基于快速成型技术的可控结构多孔硅酸钙支架的制备及体外研究

Fabrication and in vitro evaluation of a novel calcium silicate scaffold with controlled architecture by rapid prototyping

目的利用快速成型技术制备可控结构多孔硅酸钙（rapid prototyping—calcium silicate，RP—CS）支架，并评价其特性和体外生物学表现。方法利用间接快速成型技术，结合固态自由成型和凝胶铸模的优点，制备可控结构RP—CS支架。与采用同法制备的多孔磷酸钙（RP—tricalcium phosphate，RP-TCP）支架相对照，将其置入体外模拟体液（simulated bodyfluid，SBF）、体外骨髓细胞共培养进行研究。结果所制备RP—CS支架具有相互连通的孔道结构，平均孔隙率为71％，平均轴向压缩强度为28MPa，平均孔道直径为（555．82±29．77）μm。体外SBF浸置试验发现RP—CS支架上有羟基磷灰石的沉积，说明此支架具有体外生物活性。体外细胞共培养试验表明，兔骨髓细胞可以在此支架表面贴附并分化。MTT表明共培养7d、14d，细胞增殖RP—CS组均明显高于RP—TCP组（P〈0．05）。共培养7d时，碱性磷酸酶活性RP—CS组明显高于RP-TCP组（P〈0．05），提示CS可能具有促进骨髓细胞向成骨细胞分化的能力。结论利用快速成型技术制备的可控结构RP—CS具有良好的生物相容性，在骨组织工程领域具有广泛应用前景。

Objective To fabricate porous calcium silicate（CS） scaffolds with controlled architecture by rapid prototyping and to evaluate the characterization of scaffolds and cell proliferation and differen- tiation on the prepared scaffolds. Methods The porous calcium silicate scaffolds with controlled architecture was fabricated by indirect rapid prototyping （RP-CS） which has the combined advantages of indirect solid freeform fabrication and gel-casting. Compared with the porous tricalcium phosphate scaffolds fabricated with the same method （RP-TCP）, the obtained RP-CS scaffolds were investigated by simulated body fluid （SBF） immersing test and in vitro incubation with bone marrow cells. Results An average compressive strength of 28 MPa for the RP-CS scaffold with the average total porosity of 71% was achieved. The scaffolds with mean channel diameter of about （555.82±29.77）μm have interconnected maeroporous architecture. The SBF test showed that hydroxyapatite could be found on the surface of RP-CS scaffold indicating its in vitro bioaetivity. The in vitro study showed that the rabbit bone marrow cells attached and proliferated on the surface of the RP-CS scaffolds. MTT tests demonstrated that the cell proliferation was significantly higher on RP-CS scaffolds than on RP-TCP scaffolds at 7 and 14 days （P〈0.05）. Moreover, the alkaline phosphatase （ALP） activities of cells on RP-CS scaffolds were increased as compared to the control at 7 days （P〈0.05）, indicating the capacity in promoting bone marrow cells differentiation into osteogenic ceils. Conclusion The obtained RP-CS scaffold in this study is biocompatible, and has promising future for bone tissue engineering.