Liquid mediated surface-particle interactions in near-surface motion of superparamagnetic particles and magnetic Janus microparticles in quiescent liquids

静态液体中超顺磁性粒子和磁性 Janus 微粒近表面运动中液体介导的表面粒子相互作用

• 批准号: 514858524
• 负责人: Professor Dr. Arno Ehresmann
• 金额: --
• 依托单位: Experimentalphysik IV: Funktionalisierte dünne Schichten und Physik mit Synchrotronstrahlung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/514858524?language=en
• 关键词: Liquid; mediated; surface; particle; interactions

Precisely controlled actuation of small magnetic particles (MP) opens new avenues for the development of new strategies for analyte detection and diagnostics, e.g., for disease marker or virus detection. MP are promising as there is as yet no indication that the magnetic fields used for their actuation would modify biological matter. Since the early 2000s external time-dependent magnetic fields have been superposed for this purpose with static magnetic field landscapes (MFLs) emerging from arrays of magnetic charges (in domains, micromagnets, or from currents in micro wires). With this approach MP-transport, fluid mixing, MP-separation, MP-sorting, and even sensing of biologically functionalized MPs, e.g., via giant magnetoresistance and Hall-effect sensors has been achieved. A central characteristic of the MFLs are strong field gradients over small distances close to the surface from which the MFL emerges. In most of the known work in this context the interactions between MP and surface via the liquid, except for the magnetic interactions, have been neglected and in most of the studies superparamagnetic particles have been used. With this proposal we want to extend knowledge on these important micro systems by two aspects: We want to (1) systematically investigate the influence of the liquid mediated interactions between the MP and a close surface on the MP motion and explore (2) the different motion types (rotation and translation) of spherical non-magnetic micro particles with a magnetic cap (magnetic Janus particles, MJPs) in MFLs. These particular particles possess a much larger magnetic moment as compared to their superparamagnetic counterparts and may not only be translated but also oriented and rotated. In particular, we will establish a technique to automatically track not only the 2D-MP positions and MJP-orientations as functions of time (of all particles in a recorded video) but also their height over the substrate surface (3D tracking). This experimentally determined quantity will be used to quantify the influence of surface – MP interactions on the MP motion. The attained understanding will then be used for a proof-of-concept application, where a virus replacement (a surface-functionalized nano particle) shall be detected by a change in MP height over the surface.

小磁性颗粒（MP）的精确控制致动为开发用于分析物检测和诊断的新策略开辟了新途径，用于疾病标记或病毒检测。MP是有希望的，因为还没有迹象表明用于其驱动的磁场会改变生物物质。自2000年代初以来，外部时间相关的磁场已经为此目的与静磁场景观（MFL）从磁荷阵列（在域，微磁体或从微导线中的电流）出现叠加。利用这种方法，MP-运输、流体混合、MP-分离、MP-分选，甚至生物功能化MP的感测，例如，通过巨磁阻和霍尔效应传感器已经实现。MFL的中心特征是在接近MFL出现的表面的小距离上的强场梯度。在大多数已知的工作在这方面的MP和表面之间的相互作用，通过液体，除了磁相互作用，已被忽略，并在大多数研究超顺磁性粒子已被使用。通过这个提议，我们希望从两个方面扩展对这些重要微系统的认识：我们希望（1）系统地研究MP和封闭表面之间液体介导的相互作用对MP运动的影响，并探索（2）不同的运动类型（旋转和平移）MFL中具有磁帽的球形非磁性微粒（磁性Janus粒子，MJPs）。这些特定的粒子具有比它们的超顺磁性对应物大得多的磁矩，并且不仅可以平移，而且可以定向和旋转。特别是，我们将建立一种技术，不仅自动跟踪的2D-MP的位置和MJP的方向作为时间的函数（在一个记录的视频中的所有粒子），但也在基板表面上的高度（3D跟踪）。该实验确定的量将用于量化表面- MP相互作用对MP运动的影响。然后将所获得的理解用于概念验证应用，其中病毒替代物（表面官能化的纳米颗粒）应通过表面上MP高度的变化来检测。