Researchers have developed a new way to track gold nanorods as they move around and re-orient themselves on metal surfaces, with significantly improved spatial resolution and speed compared with existing methods. Fluorescent dyes are commonly attached to molecules to make it possible to study their orientation and rotation. However this approach has drawbacks, because of limited signal stability and long observation times. One solution is to replace the fluorescent molecules with gold nanoparticles, providing better stability but making it harder to get detailed orientation data. Focused orientation and position imaging (FOPI) overcomes a key limitation of older methods — not being able to distinguish the full 360° orientation of the nanorods. This technique is capable of faster, higher throughput detection of the position and the 3D orientation of the gold nanoparticles, a key step towards allowing researchers to follow the motion of gold-tagged molecules as they move, interact and react on metal surfaces. This could impact a number of technologies ranging from catalysis to corrosion protection.
Focused Orientation and Position Imaging (FOPI) of Single Anisotropic Plasmonic Nanoparticles by Total Internal Reflection Scattering Microscopy