Investigation of multiphoton-induced fluorescence from solutions of 5-hydroxytryptophan

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Bisby, RH ; Arvanitidis, M ; Botchway, CW ; Clark, IP

It is reported (Shear et al, Photochem.Photobiol. 65, 931 (1997) ) that multiphoton near infrared excitation of 5-hydroxytryptophan results in a transient product with green fluorescence. Visible fluorescence from multiphoton excitation enables detection of 5 hydroxytryptophan with extremely high sensitivity and also has potential applications in imaging of biological systems and investigation of protein dynamics. The characteristic fluorescence at 500 nm has now also been observed on one-photon photolysis of solutions at 308 nm, followed by excitation of fluorescence at 430 nm. Fluorescence was observed in aerated and deaerated solutions and in the presence of ascorbate. Enhancement of fluorescence was observed on addition of ethanol. Transient absorption experiments with 308 nm photolysis showed the formation of three transient species. In the presence of ascorbate the radical formed by photoionisation was removed, revealing a long-lived species (τ > 1 ms)) with a similar absorption spectrum, which is ascribed to the fluorescing species. Fluorescence induced by multiphoton excitation had a lifetime of 910 ± 10 ps and was also unaffected by ascorbate. In the presence of organic solvents there was an increase in fluorescence lifetime, but a decrease in overall fluorescence intensity. The fluorescence intensity and fluorescence lifetime both decreased in acidic solution (pH < 3). It is suggested that the fluorescence originates not from the 5-indoxyl radical, but from a transient product formed by intramolecular rearrangement.
  • References (22)
    22 references, page 1 of 3

    1. C.Xu, W.Zipfel, J.B.Shear, R.M.Williams and W.W.Webb, Multiphoton fluorescence excitation: new spectral windows for biological nonlinear microscopy, Proc.Natl.Acad,Sci. USA, 1996, 93, 10763-10768.

    2. B.R.Masters, P.T.C.So, K.H.Kim, C.Beuhler and E.Gratton, Multiphoton excitation microscopy, confocal microscopy, and spectroscopy of living cells and tissues, Adv.Enzymol., 1999, 307, 513-536.

    3. D.J.S.Birch, Multiphoton excited fluorescence spectroscopy of biomolecular systems, Spectrochim. Acta A, 2001, 57, 2313-2336.

    4. J.B.S.Shear, C.Xu and W.W.Webb, Multiphoton-excited visible emission by serotonin solutions, Photochem.Photobiol., 1997, 65, 931-936.

    5. a) M.L.Gostkowski, J.Wei and J.B.Shear, Measurements of serotonin and related indoles using capillary electrophoresis with multiphoton-induced hyperluminescence, Anal.Biochem., 1998, 260, 244-250. b) M.L.Gostkowski, J.B.McDoniel, J.Wei, T.E.Curey and J.B.Shear, Characterizing spectrally diverse biological chromophore using capillary electrophoresis with multiphoton-excited fluorescence, J.Amer.Chem.Soc., 1998, 120, 18-22.

    6. S.W.Botchway, A.W.Parker, I.Barba and K.Brindle, Development of a time-correlated single photon counting multiphoton laser scanning confocal microscope, Central Laser Facility Annual Report, 2000-2001, RAL-TR-2001-030:pp. 170-171.

    7. M.L.Gostkowski, T.E.Curey, E.Okerberg, T.J.Kang, D.A.V.Bout and J.B.Shear, Effects of molecular oxygen on multiphoton-excited photochemical analysis of hydroxyindoles, Anal.Chem., 2000, 72, 3821-3825.

    8. S.Udenfriend, D.F.Bogdanski and H.Weissbach, Fluorescence characteristics of 5- hydroxytryptamine (serotonin), Science, 1955, 122, 972-973.

    9. S.V.Jovanovic, S.Steenken and M.G.Simic, One-electron reduction potentials of 5- indoxyl radicals, J.Phys.Chem., 1990, 94, 3583-3588.

    10. S.V.Jovanovic and M.G.Simic, Tryptophan metabolites as antioxidants, Life Chem.Rep., 1985, 3, 124-130.

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