PAMAM树枝状体经历pH响应的形状变化而没有胀.
Yi Liu1, Vyacheslav S Bryantsev, Mamadou S Diallo
1Materials and Process Simulation Center (M/C 139-74), California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.
Journal of the American Chemical Society
|February 10, 2009
概括
原子学分子动力学模拟显示,聚胺胺 (PAMAM) 树枝状体会随着pH的变化而发生显著的构造变化. 这种由pH触发的从密集的核心到密集的外结构的转变可以提高它们作为药物输送载体的实用性.
科学领域:
- 计算化学是一种计算化学.
- 材料科学是一种材料科学.
- 纳米技术 纳米技术
背景情况:
- 聚胺胺 (PAMAM) 树突体是高度分支的大分子,在药物输送中具有潜在的应用.
- 了解它们在溶液中的构造性行为对于优化它们的功能至关重要.
- 以前的研究表明pH值依赖的结构变化,但缺少原子细节.
研究的目的:
- 使用原子分子动力学 (MD) 模拟来研究G4-NH(2) PAMAM树状体的pH依赖性构造变化.
- 将模拟预测与小角度中子散射 (SANS) 的实验数据进行比较.
- 阐明pH触发封装和释放客分子的结构基础.
主要方法:
- 原子分子动力学 (MD) 模拟在水溶液中的G4-NH(2) PAMAM树状体上进行.
- 在模拟中包含了明确的水分子和 counterions.
- 使用了使用量子力学的优化Dreiding III力场.
主要成果:
- 模拟预测了大约5到10的pH范围内的树枝状体旋转半径 (R(g)) 的最小变化.
- R (g) 从pH10到pH5的21.1 Å变化到pH5的22.1 Å,与实验SANS数据 (21.4 Å到21.5 Å) 一致.
- 尽管R ((g) 变化很小,但观察到一个显著的形状变化:由于离子配对,在高pH时有一个密集的核心,在低pH时有一个密集的外.
结论:
- PAMAM树突体表现出显著的pH诱导的构造变化,从"密集的核心"过渡到"密集的外"结构.
- 这种pH触发的结构转变,特别是低pH时形成密集的外,可以促进客分子的封装和释放.
- 登德里默表现出作为可调节的药物输送载体的承诺,pH值作为有效的触发机制.
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