Microfluidic single-cell analysis in biotechnology: from monitoring towards understanding

Our understanding of the microbial cell is based on averaged values from bulks. Microfluidic single-cell analysis holds the promise of understanding cellular processes from a single cell perspective. But what is needed to measure single-cell physiology and to disclose the consequences of individuality for biotechnology? Current single-cell research is not yet able to provide all the necessary insights, but innovative approaches now emerge that propel the field towards a better understanding of cellular processes via quantitative physiology. Here, we critically review novel single-cell technologies that enable us to control cellular input parameters such as environmental conditions and to measure intracellular processes, as well as novel approaches that enable for the first time to quantify non-averaged cell-specific rates and yields. Finally, we demonstrate how integrating microfluidic single-cell analysis into established population-based experimental workflows might unlock its full potential for biotechnology research in the future.