Institute of Physics, University of Mainz, 55128, Mainz, Germany.
Department of Clinical Application, Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan.
Sci Rep. 2024 Apr 3;14(1):7879. doi: 10.1038/s41598-024-58091-x.
Achieving non-invasive spatiotemporal control over cellular functions, tissue organization, and behavior is a desirable aim for advanced therapies. Magnetic fields, due to their negligible interaction with biological matter, are promising for in vitro and in vivo applications, even in deep tissues. Particularly, the remote manipulation of paramagnetic (including superparamagnetic and ferromagnetic, all with a positive magnetic susceptibility) entities through magnetic instruments has emerged as a promising approach across various biological contexts. However, variations in the properties and descriptions of these instruments have led to a lack of reproducibility and comparability among studies. This article addresses the need for standardizing the characterization of magnetic instruments, with a specific focus on their ability to control the movement of paramagnetic objects within organisms. While it is well known that the force exerted on magnetic particles depends on the spatial variation (gradient) of the magnetic field, the magnitude of the field is often overlooked in the literature. Therefore, we comprehensively analyze and discuss both actors and propose a novel descriptor, termed 'effective gradient', which combines both dependencies. To illustrate the importance of both factors, we characterize different magnet systems and relate them to experiments involving superparamagnetic nanoparticles. This standardization effort aims to enhance the reproducibility and comparability of studies utilizing magnetic instruments for biological applications.
实现对细胞功能、组织构造和行为的非侵入式时空控制，是先进治疗方法的理想目标。由于磁场与生物物质的相互作用可忽略不计，因此它们有望应用于体外和体内环境，甚至是在深层组织中。特别是，通过磁仪器对顺磁体（包括超顺磁体和铁磁体，都具有正磁导率）的远程操纵，已经成为各种生物环境中一种很有前途的方法。然而，这些仪器的特性和描述的变化导致了研究之间缺乏可重复性和可比性。本文针对需要标准化磁仪器的特性进行了描述，特别关注它们在控制生物体内部顺磁物体运动的能力。虽然众所周知，磁场对磁性颗粒施加的力取决于磁场的空间变化（梯度），但在文献中往往忽略了场的大小。因此，我们全面分析和讨论了这两个因素，并提出了一个新的描述符，称为“有效梯度”，它结合了这两个依赖关系。为了说明这两个因素的重要性，我们对不同的磁系统进行了表征，并将它们与涉及超顺磁纳米粒子的实验联系起来。这种标准化工作旨在提高利用磁仪器进行生物应用的研究的可重复性和可比性。
