Plasmonics for advance single-molecule fluorescence spectroscopy and imaging in biology

The elucidation of complex biological processes often requires monitoring the dynamics and spatial organization multiple distinct proteins organized on sub-micron scale. This length scale is well below diffraction limit light, as such not accessible by classical optical techniques. Further, high molecular concentrations found in living cells, typically micro- to mili-molar range, preclude single-molecule detection confocal volumes, essential quantify affinity constants protein-protein reaction rates their physiological environment. To push boundaries current state art fluorescence imaging spectroscopy, plasmonic materials offer encouraging perspectives. From thin metallic films nano-antenna structures, near-field electromagnetic coupling between electronic transitions single emitters plasmon resonances can be exploited expand toolbox based spectroscopy approaches. Here, we review two most promising approaches study with unattainable level detail. On one side, discuss how reduction lifetime a molecule it film decode axial information nanoscale precision. other, tremendous progress design antennas that amplify confine fields at nanoscale, powered revolution correlation spectroscopy. Besides method development, also focus describing interesting application both technologies.