Time-autocorrelated two-photon counting technique for time-resolved fluorescence measurements

1999 ◽  
Vol 70 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Walter L. Borst ◽  
Lin-I Liu
Keyword(s):  
Photon Counting ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Two Photon ◽  
Counting Technique ◽  
Fluorescence Measurements

scholarly journals A Luminescent, Water-Soluble Ir(III) Complex as a Potential Photosensitizer for Two-Photon Photodynamic Therapy

2021 ◽  
Vol 11 (24) ◽  
pp. 11596
Author(s):  
Elisabeta I. Szerb ◽  
Sharmistha Chatterjee ◽  
Massimo La Deda ◽  
Giovanna Palermo ◽  
Lucie Sancey ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Water Soluble ◽  
In Vitro Experiments ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Biologically Relevant ◽  
Two Photon ◽  
Fluorescence Measurements ◽  
Detection Probe

This work reports the study of two-photon induced properties of a highly luminescent cyclometalated Ir(III) complex, [Ir(ppy)2(en)] OOCCH3 (1), ppy = 2-phenylpyridine, en = ethylenediamine. Steady-state and time-resolved fluorescence measurements were performed by exciting 1 at the biologically relevant wavelength of 800 nm, whereas, the generation of singlet oxygen (1O2) was evaluated using 9,10-Anthracenediyl-bis(methylene)dimalonic acid (ABDA) as a detection probe. Preliminary in vitro experiments with U87-MG cells were performed, showing the potential of this compound as a two-photon photodynamic therapy (2P-PDT) agent at NIR wavelengths.

Time-resolved fluorescence from biological systems: tryptophan and simple peptides

1980 ◽  
Vol 298 (1439) ◽  
pp. 321-334 ◽  
Keyword(s):  
Time Resolution ◽  
Single Photon ◽  
Photon Counting ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Single Photon Counting ◽  
Fluorescence Measurements ◽  
Mode Locked Lasers ◽  
Electron Transfers ◽  
Sensitive Method

Four methods of applying mode-locked lasers to time-resolved fluorescence measurements in the subnanosecond region are compared. When time resolution below 100 ps is not required, the most precise and sensitive method is single-photon counting, and the application of this method to studies of time-resolved fluorescence of tryptophan in simple peptides is described. The dependence of lifetimes on pH and temperature are interpreted in terms of quenching by intramolecular proton and electron transfers.

Sensitive, rapid procedure for time-resolved immunofluorometry of lutropin.

1988 ◽  
Vol 34 (8) ◽  
pp. 1640-1644 ◽  
Author(s):  
M J Khosravi ◽  
R C Morton ◽  
E P Diamandis
Keyword(s):  
Monoclonal Antibody ◽  
Solid Phase ◽  
Detection System ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Practical Procedure ◽  
Daily Monitoring ◽  
Fluorescence Measurements ◽  
Capture Antibody ◽  
Europium Chelate

Abstract In this new immunofluorometric method for quantification of lutropin in serum, the "sandwich" principle is combined with time-resolved fluorescence measurements, with the europium chelate 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid (BCPDA) used as label. A monoclonal antibody to the alpha-subunit of lutropin is adsorbed onto the walls of white-opaque microtiter wells to form the solid-phase capture antibody, and a biotin-labeled soluble monoclonal antibody is used for antigen quantification. The detection system is completed with streptavidin, which has been linked to a protein bulking agent labeled with multiple BCPDA residues. In the presence of excess europium, the fluorescence of the final complex attached to captured lutropin molecules is measured on the dried solid phasse with an automated time-resolved fluorometer. The assay can be performed as a rapid (less than 60 min incubation) or regular (150 min incubation) procedure. The rapid assay is well-suited for routine daily monitoring of increasing or ovulatory lutropin concentrations; the regular assay, with its greater sensitivity (0.5 int. unit/L), is a practical procedure for lutropin measurements in hyposecretory states. The assay measures up to 240 int. units/L, and results compare well with those by a commercially available radioimmunoassay, an immunoradiometric assay, and another time-resolved immunofluorometric procedure.

Local Environment of Surface-Polyelectrolyte-Bound DNA Oligomers

2000 ◽  
Vol 651 ◽  
Author(s):  
Sangmin Jeon ◽  
Sung Chul Bae ◽  
Jiang John Zhao ◽  
Steve Granick
Keyword(s):  
Aqueous Solution ◽  
Salt Concentration ◽  
Fluorescence Anisotropy ◽  
Local Environment ◽  
Time Resolved Fluorescence ◽  
Surface Complexes ◽  
Dna Oligomers ◽  
Time Resolved ◽  
Two Photon ◽  
Anisotropy Decay

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.

scholarly journals Development, Characterization, and Application of a Versatile Single Particle Detection Apparatus for Time-Integrated and Time-Resolved Fluorescence Measurements—Part II: Experimental Evaluation

2009 ◽  
Vol 2009 ◽  
pp. 1-14
Author(s):  
Xihong Wu ◽  
J. A. Merten ◽  
N. Omenetto ◽  
B. W. Smith ◽  
J. D. Winefordner
Keyword(s):  
Single Particle ◽  
Narrow Beam ◽  
Time Resolved Fluorescence ◽  
Particle Detection ◽  
Time Resolved ◽  
Endogenous Fluorophores ◽  
Fluorescence Measurements ◽  
On Line ◽  
Single Particle Detection ◽  
Speed Mode

This paper describes the experimental realization and characterization of a versatile single particle detection apparatus. The system utilizes a novel particle beam inlet that can serve as either an on-line particle concentrator (i.e., all diameters confined in a narrow beam) or as a segregator (i.e., selected diameters confined in a narrow beam) and can be operated in a high-speed mode as well as in a low-speed mode, thus allowing different interaction times between the particles and the laser beam. An aerodynamic sizing technique has been incorporated into the system to provide rapid, real-time, and high-resolution sizing. Parameters such as transmission efficiency and size-segregation efficiency have been measured. The performance of the instrument has been demonstrated by on-line detection of spectrally resolved and time resolved fluorescence detection from airborne dye-doped particles and aerosolized endogenous fluorophores found in biological agents.

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