Integration of optically pumped magnetometers and microfluidics for the determination of the magnetic moments of single micro-particles (Micromagnetic Moments)

趋磁细菌(MTB)产生磁性纳米晶体，呈链状排列，称为磁小体。它们的完美性能超过了非生物生产的纳米颗粒，这使得它们在几个技术应用中都很有趣。对于MTB本身来说，磁小体服务于地球磁场内的定向。磁小体的大小、排列和磁化强度取决于环境的各种影响因素。对这些相互关系的研究越来越引起人们的兴趣，因为微生物在全球生物地球化学循环中发挥着重要作用。对于结核分枝杆菌和生物产生的磁小体的特性，了解它们各自的磁矩将是非常有益的。要在许多MTB的集合中获得这种单独的性质，到目前为止还没有方法存在。因此，在这个项目中，将创造一种可能性，其中可以以高吞吐量单独表征更大量的磁小体或MTB(更普遍地称为微粒子)的磁化强度。为此，光泵磁强计(OPM)和微流控元件将集成在一个共同的芯片中。由于绕过的磁性微粒和碱性蒸汽室之间的距离很小，利用这种积分可以首次测定m=1x10exp(-15)am^2量级的磁矩(尽管需要微型的蒸汽室来分解单个微粒)。为了获得相应的磁场分辨率，将多个碱气室与微流控通道集成在一起，以消除噪声源，提高信号质量。此外，还必须开发OPM的物理工作模式，并与综合安排中的技术情况相适应。

Magnetotactic bacteria (MTB) produce magnetic nano-crystals, arranged in chains and called magnetosomes. Their perfection outperforms abiotically produced nanoparticles, making them interesting for several technical applications. For the MTB themselves the magnetosomes serve for the orientation within the Earth magnetic field. Size, arrangement, und magnetization of the magnetosomes depend on various influencing factors of their environment. The investigation of these interrelations is of growing interest, because the microbes play an important role within the global biogeochemical cycles. For the characterization of MTB as well as biogenically produced magnetosomes the knowledge of their individual magnetic moments would be of great benefit. To gain this individual property within an ensemble of many MTB, no method exists up to now. Hence, in this project a possibility shall be created, where a larger quantity of magnetosomes or MTB (more generally called micro-particles) can be characterized individually with respect to their magnetization with high throughput. For that purpose optically pumped magnetometers (OPM) and micro-fluidic elements are to be integrated in a common chip. Due to the small distance between the bypassing magnetic micro-particles and the alkali vapor cells achievable with this integration, for the first time the determination of magnetic moments of the order of m = 1x10exp(-15) Am^2 will be possible (despite the miniaturized vapor cells, which are needed to resolve individual micro-particles). In order to gain the corresponding magnetic field resolution, several alkali vapor cells will be integrated together with the microfluidic canal, what serves for the elimination of noise sources and improvement of the signal quality. Furthermore, the physical working mode of the OPM has to be developed and fit to the technical situation in the integrated arrangement.