Aluminosilicate Glasses As Yttrium Vectors for in situ Radiotherapy: Understanding Composition-Durability Effects through Molecular Dynamics Simulations
Aluminosilicate Glasses As Yttrium Vectors for in situ Radiotherapy: Understanding Composition-Durability Effects through Molecular Dynamics Simulations
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DOI：
10.1021/cm100847p
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发表时间：
2010-06-22
影响因子：
8.6
通讯作者：
Tilocca, Antonio
中科院分区：
文献类型：
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作者：
Christie, Jamieson K.;Tilocca, Antonio
Y铝硅酸盐(YAS)玻璃作为放射治疗载体的使用受到玻璃在生理介质中的耐久性的严重影响。为了在原子水平上了解玻璃成分、结构和耐久性之间的关系，WC对两种不同耐久性的YAS成分进行了经典的分子动力学(MD)模拟。对MD轨迹的分析表明，高Y(2O)O(3)浓度下的耐久性能较差是由于玻璃网络连接性降低和Y团簇减少的共同作用。增加Y含量增加了所有原子物种的配位数，使更大范围的原子环境成为可能，并减少了网络连接，特别是与硅有关的网络连接。铝离子表现出强烈的自聚集性，可以形成额外的Al-O-Al键，以平衡高Y(2)O(3)组分中减少的Si网络形成者的数量：这导致了一些高度连接的铝原子，其特征是在相应的分布中出现了大的-nQ(N)(Al)物种。只有在更耐用的低Y(2)O(3)组分中才存在显著的Y聚集，这表明修饰剂离子的聚集可以进一步提高玻璃的耐久性，这与以前的生物活性玻璃的结果一致。(Tilocca等人)化学。马特。2007、19、95。)
The use of yttrium aluminosilicate (YAS) glasses as vectors for radiotherapy is critically affected by the glass durability in a physiological medium. To understand the relation between glass composition, structure, and durability at an atomistic level, WC have carried out classical molecular dynamics (MD) simulations of two YAS compositions with different durability. The analysis of the MD trajectories shows that the lower durability at high Y(2)O(3) concentration is due to the combined effect of lower connectivity of the glass network and reduced yttrium clustering. Increasing the yttrium content increased the coordination numbers of all atomic species, made possible a greater range of atomic environments, and reduced the network connectivity, particularly related to silicon. Aluminum ions show a strong tendency to self-aggregate, and can form additional Al-O-Al linkages to balance the reduced number of Si network-formers in the high Y(2)O(3) composition: this leads to some very highly connected aluminum atoms, characterized by the appearance of large-n Q(n)(Al) species in the corresponding distribution. The presence of significant yttrium clustering only in the more durable, low Y(2)O(3) composition denotes that clustering of modifier ions can further enhance the glass durability, in agreement with previous results for bioactive glasses. (Tilocca et al. Chem. Mater. 2007, 19, 95.)