Microdroplet-Assisted Screening of Biomolecule Production for Metabolic Engineering Applications

Success in synthetic biology and metabolic engineering is quickly becoming 'test' limited within the design-build-test cycle. Commonly used methods for high-throughput screening, including fluorescence-activated cell sorting (FACS) and microtiter plates, have intracellular product and throughput limitations. A growing alternative to these challenges is the use of microfluidic microdroplet-based methods, which offer the advantages of microtiter plates with the throughput and ease of flow-based approaches. In this review, we examine available microdroplet technologies and their applications from droplet generation to sensing and finally sorting and evaluation for metabolic engineering applications. Additionally, we cover recent microdroplet advances, including the ability to perform mass spectrometry (MS) on individual microdroplets and dispense them into microtiter plates after sorting via fluorescence-activated droplet sorting (FADS).