Water-soluble Cyanine Dyes Research Articles

Pulse Radiolysis Investigation of Radicals Derived from Water-Soluble Cyanine Dyes: Implications for Super-resolution Microscopy.

Light-induced blinking, an inherent feature of many forms of super-resolution microscopy, has been linked to transient reduction of the fluorescent cyanine dye used as an imaging agent. There is, however, only scant literature information related to one-electron reduced cyanine dyes, especially in an aqueous environment. Here, we examine a small series of cyanine dyes, possessing disparate π-conjugation lengths, under selective reducing or oxidizing conditions. The experiment allows recording of both differential absorption spectra and decay kinetics of the resultant one-electron reduced or oxidized transient species in water. Relative to the ground state, absorption transitions for the various radicals are weak and somewhat broadened but do allow correlation with the π-conjugation length. In all cases, absorption maxima lie to the blue of the main ground-state transition. Under anaerobic conditions, the transient species decay on the microsecond to millisecond time scale, with the mean lifetime depending on molecular structure, radiation dose, and dye concentration. The experimental absorption spectra recorded for the one-electron reduced radicals and the presumed dimer cation radical compare well to spectra obtained from time-dependent density functional theory calculations. The results allow conclusions to be drawn regarding the plausibility of the reduced species being responsible for light-induced blinking in direct stochastic optical reconstruction microscopy.

Peg derivatives for the synthesis of water-soluble cyanine dye Cy5

An effective method for the preparation of water-soluble cyanine dye Cy5 using the soluble polymers supported liquid-phase organic synthesis (LPOS) was proposed. Poly (ethylene glycol) methyl ether with a molecular weight of 2000 was used as a polymer substrate, which allowed us to simplify the characterization of products at intermediate stages of synthesis by NMR spectroscopy. This approach makes it easy to obtain the necessary cyanine dyes, which are widely used as fluorescent labels and are popular modifying reagents in biochemistry and medicine.

Synthesis of PEG derivatives bearing aminophenyl and their application for liquid-phase synthesis of water-soluble unsymmetrical cyanine dyes

The synthesis and NMR characterization of soluble PEG-supported polymers were described, and their subsequent application for liquid-phase synthesis of water-soluble cyanine dyes was also studied. Nucleophilic substitution of tosylation of PEG 16 with 1,3-bis(4-nitrophenoxy)-2-propanol 15 under basic conditions, followed by nitro group reduction, gave PEG-bound aminophenyl 18. Another PEG-bound aminophenyl 28 was prepared by condensation reaction of PEG-bound pentaerythritol 25 and 4-aminobenzoic acid followed by the cleavage of BOC group. Subsequent loading and activation of sulfoindoleninium to PEG derivatives 18 or 28 were achieved via simple strategies. Cyanine dyes were released by the attack of heterocyclic carbon nucleophile and the cleavage of PEG-bound hemicyanine without the chromatographic separation. The efficient, facile, and practical approaches appear to be robust and versatile strategies to deliver not only indocyanine dyes but also benzoindocyanine dyes.

Water-soluble cyanine dyes for biological microchip technology

Novel indodicarbocyanine dyes were obtained and their spectroscopic characteristics were determined. For equal concentrations of the dyes, the relative fluorescence efficiency was measured at the excitation wavelengths λ = 635 and 655 nm and the emission wavelengths λ = 670 and 690 nm, respectively.

An efficient approach to the synthesis of water-soluble cyanine dyes using poly(ethylene glycol) as a soluble support

An efficient synthesis approach to unsymmetrical water-soluble cyanine dyes has been established. Loading and activation of sulfoindolenium to poly(ethylene glycol) (PEG) have been achieved via a simple strategy. Cyanine dyes are released by the attack of heterocyclic carbon nucleophile and the cleavage of PEG-bound hemicyanine. The efficient approach delivers cyanine dyes in high purity without the nontrivial chromatographic separation.

Solid-Phase Methods for the Synthesis of Cyanine Dyes

We report here a series of studies that explore solid-phase methodologies for the synthesis of various cyanine dyes. The scope of the previously reported catch-and-release method using sulfonyl chloride resin(1) has now been extended to include pentamethine and water-soluble cyanine dyes. We also report a new and chemically distinct synthetic strategy, employing the stepwise attack of heterocyclic carbon nucleophiles on immobilized polyene-chain precursors, allowing the clean synthesis of hydrophobic and hydrophilic trimethine and pentamethine dyes from more easily obtained starting materials. Overall, both approaches appear to be robust and versatile strategies to delivering a wide range of cyanine-based dyes in high purity.

Layer-by-layer self-assembly of polyelectrolyte and water soluble cyanine dye

We have fabricated multilayer assemblies consisting of cyanine dye and polyelectrolyte by means of alternate adsorption method. In this study we used two kinds of water soluble thiacyanine dyes and poly(diallyldimethylammonium chloride) (PDDA) as polycation. Anionic cyanine dye molecules were adsorbed onto the positively charged surface of PDDA layer, giving rise to the J-aggregate. The sequential alternate adsorption yielded the PDDA-(dye/PDDA) n assemblies ( n, repeating number). UV-vis spectroscopy measurements indicated that peak absorbance at the J-band increased linearly with the increasing adsorption cycles. These results demonstrate the advantage of the alternate adsorption method for investigating J-aggregate-containing multilayer assemblies.

New glycoconjugated cyanine dyes as fluorescent labeling reagents

New highly water soluble cyanine dyes incorporating methyl glucopyranoside residues and reactive functionality are synthesised. The new dyes are conjugated to aminodextrans and to antibodies. The absorption and fluorescence properties of the new dyes and of the labeled substrates are discussed.

Formation of Herringbone Structure with Davydov Splitting in Cyanine Dye-Adsorbed Langmuir-Blodgett Films

Interface-adsorbed complex Langmuir-Blodgett (LB) films of arachidic acid and a water-soluble cyanine dye were fabricated using the diffusion-adsorption method. Formation of an H-aggregate with absorption band split was observed in the LB film. This split is assignable as Davydov splitting, which is characterized as the split of the band into two bands, whose transition moments are orthogonal to each other, due to formation of herringbonelike aggregates. The estimation of the molecular arrangement in the aggregate was performed based on Davydov's theory and the extended dipole model.

Modification of aggregate formation in arachidic-acid–cyanine-dye complex Langmuir–Blodgett films by substituent groups

Water-soluble cyanine dye derivatives can be adsorbed from aqueous solution to an arachidic acid monolayer at the air-water interface. Interface-adsorbed complex Langmuir–Blodgett films of arachidic acid and four different derivatives of thiacarbocyanine dyes were fabricated using this method, and their optical properties were examined employing a linearly polarized incident. Clear differences in both spectral shape and in-plane anisotropy were found among the films of different derivatives, each associated with an aggregate form characteristic of the substituent group. They can be classified as a dimer with Davydov splitting, a monomer, and a J aggregate. Estimation of the configuration of the molecules in the dimers and measurement of the photoluminescence spectrum for the J aggregate were performed to clarify the nature of aggregates. The results suggest the possibility of systematic control of aggregate formation in the system by introducing substituent groups for dyes.

Davydov splitting in arachidic acid-cyanine dye complex Langmuir–Blodgett films

A water-soluble cyanine dye is adsorbed from the solution to form a salt with an arachidic acid monolayer at the air-water interface. Complex monolayers thus formed were deposited onto substrates by the vertical dipping method to form Langmuir–Blodgett (LB) films. The optical properties of these films were examined employing a linearly polarized incident light. The films showed a large in-plane anisotropy of light absorption in both visible (electronic transition) and infrared (vibrational transition) regions. The in-plane anisotropy of the LB film is explained as due to the alignment of dimers, each showing Davydov splitting, by flow orientation during dipping. The configuration of the dye molecules in the dimer was estimated using Davydov’s theory and the extended dipole model. The layered structure of the film was determined by the x-ray diffraction technique.

Epitaxial growth of two-dimensional cyanine dye single crystals by adsorption at a pre-conditioned fatty acid monolayer

We have studied the adsorption of water-soluble cyanine dyes (pseudoisocyanine, PIC and “stains all”, SA) to monomolecular layers of arachidic acid (AA) at the water-air interface in a Langmuir trough. Upon adsorption the dye molecules organize themselves and form two-dimensional J-aggregates that can easily be observed and characterized in the fluorescence microscope. We show that AA can be “conditioned” by the adsorption of PIC in a lateral order that can be read-out after desorption of this first dye, by the adsorption of another dye, SA in our case. We interpret this memory effect as being caused by a structural and/or orientational modification of the AA monolayer that controls in addition to an electrostatic contribution, details of the crystal morphology and in this sense is a first example of epitaxial growth of two-dimensional organic crystals.

Crystalline two-dimensional domains of cyanine dyes at interfaces

The formation of two-dimensional crystalline J-aggregates of a negatively charged water-soluble cyanine dye at a monolayer of a dimethylammonium amphiphile is observed by fluorescence microscopy and spectroscopy. It is demonstrated that domain size and morphology and spectroscopic properties can be controlled via the surface layer. The formation of rod-shaped crystalline aggregates tightly bound to the surface layer is established. These domains are of uniform size and shape, and order due to long-rang electrostatic repulsion.