title: Two-photon interactions at single fluorescent molecule level.
abstract: Single-molecule spectroscopy and single-molecule detection are emerging areas that have many applications when combined with scanning, imaging, and spectroscopy techniques. We have combined a commercial confocal scanning head, to a Ti:sapphire laser and to an inverted microscope, for the detection of single molecule fluorescence of varies dyes by two-photon excitation. We collected spot images of fluorescent molecules that have been deposited on a substrate considering both blinking and photobleaching behavior of fluorescent spots. Here, we report data related to two-photon interactions that occur with the following fluorescent molecules: Indo-1, Rhodamine 6G, Fluorescein, and Pyrene. The choice of these specific dyes is based upon their wide use in biological and medical applications together with the varying complexity of their chemical structure that increases from Pyrene to Indo-1. Moreover, we report some data about single molecule studies related to denaturation of an enhanced green fluorescent protein, GFPmut2, under one photon excitation regime, that show a very similar trend to that observed for the already mentioned fluorescent molecules.
authors.affiliation: National Institute for the Physics of Matter, Laboratory for Advanced, Microscopy, Bioimaging, and Spectroscopy, Genoa, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Cannone
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Chirico
authors.forename: Alberto
authors.initials: A
authors.lastname: Diaspro
mesh_terms: D019793:Fluorescein / Q000737:chemistry / Q000528:radiation effects; D005456:Fluorescent Dyes / Q000737:chemistry* / Q000528:radiation effects; D049452:Green Fluorescent Proteins; D007211:Indoles / Q000737:chemistry / Q000528:radiation effects; D007834:Lasers; D008164:Luminescent Proteins / Q000737:chemistry / Q000528:radiation effects; D018613:Microscopy, Confocal / Q000379:methods*; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D011721:Pyrenes / Q000737:chemistry / Q000528:radiation effects; D012235:Rhodamines / Q000737:chemistry / Q000528:radiation effects
chemical_list: D005456:Fluorescent Dyes; D007211:Indoles; D008164:Luminescent Proteins; D011721:Pyrenes; D012235:Rhodamines; C026188:rhodamine 6G; D049452:Green Fluorescent Proteins; C030984:pyrene; C048960:indo-1; D019793:Fluorescein