Modelling composition-solubility relationships in bio-active phosphate glasses

组织置换用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课题。骨移植材料的自然来源受到可获得性和成本的影响，既来自个体患者作为自体移植，也来自其他捐赠者作为同种异体移植。第三代生物活性植入材料在组织再生和组织愈合后降解方面发挥着积极的作用，在许多临床应用中都取得了显著的成功，特别是在牙科和骨科领域。在第三代生物医学材料中，磷酸盐生物活性玻璃(PBGs)因其独特的性质而越来越受欢迎：(I)其组成与周围组织的化学组成有关；(Ii)它们完全溶解在水介质中；(Iii)它们的溶解速度可以通过改变磷酸盐-钠-钙玻璃的组成来控制。PBG的溶解性可以说是它们在生物医学应用中最重要的特性，因此可以根据最终应用进行定制。由于玻璃的溶解度与其原子级结构有关，深入了解分子水平上的P2O5网络结构；不同浓度的钙、钠和其他阳离子对网络结构的影响；以及主要的表面和溶解过程，对于组织工程中应用的磷酸盐玻璃组合物的设计具有重要意义。然而，在对这些材料的研究中，一个共同的问题是缺乏关于玻璃微观结构的详细信息，以及组成玻璃成分的不同离子如何影响这种结构。因此，这项研究建议旨在开发可靠的模型，以在原子水平上提供对一系列磷酸盐生物玻璃的结构、物理化学性质和溶解度的定量洞察，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.