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

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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.