Microfluidic tools for monitoring: from gas detection to applications in microbiology

Here we present two very different projects (chemistry and microbiology) to show the versatility of microfluidics as monitoring tool.

The detection of toxic gases is becoming an important element in tackling increased air pollution. This has led to the development of gas sensors based on porous solid materials, which are produced using sol-gel chemistry and functionalized to change their optical qualities when in contact with the gas. In this context it is interesting to explore how microfluidics can be used to miniaturize these sensors, to improve their sensitivity and dynamic range, or to multiplex many gas measurements on a single chip. Here we show how the sol-gel process can be implemented using anchored droplet microfluidics. The sensor material is partitioned into droplets while in the sol phase and maintained using capillary anchors. The ability to hold the droplets in place first allows us to study the sol-gel process. Finally, we show that the beads can be functionalized and used to detect the presence of formaldehyde. These results first provide a new way to observe the physics of the sol-gel process in a well-controlled and quantitative fashion. Moreover, they highlight how the coupling of microfluidics and sol-gel chemistry can be used to detect toxic gases, in view of answering the challenges surrounding gas detection in real-world settings.

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The integrity and expression of the genome are essential functions of the cell. In this project we propose to develop a new monitoring system for spontaneous mutations accumulation in yeast Saccharomyces cerevisiae to analyse new DNA repair mechanisms coupled with transcription. The tool developed will allow us to use the technology derived from physics to answer important biological questions related to the expression and integrity of genomes and to better understand human pathologies such as cancer and rare diseases. It also presents a potential for using the tool developed to mimic the accumulation of mutations according to the genetic context in the digital patient or mutagen identification programs, or the innovative concepts connecting gene expression and DNA repair to propose potential therapeutic targets. This project proposed the development of a microfluidic system for mutation monitoring. The system will allow the growth of yeast populations over 100 generations through population bottlenecks and the analysis of the mutation spectrum in different genetic contexts by high-throughput sequencing (NGS).