Microfluidic is a science born in the 1980’s which revolves around the manipulation of fluids at a microscopic scale. Fluids are injected in sub-millimeter scale channels imprinted in microfluidic devices called microfluidic chips. It found many applications in different fields: engineering, physics, chemistry, biotechnology, etc. The scientific rsearcher came to well control fluid behaviours at this scale. It then became a technology and a powerful toolbox for application in the above mentionned fields and other.
Droplet-based microfluidics is one aspects of microfluidics. By injecting non-miscible fluids into microfluidic chips, it is possible to generate emulsion with droplet- size well defined and highly reproducible. Many tools were developped to manipulate droplets:
- pico-inject: inject additionnal chemicals into droplets after generation
- incubate: keep droplets stable for a set amount of time at a set temperature
- reinject: reinject droplets in chip for analysis, (usually after incubation)
- sort: sort droplets
Droplet-based microfluidic is a powerful technology for screening activity. By using specifically design fluorescent probes, it is possible to detect elements, like enzym or protein, and their activity. The common issue with fluorescent dye in droplet-based microfluidic is the leakage of these dyes outside of the droplets. Therefore, the quantification of elements or their activity is biaised due to loss of signal. Fluosurf was design to mimize this leakage and make experiments with fluorescent dye more precise.
Droplet-based microfluidic is a powerful technology for encapsulation of single cell in droplet. Poisson statistical law allows to predict the number of cells per droplets depending on the concentration in the sample and the intended droplet size. The model can also be used to determine the concentration needed to get at most one cell per droplet. Once the cells are individually encapsulated, it is possible to :
- test their behavior toward chemicals
- sequence their genomes
- study their proliferation
These applications require a specific surfactant to obviously stabilize droplets, but it also need to be biocompatible to not interfer with the content of droplets. Which is the case of our product FluoSurf.
Droplet-based microfluidic is a powerful technology for Polymerase Chain Reaction (PCR) PCR is a process were samples of DNA or RNA are amplified through action of heat to denaturate the two strands of DNA and of an enzyme which will make the complementray DNA strands. By cycling several time this step, it is possible to amplify the DNA numerous times. By extension, PCR also the detection of specific DNA sequence that amplification make easier. The use of droplet-based microfluidic allowed for a better effiency and sensitivity: detection from 10% of different DNA to 0.01%. This efficency requires use of perfomant surfactant which wil keep droplets stable all along the thermocycling. FluoSurf was succesfully tested for these applications.