Chemical Modification As a Versatile Tool for Tuning Stability of Silica Based Mesoporous Carriers in Biologically Relevant Conditions
Chemical Modification As a Versatile Tool for Tuning Stability of Silica Based Mesoporous Carriers in Biologically Relevant Conditions
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DOI：
10.1021/cm302142k
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发表时间：
2012-11-27
影响因子：
8.6
通讯作者：
Boissiere, Cedric
中科院分区：
文献类型：
--
作者：
Fontecave, Thomas;Sanchez, Clement;Boissiere, Cedric
本文报道了介孔氧化硅-氧化锆混合材料和杂化有机硅材料在模型磷酸盐缓冲盐水（PBS）介质中的降解比较研究，并讨论了它们的热力学和动力学稳定性。首次利用薄膜形态学直接监测了这些材料在液体和欠饱和介质中的降解率。介孔材料中锆中心的引入强烈地抑制了降解，并允许在载体的直接环境中对可溶性二氧化硅浓度进行自我限制。这避免了在释放介质中具有不受控制的表面化学的潜在有毒二氧化硅小纳米颗粒的再核。介孔二氧化硅的化学修饰（杂化或氧化锆掺杂）允许从数小时到数天对其降解进行微调。当功能化率高（50%）时，甲基化薄膜具有很高的稳定性。巯基丙基和氨基丙基的杂化可以在没有任何高温处理的情况下成功进行，不仅可以减缓二氧化硅的溶解，而且可以在一个锅中引入其他热脆弱分子到载体中。首次测定的不同生物相关温度下的溶出速率K遵循阿伦尼乌斯定律：K = K(0)Exp（-E-a/RT）。这些化学改性二氧化硅的稳定性主要与改性二氧化硅指数前因子K-0的显著降低有关。与直觉相反，活化能E-a随着杂化/二氧化硅或氧化锆/二氧化硅比例的增加而降低。
A comparative study of the degradation in a model phosphate buffered saline (PBS) medium of mesoporous mixed silica-zirconia oxides and hybrid organosilica materials is reported, and their thermodynamic and kinetic stability are discussed. Thin film morphology was used to monitor the degradation rates of all these materials for the first time directly in liquid and undersaturated medium. The introduction of zirconium centers in mesoporous materials strongly inhibits degradation and allowed the self-limitation of soluble silica concentration in the immediate environment of the vector. This avoids renucleation of potentially toxic silica small nanoparticles with uncontrolled surface chemistry in the release medium. Chemical modifications (hybridation or zirconia doping) of mesoporous silica allow the fine-tuning of its degradation from hours to days. Methylated thin films are highly stable when the functionalization ratio is high (50%). The hybridation by mercaptopropyl and aminopropyl moieties can be successfully performed without any high thermal treatment, allowing not only slowing down silica dissolution but also opening the possibility to introduce in one-pot other thermally fragile molecules into the vector. Dissolution rates K measured for the first time at different biologically relevant temperatures follows an Arrhenius law: K = K(o)Exp(-E-a/RT). Stabilities of these chemically modified silicas are mainly associated with a strong decrease of the pre-exponential factor K-0 of modified silicas. Counterintuitively, activation energies E-a decrease with increasing the hybrid/silica or the zirconia/silica ratios.