Complex NAPL Site Characterization Using Fluorescence Part 1: Selection of Excitation Wavelength Based on NAPL Composition

2004 ◽  
Vol 13 (2) ◽  
pp. 103-118 ◽  
Author(s):  
MARK L. KRAM ◽  
ARTURO A. KELLER ◽  
STEVE M. MASSICK ◽  
LEROY E. LAVERMAN
Keyword(s):  
Site Characterization ◽  
Excitation Wavelength ◽  
Selection Of

Multispectral Imaging in Light Microscopy

1998 ◽  
Vol 4 (S2) ◽  
pp. 126-127
Author(s):  
K. R. Spring
Keyword(s):  
Light Microscopy ◽  
Multispectral Imaging ◽  
Signal To Noise Ratio ◽  
Monochromatic Light ◽  
Tunable Filters ◽  
Excitation Wavelength ◽  
Wavelength Selection ◽  
Emission Signal ◽  
Excitation Laser ◽  
Selection Of

Many recent applications in light microscopy involve the use of multiple fluorophores or the delineation of signals arising from spectrally distinct sources. In microspectroscopy, it is always desirable to illuminate fluorescently-labeled microscopic specimens with monochromatic light as the narrowest possible excitation wavelength range usually results in the highest emission signal-to-noise ratio. Generation of polychromatic light from an arc lamp and selection of the excitation wavelength by interference filters or monochrometers are the most common techniques for excitation microspectrofluorometry. Emission spectroscopy is usually done with filter wheels, monochrometers, or interferometers inserted between the microscope detection port and the detector. This presentation will be directed toward other, less frequently-used, approaches for spectral scanning of the specimen in the light microscope. Three topics will be considered: 1) the use of acousto-optical tunable filters and lasers for rapid, narrow-band, excitation wavelength selection; 2) the use of holographic notch filters for rejection of unwanted excitation laser light; 3) using liquid-crystal tunable filters for emission scanning.

scholarly journals Optimization of Nonspherical Gold Nanoparticles for Photothermal Therapy

2019 ◽  
Vol 9 (20) ◽  
pp. 4300
Author(s):  
Paerhatijiang Tuersun ◽  
Xiayiding Yakupu ◽  
Xiang’e Han ◽  
Yingzeng Yin
Keyword(s):  
Gold Nanoparticles ◽  
Refractive Index ◽  
Photothermal Therapy ◽  
Therapeutic Agents ◽  
Tissue Type ◽  
Excitation Wavelength ◽  
Objective Functions ◽  
Design Tolerance ◽  
T Matrix ◽  
Selection Of

Previous investigations devoted to the optimization of nonspherical gold nanoparticles for photothermal therapy (PTT) encountered two issues, namely, the appropriate selection of objective functions and the processing of particle random orientations. In this study, these issues were resolved, and accurate optimization results were obtained for the three typical nonspherical gold nanoparticles (nanospheroid, nanocylinder, and nanorod) by using the T-matrix method. The dependence of the optimization results on the excitation wavelength and the refractive index of tissue was investigated. Regardless of the excitation wavelength and tissue type, gold nanospheroids were found to be the most effective therapeutic agents for PTT. The light absorption ability of optimized nanoparticles could be enhanced by using a laser with a longer wavelength. Finally, the design tolerance for the different sizes of nanoparticles was provided.

Consideration of end effects of DNA hybridization in selection of fluorescent dyes for development of optical biosensors

1999 ◽  
Vol 77 (12) ◽  
pp. 2083-2087 ◽  
Author(s):  
S C Jakeway ◽  
U J Krull
Keyword(s):  
Quantum Efficiency ◽  
Dna Hybridization ◽  
Fluorescent Dyes ◽  
Hydrocarbon Chain ◽  
Spectroscopic Properties ◽  
Excitation Wavelength ◽  
End Effects ◽  
High Quantum Efficiency ◽  
The Stability ◽  
Selection Of

Intercalating fluorescent dyes are in widespread use to detect the presence of double-stranded DNA. Applications include the development of biosensors that rely on the attachment ("tethering") of a dye molecule by a short hydrocarbon chain to the terminus of a strand of DNA so that dye is continuously available and the biosensor is fully reversible. Double strands of DNA have end effects that limit the stability of hybridization and dye intercalation near the termini of the duplexes. Therefore, the selection of the dye must be based on consideration of spectroscopic properties and also issues associated with tether length and the stoichiometry of the binding of the dye with double- and single-stranded DNA. Ethidium bromide (EB) has been used extensively to detect hybridization of DNA in applications such as electrophoresis, gene chips, and biosensors. A number of dyes with greater quantum efficiency than EB for detection of hybridization have been reported. Furthermore, other practical spectroscopic advantages can be gained in terms of improved S/N by use of dyes that have excitation that is red shifted relative to EB. Pyrilium iodide has been disclosed as an intercalator of high quantum efficiency and long excitation wavelength. This work investigates pyrilium iodide in comparison to EB as a candidate for preparation of a tethered dye for detection of hybridization of DNA 20-mers.Key words: biosensors, DNA, hybridization, fluorescence, end effects.

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