PMID- 26874502
OWN - NLM
STAT- MEDLINE
DCOM- 20161027
LR  - 20161230
IS  - 1089-7690 (Electronic)
IS  - 0021-9606 (Linking)
VI  - 144
IP  - 6
DP  - 2016 Feb 14
TI  - Structural relaxation of acridine orange dimer in bulk water and inside a single 
      live lung cell.
PG  - 065101
LID - 10.1063/1.4941415 [doi]
AB  - Structural relaxation of the acridine orange (AO) dimer in bulk water and inside 
      a single live lung cell is studied using time resolved confocal microscopy and 
      molecular dynamics (MD) simulations. The emission maxima (lambdaem (max) approximately  630 nm) of 
      AO in a lung cancer cell (A549) and a non-cancer lung fibroblast cell (WI38) 
      suggest that AO exists as a dimer inside the cell. Time-dependent red shift in 
      emission maximum indicates dynamic relaxation of the AO dimer (in the excited 
      state) with a time constant of 500-600 ps, both in bulk water and inside the 
      cell. We have calculated the equilibrium relaxation dynamics of the AO dimer in 
      the ground state using MD simulations and found a slow component of time scale  approximately  
      350 ps. The intra- and inter-molecular components of the total relaxation 
      dynamics of the AO dimer reveal the presence of a slow component of the order of 
      a few hundred picoseconds. Upon restricting intra-molecular dye dynamics by 
      harmonic constraint between AO monomers, the slow component vanishes. Combining 
      the experimental observations and MD simulation results, we ascribe the slow 
      component of the dynamic relaxation of the AO dimer to the structural relaxation, 
      namely, fluctuations in the distance between the two monomers and associated 
      fluctuation in the number of water molecules.
FAU - Chowdhury, Rajdeep
AU  - Chowdhury R
AD  - Department of Physical Chemistry, Indian Association for the Cultivation of 
      Science, Jadavpur, Kolkata 700032, India.
FAU - Nandi, Somen
AU  - Nandi S
AD  - Department of Physical Chemistry, Indian Association for the Cultivation of 
      Science, Jadavpur, Kolkata 700032, India.
FAU - Halder, Ritaban
AU  - Halder R
AD  - Department of Physical Chemistry, Indian Association for the Cultivation of 
      Science, Jadavpur, Kolkata 700032, India.
FAU - Jana, Biman
AU  - Jana B
AD  - Department of Physical Chemistry, Indian Association for the Cultivation of 
      Science, Jadavpur, Kolkata 700032, India.
FAU - Bhattacharyya, Kankan
AU  - Bhattacharyya K
AD  - Department of Physical Chemistry, Indian Association for the Cultivation of 
      Science, Jadavpur, Kolkata 700032, India.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Chem Phys
JT  - The Journal of chemical physics
JID - 0375360
RN  - 059QF0KO0R (Water)
RN  - F30N4O6XVV (Acridine Orange)
SB  - IM
MH  - Acridine Orange/*chemistry
MH  - Cell Line
MH  - Cell Survival
MH  - *Dimerization
MH  - Humans
MH  - Lung/*chemistry/*cytology
MH  - Microscopy, Confocal
MH  - Molecular Dynamics Simulation
MH  - Molecular Structure
MH  - Water/*chemistry
EDAT- 2016/02/16 06:00
MHDA- 2016/11/01 06:00
CRDT- 2016/02/15 06:00
PHST- 2016/02/15 06:00 [entrez]
PHST- 2016/02/16 06:00 [pubmed]
PHST- 2016/11/01 06:00 [medline]
AID - 10.1063/1.4941415 [doi]
PST - ppublish
SO  - J Chem Phys. 2016 Feb 14;144(6):065101. doi: 10.1063/1.4941415.