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Droplet Microfluidics

The droplet microfluidics team use emulsion technology to create single cell, protein and genetic analysis methods to extend the limits of bioanalysis for single cells, high throughput library screening and proteins.

Droplet microfluidics is a technique to encapsulate, process and analyze cells and reagents in monodisperse aqueous microreactors on the picoliter scale, the size scale of the single cell. Picoliter droplets can be created and manipulated at rates of millions per hour using microfluidic devices and automated control.

Droplet manipulations include for example generation, fusion, splitting and sorting by fluorescence or droplet size. These manipulations allow us to miniaturize biological assays in order to perform them inexpensively at higher throughput and with capabilities beyond those of traditional analysis methods. Thus far, we have developed a number of different assays including an assay for detection and analysis of cell surface protein biomarkers on individual human cells using enzymatic amplification inside microscale droplets. The method provides increased sensitivity with high throughput, and permits analysis of several cell samples concurrently by incorporation of droplet optical labels. This work was recognized in Nature Materials as a research highlight.

We have also developed a fluorescence based homogeneous assay for protein analysis, passive separation of droplets by size based on cell-induced droplet shrinkage and improvements in robust and inexpensive microfluidic device fabrication for optical analysis. Another research focus is droplet-based assays for directed-evolution of industrially relevant enzymes. Recently we have presented a novel microdroplet-based device for simultaneous and extensive characterization of the reaction kinetics of enzyme-inhibitor systems, for the first time utilizing picoinjectors for droplet bioanalysis.

Figure 1. Artist’s view of biological assays in droplet microfluidics