Background and objective: Nanoparticle-mediated targeted drug delivery is a promising option for treatment of atherosclerosis. However, the drug targeting may be affected by multiple factors. Considerable attentions have been focused on the influences of external factors, e.g., magnetic field, drug-loaded particle, but internal factors, e.g., plaque morphology (stenosis degree and shoulder length), have not received any attention yet. Therefore, we investigate the impact of plaque morphology on magnetic nanoparticles targeting under the action of an external field. Method: Numerical simulation, based on Eulerian-Lagrangian coupled Fluid-Solid Interaction, is performed in ANSYS Workbench platform. Blood flow is solved by Navier-Stokes equation, particles are tracked by discrete phase model, and the incorporated effect is obtained by two-way method. Plaques with varying stenosis degrees and shoulder lengths are acquired by manually modifying the geometry of patient-specific. The quantified variables include targeted delivery efficiency (deposition+adhesive strength) of particles and plaque injury characterized by temporal-spatial averaged shear stress ($\overline{\text{TAWSS}}$) during the process of drug transport, in which the critical deposition velocity is determined by plaques and particles, the DEFINE$\_$DPM$\_$BC and User Defined Memory are employed to evaluate whether the particles are deposited, and to store the total number and the adhesive strength of particles deposited on the plaque. Results: Results signify that, with an increment of plaque stenosis degree, the deposition of particle and the adhesive strength between particle and plaque decrease, while the $\overline{\text{TAWSS}}$ increases. Furthermore, for the same stenosis degree, with the increase of plaque shoulder length, the deposition and the adhesive strength of particle increase, and the $\overline{\text{TAWSS}}$ decreases. Conclusions: Results demonstrates that the plaque with smaller stenosis degree or longer shoulder length may achieve a better treatment effect in view of the higher targeted delivery efficiency of particles and the lighter shear damage to plaque itself during the process of drug transport.

背景与目的：纳米粒子介导的靶向药物递送是治疗动脉粥样硬化的有前途的选择。但是，药物靶向可能会受到多种因素的影响。相当多的注意力集中在外部因素（例如磁场，载药颗粒）的影响上，但是内部因素（例如斑块形态（狭窄程度和肩长））尚未受到任何关注。因此，我们调查斑块形态对磁性纳米粒子在外场作用下的影响。方法：在ANSYS Workbench平台上进行了基于欧拉-拉格朗日耦合的流固耦合的数值模拟。用Navier-Stokes方程求解血流，用离散相模型跟踪颗粒，并通过双向方法获得结合效果。通过手动修改患者特定的几何形状，可以获得狭窄程度和肩部长度不同的斑块。量化变量包括目标颗粒的递送效率（沉积+粘附强度）和斑块损伤，斑块损伤的特征在于时空平均剪切应力（$\overline{\text{任务}}$），在药物运输过程中，临界沉积速度由噬菌斑和颗粒决定，DEFINE$\_$DPM$\_$BC和用户定义的内存用于评估是否沉积了颗粒，并存储了沉积在菌斑上的颗粒的总数和粘合强度。结果：结果表明，随着斑块狭窄程度的增加，颗粒的沉积以及颗粒与斑块之间的粘附强度降低，而$\overline{\text{任务}}$增加。此外，对于相同的狭窄程度，随着斑块肩长的增加，颗粒的沉积和粘附强度也会增加，并且$\overline{\text{任务}}$减少。结论：结果表明，考虑到更高的颗粒靶向递送效率和在药物运输过程中对斑块本身的剪切损伤较轻，狭窄程度较小或肩长较长的斑块可达到更好的治疗效果。