Optical section structured illumination microscopy (OS-SIM), like confocal microscopy, has about 200 nm spatial resolution.  In this report, we performed quantitative 3-cube FRET imaging in OS-SIM mode and widefield microscopy (WF) mode, respectively, for living cells expressing FRET constructs consisting of Cerulean (C, donor) and Venus (V, acceptor).  OS-SIM images exhibited higher resolution than WF images.  Four spectral crosstalk coefficients measured under OS-SIM mode are consistent with those measured under WF mode.  Similarly, the system calibration factors G and k measured under OS-SIM mode were consistent with those measured under WF mode.  Collectively, our data demonstrates that OS-SIM can be integrated into FRET microscopy to build an OS-SIM-FRET with confocal microscopy-like resolution.
OS-SIM
In this report, we performed quantitative 3-cube FRET imaging in OS-SIM mode and widefield microscopy (WF) mode, respectively, for living cells expressing FRET constructs consisting of Cerulean (C, donor) and Venus (V, acceptor).  OS-SIM images exhibited higher resolution than WF images.  Four spectral crosstalk coefficients measured under OS-SIM mode are consistent with those measured under WF mode.  Similarly, the system calibration factors G and k measured under OS-SIM mode were consistent with those measured under WF mode. 
WF