Novel superparamagnetic, luminescent nanoparticles for magnetic particle imaging (MPI) applications (SuLuMaP)

该研究概念的目的是提供结合超顺磁性和发光性质的新型双功能MPI示踪剂，考虑到最重要的因素，如量子效率、生物兼容性、细胞渗透性、超顺磁性和流体动力学半径，以增加多模式诊断的意义。这种双功能可实现互补的成像方法。这些示踪剂可用于光学成像，以相对较低的仪器费用测量具有高空间分辨率的二维投影形式的近地表示踪剂分布。它在MPI中的使用具有相当高的仪器费用，提供了感兴趣对象的低洼区域中示踪剂分布的三维图像。多模式混合系统，如最近推出的3D双模式MPI-MRI系统，将在未来得到越来越多的使用。最近的研究活动涉及细胞跟踪，并描述了超顺磁性氧化铁纳米颗粒(SPIO)或19F纳米乳剂的应用，以使用X射线和核磁共振进行多模式成像。除了发光的稀土元素外，还将使用生物兼容的有机染料。导致松弛减慢的流体动力学半径应根据亲水/疏水表面性质进行调整。为此，正在考虑使用含氟化合物。颗粒的氟化有四种可能性：1)使用氟化聚合物作为磁铁矿的涂层；2)氟化有机染料的偶联；3)使用能够实现细胞渗透性的氟化连接物；4)用氟化烷或树枝将表面上的游离羧基或硅醇基团封顶。由于粒子氟化的这些不同选项，可以对表面极性进行精细调整，这将在系统试验中详细阐述。

The aim of the research concept is to provide new bifunctional MPI tracer that combine superparamagnetic and luminescent properties, taking into account the most important factors such as quantum efficiency, biocompatibility, cell permeability, superparamagnetic and hydrodynamic radius, in order to increase the significance of multimodal diagnoses. The bifunctionality allows a complementary imaging approach. These tracers can be used for optical imaging to measure near-surface tracer distributions as two-dimensional projections with great spatial resolution at relatively low instrumental expense. Its use in MPI with substantially higher instrumental expense provides three-dimensional images of the tracer distribution in low-lying areas of the object of interest. Multimodal hybrid systems such as the recently introduced 3D dual-modal MPI-MRI system will be increasingly used in future. Recent research activities are concerned with cell tracking and describe the application of SPIO (superparamagnetic iron oxide nanoparticles) or 19F nanoemulsions, to perform multi-modal imaging using X-ray and MRI. In addition to luminescent lanthanide, also biocompatible organic dyes are going to be used. The hydrodynamic radius, which is responsible for the slowing of the relaxation, should be adjusted by means of the hydrophilic / hydrophobic surface property. For this purpose fluorinated compounds are being considered. There are four possibilities for the fluorination of the particles: 1) use of fluorinated polymers as coating for the magnetite 2) coupling of fluorinated organic dyes 3) use of fluorinated linkers with which the cell permeability can be enabled 4) end capping the free carboxyl - or silanol groups on the surface with fluorinated alkanes or dendrons. Due to these various options of fluorination of the particles, a fine adjustment of the surface polarity is possible which will be elaborated in systematic trials.