Magnetic millifluidic fractionation of a heterogeneous cell culture for statistically relevant ananlysis of age-dependent population development

磁性纳米颗粒是最多样化的纳米材料之一，并且由于它们可以用磁场处理并从复杂的混合物中分离而获得越来越多的工业兴趣。这个创新项目的目标是开发一种毫流体分离过程，可以分离单一的酵母菌群。这使得研究外源性应激对酵母菌生理特性的影响取决于它们的年龄。为了对酵母细胞的细胞龄和异质性对食品工业生产的影响给出可靠的说明，酵母细胞的细胞分裂会导致母细胞上的芽痕，使用毫流体流动池根据细胞龄对酵母进行磁性分类。因此，芽痕的数量直接与细胞生成相关。芽痕含有大量的几丁质，因此几丁质也是细胞生成的指标。为了根据细胞年龄分离细胞，磁性纳米颗粒通过ChBD与芽痕结合，所述磁性纳米颗粒通过具有含几丁质结合结构域（ChBD）的蛋白质的His标签系统可逆地功能化。MNP与芽痕的这种结合充当磁性标记。酵母细胞在通过流动池时受到磁场的影响，因此根据其磁性进行分级。磁场的布置、流动的几何形状和流速促进了根据MNP含量和聚集体尺寸的分级分离，根据酵母细胞的年龄分级分离酵母细胞将有助于回答关于单个细胞中应激相关基因的表达以及细胞年龄对发酵性能的影响的基本问题。此外，可以研究依赖于生理特性的种群动态。要回答这些问题是巨大的科学兴趣，因为它是非常困难的，以确定酵母细胞的年龄，这项调查将铺平道路，以更深入地了解异质和同质的细胞系统。

Magnetic nanoparticles are among the most diverse nanomaterials and gain increasing industrial interest since they can be processed with magnetic fields and separated from complex mixtures. The goal of this innovative project is to develop a millifluidic separation process which allows the fractionation of singular yeast populations. This allows to investigate the influence of exogenous stressors on the physiological properties of yeasts depending on their age. Yeast will be classified magnetically according to cell age with a millifluidic flow cell in order to give a reliable statement on the influence of cell age and heterogeneity of yeast cells on the production in the food industry.Cell division of yeast cells leads to a bud scar on the mother cell. Thus, the number of bud scars directly correlates with the cell generation. Bud scars contain significant amounts of chitin which is therefore an indicator for cell generation as well. To separate the cells according to their cell age, magnetic nanoparticles, which are functionalized reversibly via a His-tag system with a protein containing chitin binding domain (ChBD), are bound to the bud scars through the ChBD. This binding of MNP to the bud scars acts as a magnetic marker. Yeast cells are affected by magnetic fields while passing the flow cell and thus fractionated according to their magnetic properties. The arrangement of the magnetic field, the flow geometry and the flow rate facilitate a fractionation depending on the MNP content and agglomeration size.The fractionation of yeast cells according to their age will help to answer fundamental questions on the expression of stress relevant genes in singular cells and the influence of the cell age on the fermentation performance. Furthermore, the population dynamic in dependence of the physiological properties can be investigated. To answer these questions is of great scientific interest since it is very difficult to determine the age of yeast cells and this investigation will pave the way to a deeper understanding of heterogeneous and homogeneous cell systems.