Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH 43606, USA.
Mater Sci Eng C Mater Biol Appl. 2013 Oct;33(7):4288-94. doi: 10.1016/j.msec.2013.06.034. Epub 2013 Jun 28.
There are two interesting features of this paper. First, we report herein a novel microwave assisted technique to prepare phosphate based orthopedic cements, which do not generate any exothermicity during setting. The exothermic reactions during the setting of phosphate cements can cause tissue damage during the administration of injectable compositions and hence a solution to the problem is sought via microwave processing. This solution through microwave exposure is based on a phenomenon that microwave irradiation can remove all water molecules from the alkaline earth phosphate cement paste to temporarily stop the setting reaction while preserving the active precursor phase in the formulation. The setting reaction can be initiated a second time by adding aqueous medium, but without any exothermicity. Second, a special emphasis is placed on using this technique to synthesize magnesium phosphate cements for orthopedic applications with their enhanced mechanical properties and possible uses as drug and protein delivery vehicles. The as-synthesized cements were evaluated for the occurrences of exothermic reactions, setting times, presence of Mg-phosphate phases, compressive strength levels, microstructural features before and after soaking in (simulated body fluid) SBF, and in vitro cytocompatibility responses. The major results show that exposure to microwaves solves the exothermicity problem, while simultaneously improving the mechanical performance of hardened cements and reducing the setting times. As expected, the cements are also found to be cytocompatible. Finally, it is observed that this process can be applied to calcium phosphate cements system (CPCs) as well. Based on the results, this microwave exposure provides a novel technique for the processing of injectable phosphate bone cement compositions.
本文有两个有趣的特点。首先，我们在此报告了一种新颖的微波辅助技术来制备磷酸盐基骨科水泥，该水泥在凝固过程中不会产生任何放热反应。磷酸钙水泥凝固过程中的放热反应会在注射组合物给药过程中引起组织损伤，因此通过微波处理来寻求解决方案。通过微波处理的解决方案基于这样一种现象，即微波辐射可以从碱性磷酸钙水泥浆中除去所有水分子，从而暂时停止凝固反应，同时保持配方中的活性前体相。可以通过添加水介质再次引发凝固反应，但不会产生任何放热反应。其次，特别强调了使用该技术来合成用于骨科应用的磷酸镁水泥，以提高其机械性能，并可能用作药物和蛋白质输送载体。对合成的水泥进行了放热反应、凝固时间、Mg-磷酸盐相的存在、抗压强度水平、在（模拟体液）SBF 中浸泡前后的微观结构特征以及体外细胞相容性反应的评估。主要结果表明，暴露于微波可以解决放热问题，同时提高了硬化水泥的机械性能并缩短了凝固时间。正如预期的那样，水泥也被发现具有细胞相容性。最后，观察到该工艺也可应用于磷酸钙骨水泥体系（CPCs）。基于这些结果，这种微波暴露为可注射性磷酸盐骨水泥组合物的处理提供了一种新的技术。
