Lyons Stephen, Mc Kiernan Eoin P, Dee Garret, Brougham Dermot F, Morrin Aoife
Insight SFI Research Centre For Data Analytics; National Centre for Sensor Research; School of Chemical Sciences, Dublin City University, Ireland.
School of Chemistry, University College Dublin, Ireland.
Nanoscale. 2020 May 21;12(19):10550-10558. doi: 10.1039/d0nr01602k.
Factors that determine magnetophoretic transport of magnetic nanoparticles (MNPs) through hydrated polymer networks under the influence of an external magnetic field gradient were studied. Functionalised iron oxide cores (8.9 nm core diameter) were tracked in real-time as they moved through agarose gels under the influence of an inhomogeneous magnetic field. Terminal magnetophoretic velocities were observed in all cases, these were quantified and found to be highly reproducible and sensitive to the conditions. Increasing agarose content reduced magnetophoretic velocity, we attribute this to increasingly tortuous paths through the porous hydrated polymer network and propose a new factor to quantify the tortuosity. The impact of MNP surface functionalisation, charge, network fixed charge content, and ionic strength of the aqueous phase on velocity were studied to separate these effects. For MNPs functionalised with polyethylene glycol (PEG) increasing chain length reduced velocity but the tortuosity extracted, which is a function of the network, was unchanged; validating the approach. For charged citrate- and arginine-functionalised MNPs, magnetophoretic velocities were found to increase for particles with positive and decrease for particles with negative zeta potential. In both cases these effects could be moderated by reducing the number of agarose anionic residues and/or increasing the ionic strength of the aqueous phase; conditions under which tortuosity again becomes the critical factor. A model for MNP transport identifying the contributions from the tortuous pore network and from electrostatic effects associated with the pore constrictions is proposed.
研究了在外部磁场梯度影响下，决定磁性纳米颗粒（MNPs）通过水合聚合物网络进行磁泳传输的因素。功能化的氧化铁核（核心直径8.9纳米）在非均匀磁场影响下穿过琼脂糖凝胶时，对其进行实时跟踪。在所有情况下都观察到了终端磁泳速度，对这些速度进行了量化，发现其具有高度可重复性且对条件敏感。琼脂糖含量的增加会降低磁泳速度，我们将此归因于通过多孔水合聚合物网络的路径越来越曲折，并提出了一个量化曲折度的新因素。研究了MNP表面功能化、电荷、网络固定电荷含量以及水相离子强度对速度的影响，以区分这些效应。对于用聚乙二醇（PEG）功能化的MNPs，链长增加会降低速度，但提取的曲折度（它是网络的函数）不变，验证了该方法。对于带电荷的柠檬酸盐和精氨酸功能化的MNPs，发现具有正zeta电位的颗粒磁泳速度增加，而具有负zeta电位的颗粒磁泳速度降低。在这两种情况下，通过减少琼脂糖阴离子残基的数量和/或增加水相的离子强度，可以缓和这些效应；在这些条件下，曲折度再次成为关键因素。提出了一个MNP传输模型，该模型确定了曲折孔网络以及与孔收缩相关的静电效应的贡献。
