Tan Jifu, Shah Samar, Thomas Antony, Ou-Yang H Daniel, Liu Yaling
Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18015, USA.
Microfluid Nanofluidics. 2013 Jan 1;14(1-2):77-87. doi: 10.1007/s10404-012-1024-5. Epub 2012 Jul 12.
Nanoparticles (NPs) are emerging as promising carrier platforms for targeted drug delivery and imaging probes. To evaluate the delivery efficiency, it is important to predict the distribution of NPs within blood vessels. NP size, shape and vessel geometry are believed to influence its biodistribution in circulation. Whereas, the effect of size on nanoparticle distribution has been extensively studied, little is known about the shape and vessel geometry effect. This paper describes a computational model for NP transport and distribution in a mimetic branched blood vessel using combined NP Brownian dynamics and continuum fluid mechanics approaches. The simulation results indicate that NPs with smaller size and rod shape have higher binding capabilities as a result of smaller drag force and larger contact area. The binding dynamics of rod-shaped NPs is found to be dependent on their initial contact points and orientations to the wall. Higher concentration of NPs is observed in the bifurcation area compared to the straight section of the branched vessel. Moreover, it is found that Péclet number plays an important role in determining the fraction of NPs deposited in the branched region and the straight section. Simulation results also indicate that NP binding decreases with increased shear rate. Dynamic NP re-distribution from low to high shear rates is observed due to the non-uniform shear stress distribution over the branched channel. This study would provide valuable information for NP distribution in a complex vascular network.
纳米颗粒（NPs）正成为用于靶向药物递送和成像探针的有前景的载体平台。为了评估递送效率，预测纳米颗粒在血管内的分布很重要。纳米颗粒的大小、形状和血管几何形状被认为会影响其在循环中的生物分布。然而，虽然纳米颗粒大小对其分布的影响已得到广泛研究，但关于形状和血管几何形状的影响却知之甚少。本文描述了一种使用纳米颗粒布朗动力学和连续介质流体力学相结合的方法，用于模拟分支血管中纳米颗粒运输和分布的计算模型。模拟结果表明，由于较小的阻力和较大的接触面积，较小尺寸和棒状的纳米颗粒具有更高的结合能力。发现棒状纳米颗粒的结合动力学取决于它们与壁的初始接触点和取向。与分支血管的直管段相比，在分叉区域观察到更高浓度的纳米颗粒。此外，发现佩克莱数在确定沉积在分支区域和直管段中的纳米颗粒比例方面起着重要作用。模拟结果还表明，纳米颗粒的结合随剪切速率的增加而降低。由于分支通道上剪切应力分布不均匀，观察到纳米颗粒从低剪切速率到高剪切速率的动态重新分布。这项研究将为纳米颗粒在复杂血管网络中的分布提供有价值的信息。
