Optical Microscopy Using the Faraday Effect Reveals in Situ Magnetization Dynamics of Magnetic Nanoparticles in Biological Samples
Optical Microscopy Using the Faraday Effect Reveals in Situ Magnetization Dynamics of Magnetic Nanoparticles in Biological Samples
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DOI：
10.1021/acsnano.3c08955
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发表时间：
2024-02
期刊：
影响因子：
17.1
通讯作者：
M. E. Sharifabad;Rémy Soucaille;Xuyiling Wang;M. Rotherham;Tom Loughran;James Everett;David Cabrera;Ying Yang;Robert Hicken;Neil Telling
中科院分区：
文献类型：
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作者：
M. E. Sharifabad;Rémy Soucaille;Xuyiling Wang;M. Rotherham;Tom Loughran;James Everett;David Cabrera;Ying Yang;Robert Hicken;Neil Telling
生物学中外源性和内源性纳米级磁性材料的研究，对于开发生物医学纳米技术以及理解铁代谢和生物矿化等基本生物学过程具有重要意义。在此，我们利用磁光法拉第效应探测细胞内磁性并进行磁成像，揭示了细胞内不同位置外源性磁性纳米粒子的磁化动力学特性。本文结合磁热疗的背景展示了该方法所带来的机遇；磁热疗是指磁性纳米粒子在高频交变磁场作用下产生局部发热的效应。磁热疗有潜力作为一种针对癌症的细胞层面热疗手段，也可用于其他针对热敏性细胞功能的生物医学应用。然而，先前的实验表明，细胞环境会改变纳米粒子的磁化动力学，进而显著影响其发热效率。通过结合磁光测量和荧光测量，我们展示了一种生物显微镜技术，并在此用于研究组织学样本和活癌细胞中纳米粒子的原位磁化动力学。相关的磁成像和荧光成像确定了与细胞溶酶体共定位的聚集磁性纳米粒子。与在水悬浮液中或在细胞其他区域聚集的相同粒子相比，在这些溶酶体内聚集的纳米粒子表现出较低的交变磁场矫顽力。此类测量揭示了该方法的强大之处，能够用于研究细胞内位置、纳米粒子聚集以及粒子间磁相互作用如何影响磁化动力学，进而影响纳米粒子在生物环境中的发热响应。
The study of exogenous and endogenous nanoscale magnetic material in biology is important for developing biomedical nanotechnology as well as for understanding fundamental biological processes such as iron metabolism and biomineralization. Here, we exploit the magneto-optical Faraday effect to probe intracellular magnetic properties and perform magnetic imaging, revealing the location-specific magnetization dynamics of exogenous magnetic nanoparticles within cells. The opportunities enabled by this method are shown in the context of magnetic hyperthermia; an effect where local heating is generated in magnetic nanoparticles exposed to high-frequency AC magnetic fields. Magnetic hyperthermia has the potential to be used as a cellular-level thermotherapy for cancer, as well as for other biomedical applications that target heat-sensitive cellular function. However, previous experiments have suggested that the cellular environment modifies the magnetization dynamics of nanoparticles, thus dramatically altering their heating efficiency. By combining magneto-optical and fluorescence measurements, we demonstrate a form of biological microscopy that we used here to study the magnetization dynamics of nanoparticles in situ, in both histological samples and living cancer cells. Correlative magnetic and fluorescence imaging identified aggregated magnetic nanoparticles colocalized with cellular lysosomes. Nanoparticles aggregated within these lysosomes displayed reduced AC magnetic coercivity compared to the same particles measured in an aqueous suspension or aggregated in other areas of the cells. Such measurements reveal the power of this approach, enabling investigations of how cellular location, nanoparticle aggregation, and interparticle magnetic interactions affect the magnetization dynamics and consequently the heating response of nanoparticles in the biological milieu.