Okada Kiyoshi, Hasegawa Fumikazu, Kameshima Yoshikazu, Nakajima Akira
Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, O-okayama, Meguro, Tokyo 152-8552, Japan.
J Mater Sci Mater Med. 2007 Aug;18(8):1605-12. doi: 10.1007/s10856-007-3059-9.
Mixing bioactive ceramic powders with polymers is an effective method for generating bioactivity to the polymer-matrix composites but it is necessary to incorporate up to 40 vol% of bioactive ceramic powder. However, such a high mixing ratio offsets the advantages of the flexibility and formability of polymer matrix and it would be highly advantageous to lower the mixing ratio. Since surface loading of ceramic powders in the polymer is thought to be an effective way of reducing the mixing ratio of the ceramic powder while maintaining bioactive activity, CaSiO(3)/poly-lactic acid (PLA) composites were prepared by three methods; (1) casting, (2) spin coating and (3) hot pressing. In methods (1) and (2), a suspension was prepared by dissolving PLA in chloroform and dispersing CaSiO(3) powder in it. The suspension was cast and dried to form a film in the case of method (1) while it was spin-coated on a PLA substrate in method (2). In method (3), CaSiO(3) powder was surface loaded on to a PLA substrate by hot-pressing. The bioactivity of these samples was investigated in vitro using simulated body fluid (SBF). Apatite formation was not observed in the samples prepared by method (1) but some apatite formation was achieved by mixing polyethylene glycol (PEG) with the PLA, producing a porous polymer matrix. In method (2), apatite was clearly observed after soaking for 7 days. Enhanced apatite formation was observed in method (3), the thickness of the resulting apatite layers becoming about 20 microm after soaking for 14 days. Since the amount of CaSiO(3) powder used in these samples was only < or =0.4 vol%, it is concluded that this preparation method is very effective in generating bioactivity in polymer-matrix composites by loading with only very small amounts of ceramic powder.
将生物活性陶瓷粉末与聚合物混合是赋予聚合物基复合材料生物活性的有效方法，但需要加入高达40体积%的生物活性陶瓷粉末。然而，如此高的混合比例抵消了聚合物基体柔韧性和可成型性的优势，降低混合比例将非常有利。由于在聚合物中对陶瓷粉末进行表面负载被认为是在保持生物活性的同时降低陶瓷粉末混合比例的有效方法，因此通过三种方法制备了CaSiO₃/聚乳酸（PLA）复合材料；（1）浇铸法，（2）旋涂法和（3）热压法。在方法（1）和（2）中，通过将PLA溶解在氯仿中并在其中分散CaSiO₃粉末来制备悬浮液。在方法（1）中，将悬浮液浇铸并干燥以形成薄膜，而在方法（2）中，将其旋涂在PLA基材上。在方法（3）中，通过热压将CaSiO₃粉末表面负载到PLA基材上。使用模拟体液（SBF）在体外研究了这些样品的生物活性。在通过方法（1）制备的样品中未观察到磷灰石形成，但通过将聚乙二醇（PEG）与PLA混合制备出多孔聚合物基体，实现了一定程度的磷灰石形成。在方法（2）中，浸泡7天后清晰观察到磷灰石。在方法（3）中观察到增强的磷灰石形成，浸泡14天后形成的磷灰石层厚度约为20微米。由于这些样品中使用的CaSiO₃粉末量仅≤0.4体积%，可以得出结论，这种制备方法通过仅负载极少量的陶瓷粉末就能非常有效地在聚合物基复合材料中产生生物活性。
