Structural relaxation of acridine orange dimer in bulk water and inside a single live lung cell.
J Chem Phys
; 144(6): 065101, 2016 Feb 14.
Article
em En
| MEDLINE
| ID: mdl-26874502
ABSTRACT
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 (λem (max)â¼ 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 â¼ 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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Laranja de Acridina
/
Água
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Dimerização
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Pulmão
Limite:
Humans
Idioma:
En
Revista:
J Chem Phys
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Índia