The dynamics of bio-conjugated magnetic nanoparticles suspended in buffer-saline solutions containing target proteins (i.e., analytes) is investigated numerically on a mesoscopic level. To simulate the dispersion of magnetic nanoparticles the dissipative particle dynamics is employed, which allows to study rather large systems, while still retaining important microscopic nanoparticle properties. In addition, the method is coupled to the Landau–Lifshitz–Gilbert equation, describing the dynamics of the magnetic nanocrystals within the macrospin approximation. The binding of multivalent analytes to the recognition ligands of the nanoparticles leads to the formation of clusters of magnetic nanoparticles, which in turn drastically changes the macroscopic magnetic response of the solution. Such colloidal changes are experimentally observable, allowing to explore new approaches to quantify the analyte amount. The ratio of the concentrations between the analytes (biomarkers) and the recognition ligands on the nanoparticles is found to play an important role in the formation and hydrodynamic size of the clusters. The proposed computational framework has great potential to be integrated with experimental efforts to advance the development of nanoparticle-based biosensors for disease diagnostics and other biomedical applications.

中文翻译：

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生物共轭磁性纳米粒子的分析物驱动聚类

在细观水平上对悬浮在含有目标蛋白（即分析物）的缓冲盐溶液中的生物共轭磁性纳米粒子的动力学进行了数值研究。为了模拟磁性纳米粒子的分散，采用耗散粒子动力学，这允许研究相当大的系统，同时仍然保留重要的微观纳米粒子特性。此外，该方法与 Landau-Lifshitz-Gilbert 方程耦合，描述了宏观自旋近似内磁性纳米晶体的动力学。多价分析物与纳米粒子识别配体的结合导致磁性纳米粒子簇的形成，这反过来又极大地改变了溶液的宏观磁响应。这种胶体变化是可以通过实验观察到的，允许探索新的方法来量化分析物的数量。发现分析物（生物标志物）与纳米颗粒上的识别配体之间的浓度比在簇的形成和流体动力学尺寸中起着重要作用。拟议的计算框架具有与实验工作相结合的巨大潜力，以推进基于纳米颗粒的生物传感器的开发，用于疾病诊断和其他生物医学应用。