolds by low-temperature rapid prototyping technology

目的:以PLGA/TCP为原料应用低温冰型快速成型技术制备山羊颅骨缺损模型的个性化组织工程支架,复合rhBMP-2,分析其性能。方法:制造山羊颅骨缺损模型,三维CT重建,获取NET运行控制文件。将PLGA与TCP按7∶3的比例配成匀浆,加入低温快速成型机。在NET文件的指导下挤出三维PLGA/TCP支架,经冷冻干燥,进行净化、消毒后,负压抽吸复合rhBMP-2形成活性支架。对活性支架孔隙率测定、电镜扫描、力学性能分析。结果:体温快速成型制备的PLGA/TCP支架材料圆形略有弧度,与颅骨缺损模型的形态非常吻合。支架结构的孔隙率为89.6%。扫描电镜观察材料密布大孔及微孔结构,大孔平均360μm,微孔为3～5μm,孔间相互贯通。复合rhBMP-2的PLGA/TCP支架在大孔及微孔中都吸附着大量微粒。支架材料的抗压强度0.68MPa,弹性模量17.87MPa。结论:低温快速成型制造的PLGA/TCP个性化支架属仿生设计,孔隙率符合人工骨支架的生理要求,生物力学强度略低于人松质骨,但强度不影响植入手术。负压抽吸法促进rhBMP-2与支架的充分复合制备成活性支架。

Objective To manufacture individual PLGA/TCP porous scaffolds by low-temperature deposition rapid prototyping technology according to the model of calvarial critical defect in a goat cranial bone and to load the PLGA/TCP scaffolds with rhBMP-2. To analyze the scaffolds＇ natures. Methods To make a critical defect in goat cranial bone and get NET files from CT scan data of critical defect. To infuse the mixture of PLGA and TCP （7：3） into low-temperature rapid prototyping machine and the machine guided by NET files manufactured individual PLGA/TCP porous scaffolds which then were cryodesiccated, cleaned, sterilized and loaded with rhBMP-2 to conform active scaffolds. The factor of porosity of the scaffold was measured. The micro structure of the scaffold was observed with electron microscope and the mechanics property of the scaffold was analyzed. Results The shape of individual PLGA/TCP porous scaffolds manufactured by low-temperature deposition rapid prototyping technology is very similar to the model of goat calvarial critical defect. The factor of porosity of the scaffold is 89.6%. The PLGA/TCP scaffolds has controlled microstructure and porosity with 360μm diameter mini-holes, 3-5μm diameter micro-holes. These holes are connected with each other. RhBMP-2 particles are evenly loaded in all mini and micro holes. The crushing strength of the scaffold is 0.68MPa and the elastic modulus of the scaffolds is 17.87MPa. Conclution The design of low-temperature deposition rapid proto- typing technology is bionic design. The individual scaffolds have appropriate factor of porosity. Although the vitodynam-ics strength of the scaffolds is less than human cancellous bones, it still meets the requires of implant operation. Negative pressure suction can facilitate rhBMP-2 evenly dispersed in scaffolds to conform active scaffolds.