Single molecule Fluorescent Resonance Energy Transfer Scanning Near-field Optical Microscopy

Abstract

We present single molecule Fluorescence Resonant Energy Transfer Scanning Near-field Optical Microscope (FRET SNOM) images of CdSe nanocrystal (donor) deposited onto the glass slide surface. Images were obtained using the earlier proposed FRET SNOM probes which are 30 – 100 nm thick polymer layers stained with the acceptor dye molecules coated onto the apex of the standard sharp aperture SNOM tip. An original SNOM construction enabling very fast scanning was used to overcome the photostability problem, so we were able to record first single molecules FRET SNOM images, but the photostability is still not enough for regular informative single molecule FRET SNOM imaging. For this, we are elaborating probes based on ultra photostable NV− color centers in nanodiamond crystals attached to the apex of a standard SNOM probe.