Reaction Control on Single Magnetic Particles with Temporal and Spatial Precision

现代社会对快速分析化学有许多需求，包括在健康和疾病监测、环境污染或犯罪现场调查中的应用。分析化学最终是基于分析物和标记分子之间的化学反应。大多数反应在烧瓶中进行，剧烈搅拌以进行湍流混合，或在微孔中进行许多小时以允许基于扩散的混合。在过去的十年中，微通道中的流体处理已经彻底改变了分析化学。由于扩散距离短和表面积与体积比大，分析反应可以快速进行;其他优点包括样品和试剂的微量消耗以及将多个分析步骤集成到一个设备中的潜力。本研究的目标是通过结合微流控技术、功能化颗粒和磁力的独特功能，研究高度特定环境中的化学反应。然而，微通道中的流体行为以层流状态和基于扩散的混合为特征，因此具有良好的特征和可控性。表面功能化的微米和纳米颗粒用于许多化学领域，包括催化，（生物）分析测定和作为色谱分离的固定相，并且可以有效地与微流体系统组合以获得非常大的表面体积比。在这项特殊的研究中，磁性颗粒将提供额外的优势，即通过磁力进行外部控制，而不会干扰珠子的化学活性。在其表面上具有化学官能团的磁性颗粒可以通过外部磁力被拉过流。可以真实的研究特定流动流中颗粒表面上的反应;可以在连续流动中研究不同试剂浓度、流体粘度和溶剂组成的影响;同时将反应产物与试剂分离。这样的平台也将是可行的颗粒表面和流动流之间的表面张力的研究。最终，多流芯片可以用作生物医学化学的研究工具，或作为现场分析和现场分析的集成设备。

Modern society has many demands for quick analytical chemistry, including applications in health and disease monitoring, environmental pollution or crime scene investigation. Analytical chemistry ultimately is based on chemical reactions between analytes and marker molecules. Most reactions are carried out in flasks with vigorous agitation for turbulent mixing or in microwells for many hours to allow for diffusion based mixing. Over the last decade, fluid handling in microchannels has revolutionised analytical chemistry. Analytical reactions can be performed quickly due to short diffusion distances and large surface to volume ratios; other advantages include minute consumption of samples and reagents as well as the potential to integrate several analysis steps into one device. The goal of this research is to study chemical reactions in highly specified environments by combining the unique features of microfluidic technology, functionalised particles and magnetic forces.Fluid behaviour in microchannels however is characterised by laminar flow regimes and diffusion based mixing and is thus well characterised and controllable. Surface functionalised micro- and nanoparticles are employed in many areas of chemistry including catalysis, (bio)analytical assays and as stationary phase for chromatographic separations and can be effectively combined with microfluidic systems to obtain a very large surface to volume ratio. In this particular study, magnetic particles will offer the additional advantage of external control by magnetic forces which do not interfere with the chemical activity of the beads.In this proposal, a microfluidic tool will be delivered featuring parallel flow streams. Magnetic particles with chemical functional groups on their surfaces can be pulled through the streams by external magnetic forces. Reactions on the particles' surface in specific flow streams can be studied in real time; the influence of varying reagent concentrations, fluid viscosity and solvent composition can be investigated in continuous flow; with the reaction product being isolated from the reagents at the same time. Such a platform would also be feasible for studies on surface tension between the particle surface and flow streams. Ultimately, the multi-flow chip could be employed as a research tool in biomedical chemistry or as an integrated device for point-of-care and in-the field analysis.