Fig. 2: SNA synthesis and purification.
From: Magnetic activation of spherical nucleic acids enables the remote control of synthetic cells
a, Schematic showing the top and bottom (azide-modified) T7 promoter strands. The transcription initiation site (+1) is marked. b, Schematic detailing the covalent attachment of the T7 promoter strands to the surface of the nanoparticle to form the magnetically activated SNAs. The azide-modified, double-stranded T7 promoter enabled copper-free click chemistry to the DBCO-modified nanoparticles. c, Agarose gel showing the SNA purification method to remove electrostatically bound DNA from the surface of the nanoparticles using an electric current. The covalently constructed SNA (with the azide-modified DNA) did not travel through the gel and was then extracted through brief sonication of the excised well in water. DNA that was not covalently attached to the surface of the nanoparticles was pulled off by applying an electric current to the agarose gel and can be seen to travel through the gel at the same speed as the free DNA and amine-only modified dsDNA incubated with the nanoparticles.
