Liebl Maik, Wiekhorst Frank, Eberbeck Dietmar, Radon Patricia, Gutkelch Dirk, Baumgarten Daniel, Steinhoff Uwe, Trahms Lutz
Biomed Tech (Berl). 2015 Oct;60(5):427-43. doi: 10.1515/bmt-2015-0055.
Quantitative knowledge about the spatial distribution and local environment of magnetic nanoparticles (MNPs) inside an organism is essential for guidance and improvement of biomedical applications such as magnetic hyperthermia and magnetic drug targeting. Magnetorelaxometry (MRX) provides such quantitative information by detecting the magnetic response of MNPs following a fast change in the applied magnetic field.
In this article, we review our MRX based procedures that enable both the characterization and the quantitative imaging of MNPs in a biomedical environment.
MRX characterization supported the selection of an MNP system with colloidal stability and suitable cellular MNP uptake. Spatially resolved MRX, a procedure employing multi-channel MRX measurements allowed for in-vivo monitoring of the MNP distribution in a pre-clinical carcinoma animal model. Extending spatially resolved MRX by consecutive magnetization of distinct parts of the sample led to a demonstration of MRX tomography. With this tomography, we reconstructed the three dimensional MNP distribution inside animal sized phantoms with a sensitivity of milligrams of MNPs per cm3. In addition, the targeting efficiency of MNPs in whole blood was assessed using a flow phantom and MRX quantification.
These MRX based measurement and analysis procedures have substantially supported the development of MNP based biomedical applications.
了解磁性纳米颗粒（MNPs）在生物体内的空间分布和局部环境的定量信息，对于指导和改进诸如磁热疗和磁性药物靶向等生物医学应用至关重要。磁弛豫测量法（MRX）通过检测施加磁场快速变化后MNPs的磁响应来提供此类定量信息。
在本文中，我们回顾了基于MRX的程序，这些程序能够在生物医学环境中对MNPs进行表征和定量成像。
MRX表征支持选择具有胶体稳定性且细胞对MNPs摄取合适的MNP系统。空间分辨MRX是一种采用多通道MRX测量的程序，可在临床前癌动物模型中对MNP分布进行体内监测。通过对样品不同部分进行连续磁化来扩展空间分辨MRX，从而实现了MRX断层扫描。利用这种断层扫描，我们在动物尺寸的模型中重建了三维MNP分布，灵敏度达到每立方厘米毫克级的MNPs。此外，使用流动模型和MRX定量评估了MNPs在全血中的靶向效率。
这些基于MRX的测量和分析程序极大地支持了基于MNP的生物医学应用的发展。
