AMPA receptor imaging by infrared scanning near-field optical microscopy

Infrared scanning near-field optical microscopy is used to detect AMPA-type glutamate receptor clusters in hippocampal neuron cells. AMPA's GluR2-subunits were marked with the fluorophore Alexa488 and high-resolution micrographs were taken at 6.25 µm wavelength, corresponding to the maker's strong infrared absorption. The use of infrared light avoids photobleaching and makes this approach suitable for long-term observations; this technique can be used in general to localize different IR-absorbing molecules over the complex background of other cell components.