A Proximity-Based Programmable DNA Nanoscale Assembly Line


            We have combined a gold nanoparticles with PX-JX2 devices and a novel walker that walks on a track on a DNA origami to produce a programmable assembly line.  There are three stations on the origami, each of which contains a PX-JX2 cassette, and can contribute a unit of cargo to the walker.  The cargoes consist of a 5 nm gold nanoparticle, a pair of joined 5 nm gold nanoparticles, and a 10 nm gold nanoparticle.  The devices will only donate a cargo if the are programmed to do so by being put in the PX state, rather than the JX2 state as the walker passes the station.  The image below shows the assembly of the 3-component product. 






















The 11 steps indicate the addition to the three cargo components to the walker.  The right column of panel (a) is shown in a tapping mode AFM image in panel (b).


With three different stations, it is possible to program eight different products from this assembly line.  These are shown in the drawing below.  Panel (a) shows the possible trajectories that the assembly line can take to produce eight different products.  Panel (b) shows the eight ending configurations of the assembly line, as a function of the programming, before release of product.  Panel (c) shows transmission electron micrographs of the individual programmed products.