Parent Dye Research Articles

Enhanced chemotherapeutic toxicity of cyclodextrin templated size-tunable rhodamine 6G nanoGUMBOS.

Nanodrugs have been widely investigated for combating the large number of side effects associated with conventional therapeutics. Several investigations of such nanomedicines have demonstrated the profound role of nanoparticle size in therapeutic efficacy. Herein, we report the role of cyclodextrin (CD)-templating on the size and therapeutic properties of rhodamine 6G (R6G) nanoGUMBOS, i.e. nanomaterials derived from a Group of Uniform Materials Based on Organic Salts (GUMBOS). In these studies, templating of nanoGUMBOS using 2-hydroxypropyl-alpha (2-HP-α), 2-hydroxypropyl beta (2-HP-β), and gamma (γ) cyclodextrin (CD) led to a significant reduction in size and enhanced uniformity as indicated by transmission electron microscopy (TEM) images. In addition, CD-templated nanoGUMBOS remarkably displayed a three to four fold enhancement in toxicity towards cancer cells as compared to nanoGUMBOS without CD-templates, suggesting a significant improvement in therapeutic efficacy. Correlation between size and toxicity suggests that CD-templated nanoparticles of ∼70 to 80 nm produced optimal toxicity. Even more interesting, all investigated nanoGUMBOS displayed no toxicity toward normal cells under examined conditions. Moreover, these nanoGUMBOS display comparable chemotherapeutic toxicity to the parent dye, [R6G][Cl], while also eliminating toxicity towards normal cells, indicating their strong chemotherapeutic potential. The studies outlined here provide further insight into an approach that may be employed for rapid synthesis of size tunable nanodrugs for enhanced chemotherapeutic efficacy.

Cu2+-selective fluorescent probe based on the hydrolysis of semicarbazide derivative of 2-(2-aminophenyl)benzothiazole

A new Cu2+-selective reaction-based fluorescent probe 1 based on the semicarbazide-bearing derivative of 2-(2-aminophenyl)benzothiazole has been developed. Designed probe 1 exhibited turn-on-type fluorescence signaling behavior that was more prominent toward Cu2+ ions than to other environmentally relevant metal ions. The signaling of probe 1 was due to the Cu2+-induced hydrolysis of semicarbazide moiety to form its strongly fluorescent parent dye. Cu2+ signaling of probe 1 was not influenced by the presence of commonly encountered metal ions, and the detection limit was 1.71 × 10−8 M (1.1 ppb). As a practical application, the determination of Cu2+ in simulated semiconductor wastewater was conducted using a smartphone as a portable signal detection tool. For the color test analysis, enhanced reproducibility of Cu2+-sensing was realized using the grayscale image rather than the red, green, or blue channel image.

Phytobeds with Fimbristylis dichotoma and Ammannia baccifera for treatment of real textile effluent: An in situ treatment, anatomical studies and toxicity evaluation

Fimbristylis dichotoma, Ammannia baccifera and their co-plantation consortium FA independently degraded Methyl Orange, simulated dye mixture and real textile effluent. Wild plants of F. dichotoma and A. baccifera with equal biomass showed 91% and 89% decolorization of Methyl Orange within 60h at a concentration of 50ppm, while 95% dye removal was achieved by consortium FA within 48h. Floating phyto-beds with co-plantation (F. dichotoma and A. baccifera) for the treatment of real textile effluent in a constructed wetland was observed to be more efficient and achieved 79%, 72%, 77%, 66% and 56% reductions in ADMI color value, COD, BOD, TDS and TSS of textile effluent, respectively. HPTLC, GC-MS, FTIR, UV–vis spectroscopy and activated oxido-reductive enzyme activities confirmed the phytotrasformation of parent dye in to new metabolites. T-RFLP analysis of rhizospheric bacteria of F. dichotoma, A. baccifera and consortium FA revealed the presence of 88, 98 and 223 genera which could have been involved in dye removal. Toxicity evaluation of products formed after phytotransformation of Methyl Orange by consortium FA on bivalves Lamellidens marginalis revealed less damage of the gills architecture when analyzed histologically. Toxicity measurement by Random Amplification of Polymorphic DNA (RAPD) technique revealed bivalve DNA banding pattern in treated Methyl Orange sample suggesting less toxic nature of phytotransformed dye products.

Phenylpyran-fused coumarin novel derivatives: combined photophysical and theoretical study on structural modification for PET-inhibited ICT emission

Synthesis and characterizations of fluorescent derivatives of 2-amino-5-oxo-4, 5-dihydropyrano[3,2-c] chromene-3-carbonitrile class are presented. Detailed photophysical characterizations were performed with different substituents, which enabled getting into the details of structural modulation to understand and tune photophysical properties in this biologically important class of dyes. One of the synthesized nitro-substituted dye (4a) is non-fluorescent due to the photoinduced electron transfer (PET) process. PET is quenched and fluorescence emission is achieved by (i) reduction of the –NO2 group to the –NH2 group, (ii) substitution of –NO2 by different substituents (−N(Me)2, −Cl, and –OH groups), and (iii) aggregate formation of 4a in the tetrahydrofuran–water system resultant from aggregation-induced enhanced emission (AIEE). Synthesized derivatives having substituents (−NH2, −N(Me)2, −Cl and –OH group) are highly fluorescent. Synthesized dyes showed positive solvatochromism and enhanced photophysical properties as compared to parent dye 7-(diethylamino)-4-hydroxy-2H-chromen-2-one. ICT characteristics of dyes are in good correlation with solvent polarity plots, multilinear regression analysis of solvent parameters, and Mulliken–Hush analysis. Mathematically deduced global and local descriptors and computationally obtained molecular orbital calculations are supporting well the PET process in 4a and ICT process in other dyes.

Fluorescence Quenching in BODIPY Dyes: The Role of Intramolecular Interactions and Charge Transfer

The fluorescence properties of the BODIPY dye and its two meso-substituted derivatives, tert-butyl- and phenyl-BODIPY, are rationalized. The non emissive behavior of the latter two are attributed to the energetically accessible low-lying conical intersection between the ground state and the lowest excited singlet state. Both intramolecular non-covalent interactions and excited state charge transfer character are identified as being crucial for “stabilizing” the intersection and prompting the nonradiative decay. Similar crossing was located in the bare BODIPY dye, however, being energetically less accessible, which correlates well with the high fluorescence quantum yields of the parent dye.

Dramatic Effect of Solvent on the Rate of Photobleaching of Organic Pyrrole‐BF2 (BOPHY) Dyes

AbstractThe photochemical stability of two symmetrical pyrrole‐BF2 (BOPHY) dyes has been assessed under continuous exposure to white light. The parent dye, lacking conjugated substituents, is highly stable when illuminated in a nonpolar film for prolonged periods but autocatalysis is observed such that the rate of degradation escalates with increasing exposure time. The rate of photofading is faster in solution and involves intermediate formation of a coloured product. The nature of the solvent exerts a small effect on the rate of bleaching. Under the same conditions, a BOPHY derivative equipped with both extended π‐conjugation and a high internal dipole moment displays a pronounced solvent effect. Here, the rate of photofading varies over a factor of 2 000‐fold on changing the solvent from cyclohexane to toluene. Most of the kinetic data can be explained in terms of polar and neutral resonance forms but, on the basis of NMR spectroscopy, it is concluded that toluene forms a weak complex with the dye that provides protection against photochemical damage.

Carbazole-Linked Near-Infrared Aza-BODIPY Dyes as Triplet Sensitizers and Photoacoustic Contrast Agents for Deep-Tissue Imaging.

Four new N-ethylcarbazole-linked aza-boron-dipyrromethene (aza-BODIPY) dyes (8 a,b and 9 a,b) were synthesized and characterized. The presence of the N-ethylcarbazole moiety shifts their absorption and fluorescence spectra to the near-infrared region, λ≈650-730 nm, of the electromagnetic spectrum. These dyes possess strong molar absorptivity in the range of 3-4×104 m-1 cm-1 with low fluorescence quantum yields. The triplet excited state and singlet oxygen generation of these dyes were enhanced upon iodination at the core position. The core-iodinated dyes 9 a,b showed excellent triplet quantum yields of about 90 and 75 %, with singlet oxygen generation efficiency of about 70 and 60 % relative to that of the parent dyes. Derivatives 8 a,b showed dual absorption profiles, in contrast to dyes 9 a,b, which had the characteristic absorption band of aza-BODIPY dyes. DFT calculations revealed that the electron density was spread over the iodine and dipyrromethene plane of 9 a,b, whereas in 8 a,b the electron density was distributed on the carbazole group and dipyrromethene plane of aza-BODIPY. The uniqueness of these aza-BODIPY systems is that they exhibit efficient triplet-state quantum yields, high singlet oxygen generation yields, and good photostability. Furthermore, the photoacoustic (PA) characteristics of these aza-BODIPY dyes was explored, and efficient PA signals for 8 a were observed relative to blood serum with in vitro deep-tissue imaging, thereby confirming its use as a promising PA contrast agent.

Redox Responsive Fluorescent Probe Development for Super Resolution and Fluorescence Lifetime Microscopy

Redox-sensing in aqueous solutions using super resolution fluorescence or lifetime microscopy has been applied extensively to image metabolic events in biological systems. Typically, such probes are designed to fluoresce following reaction with (or capture of) a particular analyte, for example, reactive oxygen species or a redox-active metal ion. Using such probes as a guide, we have designed and characterized new redox-responsive fluorescent probes intended for fluorescence-based imaging of aqueous electrochemical systems. We present solution spectroelectrochemical characterization of the parent dye molecules as well as initial optical microscopy characterization of these redox-sensitive fluorophores attached to a thermally-responsive polymer gel. Using thermal-control of polymer matrix thickness, the surface density of dye on the electrode can be modulated and imaged using fluorescence lifetime with super resolution microscopy.

A characteristic study on generation and interactive effect of electrocoagulated floc with Direct Green 1 and Reactive Red 2

Abstract The present investigation involves an optimization of the electrocoagulation on aqueous organic dye solutions with two different group of operational conditions namely reactor design such as applied voltage, effective surface area, inter electrode distance, stirring speed and nature of the organic dye solutions such as pH, conductivity, dye concentration, temperature. The experiments are focused on the maximum colour and COD removal with minimum energy and electrode consumption. The kinetic study reveals the colour removal efficiency of two organic dye solutions is decreases from 0.142 to 0.026 min− 1 for DG1 and from 0.119 to 0.023 min− 1 for RR2 with increase in pH. Thermodynamic parameter of ΔH and ΔS shows the endothermic nature of adsorption of dyes. Freundlich constant evidenced the adsorption of both dyes over floc surface is spontaneous. The maximum dye removed per unit area of electrode is 26.8 ppm/cm2 for DG1 and 21.2 ppm/cm2 for RR2 observed at the 10 cm2 effective surface area. The FTIR analysis of floc residue, peak values at 3452.56 and 1496.93 cm− 1 of RR2 alone shifted to 3418.31 and 1425.78 cm− 1 in electrocoagulated floc residue suggests the adsorption of RR2 over iron flocs. The peak at 1493.32 cm− 1 supports the presence of azo group in the parent dye structure of DG1 and disappearance of the peak in electrocoagulated flocs residue evidenced the adsorption of partially degraded dyes on electrocoagulated flocs.

Extraction and quantification of phenolic compounds from Prunus armeniaca seed and their role in biotransformation of xenobiotic compounds

The current research project has been devoted to isolating new low cost and eco-friendly phenolic compounds from fruit seeds, peels and vegetables to reduce the atmospheric pollution. Natural phenolic compounds were extracted from different fruit seeds and agriculture waste: P. armeniaca, P. persica, P. domestica and Triticum aesativum. The total phenolic content was quantified, and the maximum value (1 mL extract having 1,933 μg) was found in P. armeniaca seed extract. Phytochemical screening showed that P. armeniaca seeds contain higher amount of alkaloid, tannins, saponins and flavonoid. P. armeniaca seeds enhanced the biotransformation of reactive yellow dye up to 69.89% with maximum laccase (322.45 IU/mL) production. Biodegradation of reactive yellow was only 23.34% without natural redox mediator at sixth day of incubation. Use of P. armeniaca seed stimulators resulted in maximum laccase activity (894.4 IU/mL) with 99.5% rate of removal. UV-Vis, HPLC & FTIR analysis confirmed the transformation of parent dye into various new products. Phytotoxicity study indicated 0% germination index of Avena sativa seeds with reactive yellow, whereas 83% germination index having 100% seed germination while 83% root elongation with treated sample. Thus, the study revealed that the natural phenolic compounds could serve as high potential redox mediators for enhanced laccase-mediated decolorization of reactive yellow dye.

Degradation products of the artificial azo dye, Allura red, inhibit esterase activity of carbonic anhydrase II: A basic in vitro study on the food safety of the colorant in terms of enzyme inhibition

Allura red is a widely used food colorant, but there is debate on its potential security risk. In the present study, we found that degradation products of the dye were more potent agents with higher carbonic anhydrase inhibitory action than the parent dye. The mechanism by which the compounds inhibit the enzyme activity has been determined as competitive mode. In addition, the enzyme binding properties of the compounds were investigated employing different spectroscopic techniques and molecular docking. The analyses of fluorescence quenching data revealed the existence of the same binding site for the compounds on the enzyme molecule. The thermodynamic parameters of ligand binding were not similar, which indicates that different interactions are responsible in binding of the parent dye and degradation products to the enzyme. It appears that enzyme inhibition should be considered, more seriously, as a new opened dimension in food safety.

Organic dyes containing fluorenylidene functionalized phenothiazine donors as sensitizers for dye sensitized solar cells

Two new organic sensitizers featuring fluorenylidene decoration on the phenothiazine donor have been synthesized and characterized as sensitizers for nanocrystalline TiO2-based dye sensitized solar cells (DSSCs). The dyes possess cyanoacrylic acid as acceptor/anchoring group and a conjugation pathway composed of fluorene and thiophene. Introduction of the fluorenylidene moiety on phenothiazine enhances the optical density of the dyes while the extension of conjugation by thiophene insertion red-shifts the absorption peak originating from the intramolecular charge transfer from phenothiazine to cyanoacrylic acid. The ground and excited state oxidation potentials of the fluorenylidene-containing dyes are upwardly shifted when compared to the parent dyes indicating a π-delocalized donor segment. The electronic properties were supported by density functional theoretical computations. Among the DSSCs fabricated, the dye (5a) having fluorene and thiophene in the spacer resulted higher power conversion efficiency (3.31 %) than the corresponding bithiophene analog (5b, 2.83 %) attributable to the relatively high electron life time and enhanced resistance for recombination in the former.

Ipomoea hederifolia rooted soil bed and Ipomoea aquatica rhizofiltration coupled phytoreactors for efficient treatment of textile wastewater

Ipomoea aquatica, a macrophyte was found to degrade a highly sulfonated and diazo textile dye Brown 5R up to 94% within 72 h at a concentration of 200 mg L−1. Induction in the activities of enzymes such as azoreductase, lignin peroxidase, laccase, DCIP reductase, tyrosinase, veratryl alcohol oxidase, catalase and superoxide dismutase was observed in leaf and root tissue in response to Brown 5R exposure. There was significant reduction in contents of chlorophyll a (25%), chlorophyll b (17%) and carotenoids (30%) in the leaves of plants. HPLC, FTIR, UV–vis spectrophotometric and HPTLC analyses confirmed the biotransformation and removal of parent dye from solution. Enzymes activities and GC-MS analysis of degradation products lead to the proposal of a possible pathway of phytotransformation of dye. The proposed pathway of dye metabolism revealed the formation of Napthalene-1,2-diamine and methylbenzene. Toxicity study on HepG2 cell lines showed a 3 fold decrease in toxicity of Brown 5R after phytoremediation by I. aquatica. Hydrophytic nature of I. aquatica leads to its exploration in a combinatorial phytoreactor with Ipomoea hederifolia soil bed system. Rhizofiltration with I. aquatica and soil bed treatment by I. hederifolia treated 510 L of effluent effectively within 72 h. I. aquatica along with I. hederifolia could decolorize textile industry effluent within 72 h of treatment as evident from the significant reductions in the values of COD, BOD, solids and ADMI. Further on field trials of treatment of textile wastewater was successfully carried out in a constructed lagoon.

Synthesis and Characterization of Porphyrin-Based GUMBOS and NanoGUMBOS as Improved Photosensitizers

Porphyrin-based GUMBOS and nanoGUMBOS were synthesized for potential application as improved photosensitizing materials. In this study, porphyrin dyes [meso-tetra(4-carboxyphenyl)porphine (TCPP) and zinc(II) meso-tetra(4-carboxyphenyl)porphine (Zn-TCPP)] were selected as anions, and trihexyltetradecylphosphonium (P66614) was employed as a cation. The resulting [P66614]4[TCPP] and [P66614]4[Zn-TCPP] GUMBOS (group of uniform materials based on organic salts) provided high photostability and excellent thermal stability for these compounds. NanoGUMBOS, i.e., nanomaterials derived from GUMBOS, were synthesized using reprecipitation and ion association methods. The surface charges of these nanoparticles were tuned from positive to negative through use of an ion association synthetic method without the need for additives or stabilizers. When compared to the parent dyes, nanoGUMBOS exhibited excellent photodynamic properties for potential applications as photosensitizers. Evaluation of the electrochemical propert...

Synthesis of Fe/ZnO composite nanocatalyst and its sonophotocatalytic activity on acid yellow 23 dye and real textile effluent

Nanocatalysts such as ZnO, Fe and Fe/ZnO composite were synthesized for better treatment of dye than the conventional treatment methods. The catalysts were characterized using SEM, EDAX, BET surface area, XRD and DRS. The degradation of acid yellow 23 dye in aqueous solution has been investigated using sonolysis, photolysis and sonophotocatalysis. The effect of different conventional operating parameters such as initial solution pH, gas purging (Argon, Oxygen, Air and Nitrogen) and H2O2 addition, under sonolysis (13 and 25 mm probe tip diameter) and photolysis (UV light), showed a maximum of 41 % colour removal for 0.0187 mmol/L dye solution under photolysis with 88.2 mmol/L H2O2 addition. Among the catalysts used, 98 % dye colour removal was obtained with 0.2 g/L Fe/ZnO composite under 60 min of sonophotolysis that had been benefitted by the synergistic effects. The HPLC spectrum of the untreated dye and treated dye supports the claim of eradication of the parent dye compound. Sonophotocatalytic treatment of real textile effluent in the presence of 6 g/L Fe/ZnO composite and 264.6 mmol/L H2O2 reduced the COD level from 792 to 174.4 mg/L in 240 min to meet the allowable effluent discharge standard into running water streams. The studied treatment methods were found to be effective for the degradation of acid yellow 23 dye and subsequently in real textile effluent too.

Improving energy relay dyes for dye-sensitized solar cells by use of a group of uniform materials based on organic salts (GUMBOS)

Energy relay dyes based on GUMBOS displayed improved characteristics in comparison to respective parent dyes including solubility and solar efficiency.

Bioinformatics aided microbial approach for bioremediation of wastewater containing textile dyes

Four textile azo dyes, Joyfix Red, Remazol Red, Reactive Red and Reactive Yellow, were studied for decolorization. Of nineteen soil bacterial isolates, two novel strains were found to highly decolorize Joyfix Red and were identified as Lysinibacillus sphaericus (KF032717) and Aeromonas hydrophila (KF032718) through 16S rDNA analysis. Laccase and Azoreductase enzyme modeling and enzyme–dye interaction performed using Schrödinger Suite imitated decolorization percentage. Results based on cumulative Glide score (Dry laboratory) and decolorization percentage of the other three dyes based on ultraviolet–visible (UV–vis) spectroscopy (Wet laboratory) were reliable. Biodegradation of Joyfix Red was confirmed by high-performance liquid chromatography (HPTLC) elution profile which showed four peaks at 1.522, 1.800, 3.068 and 3.804min with that of parent dye which showed single peak at 1.472min. Fourier transform infrared spectroscopy (FT-IR) analysis supported the biotransformation of Joyfix Red. Gas chromatography–mass spectroscopy (GC–MS) analysis showed sodium (3E,5Z)-4-amino-6-hydroxyhexa-13,5-triene-2-sulfonate was formed as end product during biodegradation. From these findings, it can be inferred that enzyme and dye interaction studies can assist in examining decolorization efficiency of bacteria and its enzyme, thereby enhancing the bioremediation process by reducing preliminary lengthy wet laboratory screening. This is the first report of a combinatorial in silico cum in vitro approach and its validation for the bioremediation of wastewater containing these textile azo dyes.

Biodegradation and detoxification of textile dye Disperse Red 54 by Brevibacillus laterosporus and determination of its metabolic fate

Bioremediation is one of the milestones achieved by the biotechnological innovations. It is generating superior results in waste management such as removal of textile dyes, which are considered xenobiotic compounds and recalcitrant to biodegradation. In the present bioremedial approach, Brevibacillus laterosporus was used as an effective microbial tool to decolorize disperse dye Disperse Red 54 (DR54). Under optimized conditions (pH 7, 40°C), B. laterosporus led to 100% decolorization of DR54 (at 50 mg L(-1)) within 48 h. Yeast extract and peptone, supplemented in medium enhanced the decolorization efficiency of the bacterium. During the decolorization process, activities of enzymes responsible for decolorization, such as tyrosinase, veratryl alcohol oxidase and NADH--DCIP reductase were induced by 1.32-, 1.51- and 4.37-fold, respectively. The completely different chromatographic/spectroscopic spectrum of metabolites obtained after decolorization confirmed the biodegradation of DR54 as showed by High pressure liquid chromatography, High pressure thin layer chromatography and Fourier transform infrared spectroscopy. Gas chromatography-Mass spectroscopy studies suggested the parent dye was biodegraded into simple final product, N-(1λ(3)-chlorinin-2-yl)acetamide. Phytotoxicity study suggested that the metabolites obtained after biodegradation of DR54 were non-toxic as compared to the untreated dye signifying the detoxification of the DR54 by B. laterosporus.

Spectral fine tuning of cyanine dyes: electron donor-acceptor substituted analogues of thiazole orange.

The introduction of electron donor and acceptor groups at strategic locations on a fluorogenic cyanine dye allows fine-tuning of the absorption and emission spectra while preserving the ability of the dye to bind to biomolecular hosts such as double-stranded DNA and a single-chain antibody fragment originally selected for binding to the parent unsubstituted dye, thiazole orange (TO). The observed spectral shifts are consistent with calculated HOMO-LUMO energy gaps and reflect electron density localization on the quinoline half of TO in the LUMO. A dye bearing donating methoxy and withdrawing trifluoromethyl groups on the benzothiazole and quinoline rings, respectively, shifts the absorption spectrum to sufficiently longer wavelengths to allow excitation at green wavelengths as opposed to the parent dye, which is optimally excited in the blue.

Strategy for tuning the photophysical properties of photosensitizers for use in photodynamic therapy.

A novel approach for tuning spectral properties, as well as minimizing aggregation, in zinc porphyrin and zinc phthalocyanine-based compounds is presented. Particular emphasis is placed on use of these compounds as photosensitizers in photodynamic therapy (PDT). To accomplish this aim, a bulky hydrophobic cation, trihexyltetradecylphosphonium, is paired with anionic porphyrin and phthalocyanine dyes to produce a group of uniform materials based on organic salts (GUMBOS) that absorb at longer wavelengths with high molar absorptivity and high photostability. Nanoparticles derived from these GUMBOS possess positively charged surfaces with high zeta potential values, which are highly desirable for PDT. Upon irradiation at longer wavelengths, these GUMBOS produced singlet oxygen with greater efficiency as compared to the respective parent dyes.