Institute for Science and Technology in Medicine, Keele University, Stoke-on-Trent, Staffordshire ST4 7QB, United Kingdom; J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, United States.
J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, United States.
J Colloid Interface Sci. 2018 Dec 15;532:536-545. doi: 10.1016/j.jcis.2018.08.014. Epub 2018 Aug 7.
The functionality of magnetic nanoparticles (MNPs) relies heavily on their surface coating, which in turn affects the interactions between MNPs, and the formation of single-core particles or multi-core clusters. In this study we assessed the use of AC susceptibility (ACS) as a magnetic probe of the kinetics of coating and agglomeration of functionalised nanoparticles. We demonstrate the precision and sensitivity of ACS measurements to small changes in MNP coating using arginine-glycine-aspartic acid (RGD) tripeptide binding, and subsequently discuss how ACS can be used to optimise the preparation of polyethyleneimine (PEI) functionalised MNPs aimed at nanomagnetic transfection applications.
We varied the PEI loading of suspensions of MNPs exhibiting a combination of Brownian and Néel relaxation, and used dialysis to study the movement of excess PEI during the coating process. Numerical ACS simulations were employed to determine particle cluster sizes and polydispersity and the results compared with conventional dynamic light scattering (DLS) size measurements.
ACS provided information on the MNP coating and agglomeration process that was not accessible through DLS due to the additional presence of non-magnetic polymer particulates in the suspensions. We consequently derived a simple method to obtain dense, uniform PEI coatings affording high-stability suspensions without excessive quantities of unbound PEI.
磁性纳米粒子（MNPs）的功能很大程度上依赖于其表面涂层，而这反过来又会影响 MNPs 之间的相互作用，以及单核心粒子或多核团簇的形成。在这项研究中，我们评估了交流磁化率（ACS）作为一种探测功能化纳米粒子涂层和聚集动力学的磁性探针的作用。我们使用精氨酸-甘氨酸-天冬氨酸（RGD）三肽结合证明了 ACS 测量对 MNP 涂层微小变化的精确性和敏感性，随后讨论了 ACS 如何用于优化旨在用于纳米磁性转染应用的聚乙烯亚胺（PEI）功能化 MNPs 的制备。
我们改变了同时表现出布朗和奈尔弛豫的 MNPs 悬浮液中的 PEI 负载，并使用透析来研究涂层过程中过量 PEI 的运动。采用数值 ACS 模拟来确定颗粒簇的大小和多分散性，并将结果与传统的动态光散射（DLS）尺寸测量进行比较。
ACS 提供了有关 MNP 涂层和聚集过程的信息，而这些信息通过 DLS 是无法获得的，因为悬浮液中还存在非磁性聚合物颗粒。因此，我们得出了一种简单的方法，可以获得高密度、均匀的 PEI 涂层，从而提供高稳定性的悬浮液，而不会有过量的未结合的 PEI。
