Model-based and experimental evaluation of microfluidic cultivation with single-cell resolution

  • Modellbasierte und experimentelle Auswertung von mikrofluidischer Kultivierung mit Einzelzellauflösung

Westerwalbesloh, Christoph; Kohlheyer, Dietrich (Thesis advisor); Mitsos, Alexander (Thesis advisor)

Aachen (2019, 2020)
Dissertation / PhD Thesis

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2019

Abstract

Microfluidic single-cell cultivation has shown enormous potential for biological research, but a lack of measurement tools and a large variety of different devices and experimental conditions complicate its application. Here, computational simulation of flow and transport phenomena was used to answer various questions arising from the use of this technology and to help understand the complex interplay of device design, cultivated organisms, and experimental conditions. A simple model was developed to predict nutrient availability in microfluidic cultivation devices for substances like glucose, which are supplied via liquid growth media. Growth chambers, the parts of the devices where nutrient limitations are most likely to occur, were modelled in detail, and model simplification was employed successfully to reduce computational effort. Additionally the supply with oxygen, which diffuses through the material of the microfluidic chip, was simulated and found to be sufficient for cultivation and better than in macroscale bioreactors. The developed models were applied to a microfluidic device for the co-cultivation of bacteria and simulation results agreed well with experimental observations. Additionally, simulations were used to compare different microfluidic cultivation site designs for their capability to reproduce time-varying nutrient concentrations, like they are expected to occur in industrial large-scale bioreactors, and growth channels were identified as most promising design. Finally, to provide a growth kinetic for future simulations and experiments, single-cell growth rates of Corynebacterium glutamicum were measured for a wide concentration range with protocatechuic acid as sole carbon source. The results showed a Monod kinetic with inhibitory effects at high protocatechuic acid concentrations and increased variability of single-cell generation times for slowly growing colonies.

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