Droplet-based synthetic biology: chemotaxis and interface with biology

Liquid droplets possess some life-like behaviors and have been the subject of artificial life studies. Life-like behaviors such as fission, fusion and movement can be artificially recreated exploiting highly simplified chemical systems. Recently we showed that droplet-based chemotactic systems can be interfaced with biological systems (1). We developed a chemotactic droplet able to move light cargos such as hydrogel alginate capsules embedded with living cells as a transporter. We transported efficiently and in a sterile way a few types of bacteria and yeast, and we are now modifying our protocols to transport efficiently human cell lines. We recently discovered that some eukaryotic cell lines release surfactants when placed in our artificial transport system, thereby reinforcing the interface between the artificial and living systems. This is an example of not only how the interface between artificial life and biological life could be designed but how the one system can augment the other. In this case the living system produces the surfactants that the droplet needs for cargo transport and the artificial system provides the transport for the otherwise sessile mammalian cells.