While the overall project is the sorting of cargos on origami, we expected verification of all of the mechanisms would take longer than one summer. Therefore, this summer was spent verifying two aspects of the project:
Verification of Overall Mechanisms in Solution
All of the essential mechanisms in our system were veriﬁed in solution using polyacrylamide gel electrophoresis. These mechanisms include: walker-track binding, triggering the walker, walking from one track to another, picking up cargo, walking while carrying cargo, triggering the cargo goal, dropping oﬀ cargo, and irreversibly walking from tracks to the walker goal. We are fairly confident that all of these mechanisms work as expected in solution, with a few mysteries that do not seem to interfere with the overall behavior of the system (see Gel Verification).
Verification of Random Walking Mechanism on Origami
We used fluorescent spectroscopy (SPEX) to verify the random walking mechanism on the origami. Goals were tagged with fluorophores whereas walkers were tagged with the corresponding quenchers. Fluorescent signals will decrease when walkers reach their goals. Unlike AFM, which studied individual origami, SPEX experiments studied the collective behavior of all the origami in solution. Hence, the SPEX results were analyzed using both Matlab simulation and mathematical formulae.