Lin Li-Chun, Chang Shwu-Jen, Kuo Shyh Ming, Chen Shu Fen, Kuo Chia Hung
Orthopedic Department, Veteran General Hospital, Kaohsiung, Taiwan.
J Mater Sci Mater Med. 2005 Jun;16(6):567-74. doi: 10.1007/s10856-005-0533-0.
Two methods, a traditional emulsion technique and a high voltage electrostatically modified encapsulation system, were used to fabricate degradable chitosan/beta -tricalcium phosphate (beta-TCP) microspheres. The two distinct kinds of microspheres both exhibited good sphericity and the beta-TCP was trapped well inside the chitosan gel. The microspheres prepared by high voltage electrostatic system exhibited a rougher outer surface and narrower size distribution. These microspheres were then used as an added constituent to commercially available PMMA bone cement. Four modified cement composites that were prepared with different composition ratios of the two kinds of chitosan/beta-TCP microspheres that were made from emulsion technique (C1P1 and C2P1) and from a process by a high voltage electrostatic system (EC1P1 and EC2P1) were compared with the PMMA cement (Pure P). The characteristics of these materials indicate that with the addition of chitosan/beta-TCP microspheres as a constituent into the PMMA cement significantly decreases the curing peak temperature. Furthermore, the setting time increases from 3.5 min to 9 min, as compared to the PMMA cement. These changes could be beneficial for the handling of the bone cement paste and causing less damage to the surrounding tissues. Understandably, the presence of chitosan/beta-TCP microspheres in the prepared composites reduced the ultimate compressive strength and bending strength. From the degradation test and SEM observations, the modified chitosan/beta -TCP/PMMA composites could be degraded gradually and create rougher surfaces that would be beneficial to cell adherence and growth.
采用两种方法制备可降解壳聚糖/β-磷酸三钙（β-TCP）微球，分别是传统乳液技术和高压静电改性封装系统。两种不同类型的微球均呈现出良好的球形度，且β-TCP被良好地包裹在壳聚糖凝胶内部。通过高压静电系统制备的微球表面更粗糙，粒径分布更窄。然后将这些微球用作市售聚甲基丙烯酸甲酯（PMMA）骨水泥的添加成分。将由乳液技术制备的两种壳聚糖/β-TCP微球（C1P1和C2P1）以及由高压静电系统制备的两种壳聚糖/β-TCP微球（EC1P1和EC2P1）按不同组成比例制备的四种改性水泥复合材料与PMMA骨水泥（纯P）进行比较。这些材料的特性表明，在PMMA骨水泥中添加壳聚糖/β-TCP微球作为成分可显著降低固化峰值温度。此外，与PMMA骨水泥相比，凝固时间从3.5分钟增加到9分钟。这些变化可能有利于骨水泥糊剂的操作，并对周围组织造成更少的损伤。可以理解的是，制备的复合材料中壳聚糖/β-TCP微球的存在降低了极限抗压强度和抗弯强度。从降解试验和扫描电子显微镜观察结果来看，改性壳聚糖/β-TCP/PMMA复合材料可逐渐降解，并产生更粗糙的表面，这将有利于细胞黏附和生长。
