Magnetic surfaces for the controlled manipulation of superparamagnetic microbeads

操纵具有功能化表面的超顺磁微珠作为单分子研究的标签，用于细胞操作以及液体环境中化学或生物物种的检测是研究项目的重点。在该项目中，超顺磁珠在功能化磁性表面上运动的基本原理将被探索。作为操纵磁珠的基础，将研究以阵列元素形式形成的微光刻图像化磁表面，以创建一个相互连接的磁网络。单个磁珠的传输是由微磁性物体完成的，如带电磁畴壁或可切换的磁化结构。在该项目中，将研究在可变多轴磁场协议的帮助下微珠状长磁结构的控制运动。人们正在探索不同的方法来研究超顺磁粒子在液体悬浮液中的输运。此外，通过施加具有不同频率分量的随时间和角度变化的磁场来利用流体动力效应。利用原位互补磁显微镜和亮场光学显微镜直接分析了磁图案的横向分布和相应的微珠运动。这些调查将得到深度模拟的支持。该研究将开辟横向操纵标记生物物体的新方法，以促进微流体环境中颗粒在相当距离上的受控运动，并以这种方式为集成无流实验室芯片设备中生物物体的操作和分离提供基础。

The manipulation of superparamagnetic microbeads withfunctionalized surfaces as labels for single-molecule studies, for cellmanipulation, and detection of chemical or biological species in liquidenvironments are in the focus of the research project. Within theproject the fundamentals for the movement of superparamagneticbeads on functionalized magnetic surfaces will be explored. As abasis for the manipulation of beads, micro-lithographically patternedmagnetic surfaces in the form of array elements creating aninterconnecting magnetic network will be investigated. The transportof individual beads is performed by micro-magnetic objects such ascharged magnetic domain walls or switchable magnetizationstructures. Within the project the controlled movement of microbeadsalong magnetic structures with the help of variable multi-axismagnetic field protocols will be investigated. Different approaches arebeing explored for the transport of superparamagnetic particles inliquid suspensions. Moreover, hydrodynamic effects will be utilized byapplying temporal and angle varying magnetic fields with differentfrequency components. The lateral distribution of the magneticpatterns and the corresponding motion of the microbeads areanalyzed directly by complementary in-situ magnetic and bright-fieldoptical microscopy. The investigations will be supported by in depthsimulations. The research will open up new ways to laterallymanipulate marked biological objects, to facilitate a controlledmovement of particles in microfluidic environments over substantialdistances, and in that way provide the foundations for themanipulation and separation of biological objects in integratedflowless lab-on-chip devices.