Planar optical sensors: A tool for screening enzyme activity in high density cell arrays

Directed evolution has become a widely used technique in enzyme development. It leads often to vast libraries of potential new variants which have to be examined. High throughput methods offer the possibility to examine huge amounts of sample in parallel. Therefore sensor platforms for new high throughput applications are in demand. We want to introduce a two-dimensional sensor platform which can be used with a variety of fluorescence dyes to screen enzymatic reactions. In this paper, we want to introduce an approach for screening micro colony chips of E. coli for enhanced esterase activity with fluoresceine as indicator and for enhanced choline oxidase activity with pO2 sensitive particles as indicator.