Microwave-assisted solvent-free synthesis and spectral properties of some dimethine cyanine dyes as fluorescent dyes for DNA detection

A series of dimethine cyanine dyes were synthesized in a fast, efficient and high yield by the condensation of quaternary salts with 1H-indole-3-carbaldehyde in the presence of piperidine under solvent-free microwave irradiation. The products were identified by ¹H NMR, IR, UV–vis spectroscopy and elemental analysis. The absorption and fluorescence properties of the dyes in both the free state and DNA or BSA were investigated. Significant enhancement of the fluorescent quantum yield was observed for all the dyes in the presence of DNA, with one compound demonstrating excellent sensitivity as a fluorescent probe.     

双羟基七甲川菁染料的合成及其光谱性能研究

通过分子设计,分别以2,3,3-三甲基吲哚和1,1,2-三甲基-1H-苯并[e]吲哚为原料,首先合成两种季铵盐,再分别同2-氯-1-甲酰-3-羟基亚甲基环己烯缩合,利用Suzuki-Miyaura反应实现染料中位C—C偶联,以超过70%的收率制备了4种带有活性羟基的七甲川菁染料。利用核磁和高分辨率质谱对染料结构进行了表征。以乙醇为溶剂,用紫外-可见光谱仪考察了染料的光谱性能。采用电流为13.4 A的高压氙灯为光源,考察了染料的光稳定性。探究了pH对染料颜色的影响,并尝试推论变色机理。结果表明,4种七甲川菁染料均在近红外区产生较强吸收,在无水乙醇中均具有良好的光稳定性。不同pH下,染料的光谱性能研究发现,七甲川菁染料吸收光谱受pH影响较大,在pH=5～7时,染料在近红外区有最佳吸收。     

Improvement of the dyeing and fastness properties of a naphthalimide fluorescent dye using poly(amidoamine) dendrimer

In this study, 4‐amino‐9‐methoxypropylnaphthalimide fluorescent dye (dye 1 ) was reacted with poly(amidoamine) dendrimer G = ?0.5 to prepare a naphthalimide–dendrimer hybrid dye (dye 2 ). The chemical structures of the synthesised dyes were confirmed by elemental analysis, Fourier transform infrared spectroscopy, ¹H nuclear magnetic resonance spectroscopy, and ultraviolet‐visible spectroscopy. The solvatochromism of the dyes was evaluated in various solvents with respect to visible absorption properties, and positive solvatochromism was observed by solvent polarity change from chloroform to ethanol. The dyeing ability of the synthesised dyes was investigated by their application onto nylon fabric, and nylon substrates dyed with dye 2 exhibited marked enhancement both in terms of colour strength and general fastness properties. The results of this study clearly demonstrated the high potential and performance of dye 2 as a novel promising fluorescent dye as compared with dye 1 . Overall, it was inferred that the modification of the naphthalimide fluorescent dye with poly(amidoamine) denderimer could markedly improve the dyeing and fastness properties of the naphthalimide fluorescent dye on nylon fabrics.     

Spectroscopic study of cyanine dyes interacting with the biopolymer,DNA

Dyes intercalated into DNA strands or bound to grooves show fluorescence intensity changes and aggregate formation depending on the conditions. In order to establish some empirical rules concerning dye intercalation, spectroscopic studies for the effects of DNA on several series of cyanine dyes with different aromatic rings, conjugated chain length and alkyl substituents were made. Absorption spectra, fluorescence intensity and circular dichroism spectra showed strong dependence on the species of dyes. Combination of preceding studies and these present results indicates that cyanine dyes tend to intercalate into DNA strand if their polymethine bridge was composed of only one carbon. For molecules with the longer chains irregular aggregates were formed by small amounts of DNA, which transformed into complexes composed of multiple dye and DNA strands. These results would serve as a useful guideline for designing of optical functional materials and devices utilizing DNA complex.     

Synthesis and characterisation of microencapsulated 7‐alkyloxy‐4‐trifluoromethylcoumarin dyes

Five new 7‐alkyloxy‐4‐trifluoromethylcoumarin fluorescent dyes were synthesised using the Pechmann and Williamson etherification reactions. The structures of these coumarin dyes were characterised by Fourier Transform–infrared, proton and carbon nuclear magnetic resonance and mass spectra. One of the new coumarin compounds, 7‐isopropyloxy‐4‐trifluoromethylcoumarin, was microencapsulated with melamine–formaldehyde as the shell material by in situ polymerisation. The microcapsules were characterised in terms of Fourier Transform–infrared spectrum, particle size distribution and scanning electron microscopy morphology. The cotton fabric finished with the microencapsulated coumarin dye showed strong fluorescence under ultraviolet light.     

Synthesis of novel tetracationic asymmetric monomeric monomethine cyanine dyes – highly fluorescent dsDNA probes

Quaternisation of monomethine cyanine dyes bearing haloalkyl chains, with the appropriate monoquaternised 1,4‐diazabicyclo[2.2.2]octane derivatives, yielded novel tetracationic asymmetric monomeric monomethine cyanine dyes belonging to the thiazole orange family. The optimal conditions for this reaction were investigated. The longest wavelength absorption maxima of the studied dyes are in the region 504–507 nm. The molar absorptivities of the target dyes are high, with values between 70 500 and 99 500 l mol^?1 cm^?1. The fluorescence intensity and the fluorescence quantum yields of the free dyes in solution or in the presence of double‐stranded DNA were determined using thiazole orange for comparison. The dyes are suitable for nucleic acid detection and have a high binding affinity, attributable to their four positive charges.     

Styryl dyes – synthesis and applications during the last 15 years

One of the most widely used and important groups of functional dyes are the styryl dyes and a review of this functional dye class has not been published for more than 15 years. In this review article, we describe the new trends in the synthesis of a range of novel intermediates and styryl dyes and include the most interesting examples of their high‐tech applications. However, this review is not intended to be comprehensive because of the large number of styryl dye studies that have been carried out in this time. Styryl cyanine dyes are widely used in optical recording media in laser discs, as flexible dyes, laser dyes, as optical sensitisers and in various other fields, for example dye‐sensitised solar cells and dyes with non‐linear optical properties. Additionally, the most important applications for these dyes are in bio‐labelling and in medicinal analysis.     

Cyanine Dyes for Photo-Thermal Therapy: A Comparison of Synthetic Liposomes and Natural Erythrocyte-Based Carriers

Cyanine fluorescent dyes are attractive diagnostic or therapeutic agents due to their excellent optical properties. However, in free form, their use in biological applications is limited due to the short circulation time, instability, and toxicity. Therefore, their encapsulation into nano-carriers might help overcome the above-mentioned issues. In addition to indocyanine green (ICG), which is clinically approved and therefore the most widely used fluorescent dye, we tested the structurally similar and cheaper alternative called IR-820. Both dyes were encapsulated into liposomes. However, due to the synthetic origin of liposomes, they can induce an immunogenic response. To address this challenge, we proposed to use erythrocyte membrane vesicles (EMVs) as “new era” nano-carriers for cyanine dyes. The optical properties of both dyes were investigated in different biological relevant media. Then, the temperature stability and photo-stability of dyes in free form and encapsulated into liposomes and EMVs were evaluated. Nano-carriers efficiently protected dyes from thermal degradation, as well as from photo-induced degradation. Finally, a hemotoxicity study revealed that EMVs seem less hemotoxic dye carriers than clinically approved liposomes. Herein, we showed that EMVs exhibit great potential as nano-carriers for dyes with improved stability and hemocompatibility without losing excellent optical properties.     

菁染料在荧光探针及光动力疗法中的应用

菁染料的研究及应用已有100多年的历史，近年来，它们在生物方面的应用研究已取得一定的成果．本就近几年菁染料及其衍生物在生物医疗方面的研究及进展情况加以综述，特别阐述了这类染料用作荧光探针在生物大分子标识以及作为光敏剂在光动力疗法(PDT)中用于恶性肿瘤的诊断与治疗这两方面的研究进展．     

DNA-templated assembly of helical cyanine dye aggregates: a supramolecular chain polymerization

Symmetrical cationic cyanine dyes assemble in cooperative fashion into helical supramolecular polymers using DNA as a template. The dyes assemble into cofacial dimers within the minor groove of the DNA and assembly of one dimer facilitates assembly of additional dimers directly adjacent to the first. Growth of the polymer ceases when the end of the DNA is reached or when the DNA sequence blocks dimerization of the dye. Thus, this process can be thought of as a supramolecular analogue of a chain polymerization. This Account describes how polymerization depends on the dye structure and DNA sequence and also summarizes the interesting optical properties exhibited by these chiral, helical materials.     

Dispersant‐free dyeing of poly(lactic acid) fabric with temporarily solubilised disperse dyes from azopyridone derivatives

Poly(lactic acid) fibre is derived from annually renewable crops and known to be 100% compostable. In order to extend its environmental friendliness into the dyeing process, dispersant‐free dyeing of poly(lactic acid) fabric with three temporarily solubilised azo disperse dyes based on hydroxypyridone moiety containing a β‐sulphatoethylsulphonyl group was investigated. The dyes were successfully applied to poly(lactic acid) fabric without the use of dispersants. The colour yields of the dyes on poly(lactic acid) fabric were observed to be dependent on dyebath pH and dyeing temperature. The optimum results were obtained at pH 4–5 and 110 °C. One of the dyes showed a colour yield as good as that of a commercial disperse dye and good build‐up on poly(lactic acid) fabric. All of the dyes could be alkali cleared owing to ionisation of the dye under mild alkaline conditions. Wash fastness was good to very good, and light fastness was good. The chemical oxygen demand levels of the poly(lactic acid) dyeing effluent from the dyes were considerably lower than those from a commercial disperse dye.     

An innovative study on dyeing silk fabrics by modified phospholipid liposomes

Modified phospholipids from the commercial soybean lecithin were prepared via acetylation of the acetone insoluble fraction phosphatidylethanolamine. N‐Acetyl‐phosphatidylethanolamine was used to prepare liposomes for encapsulating anionic dyes (acid and reactive dyes) to be used in dyeing silk fabric. Size measurements of the liposomes showed that the maximum vesicle size was 36.61 nm for empty liposomes in comparison with 39.08 and 39.75 nm for acid dyes and 51.78 and 59.20 nm for reactive dyes. The efficiency of the micro‐encapsulated dyes to dye silk fabric has been investigated and compared with the conventional dyeing process using different parameters. It was confirmed that the acetylated acetone insoluble fraction liposome shows better encapsulation of the reactive dyes and achieves more dye uptake than the acid dyes. It was also found that fastness properties of dyed silk with micro‐encapsulated anionic dyes did not change significantly more than the conventional dyeing method. Reuse of the micro‐encapsulated dyebath produces low water pollution as the effluent is virtually colourless. As a result, the process is also economic and eco‐friendly.     

菁染料与溴化银相互作用性质的研究

本文用计时电位法及电位滴定研究了十六种不同染料与溴化银之间的相互作用,进一步证明了具有离域π-电子的菁染料才能与卤化银形成络合物的论点。从得到的平衡常数K表明,固体表面上的卤化银-染料与溶液中银离子-染料具有相同键性质,都是银离子与染料离域π-电子作用的结果。     

菁染料和份菁染料溶液的光降解机理的研究

利用UV－Vis吸收光谱仪和光化学反应器,研究了菁染料和份菁染料溶液的光降解动力学,认为染料在乙腈溶液中的光褪色反应服从假一级或零级动力学,利用GC／MS光谱仪检测了染料的光降解产物,与相应的份菁染料相比,携带正电荷的菁染料具有相对较好的光稳定性,研究结果表明,菁染料光降解反应的中间体可能是染料的半氧化态Dye^ ,并利用纳秒级闪光光解技术研究了Dye^ 的瞬态吸收光谱。     

Study on the dyeing properties of hemicyanine dyes. II. Cationic dyeable polyester

The absorption spectra of two hemicyanine fluorescent dyes, namely, trans‐4‐[p‐(N,N‐di(2‐hydroxyethyl))‐amino‐styryl]‐N‐ethyl pyridinium bromide (DHEASPBr‐C₂) and trans‐4‐[p‐(N,N‐di(2‐hydroxyethyl))‐amino‐styryl]‐N‐octyl pyridinium bromide (DHEASPBr‐C₈), were studied at various levels of pH and high temperatures, and were then employed to dye cationic dyeable polyester. Their dyeing properties, fluorescent reflectance and colorimetric properties were explored. The novel fluorescent dyes existed in two forms of monocation and dication in solutions at low pH and high temperature. Overall, the influence of pH on colour depth and the maximum reflectance of dyed cationic dyeable polyester was extremely small. The adsorption mechanism of DHEASPBr‐C₂ and DHEASPBr‐C₈ on cationic dyeable polyester fibres was in good accord with the Langmuir type. Compared with DHEASPBr‐C₂, DHEASPBr‐C₈ exhibited comparatively faster adsorption rate, higher affinity and dye uptake, while its fluorescence shown by cationic dyeable polyester was slightly weak.     

Decolorisation of reactive dye wastewater and the effect of surfactants using laccase

Laccase (benzenediol, oxidoreducase; Enzyme Commission Number) is a multi‐copper oxidase from biomass. Laccase enzyme recycling on molecular oxygen as an electron acceptor can be applied for the decolorisation of synthetic dyes. The decolorisation of 49 commercial reactive dyes using laccase was investigated. The effects of diverse structure surfactants on decolorisation are discussed. The absorption spectra of reactive dyes after a laccase biodegradable reaction were analysed. Reactive dyes based on anthraquinone and azo structures could be decolorised using the enzyme and their chemical structures broken. Reactive dyes based on an anthraquinone structure were easier to decolorise than those based on an azo structure. Surfactants could affect the decolorisation of dyes with an enzyme. The effect of nonionic surfactant on the decolorisation of anthraquinone dyes was the reverse. The cationic surfactant could improve the decolorisation rate of diazo dye. The effect of the anionic surfactant on dye decolorisation was small. Most commercial reactive dyes could be decolorised and biodegraded using a laccase enzyme under mild conditions. Laccase enzyme biotechnology has potential applications in the decolorisation of reactive dye wastewater.     

Synthesis and colour spectroscopic investigation of some hemicyanine dyes

New hemicyanine dyes with a benzo[2,3‐b;2′,3′‐b′]bis‐furo[3,2‐d]pyrazolium nucleus were prepared. Spectroscopic investigations were carried out in 95% ethanol for all the synthesised cyanine dyes and/or in pure solvents which have different polarities for some selected dyes. Structural identification was carried out via elemental analysis, infra‐red and proton nuclear magnetic resonance spectral data.     

Physical,chemical, and dyeing properties of Bombyx mori silks grafted by 2‐hydroxyethyl methacrylate and methyl methacrylate

To obtain silk weight gain and to improve silk properties, Bombyx mori silks were grafted with either 2‐hydroxyethyl methacrylate (HEMA) or methyl methacrylate (MMA). The moisture regain of the HEMA‐grafted and MMA‐grafted silks depended on the hydrophilicity of the used monomers. The acid and alkaline resistances of the HEMA‐grafted and MMA‐grafted silks were clearly improved. Both commercial synthetic dyes, that is, acid and reactive dyes, and a natural dye extracted from turmeric, with potassium aluminum sulfate as a mordant, were used in this study. The results suggested that the dye uptake increased in the presence of poly(2‐hydroxyethyl methacrylate) or poly(methyl methacrylate) in the silk fibroin structures when acid and curcumin dyes were used. The washfastness level of the HEMA‐grafted silk dyed by acid and reactive dyes was similar to that of the degummed silk. However, the colorfastness to washing of the MMA‐grafted silk dyed by an acid dye was improved when the polymer add‐on concentration was 65%. In addition, the washfastness for both grafted silks was improved when they were dyed with natural curcumin dyestuff. The acid and alkaline perspiration fastness properties remained unchanged for the HEMA‐grafted and MMA‐grafted silks when acid, reactive, and curcumin dyes were applied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis,absorption spectra studies,solvatochromism and halochromism of polymethine cyanine dyes

New polymethine cyanine dyes, including tetramethine and bis‐tetramethine cyanine dyes derived from benzo[2,3‐b;2′,3′‐b′]bis‐pyrazolo[4,5‐b]‐1,4‐(oxa‐, thia‐ and pyra‐)‐zine‐6,12‐dione, were synthesised. Absorption spectra for all the synthesised cyanine dyes were examined in 95% ethanol. The solvatochromism and halochromism for some selected dyes were investigated in pure solvents and in aqueous universal buffer solutions, respectively. Structural confirmations were carried out through elemental and spectroscopic analysis.     

Study of the Influence of Gemini Cationic Surfactants on the Dyeing and Fastness Properties of Polyester Fabrics Using Naphthalimide Dyes

In this paper, the dyeing and fastness properties of three monoazo naphthalimide dyes including different imide groups (dye 1: ethyl amine, dye 2: ethyl glycinate and dye 3: glycine) on a polyester fabric were investigated in the presence of two gemini cationic surfactants (symbolized as 12‐4‐12 or 14‐4‐14) and a conventional single chain surfactant, dodecyltrimethylammonium bromide (DTAB). The color strength (K/S) of naphthalimide dyes on polyester fabric was measured through the reflectance spectrophotometric method, and the values obtained in the presence of different cationic surfactants increased in the order of dye 3 < dye 2 < dye 1. Although the K/S values indicated that the gemini cationic surfactants had almost no effect on the dyeing behavior of dye 1, but they were effective in dyeing ability of dye 2 and dye 3. The data for dye 2 demonstrated that build up of polyester fabrics in the presence of gemini surfactants are more than the conventional cationic surfactant, and also K/S values of dye 3 on polyester fabrics were in the order: DTAB > 12‐4‐12 > 14‐4‐14. It was found that the washing and rubbing fastness properties improved with increasing the concentration of surfactants. In addition, the sublimation fastness of dye 3 was more than the other dyes owing to the presence of a polar group in its chemical structure, and the light fastness of naphthalimide dyes on polyester fabrics was generally moderate.