超声波在水凝中增强扩散:一种实验性和非平衡分子动力学研究
Sebastian E N Price1, Caroline Einen2, Othonas A Moultos3
1PoreLab and Department of Chemistry, The Norwegian University of Science and Technology, NTNU, N7491 Trondheim, Norway.
The Journal of chemical physics
|April 19, 2024
概括
聚焦超声波增强了水凝中的纳米粒子扩散. 实验和分子动力学模拟都显示了粒子运动的增加,粒子速度是这种超声波增强扩散的关键因素.
科学领域:
- 生物物理学的生物物理.
- 材料科学 材料科学 材料科学
- 声学工程 声学工程
背景情况:
- 已知聚焦超声波可以增强纳米粒子扩散.
- 了解这种现象对于有针对性的药物输送和医学成像至关重要.
- 之前的研究表明扩散增强,但潜在的机制需要进一步研究.
研究的目的:
- 为了研究聚焦超声波对水凝中纳米粒子扩散的影响.
- 将实验结果与非平衡分子动力学 (NEMD) 模拟进行比较.
- 为了确定超声波增强扩散的频率和振幅依赖.
主要方法:
- 用40nm和100nm聚乙烯纳米粒子在糖水凝中的单颗粒追踪实验.
- 开发一个粗粒度的NEMD模型,使用振荡的外部力场模拟聚焦超声波.
- 将实验结果与模拟数据和理论扩散方程进行比较.
主要成果:
- 聚焦超声波显著增加了水凝中纳米粒子的平均平方位移 (MSD).
- NEMD模拟重现了实验性MSD趋势,突出了粒子速度的作用.
- 该模型显示频率依赖与两次连续时间随机步行 (CTRW) 模型相匹配.
- 在高超声强度下,扩散系数接近非受阻扩散系数.
结论:
- 聚焦超声波有效地增强了水凝中的纳米粒子扩散.
- 粒子速度是超声波增强扩散的一个重要因素.
- 开发的NEMD模型准确地捕获了观察到的扩散行为.
- 不受阻扩散系数适用于水凝中的高超声强度.
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