Modelling composition-solubility relationships in bio-active phosphate glasses

用于组织替代的生物相容性材料的制造是生物医学和组织工程研究领域的中心主题。骨移植材料的天然来源受到可用性和成本的影响，无论是来自个体患者的自体移植物还是来自其他供体的同种异体移植物。“第三代”生物活性植入材料在组织再生中发挥积极作用，并在组织愈合后降解，在许多临床应用中取得了显著成功，特别是在牙科和骨科领域。在第三代生物医学材料中，基于磷酸盐的生物活性玻璃（PBG）由于其独特的性质而变得越来越受欢迎：（i）其组成与周围组织化学相关;（ii）其在水性介质中完全溶解;（iii）其溶解速率可以通过改变磷酸盐-钠-钙玻璃的组成来控制。PBG的溶解度可以说是它们在生物医学应用中最重要的特性，因此可以定制以适合最终应用。由于玻璃的溶解度与其原子级结构有关，因此深入了解分子水平上的P2 O 5网络结构;不同浓度的钙和钠以及其他阳离子对网络的影响;以及主要的表面和溶解过程，对于设计用于组织工程的磷酸盐玻璃组合物具有根本意义。然而，在这些材料的研究中，通常与它们的非晶性质有关的一个共同问题是缺乏关于玻璃的微观结构以及这种结构如何受到构成玻璃组合物的不同离子的影响的详细信息。因此，这项研究提案的目的是开发强大的模型，以提供定量的洞察力，在原子水平上的结构，物理化学性质和溶解度的范围内的磷酸盐为基础的微晶玻璃作为其组成的函数。

The manufacture of biocompatible materials for tissue replacement is a central theme in the fields of biomedicine and tissue engineering research. Natural sources of bone graft material are compromised by availability and cost, both from the individual patient as autograft and from other donors as allograft. "Third generation" bioactive implant materials, which play an active role in tissue regeneration and degrade after the tissue has healed, have been remarkably successful in many clinical applications, especially in dental and orthopaedic fields. Among the third-generation biomedical materials, phosphate-based bio-active glasses (PBGs) are becoming increasingly popular owing to their unique properties: (i) their composition is chemically related to the surrounding tissue; (ii) they dissolve completely in aqueous media; (iii) their dissolution rate can be controlled by changing the composition of the phosphate-sodium-calcium glass. The solubility of the PBGs, which is arguably their most important property to be exploited in biomedical applications, can thus be tailored to suit the end application. As the solubility of a glass is linked to its atomic-level structure, insight into the P2O5 network structure at the molecular level; the effect of varying concentrations of calcium and sodium and other cations on the network; and the dominant surface and dissolution processes, are of fundamental interest to the design of phosphate glass compositions for applications in tissue engineering. However, a common problem in the investigation of these materials, generally related to their amorphous nature, is the lack of detailed information on the microscopic structure of the glasses and how this structure is affected by the different ions making up the glass composition. This research proposal therefore aims to develop robust models to provide quantitative insight at the atomic level into the structures, physico-chemical properties and solubilities of a range of phosphate-based bioglasses as a function of their composition.