Brendan Deveney

 

“Velcro” Surfactant for Biological Assays Performed in Droplets

Microfluidic droplets are widely used as small containers for biological tests. Single cells or molecules can be isolated within droplets and individually studied, allowing for investigations of gene expression levels, environmental testing, cancer biomarker and pathogen detection, and quantitative analysis of rare genetic species.

However, not all biological tests can be performed in droplets. Large droplets, such as those required for cell incubation to dilute cytotoxic molecules, are less stable than smaller droplets and often merge during tests. Droplets subjected to repeated thermal cycling for the amplification of low levels of genetic material by polymerase chain reaction (PCR) are also often found to merge. Merging prohibits the ability to perform individualized analyses of droplet contents.

To extend the ability to perform biological tests in droplets, we have developed a new, biocompatible surfactant that forms a stabilizing interfacial film on the surface of droplets. Using the surfactant we are able to stabilize drops much more effectively than with existing surfactants. We can use the surfactant to generate extremely large droplets in which we can selectively amplify genetic targets and culture cells. In the future, we will use this surfactant in support of ongoing work categorizing antibody-producing immune cells for the discovery of new therapeutics. 

A microscope image of the interfacial film formed by our surfactant  on the surface of a droplet

 

Figure A microscope image of the interfacial film formed by our surfactant on the surface of a droplet

 Contact: Brendan Deveney bdeveney@g.harvard.edu