Department of Electromechanical, Systems and Metal Engineering, Ghent University, 9052 Zwijnaarde, Belgium.
Cancer Research Institute Ghent, 9000 Ghent, Belgium.
Sensors (Basel). 2020 Jul 12;20(14):3882. doi: 10.3390/s20143882.
Magnetic nanoparticles are increasingly employed in biomedical applications such as disease detection and tumor treatment. To ensure a safe and efficient operation of these applications, a noninvasive and accurate characterization of the particles is required. In this work, a magnetic characterization technique is presented in which the particles are excited by specific pulsed time-varying magnetic fields. This way, we can selectively excite nanoparticles of a given size so that the resulting measurement gives direct information on the size distribution without the need for any a priori assumptions or complex postprocessing procedures to decompose the measurement signal. This contrasts state-of-the-art magnetic characterization techniques. The possibility to selectively excite certain particle types opens up perspectives in "multicolor" particle imaging, where different particle types need to be imaged independently within one sample. Moreover, the presented methodology allows one to simultaneously determine the size-dependent coercivity of the particles. This is not only a valuable structure-property relation from a fundamental point of view, it is also practically relevant to optimize applications like magnetic particle hyperthermia. We numerically demonstrate that the novel characterization technique can accurately reconstruct several particle size distributions and is able to retrieve the coercivity-size relation of the particles. The developed technique advances current magnetic nanoparticle characterization possibilities and opens up exciting pathways for biomedical applications and particle imaging procedures.
磁性纳米粒子在疾病检测和肿瘤治疗等生物医学应用中得到了越来越广泛的应用。为了确保这些应用的安全高效运行，需要对粒子进行非侵入性和准确的特性描述。在这项工作中，提出了一种磁性特性描述技术，其中通过特定的脉冲时变磁场来激发粒子。通过这种方式，我们可以选择性地激发给定尺寸的纳米粒子，从而使得到的测量结果直接提供关于尺寸分布的信息，而无需任何先验假设或复杂的后处理程序来分解测量信号。这与现有的磁性特性描述技术形成了对比。选择性激发某些特定类型粒子的可能性为“多色”粒子成像开辟了新的前景，因为在一个样本中需要独立地对不同类型的粒子进行成像。此外，所提出的方法还可以同时确定粒子的尺寸相关矫顽力。这不仅从基础的角度来看是一个有价值的结构-性质关系，而且在优化磁粒子热疗等应用方面也具有实际意义。我们通过数值模拟证明了新的特性描述技术可以准确地重建几个粒子尺寸分布，并能够获取粒子的矫顽力-尺寸关系。所开发的技术提高了当前磁性纳米粒子特性描述的可能性，并为生物医学应用和粒子成像程序开辟了令人兴奋的途径。
