title: Coherent manipulation of free amino acids fluorescence.
abstract: Coherent manipulation of molecular wavepackets in biomolecules might contribute to the quest towards label-free cellular imaging and protein identification. We report the use of optimally tailored UV laser pulses in pump-probe depletion experiments that selectively enhance or decrease fluorescence between two aromatic amino acids: tryptophan (Trp) and tyrosine (Tyr). Selective fluorescence modulation is achieved with a contrast of ~35%. A neat modification of the time-dependent fluorescence depletion signal of Trp is observed, while the Tyr transient trace remains unchanged. The mechanism invoked for explaining the change of the depletion of Trp is a less efficient coupling between the fluorescing state and the higher non-radiative excited states by the optimally shaped pulse, than by the reference pulse.
authors.affiliation: GAP-Biophotonics, University of Geneva, 22 ch. de Pinchat, CH-1211 Geneva 4, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Rondi
authors.forename: L
authors.initials: L
authors.lastname: Bonacina
authors.forename: A
authors.initials: A
authors.lastname: Trisorio
authors.forename: C
authors.initials: C
authors.lastname: Hauri
authors.forename: J-P
authors.initials: JP
authors.lastname: Wolf
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D005453:Fluorescence; D015394:Molecular Structure; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry
chemical_list: D000596:Amino Acids; D014443:Tyrosine; D014364:Tryptophan