Full-field supercritical angle fluorescence microscopy for live cell imaging.

We introduce a full-field fluorescence imaging technique with axial confinement of about 100 nm at the sample/substrate interface. Contrary to standard surface imaging techniques, this confinement is obtained through emission filtering. This technique is based on supercritical emission selectivity. It can be implemented on any epifluorescence microscope with a commercial high numerical aperture objective and offers a real-time surface imaging capability. This technique is of particular interest for live cell membrane and adhesion studies. Using human embryonic kidney cells, we show that one can observe simultaneously the surface and in-depth cell phenomena.