Development of hybrid matrices for bone tissue engineering scaffolds

本研究的目的是制备用于骨再生的新型生物可吸收基质。以聚乳酸（PLA）和碳酸钙（vaterite）为原料，通过热压法制备了一种在模拟体液（SBF）中具有良好磷灰石形成能力的新型陶瓷-聚合物生物材料。复合材料中含有30%的水晶石，无脆性断裂行为，抗弯强度高达~ 50 MPa。在37℃的SBF中浸泡1天后，其表面形成数微米厚的磷灰石层。破骨细胞培养试验表明，磷灰石包覆的复合材料具有良好的生物可吸收性。人成骨细胞孵育后，表面可见矿化骨结节形成。海绵由复合骨架组成，表面涂有骨状羟基碳酸盐磷灰石（HCA），通过颗粒浸出技术与仿生处理相结合得到。将碳酸钙/聚乳酸复合材料（CCPC）与蔗糖通过热压形成的致密体浸泡在37℃的模拟体液中。在最初的1 h内，蔗糖完全溶解出来，在致密体中形成了较大的孔隙，随后，浸泡3天后，在由CCPC组成的骨架上形成了骨状的HCA。形成的海绵具有许多直径约500 μm的大孔隙，这些孔隙与直径约100 μm的通道相连，孔隙率高达75% .3。用CCPC制备了含细胞骨填充物（细胞递送系统）的空心球体。利用化学蚀刻法可以很容易地形成一个直径约800 μm的开放通道，从而提供了通往球体内部的通道。细胞可以通过开放的通道迁移到球体内部。

The objective in the present research is to prepare new types of biodresorbable matrices for bone regeneration.1.Anew type of ceramic-polymer biomaterial having excellent apatite-forming ability in simulated body fluid(SBF) was prepared by hot-pressing a mixture consisting of poly (-L-lactic acid)(PLA) and calcium carbonate (vaterite). The composite containing 30% vaterite showed no brittle fracture behavior and comparably high bending strength of 〜50 MPa. Apatite layer of several micrometers in thickness formed on its surface after soaking in SBF at 37℃ only for 1 day. Osteoclast culture tests showed that the composite coated with apatite has excellent bioresorbability. After incubation of human osteoblasts, mineralized bone nodule formation was seen on the surface.2.A sponge consisting of the composite skeleton, coated with bonelike hydroxycarbonate apatite(HCA) on its surface, was derived via a particle-leaching technique combined with a biomimetic processing. A compact consisting of calcium carbonate/poly(lactic acid) composite(CCPC) and sucrose formed by hot-pressing, was soaked in the simulated body fluid at 37℃. Within initial 1 h, the sucrose was completely dissolved out, resulting in the formation of large-sized pores in the compact, and subsequently, after 3 days of soaking, bonelike HCA formed on the skeleton consisting of CCPC. The formed sponge has numerous, large pores of 〜500 μm in diameter, which are connected with channels having a diameter of 〜100 μm, as well as a high porosity of 75 %.3.Hollow spheres for bone fillers incorporating cells (cell-delivery system) were prepared using CCPC. An open channel of 〜800 μm in diameter was easily formed using a chemical etching method to provide a pathway to the interior of the sphere. Cells could migrate through the open channel into the interior of the sphere.