As we all know that there are several tapes of DNA-walkers, which belongs to a specific kind of DNA nano-robot. This kind of device has a very bright future in molecular transport, but sometimes it’s not that convenient to build a special track for the particular walker, especially in vivo transportation. So, compact with the transportation that really happened in human body, we hope to design a delivery system that can perform an automatic transport, and we really made efforts to it this summer vacation.
We came across a method called HCR (Hybridization Chain Reaction) last year. This method was used as an amplifier in detection of some specific molecular. We try to use this method to construct a track, and make this track could be induced and self-assembled. We designed 4 DNA strands numbered T1 to T4, which could be induced to perform a polymerize reaction and form a track for the DNA-walker to walk. These 4 strands each has 2 stem-loop structures, so that they will be stable enough to keep no polymerize reaction without the inducer. We can also make a terminator for this track. The terminate DNA will stop the DNA from polymerizing. This kind of track forming technique makes DNA-walker a better potential in transportation in vivo or some other conditions that could be difficult to build DNA-tracks with planting or a huge annealing.
As for the inducer, it’s just a short DNA strand, and we can call it trigger DNA. If it could be attached to a DNA-origami box full of workers, a delivery device is just in to use. The track will form along the trigger, and it will stop when meeting another DNA-origami box attached with the terminate DNA. Then, the walker could be released and transport the cargo between two DNA-origami boxes. These are just future fantasies, we’ve not been gone that far, but we really think the self-assembly track as an amazing tool.