What did we do?
In the first panel, we see a central giant vesicle, which is called a GUV (Giant Unilamellar Vesicle). Vesicles are spherical assemblies of lipid molecules that have special appeal as transport vehicles. On this giant vesicle we see multiple DNA origami boxes. DNA origami boxes are made by the nanoscale folding of DNA. These boxes are closed shut with aptamer locks. Aptamers are oligonucleotidic strands that can bind to specific molecules. Smaller vesicles called LUVs (Large Unilamellar Vesicles) are present in solution around the GUV. On these vesicles, oligonucleotidic strands called "catcher-complementary strands" are present. In the next panel, we see that specific molecules, which are keys to our locks, are flushed in and they interact with the locks. In the subsequent panel we see that the keys have opened up the locks and hence, the origami box opens to reveal short "catcher strands". The catcher-complementary strands, as the name implies are complementary to the catcher strands. In the last panel we see LUVs tethered around the GUV when the origami boxes open up.
The applications of such a signal-driven tethering system are diverse because the underlying concept can be adapted and applied to a wide range of scenarios and environments. Most strikingly, the system may be used as a signal-driven targeted drug delivery system in which drugs or compounds encapsulated in vesicles are delivered to specific targets like cancer cells. Other potential applications include vesicle fusion by membrane destabilization, using the system to ‘fish’ for a specific target in solution and forming highly ordered vesicle networks which may be extended to artificial tissue formation.
Right below, there are actual images of attached vesicles taken during the course of our experiments.
Checklist of achievements
On our way of achieving a fully functioning signal-driven tethering system certain tasks needed to be fulfilled. The graphic belows illustrates what we have accomplished throughout our work.