| In two-photon laser fluorescence microscopy, the light source is a pulsed laser delivering high intensity beams, which raises questions concerning the interactions between the laser beam and the cells as between the laser beam and the growth substrates. This thesis presents results of laser-induced interactions with two kinds of growth substrates: a polymer based on polytrichlorofluoroethylene called Aclar and a borosilicate glass. While presenting advantages over glass by improving adhesion and offering greater flexibility, Aclar is damaged by the laser because of the presence of impurities, its low thermal conductivity and low melting point. This interaction starts at a mean intensity at the focus of 105 W.cm-2 for exposure time below that necessary to cause cell damage. At the damage sites, vapor bubbles appear and lead to destruction of the cells. In contrast, no interaction with the laser occurs on borosilicate coverglass. Thus cell cultures on glass remain intact. The use of Aclar with ultra-fast lasers is then precluded. |
