Correlation Engine 2.0
Clear Search sequence regions

  • 2 me (3)
  • anion (2)
  • b 3 (2)
  • behavior (2)
  • cell (4)
  • cell membrane (1)
  • cellular (1)
  • compartments cells (1)
  • essential (1)
  • humans (1)
  • light (1)
  • organosilicon compounds (2)
  • phosphate (1)
  • protons (3)
  • silicon (4)
  • xanthenes (2)
  • Sizes of these terms reflect their relevance to your search.

    Dyes with near-red emission are of great interest because of their undoubted advantages for use as probes in living cells. In-depth knowledge of their photophysics is essential for employment of such dyes. In this article, the photophysical behavior of a new silicon-substituted xanthene, 7-hydroxy-5,5-dimethyl-10-(o-tolyl)dibenzo[b,e]silin-3(5H)-one (2-Me TM), was explored by means absorption, steady-state, and time-resolved fluorescence. First, the near-neutral pH, ground-state acidity constant of the dye, pKN-A, was determined by absorbance and steady-state fluorescence at very low buffer concentrations. Next, we determined whether the addition of phosphate buffer promoted the excited-state proton-transfer (ESPT) reaction among the neutral and anion form of 2-Me TM in aqueous solutions at near-neutral pH. For this analysis, both the steady-state fluorescence method and time-resolved emission spectroscopy (TRES) were employed. The TRES experiments demonstrated a remarkably favored conversion of the neutral form to the anion form. Then, the values of the excited-state rate constants were determined by global analysis of the fluorescence decay traces recorded as a function of pH, and buffer concentration. The revealed kinetic parameters were consistent with the TRES results, exhibiting a higher rate constant for deprotonation than for protonation, which implies an unusual low value of the excited-state acidity constant pK*N-A and therefore an enhanced photoacid behavior of the neutral form. Finally, we determined whether 2-Me TM could be used as a sensor inside live cells by measuring the intensity profile of the probe in different cellular compartments of HeLa 229 cells.


    Luis Crovetto, Angel Orte, Jose M Paredes, Sandra Resa, Javier Valverde, Fabio Castello, Delia Miguel, Juan M Cuerva, Eva M Talavera, Jose M Alvarez-Pez. Photophysics of a Live-Cell-Marker, Red Silicon-Substituted Xanthene Dye. The journal of physical chemistry. A. 2015 Nov 5;119(44):10854-62

    Expand section icon Mesh Tags

    Expand section icon Substances

    PMID: 26465171

    View Full Text