Visualization of molecular fluorescence point spread functions via remote excitation switching fluorescence microscopy

• Published in: Nature communications Vol. 6; no. 1; p. 6287
• Main Authors: Su, Liang, Lu, Gang, Kenens, Bart, Rocha, Susana, Fron, Eduard, Yuan, Haifeng, Chen, Chang, Van Dorpe, Pol, Roeffaers, Maarten B. J., Mizuno, Hideaki, Hofkens, Johan, Hutchison, James A., Uji-i, Hiroshi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17.02.2015; Nature Publishing Group; Nature Pub. Group
• Subjects: 140/125; 639/624/400/1021; 639/638/439/945; 639/766/25; 639/925/357/354; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms7287

The enhancement of molecular absorption, emission and scattering processes by coupling to surface plasmon polaritons on metallic nanoparticles is a key issue in plasmonics for applications in (bio)chemical sensing, light harvesting and photocatalysis. Nevertheless, the point spread functions for single-molecule emission near metallic nanoparticles remain difficult to characterize due to fluorophore photodegradation, background emission and scattering from the plasmonic structure. Here we overcome this problem by exciting fluorophores remotely using plasmons propagating along metallic nanowires. The experiments reveal a complex array of single-molecule fluorescence point spread functions that depend not only on nanowire dimensions but also on the position and orientation of the molecular transition dipole. This work has consequences for both single-molecule regime-sensing and super-resolution imaging involving metallic nanoparticles and opens the possibilities for fast size sorting of metallic nanoparticles, and for predicting molecular orientation and binding position on metallic nanoparticles via far-field optical imaging. Plasmonic nanoparticles can dramatically enhance the optical properties of molecules but background scattering is a limiting factor. Su et al. use remote excitation by plasmons on nanowires to better access single fluorophore point spread functions for improved sensing and super-resolution imaging.