Potter, S. M., Wang, C. M., Garrity, P. A. and Fraser, S. E. (1996) "Intravital imaging of green fluorescent protein using 2-photon laser-scanning microscopy." Gene 173: 25-31.

Imaging a fluorophore in a living tissue presents several unique problems. The fluorescence from the labeled cell@) may be weak, the labeled cells may be buried deep within tissue and the presence of a fluorophore may render the cells photo-sensitive. Two-photon laser-scanning microscopy (TPLSM) offers several advantages in meeting these challenges. We show that TPLSM provides greater sensitivity, better resolution and less photo-bleaching, as compared to confocal laser-scanning microscopy. The dramatically reduced photo-bleaching makes it possible to image cells continuously for long periods of time. Therefore, TPLSM allows a safer and higher-resolution means of imaging living cells labeled with a variety of fluorophores, including green fluorescent protein.