Interplay of Nanoparticle Resonance Frequency and Array Surface Coverage in Live-Cell Plasmon-Enhanced Single-Molecule Imaging

Super-resolution imaging has provided new insights into nanoscale optics. Plasmonic gold nanotriangle arrays created by nanosphere lithography can enhance single-molecule fluorescence intensity to further improve imaging. Here, gold nanotriangle arrays on glass coverslips were used as inexpensive, facile, and broadly applicable imaging substrates for living Vibrio cholerae cells expressing photoactivatable fluorescent proteins-the red PAmCherry or the green PAGFP-and resulted in fluorescence enhancements upon coupling living cells to nanotriangle arrays. Within the requirements for this wide-field coupling geometry, we analyze and optimize the coupling as a function of local surface plasmon resonance frequency and particle coverage.