Absorption spectra were studied for two series of 3 cyanine dyes with varying length of conjugated hydrocarbon chains. Fine sturctures in absortpiton spectra were analyzed to determine its concentraion dependence as the concentraion of dyes were changed from 10 –8 M to 10 –4 M. In all 6 dyes studied, ratios of minor peaks to the major peak remained constant within the experiemntal error. These ...

The quantum yields for singlet oxygen generation of several squarylium cyanine dyes derived from benzothiazole, benzoselenazole and quinoline, displaying absorption within the so-called “phototherapeutic window” (600–1000 nm), were determined, envisioning their potential usefulness for photodynamic therapy (PDT). The determination was performed by a direct method measuring the luminescence deca...

Fluorescence probes and labels have become indispensable tools for clinical diagnostics, high-throughput screening, and other biomedical applications. We have developed several classes of new squaraine-based red and near-infrared (NIR) probes and labels (SETA and Square series), naphthalimide-based fluorescence lifetime dyes (SeTau series), and cyanine- and squaraine-based quenchers (SQ series)...

Spectroscopic properties, two-photon absorption (TPA) and excited state absorption (ESA), of two organic cyanine dyes and of a ruthenium based organometallic cyanine are compared in order to rationalize their similar ns-optical power limiting (OPL) efficiency in the telecommunication wavelength range. The TPA contribution to the ns-OPL behavior is higher for both organic cyanines, while the mai...

A series of ratiometric probes based on heptamethine cyanine dyes for detecting hypochlorous acid have been developed. Here we present the synthesis, characterization and fluorescence properties of these probes. And it turns out that the probes are highly sensitive and selective toward hypochlorous acid. More importantly, the application in living cells for ratiometric imaging of hypochlorous a...

Volume 1 • Issue 4 • 1000e111 Biochem Anal Biochem ISSN:2161-1009 Biochem, an open access journal Labeling molecules without losing its activity has a long track in science. The first labeling method for detection of the biomolecules was the use of radioisotope entities like 32P, which have been successfully employed to study protein–protein, protein–DNA, protein–RNA and protein–ligand interact...

As continuation of previous studies, the ability of T-284 and SH-516 cyanine dyes (Figure 1) to selectively detect fibrillar proteins of various amino acids composition (insulin, lysozyme, αsynuclien) was evaluated using fluorescence spectroscopy methods (Table). Both dyes were shown to be applicable for detection of various fibrillar protein species (Figure 2). T-284 demonstrated particular se...

Structurally diverse near-infrared (NIR) absorbing polymethine dyes were prepared and their fluorescence lifetimes (FLT) were evaluated in relation to their structural features. Comparative FLT analysis based on the modification of methine chain length and heterocyclic system showed that indolium or benz[e]indolium heptamethine dyes exhibited longer FLT than the benz[c,d]indolium trimethine dye...

Cyanine dyes are commonly used for fluorescent labeling of DNA and RNA oligonucleotides in applications including qPCR, sequencing, fluorescence in situ hybridization, Förster resonance energy transfer, and labeling for microarray hybridization. Previous research has shown that the fluorescence efficiency of Cy3 and Cy5, covalently attached to the 5' end of single-stranded DNA, is strongly sequ...

Super-resolution (SR) fluorescence imaging relies on specially adapted microscopes and analysis software, but equally important are the fluorescent probes used to label biological proteins and molecules of interest. In point-localization SR, the on and off rates of fluorophore photoswitching must be controlled to separate the signals from individual molecules temporally. The fluorescence from e...