Ten years ago, when Alain Wagner, Director of the BioFunctional Chemistry Lab at the University of Strasbourg, began investigating single-cell secretion, there was no technology to identify what cytokines or chemokines a cell-secreted in a specific context. Wagner discussed analysing single-cell secretion to understand biological processes like immune response, migration, differentiation, and killing. This requires measuring the secretion of cytokines and chemokines at the single-cell level.
Wagner opted for method to analyse single cells not based on DNA or RNA due to sensitivity constraints associated with these methods. He selected a droplet micro-fluidics method. The lab uses droplet microfluidics to process thousands of droplets per second, which is cost-effective and allows for high-throughput analysis. Furthermore, the equipment is cheap and can be bought off the shelf from providers. It is also easy for chemists to assemble.  Wagner explained that this technology helps create tight compartments, and everything secreted by the cell will remain in the lumen of the cell, making it easier to measure and analyse the material.
Wagner commented that by coating the surface of the droplet with an antibody, he would have a capture system that would allow him to measure the affinity of what was secreted by the cell to the surface in order to do that. This technique uses a surfactant with a reactive group to bind biomolecules to the droplet surface. Wagner added: “This chemistry is compatible with cell so it's not affecting cell viability. It's compatible with cultural media and with most of the additives you can put in the lumen of the droplet.” Therefore, this chemical optimisation process is very reliable.
Next, Wagner gave an overview of how the technology has been applied to screen for antibody-producing cells, allowing for the selection of hybridomas that produce high-affinity antibodies. This process is efficient and can be completed in a few hours. For instance, in the case of B cells, only a one-hour incubation is enough to reach sufficient sensitivity, and the sorting process and cell recovery take around three hours. On top of this, the technology can be used in immune response profiling, multiplexing, and AI integration, emphasising its versatility.
The technology has been licensed to a company called LiveDrop, making it available for broader use within the scientific community. The system is designed to be cost-effective and user-friendly, with minimal reagent consumption.