Multimodal spectroscopic investigation of the conformation and local environment of biomolecules at an electrified interface

AbstractTwo-photon time-resolved fluorescence anisotropy methods were used to study the dynamical environment when fluorescent-labelled DNA oligomers (labelled with FAM, 6-fluorescein-6-carboxamido hexanoate) formed surface complexes with quaternized polyvinylpyridine (QPVP) cationic layers on a glass surface. We compared the anisotropy decay of DNA in bulk aqueous solution, DNA adsorbed onto QPVP, and QPVP-DNA-QPVP sandwich structures. When DNA was adsorbed onto QPVP, its anisotropy decay was dramatically retarded compared to the bulk, which means it had very slow rotational motion on the surface. Motions slowed down with increasing salt concentration up to a level of 0.1 M NaCl, but mobility began to increase at still higher salt concentration owing to detachment from the surface-immobilizing QPVP layers.

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Time-resolved fluorescence spectroscopic investigation of cationic polymer/DNA complex formation

Clinical and Biomedical Spectroscopy and Imaging II ◽

10.1364/ecbo.2011.80871j ◽

2011 ◽

Author(s):

Cosimo D'Andrea ◽

Andrea Bassi ◽

Paola Taroni ◽

Daniele Pezzoli ◽

Alessandro Volonterio ◽

...

Keyword(s):

Complex Formation ◽

Spectroscopic Investigation ◽

Cationic Polymer ◽

Time Resolved Fluorescence ◽

Time Resolved ◽

Dna Complex

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Perturbations of the local environment of the single tyrosine residue in neurophysin upon ligand binding as determined by steady-state and time-resolved fluorescence quenching

10.1117/12.58251 ◽

1992 ◽

Author(s):

Carol A. Hasselbacher ◽

Zhen H. Shen ◽

William R. Laws

Keyword(s):

Steady State ◽

Fluorescence Quenching ◽

Ligand Binding ◽

Local Environment ◽

Tyrosine Residue ◽

Time Resolved Fluorescence ◽

Time Resolved

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On the Local Environment Surrounding Pyrene in Near- and Supercritical Water

Applied Spectroscopy ◽

10.1366/0003702971939091 ◽

1997 ◽

Vol 51 (10) ◽

pp. 1547-1553 ◽

Cited By ~ 9

Author(s):

Emily D. Niemeyer ◽

Richard A. Dunbar ◽

Frank V. Bright

Keyword(s):

Supercritical Water ◽

Critical Density ◽

Local Environment ◽

Time Resolved Fluorescence ◽

Decay Kinetics ◽

Optical Cell ◽

Time Resolved ◽

Bulk Fluid ◽

Fluorescence Measurements ◽

System Temperature

We use steady-state and time-resolved fluorescence spectroscopy to probe local solvent–solute interactions between pyrene (the solute) and supercritical water (SCW). Toward this end, we have developed a new fiber-optic-based titanium high-pressure optical cell which can withstand the temperatures and pressure needed to generate supercritical water. Static fluorescence measurements indicate that there is an increase in the local water density surrounding the pyrene molecules (clustering) up to five times the bulk fluid density. This extent of clustering is most prevalent at about one-half the critical density. Consistent with previous work on more mild supercritical fluids (e.g., CO2, CF3H, C2H6), the extent of this solute–fluid clustering decreases as the system temperature and pressure are increased. Time-resolved fluorescence measurements show that the excited-state decay kinetics are exponentially activated and not themselves affected by this solute–fluid clustering process.

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