Promising Dye Research Articles

Beam profiles and radiation coherence at the output of solid-state and dye lasers with an intra-cavity immersion diffuser

Lasers on mixtures of solid particles and liquids have long been an attractive subject of research as they can serve as sources of low-coherent radiation and provide a good thermal management using a medium flow. One of such schemes is a laser with an intra-cavity cuvette-diffuser filled by a dense immersion mixture of activated solid micro-particles and a liquid (slurry), similar to the known Christiansen filter. The properties of perspective slurry lasers and features of beams formation in such media were studied in model experiments on bulk Nd:YVO4 and Nd:YAG active elements pumped by 808 nm diodes in quasi-continuous (1 ms, 10 Hz) regime, and on a Rhodamine 101 dye laser pumped by 20 ns, 532 nm light pulses. Laser media were tested in compact (7–50 mm) resonators using a diffuser on a mixture of non-doped LiF micro-particles and isobutanol. The laser spatial coherence was estimated by the contrast C of speckle patterns or by the visibility of Young interferograms γ. Near the threshold separate deformed Laguerre-Gaussian modes and concentric rings were observed at lasers’ output, indicating radiation coherence of C=0.5−0.7. At 100 W pumping Nd:YVO4 and Nd:YAG lasers with diffusers in plano-spherical (PS) resonators provided 1 ms pulses of 1–6 W multimode 1064 nm generation with smoothed beam profiles, divergence up to 0.11 rad and C=0.02−0.1. For a dye laser with a diffuser in PS resonators, 17 ns pulses of 627 nm multimode radiation with 1–3.5 mJ energy, beam divergence 60–280 mrad, γ=0.01−0.05 and up to 30% optical efficiency were obtained. Thus, an intra-cavity diffuser with an immersion mixture is a convenient and simple device to reduce the laser coherence. C and γ values, close to those for thermal light sources make it possible to use the developed lasers for speckles suppression at laser projection, in speed photography, etc. Promising solid-state and dye slurry lasers are discussed. The obtained results show the specific of beam formation in slurry media and give grounds to expect successful development and applications of low-coherent solid-state and dye slurry lasers operating in the visible and infra-red spectral regions.

Molecular Engineering of Sulfone-Xanthone Chromophore for Enhanced Fluorescence Navigation.

Enriching the palette of high-performance fluorescent dyes is vital to support the frontier of biomedical imaging. Although various rhodamine skeletons remain the premier type of small-molecule fluorophores due to the apparent high brightness and flexible modifiability, they still suffer from the inherent defect of small Stokes shift due to the nonideal fluorescence imaging signal-to-background ratio. Especially, the rising class of fluorescent dyes, sulfone-substituted xanthone, exhibits great potential, but low chemical stability is also pointed out as the problem. Molecular engineering of sulfone-xanthone to obtain a large Stokes shift and high stability is highly desired, but it is still scarce. Herein, we present the combination modification method for optimizing the performance of sulfone-xanthone. These redesigned fluorescent skeletons owned greatly improved stability and Stokes shift compared with the parent sulfone-rhodamine. To the proof of bioimaging capacity, annexin protein-targeted peptide LS301 was introduced to the most promising dyes, J-S-ARh, to form the tumor-targeted fluorescent probe, J-S-LS301. The resulting probe, J-S-LS301, can be an outstanding fluorescence tool for the orthotopic transplantation tumor model of hepatocellular carcinoma imaging and on-site pathological analysis. In summary, the combination method could serve as a basis for rational optimization of sulfone-xanthone. Overall, the chemistry reported here broadens the scope of accessible sulfone-xanthone functionality and, in turn, enables to facilitate the translation of biomedical research toward the clinical domain.

Enhanced photocatalytic degradation, antimicrobial and anticancer efficiency of mycosynthesized TiO2 nanoparticles using Pleurotus ostreatus mushroom extract: An eco-friendly approach

This study is one such study where an eco-friendly approach has been followed in biosynthesizing TiO2NPs from Pleurotus ostreatus mushroom extract. Therefore, we object to biosynthesizing TiO2NPs and characterize them morphologically using UV, XRD, FTIR, FESEM, EDX, HR-TEM, AFM, and GCMS. The UV–visible spectroscopy absorption of synthesized TiO2NPs has peaked at 335 nm. The antibacterial activity was investigated by both isolated bacteria pathogens (gram-positive and gram-negative). The maximum growth inhibition zone was noted in S. mutans (14.3 ± 0.4), E. coli (14.1 ± 0.3), and S. epidermidis (13.3 ± 0.2). The in vitro cytotoxicity assay of TiO2NPs showed an IC50 value of 47.42 µg/mL against MG-63 cancer cells. The photocatalytic degradation of methylene blue by TiO2NPs was investigated under UV–visible light irradiation. Due to the NPs tiny size and high dispersion, a rapid degradation (between 30 and 180 min) of almost 84.24% was accomplished. Even after the photocatalyst was used three times, there was no discernible difference in the TiO2NPs photocatalytic activity. The synthesized TiO2NPs successfully destroyed the Methylene Blue (MB) dye in an aqueous solution, promising wastewater dye remediation. Therefore, our research shows for the first time that biosynthesis of TiO2NPs using P. ostreatus extract can be an excellent outcome for emerging multipurpose and organic products.

Structural and spectroscopic features of naphthol green B integrated for improved light harvesting capability of organic/inorganic hybrid solar cells

Regarding the intensified interest in photovoltaic devices for a wide range of applications, here, we exploited a promising naphthol green organic dye for designing efficient organic/inorganic heterojunction for solar cell applications. The crystal and molecular structures of the spin-coated NGB thin films were inspected using XRD and FTIR techniques, respectively. A nanostructured polycrystalline film was obtained with a crystallite size of ∼76.2 nm with a stable molecular configuration. The optical properties of the films were analyzed using spectrophotometrically measured transmission and reflection. The prepared films showed high absorption over the UV–Vis–NIR regimes with a relatively small energy gap of ∼1.42 eV and a low refractive index of ∼1.48 which increased its suitability for photosensing applicability. The photovoltaic performance of the fabricated Ag/NGB/p-Si/Al heterojunction was evaluated in detail yielding promising photovoltaic characteristics with Voc ∼0.77 V, Jsc ∼18.64 mA/cm2, and PCE ∼6.49 %.

Adsorption of anionic dyes onto 1,5-Diphenylcarbazide functionalized magnetic hybrid polymer: Impact of water salinity and surfactants on adsorption isotherms

Herein, an effective hybrid adsorbent based on magnetic chitosan (MC) and magnetic glycidyl methacrylate (Mp(GMA)) was synthesized. The prepared hybrid material was functionalized by 1,5-Diphenylcarbazide (DPC), then employed for the adsorption of two anionic dyes (Coomassie brilliant blue G-250; CBB, and Eosin Y; EO) from their synthetic solutions. The as-fabricated adsorbent (MC-Mp(GMA)/DPC) was specifically investigated via FTIR, SEM-EDX, BET, TGA, and VSM analyses. The influence of several operational key factors; initial solution pH, initial dye concentration, contact time, temperature, and influence of cationic, anionic surfactant, and salinity on adsorption isotherms were investigated. The findings revealed that MC-Mp(GMA)/DPC highest adsorption capacities were recorded in the presence of cationic surfactant (0.795, 0.817 mmol g−1 for CBB and EO, respectively) and salinity hardly affects adsorption isotherms. Moreover, the adsorption process of each dye was reported to fit with the Langmuir model at all conditions, while the PSORE model well-defined their adsorption kinetics. Meanwhile, thermodynamics revealed that the separation of CBB and EO dyes was endothermic. Moreover, MC-Mp(GMA)/DPC possessed a desirable efficacy for the regeneration (e.g., 77.9% and 71.7 for CBB and EO, respectively) up to the 4th cycle, affirming its outstanding renewability. Overall, the produced MC-Mp(GMA)/DPC can potentially be offered as a promising recyclable dye scavenger for wastewater remediation.

Design and Photonics of Merocyanine Dyes.

Merocyanines, thanks to their easily adjustable electronic structure, appear to be the most versatile and promising functional dyes. Their D-π-A framework offers ample opportunities for custom design through variations in both donor/acceptor end-groups and the π-conjugated polymethine chain, and leads to a broad range of practical properties, including noticeable solvatochromism, high polarizability/hyperpolarizabilities, and the ability to sensitize various physicochemical processes. Accordingly, merocyanines are applied and extensively studied in various fields, such as light-converting materials for optoelectronics, nonlinear optics, optical storage, solar cells, fluorescent probes, and antitumor agents in photodynamic therapy. This review encompasses both classical and novel more important publications on the structure-property relationships in merocyanines, with particular emphasis on the results by A. I. Kiprianov and his followers in Institute of Organic Chemistry in Kyiv, Ukraine.

Aroyl-S,N-Ketene Acetals: Luminous Renaissance of a Class of Heterocyclic Compounds.

Aroyl-S,N-ketene acetals represent a peculiar class of heterocyclic merocyanines, compounds bearing pronounced and rather short dipoles with great push-pull characteristics that define their rich properties. They are accessible via a wide array of synthetic concepts and procedures, ranging from addition-elimination and condensation procedures up to rearrangement and metal-mediated reactions. With our work from 2020, aroyl-S,N-ketene acetals have been identified as powerful and promising dyes with pronounced and vastly tunable solid-state emission and aggregation-induced emission properties. One characteristic trademark of this class of dye molecules is the level of control that could be exerted and which was thoroughly explored. Based on these results, the field was opened to extend the system to bi- and multichromophoric systems by the full toolkit of synthetic organic chemistry thus giving access to even more exciting properties and manifolded substance libraries capitalizing on the AIE properties. This review aims at outlining the reaction-based principles that allow for a swift and facile access to aroyl-S,N-ketene acetals, their methodological and structural evolution and the plethora of fluorescence and aggregation properties.

Is natural better? An ecotoxicity study of anthraquinone dyes

The concept of sustainability has gained prominence in recent years, enhancing the need to develop products that are less harmful to the environment. Dyes are used by various industrial sectors and have a lot of market value; they are used on a large scale mainly by the textile industry that uses large volumes of water and is one of the main contributors to the contamination of water bodies. Some natural compounds, especially anthraquinones are re-emerging as possible alternatives to synthetic dyes, some of which are known for their toxic and/or mutagenic effects. The BioColour project (https://biocolour.fi/) which is interested in promoting the development of new alternative molecules to synthetic dyes, provided us highly purified anthraquinone dyes dermocybin and dermorubin (>98% purity) extracted from a specie of fungus Cortinarius sanguineus. Dyes were tested for their acute and chronic toxicity using different aquatic organisms. Dermorubin was not toxic to any of the organisms tested for the highest test concentration of 1 mg L−1 and it was the most promising dye. Dermocybin was toxic to Daphnia similis (EC50 = 0.51 mg L−1), Ceriodaphnia dubia (IC10 = 0.13 mg L−1) and Danio rerio embryos (extrapolated LC50 = 2.44 mg L−1). A safety limit, i.e, predicted no-effect concentration (PNEC) of 0.0026 mg L−1 was derived based on the toxicity of dermocybin. The PNEC value can be used to provide hazard information for future application in commercial dyeing processes. Then, we compared the toxicity of dermocybin and dermorubin with ecotoxicity data available in the literature on other anthraquinone dyes of natural and synthetic origin. Some natural dyes can be as toxic as synthetic ones, or more toxic when chronic effects are considered. Despite natural dyes being used since centuries past, there are few ecotoxicological studies available. This study is designed to help develop a more comprehensive understanding of their toxicological properties.

Efficient malachite green biodegradation by Pseudomonas plecoglossicide MG2: process optimization, application in bioreactors, and degradation pathway

Microbial degradation of synthetic dyes is considered a promising green dye detoxification, cost-effective and eco-friendly approach. A detailed study on the decolorization and degradation of malachite green dye (MG) using a newly isolated Pseudomonas plecoglossicide MG2 was carried out. Optimization of MG biodegradation by the tested organism was investigated by using a UV–Vis spectrophotometer and the resultant degraded products were analyzed by liquid chromatography–mass spectrometry and FTIR. Also, the cytotoxicity of MG degraded products was studied on a human normal retina cell line. The optimum conditions for the significant maximum decolorization of MG dye (90–93%) by the tested organism were pH 6–7, inoculum size 4–6%, and incubation temperature 30–35 °C, under static and aerobic conditions. The performance of Pseudomonas plecoglossicide MG2 grown culture in the bioreactors using simulated wastewater was assessed. MG degradation (99% at 100 and 150 mg MG/l at an optimal pH) and COD removal (95.95%) by using Pseudomonas plecoglossicide MG2 culture were the best in the tested culture bioreactor in comparison with that in activated sludge or tested culture-activated sludge bioreactors.The FTIR spectrum of the biodegraded MG displayed significant spectral changes, especially in the fingerprint region 1500–500 as well as disappearance of some peaks and appearance of new peaks. Twelve degradation intermediates were identified by LC–MS. They were desmalachite green, didesmalachite green, tetradesmalachite green, 4-(diphenylmethyl)aniline, malachite green carbinol, bis[4-(dimethylamino)phenyl]methanone, [4-(dimethylamino)phenyl][4-(methyl-amino)phenyl]methanone, bis[4-(methylamino)phenyl]methanone, (4-amino- phenyl)[4-(methylamino)phenyl]methanone, bis(4-amino phenyl)methanone, (4-amino phenyl)methanone, and 4-(dimathylamino)benzaldehyde. According to LC–MS and FTIR data, two pathways for MG degradation by using Pseudomonas plecoglossicide MG2 were proposed. MG showed cytotoxicity to human normal retina cell line with LC50 of 28.9 µg/ml and LC90 at 79.7 µg/ml. On the other hand, MG bio-degraded products showed no toxicity to the tested cell line. Finally, this study proved that Pseudomonas plecoglossicide MG2 could be used as an efficient, renewable, eco-friendly, sustainable and cost-effective biotechnology tool for the treatment of dye wastewater effluent.

Synthesis of chitosan-based perylene dye material for photovoltaic solar-cell application

Renewable energy, such as solar energy, is infinite, readily available, and has extensive applications. Dye-sensitized solar cells (DSSCs) have been well developed; thus, they can be developed with low production costs, high efficiency, and facile manufacturing techniques. This study proposes a novel chitosan biopolymer-based perylene dye; the dye is modified by chitosan with perylene-3,4,9,10-tetracarboxylic anhydride using a one-pot acylation of nitrogen nucleophiles for DSSCs. The chitosan biopolymer-based perylene dyes were characterized using attenuated total reflection infrared spectroscopy, solid-state 13C CP-TOSS nuclear magnetic resonance spectroscopy, X-ray powder diffraction analysis, thermogravimetric analysis, X-ray photoelectron spectrometry, and high-resolution field-emission scanning electron microscopy. The ultraviolet-visible and fluorescence spectroscopy of chitosan biopolymer-based perylene dye exhibited a red-shift compared with perylene-3,4,9,10-tetracarboxylic anhydride and chitosan. The DSSC properties of chitosan biopolymer-based perylene dye were investigated, and it exhibited a 2.022 % power-conversion efficiency. Thus, this promising chitosan biopolymer-based perylene dye may have potential applications in solar-cell technology.

Bioproduction and Application of Orange and Yellow Pigments Obtained from Chryseomicrobium palamuruense and Micrococcus luteus

Colour is a fundamental and most likely one of the primary attributes to be observed by the human senses, making it an essential part of human life and culture. This study investigates the bioproduction and potential application of bacterial pigments obtained from abattoir wastewater. Bacteria isolates recovered from abattoir wastewater were screened for pigment production and identified using the 16S rRNA gene sequence. Optimal physicochemical conditions of parameters were investigated and harnessed for bulk pigment production. Pigments produced were characterised using UV-Visible Spectrophotometer and Fourier Transform Infra-Red (FTIR) Analysis. The antibacterial and dyeing ability of the extracted pigments were evaluated. Two bacteria namely, Chryseomicrobium palamuruense strain PUI and Micrococcus luteus strain 1k produced orange and yellow pigments respectively. The UV-visible spectrum of the orange pigment produced by Chryseomicrobium palamuruense showed surface plasmon resonance peaks at 262, 426, and 453 nm while that of the yellow pigment produced by Micrococcus luteus showed a single peak at 260 nm. The FTIR analysis of the extracted pigments indicated the presence of some functional groups namely hydroxyl (OH), C-H, primary and secondary C-O, and skeletal C-C vibrations. Chryseomicrobium palamuruense and Micrococcus luteus showed no antibacterial activity against the selected typed bacterial isolates assessed in this study. The orange pigment extracted from Chryseomicrobium palamuruense was retained on cotton and polyester producing different shades of colour on the two fabrics when used as a dyeing agent. The pigment-producing potentials of these organisms suggest their relevance as promising dyes in textile industry.

Physicochemical parameters optimization and peroxidase characterization from Aspergillus niger native strain by solid-state fermentation for improved dye decolorization

The hyper yield of peroxidase (POX) was investigated for a novel native Aspergillus niger strain identified by 18S RNA analysis. A. niger strains sequences were submitted to GenBank; IDs allotted were MN611114.1 (BMB 17) and MN559756.1 (BMB-18). The identified Aspergillus strains in combination showed enhanced (POX) activity (601.5 U/mL) by solid-state fermentation in comparison to their individual activities. POX was purified by ammonium sulfate, and size exclusion gel chromatography exhibited a 7.83-fold increase in POX concentration (13.3 U/mg) in comparison to BMB17 and BMB 18 (11.8 & 7.6 U/mg respectively). The best POX activity was obtained with pH 6.5, 37 °C, and 5 days of incubation. Using guaiacol as substrate, POX showed maximum activity (Vmax) of 537 U/mL with a corresponding Michaelis constant (Km) value of 126 µM. Calcium chloride worked as a POX activator at 300 & 400 mM. Zinc sulfate (500 mM), EDTA (5 mM); ethanol, propanol, and acetonitrile (50%) inhibited (18-30%) POX. Urea (1M), and copper sulfate (500 mM) strongly inhibited POX up to 40%. Polysorbate-80 (1%) slightly reduced the POX by 10% to 15%. BMB17+18-induced promising dye decolorization (88-98%) against all vat dyes, methylene blue, and phenol red.

Brazilin: An updated literature-based review on its promising therapeutic approaches and toxicological studies

Brazilin is a promising natural red dye, extracted from the wood of Caesalpinia sappan L. It exhibits several pharmacological activities including anti-inflammatory, antioxidant, anti-depressant and anxiolytic, anti-diabetic, anticancer, antibacterial, and vasorelaxant. Moreover, bioavailability studies demonstrated that brazilin is quickly absorbed into the bloodstream. The data were collected from several databases as ScienceDirect, Web of Science, Pubmed and Proquest. This review is designed to conduct an in-depth search on its pharmacological activities, as well as the underlying cell signaling pathways and mechanism of actions. In addition, we have addressed the bioavailability and structural analysis of brazilin and its close derivatives, safety and quality profiles, and toxicological status. Brazilin with its safety characteristics and acceptable bioavailability, has the potential to touch numerous natural grids, thus, it is possible that this medicinally effective molecule will assist as a promising principal for the development of drug in management of different disorders.

Study on Dyeing Properties and Color Characteristics of Wool Fabrics Dyed with Geranium caespitosum L. Extract—A New Natural Yellow Dye

Natural dyes play an important role in sustainable dyeing processes. However, natural yellow dyes with good performance are rare. Traditional natural yellow dyes have issues, such as a narrow color range and poor light fastness. In this paper, a new natural yellow dye was extracted from a low-cost herb Geranium caespitosum L. (G. caespitosum). In addition, the dye composition was analyzed using UV-visible spectroscopy. The dyeing process of G. caespitosum dye on wool fabrics was optimized using single-factor experiments. Standard fastness tests were conducted to evaluate the sunlight, washing, and rubbing fastness of the dyed fabrics. The color characteristics and color gamut range of the dyed fabrics were evaluated. The obtained colors were compared and assessed with Pantone Matching Systems and Chinese traditional colors. The results showed that phenolic acids and flavonoids were present in the G. caespitosum dye solution as yellow dye compounds. The best dyeing process for wool fabrics was meta-mordanting. The dyed fabrics were bright yellow at 60 °C and golden yellow at 90 °C. All the obtained colors were in the yellow-red range. According to the ISO color fastness standards, wool fabrics dyed with G. caespitosum dye had good color fastness ratings, particularly sunlight fastness. Therefore, G. caespitosum dye is a promising natural yellow dye that can be used for wool fabric dyeing. It has advantages over other known natural yellow dyes and has certain application value.

BAr2 -Bridged Azafulvene Dimers with Tunable Energy Levels for Photostable Near-Infrared Dyes.

Organic dyes with strong absorption in the near-infrared (NIR) region are potentially useful in medical applications, such as tumor imaging and photothermal therapy. In this work, new NIR dyes combining BAr2 -bridged azafulvene dimer acceptors with diarylaminothienyl donors in a donor-acceptor-donor configuration were synthesized. Surprisingly, it was found that in these molecules the BAr2 -bridged azafulvene acceptor adopts a 5-membered, rather than 6-membered ring structure. The influence of the aryl substituents on the HOMO and LUMO energy levels of the dye compounds was assessed from electrochemical and optical measurements. Strong electron-withdrawing fluorinated substituents (Ar=C6 F5 , 3,5-(CF3 )2 C6 H3 ) lowered the HOMO energy while preserving the small HOMO-LUMO energy gap, resulting in promising NIR dye molecules that combine strong absorption bands centered around 900 nm with good photostability.

Application of Covalent Organic Frameworks (COFs) as Dyes and Additives for Dye-Sensitized Solar Cells (DSSCs).

Five Covalent Organic Frameworks (COFs) were synthesized and applied to Dye-Sensitized Solar Cells (DSSCs) as dyes and additives. These porous nanomaterials are based on cheap, abundant commercially available ionic dyes (thionin acetate RIO-43, Bismarck brown Y RIO-55 and pararosaniline hydrochloride RIO-70), and antibiotics (dapsone RIO-60) are used as building blocks. The reticular innovative organic framework RIO-60 is the most promising dye for DSSCs. It possesses a short-circuit current density (Jsc) of 1.00 mA/cm2, an open-circuit voltage (Voc) of 329 mV, a fill factor (FF) of 0.59, and a cell efficiency (η) of 0.19%. These values are higher than those previously reported for COFs in similar devices. This first approach using the RIO family provides a good perspective on its application in DSSCs as a dye or photoanode dye enhancer, helping to increase the cell's lifespan.

Novel Metal Complexes Unit of Phenanthroline Derivative for Being Used as Auxiliary Electron Acceptor in Dye Sensitizer Molecules

AbstractDonor‐acceptor‐π bridge‐acceptor (D−A−π−A) motif dyes are promising dye sensitizers in dye‐sensitized solar cells (DSSCs). In this study, to strengthen with‐drawing electron force of the auxiliary electron acceptors(A) in D−A−π−A motif dye sensitizers, the metal complexes unit is be used as auxiliary electron acceptor(A) instead of organic electron‐withdrawing monomer. The four polymeric metal complexes were designed, synthesized, and characterized, which used metal complexes of phenanthroline derivatives as auxiliary acceptors (A), benzodithiophene‐dithiophene derivatives (BDTT) as donors (D), and 8‐hydroxyquinoline derivatives as π‐bridges and acceptors of the dye sensitizers, and have been used for dye sensitizers. Under AM 1.5 G (100 mW cm−2), the photovoltaic test results indicated that the short‐circuit photocurrent density (Jsc) of the DSSCs based four polymeric metal complexes are 11.26, 13.68, 14.42 and 15.57 mA cm−2and power conversion efficiency (PCE) are 5.96 %, 7.83 %, 8.07 %, 9.28 % respectively. BothJscandPCEvalue of the four polymeric metal complexes increased in order. This may be due to the fact that larger radius of metal ion under the same change number can enhance the coordination bond and cause stronger electron‐withdrawing ability of auxiliary acceptor and stronger charge‐transfer ability between the donor and the acceptor, which results in higherJscand higherPCEof the polymeric complex dye sensitizer.

Benz[e]indole-bearing aminosquaraine dyes: Which of the amines introduced into the squaric ring will be able to induce the best in vitro photodynamic effect?

The introduction of amines into the four-membered central ring of squaraine dyes has proven to be a good way to improve certain attributes of the molecules such as their aqueous solubility, their absorption at higher wavelengths, as well as inducing a more effective interaction with certain biological targets. Therefore this chemical modification has been studied regarding their application in the development of potential photosensitizers for photodynamic therapy. This work presents the synthesis of several N-ethyl chain benz[e]indole-based aminosquaraine dyes with amines of increasing complexity (amino < methylamino < dimethylamino < hydroxyethylamino < hydroxyethylmethylamino < bis(hydroxyethyl)amino), in order to understand the effect of small modifications in the chemical structure on the photobiological activity of these compounds. Within the group of compounds prepared and evaluated, amino- and hydroxyethylamino-bearing dyes were the ones that showed the most interesting in silico and cytotoxicity assay results: low free binding energies for human serum albumin protein, especially hydroxyethylamino for Sudlow site I (−13.58 kcal/mol); higher rates of photocytotoxicity (4–48 times more toxic in the presence of light, depending on the tumor cell line under study) and reasonable rates of tumor selectivity (up to approximately 10 times more photocytotoxic to tumor cells compared to the effects on normal cells). Further studies involving the most promising dyes demonstrated that they are somehow linked or internalized in the mitochondria, that they are little genocytotoxic even after irradiation, that apoptosis, although it occurs, should not be the preferred death mechanism after photodynamic treatment and that a slight increase in the number of cells in the G2/M phase was perceived.

Effect of Molar Concentration and Solvent Type on Linear and NLO Properties of Aurintricarboxylic (ATA) Organic Dye for Image Sensor and Optical Limiter Applications

Aurintricarboxylic (ATA) organic dye is a promising chemical compound candidate for several optical and electronic applications. However, this study aims to investigate the impact of molar concentrations and solvent type on the linear/nonlinear optical (NLO) properties of 5,5[Formula: see text]-[(3-carboxy-4-oxocyclohexa-2,5-dien-1-ylidene) methylene] bis (2-hydroxybenzoic acid) organic laser dyes. Three molar concentrations of organic dyes ([Formula: see text], [Formula: see text], and [Formula: see text]) M were respectively dissolved in distilled water and dimethylsulfoxide (DMSO) at room temperature. The samples were investigated using1H-NMR and UV/Visible spectrums. The bandgap ([Formula: see text]) of ([Formula: see text] M) ATA/water is 4.75[Formula: see text]eV, but Eg of ATA/DMSO was 2.93[Formula: see text]eV and 2.65[Formula: see text]eV. The measurements were performed by employing a diode-pumped solid-state laser operating at a 457 nm wavelength and 112[Formula: see text]mW of power. The [Formula: see text]-scan technique was applied to characterize open and close apertures, nonlinear refractive index ([Formula: see text]), and nonlinear absorption coefficient ([Formula: see text]). The obtained results predicted that both the [Formula: see text] and [Formula: see text] coefficients decreased with the reduction of molar concentrations. Additionally, DMSO exhibited better linear/NLO properties than water. The results revealed promising laser dye samples for image sensor and optical limiter applications.

Classical thiazole orange and its regioisomer as fluorogenic probes for nucleolar RNA imaging in living cells.

In contrast to well-established DNA-selective dyes for live cell imaging, RNA-selective dyes have been less developed owing to the challenges of making small molecules have RNA selectivity over DNA. Two kinds of dyes are now commercially available for nucleolar RNA imaging in cells, but these two dyes do not apply to living cells and have limited use in fixed and permeabilized cells. Herein, we report on thiazole orange (TO), a well-known nucleic acid stain, as a promising fluorogenic dye for nucleolar RNA imaging in living cells. TO shows clear response selectivity for RNA over DNA with a significant light-up property upon binding to RNA (λem = 532 nm, I/I0 = 580-fold, and Φbound/Φfree = 380) and is even applicable to wash-free imaging of living cells. More interestingly, 2TO, a regioisomer of TO in which the benzothiazole unit is connected to position 2 in the quinoline ring, performs much better (λem = 532 nm, I/I0 = 430-fold, Φbound/Φfree = 1200), having superior selectivity for RNA in both solution and living cells. The comparison with TO derivatives carrying different substituents at N1 of the quinoline ring reveals that the slight change in the TO framework significantly affects RNA selectivity, photostability and membrane permeability.