可控多孔结构支架制备及灌注式体外培养

利用CAD和快速成形技术设计制造具有可控多孔结构的支架。构建灌注式生物反应器系统，实现氧气和营养物质的大量输送，同时产生一定流体剪应力，调节细胞功能的发挥。根据支架负型结构制造出相应的树脂原型，用磷酸钙骨水泥进行填充烧结，得到与设计相符的多孔支架。接种兔成骨细胞，分别采用静态和灌注式三维动态培养方法，观察不同培养条件下细胞在支架表面以及所构造微管道内的生长情况。试验结果表明，灌注式体外培养方法更有利于细胞在支架微管道内的存活和功能的发挥，此灌注式系统能够改善支架微管道内细胞生存的微环境，增强黏附在支架微管道内细胞的活性，促进细胞进一步的增殖和矿化基质的产生。

Fabrication of Scaffold with Controlled Porous Structure and Flow Perfusion Culture in vitro

3D Scaffolds with controlled porous structure were designed and fabricated by utilizing CAD and rapid prototyping techniques. A flow perfusion bioreactor, which allowed exposure of the culture cells to low levels of mechanical stimulation by fluid flow-induced shear stress, was developed in our lab. The scaffolds were pre-designed and the negative images of the designs were used to build the molds on a stereolithography (SL) apparatus with epoxy resins. Calcium phosphate cement paste was cast into the molds. And after pyrolysis, the 3D scaffolds with controlled internal pore architectures were obtained. Rabbit osteoblasts were seeded in 3D porous scaffolds, cultured in the flow perfusion bioreactor with media flow rate set at 2 mL/min and 6-well plates. At 3, 7, and 14 days, scanning microscopic evaluation showed excellent growth on the surface of scaffolds and poor viability of cells within microchannels in static cultures. In flow perfusion bioreactor, there was greater cellularity throughout the scaffolds and abundant deposition of extracellular matrix. Cells were also seen throughout the internal microchannels of scaffolds. These results represent that better mass transport of oxygen and nutrient occurred in the flow perfusion bioreactor and cells distribution in 3D porous scaffolds was improved.