Miniature 'knot lab' could help untangle DNA mysteryEach silica particle was coated with a surfactant, making its surface hydrophobic. This disrupted the crystal's highly ordered structure – any liquid crystal molecule adjacent to a silica particle aligned itself perpendicular to the curved surface of the particle and these "disordered" molecules formed a three-dimensional Saturn's ring around the surface. "It's visible like a black ring around the particle," says Tkalec.
When the team trapped the loops with a laser and brought them close together, they immediately joined up to form a bigger, twisted loop around both the particles. A similar thing happened with three particles. By bringing just the right combination of twisted loops into contact, these arrays could be made to unknot and then re-knot to form loops that aren't just twisted, but are intertwined.