Interaction Of Dyes Research Articles

Rapid and efficient removal of water-soluble dyes via natural asphalt oxide as a new carbonaceous super adsorbent; NA-oxide synthesis and characterization

In this study, natural asphalt was oxidized to synthesize a new nano-structure adsorbent for dye removal. The functionalization of natural asphalt by oxidation introduced new properties that influenced its activity. The process of oxidizing natural asphalt with potassium permanganate resulted in a low-cost adsorbent, which can potentially be a more affordable option compared with synthetic alternatives. Characterization analysis confirmed the enhanced surface area, improving dye interaction and adsorption. The interconnected channels and capillaries of the oxidized natural asphalt facilitated the capillary action drawing in liquids, including dyes. The distinctive porosity of natural asphalt oxide (NA-oxide) was noted, and the experimental results showed that the NA–oxide nanoadsorbent efficiently adsorbed cationic and anionic dyes in water, with maximum capacities of 14.68 mg.g−1, 17.81 mg.g−1 and 16.47 mg.g−1 for methyl orange, methylene blue and Rhodamine B, respectively. The study investigated various parameters, such as concentration, adsorption dose, pH, contact time, and temperature, affecting the dye removal process. Langmuir, Freundlich, and Temkin isotherms along with pseudo-first and pseudo-second-order kinetic equations were applied to assess the adsorption process, indicating that dyes adhered to the pseudo-first-order model and Langmuir isotherm. Analysis of MO, MB, and RhB dyes revealed conformity to Langmuir isotherm and first-order kinetics. Thermodynamic evaluations like ΔH°, ΔS°, and ∆G° displayed the exothermic and spontaneous nature of dye adsorption on the NA-oxide adsorbent. Furthermore, the absorbent displayed remarkable stability with a recovery rate of 98.45% after ten cycles, signifying its potential for enduring effectiveness in dye removal processes.

The Dynamic Impact of Synthetic Dyes on the Physicochemical Parameters of Cationic and Anionic Surfactants

Introduction: The interaction of dyes (crystal violet, malachite green, and congo red) with cationic (cetrimide) and anionic surfactants (sodium dodecyl sulfate) in the aqueous medium were studied via conductometric and UV-visible spectroscopy. Method: The critical micelle concentration (CMC) of both cetrimide and SDS upsurges in all the selected dyes on increasing the temperature. Thermodynamic parameters like change in Gibb’s free energy of micellization (Δ G°m ), change in enthalpy of micellization (Δ H°m ) as well as change in entropy of micellization (Δ S°m ) were calculated by employing mass action model. Result: The Δ S°m values obtained are positive with Δ G°m and Δ H°m values being negative signified that the phenomenon of micellization is spontaneous as well as exothermic in nature. Moreover, the more negative Δ H°m in water as well as in the presence of dyes signify the presence of electrostatic forces of attraction between the oppositively charged dyes and surfactant moieties. UV-spectroscopy reveals that spectral changes occur because of the interaction of surfactants with dye molecules. Conclusion: By analyzing shifts in absorption peaks, changes in intensity, and alterations in band shape, insights into the nature of surfactant-dye complexes and their potential applications in various industries can be assessed. This understanding can help in the design and optimization of products and processes involving surfactants and dyes.

Enhancing Photothermal Energy Transduction through Inter- and Intramolecular Interactions of Multiple Two-Photon Dyes Appended onto Calix[4]arene.

Organic dyes-based photothermal agents (OPTAs) have received increasing attention as alternative to inorganic materials due to their higher biocompatibility and extensive diversification. Maximizing nonradiative deexcitation channels is crucial to improve the photothermal conversion efficiency (PCE) of OPTAs. This is typically achieved through individual molecular design or collective enhancement using supramolecular strategies. Furthermore, photothermal therapy (PTT) generally relies on linear one-photon absorption of the light source by the OPTA, with less consideration given to nonlinear two-photon absorption (2PA) strategies, despite their potential benefits. Here, a synergistic strategy, which combines intramolecular and intermolecular quenching, is employed to maximize the photothermal efficiency of diphenylamino-substituted distyryl dicyanobenzene (DSB), an outstanding two-photon-absorbing chromophore. One to three DSB units have been introduced on the conic p-tert-butyl-calix[4]arene (CX), serving as a preorganizing platform to allow aggregate formation and promote intramolecular quenching within the multichromophoric systems. Importantly, the multichromophoric molecules had very high two-photon absorption capabilities with cross sections (δ2PA) reaching maximal values of 3290 GM at 810 nm. Experimental data accompanied by large-scale molecular dynamics simulations and time-dependent density functional theory calculations shed light onto the interaction mechanism in those multiple DSB-appended CX compounds to rationalize their optical properties. Then, the formulation with Pluronic F127 amphiphile yields water-dispersible nanoprecipitates (Nps), in which the PCE is further maximized and the photobleaching is reduced due to the combination of intra- and intermolecular quenching. The high two-photon absorption in the near-infrared (NIR) window associated with the high PCE of these nanosized OPTAs could serve as a basis to future in vivo 2P-PTT applications.

Sctudies on adsorption of Brilliant Green from aqueous solution onto nutraceutical industrial pepper seed spent

The study proposed the removal of Brilliant Green, a cationic dye, by adsorption process from wastewater solution utilizing a low-cost adsorbent such as Nutraceutical Industrial Pepper Seed Spent (NIPSS). The study comprises an investigation of the parametric influence on the adsorption process. The parameters identified are pH, dye concentration, process temperature, quantity of the adsorbent, and particle size. The study of statistics found from experiments was carried out by incorporating Freundlich, Brouers-Sotolongo, Langmuir, Toth, Sips, Jovanovic, and Redlich-Peterson isotherm models. The adsorption kinetics were determined by implementing pseudo-first-order and second-order models, diffusion film models, and Dumwald-Wagner and Weber-Morris models. The experimental adsorption capacity qe was found to be about 130 mg/g. This value was closest to the maximum adsorption of 144.6mg/g predicted by the Brouers-Sotolongo isotherm which had a correlation coefficient (R2) of 0.998. The adsorption kinetics data was confirmed to be a pseudo-second-order model. The change in free energy, enthalpy change, and entropy change were vital thermodynamic factors in concluding that adsorption is almost spontaneous and endothermic process. Change in enthalpy (ΔH°) reduced value indicates the physical nature of the process. The adsorption of BG dye on the adsorbent surface was authenticated by FTIR spectroscopy and SEM imaging. A Central Composite Design (CCD) Quadratic model under Response Surface Methodology (RSM) was implemented for statistical optimization of adsorption capacity for the five parameters studied, namely, time, temperature, concentration of the dye, weight of the adsorbent, and pH. Software Design Expert 7.0 was used to evaluate 3D contour plots. The process of optimization yielded a value of 350 mg/g. Thus, incrementing the adsorption process by 84.2 %. The study provides insights on various dye and adsorbent interaction possibilities and derives that NIPSS is an efficient adsorbent to extract BG dye from wastewater solutions.

A semi-automated quantum-mechanical workflow for the generation of molecular monolayers and aggregates.

Organic electronics (OE) such as organic light-emitting diodes or organic solar cells represent an important and innovative research area to achieve global goals like environmentally friendly energy production. To accelerate OE material discovery, various computational methods are employed. For the initial generation of structures, a molecular cluster approach is employed. Here, we present a semi-automated workflow for the generation of monolayers and aggregates using the GFNn-xTB methods and composite density functional theory (DFT-3c). Furthermore, we present the novel D11A8MERO dye interaction energy benchmark with high-level coupled cluster reference interaction energies for the assessment of efficient quantum chemical and force-field methods. GFN2-xTB performs similar to low-cost DFT, reaching DFT/mGGA accuracy at two orders of magnitude lower computational cost. As an example application, we investigate the influence of the dye aggregate size on the optical and electrical properties and show that at least four molecules in a cluster model are needed for a qualitatively reasonable description.

NEUROTOXIC RISK AND ADSORPTION PROPERTIES OF COARSE NON-FUNCTIONALIZED CARBON PARTICLES DERIVED FROM APPLE WASTE

Aim. Carbon particles have been widely used in different technologies and have great potential for new biological application. Synthesis of carbon particles from agricultural waste using “green” principles is in the mainstream of biotechnology area and attract a great attention in biomedical application. Here, coarse carbon particles (CCPs) were synthesized using “green” principles from dry apple and used in the biological experiments without preliminary functionalization. Methods. Neurotoxic features of CCPs were analysed in isolated presynaptic cortex nerve terminals (synaptosomes) monitoring the extracellular levels of excitatory neurotransmitter L-[14C] glutamate and inhibitory one [3H]GABA, as well as the membrane potential. Results. Measuring the membrane potential of the nerve terminals, it was revealed an inadequate decrease in the fluorescence intensity of the potential-dependent dye rhodamine 6G in the presence of CCPs (1 mg/ml). This decrease was not due to membrane hyperpolarisation because CCPs did not change the extracellular synaptosomal levels of L-[14C] glutamate and [3H]GABA. CCP-induced decrease in the fluorescence intensity of the dye in nerve terminals can be due to its interaction with CCPs. Indeed, the ability of CCPs to interact with rhodamine 6G was shown in synaptosome-free incubation media. Conclusions. Therefore, CCPs did not possess neurotoxic signs, and so are biocompatible. In both experiments, i.e. without bio object and in biological system, CCPs were able to interact with fluorescent dye rhodamine 6G. In prospect, this feature of CCPs can be used in biotechnology after further investigation of dye interaction conditions.

Some aspects of adsorption, catalytic and photocatalytic interactions of organic dyes with TiO2-based binary nanocomposites

Some aspects of adsorption, catalytic and photocatalytic interactions of organic dyes with TiO2-based binary nanocomposites

Bioremediation of Brilliant Green cationic dye from water using Nutraceutical Industrial Coriander Seed Spent as an adsorbent: adsorption isotherms, kinetic models, and thermodynamic studies.

The article details a feasibility study of removing Brilliant Green (BG), a mutagenic dye from an aqueous solution by adsorption using low-cost coriander seed spent as a by-product in the nutraceutical industry. The study includes an analysis of the parameters that affect the adsorption process. The variables that have been identified include pH, dye concentration, process temperature, adsorbent amount, and particle size of the adsorbent. To obtain information on the adsorption process and to design the mechanism of the adsorption system on experimental equilibrium, 10 isotherm models, namely, Langmuir, Freundlich, Jovanovic, Dubinin-Radushkevich, Sips, Redlich-Peterson, Toth, Vieth-Sladek, Brouers-Sotolongo, and Radke-Prausnitz were applied. It was discovered that the experimental adsorption capacity, qe, was roughly 110mgg-1. The result has a maximum adsorption of 136.17 mgg-1 as predicted by Dubinin-Radushkevich isotherm. Diffusion film models, Dumwald-Wagner and Weber-Morris models, and pseudo-first- and second-order models, were used to determine the adsorption kinetics. It was realized that the adsorption kinetics data fit into a pseudo-second-order model. Thermodynamic analysis with a reduced enthalpy change suggests a physical process. The values of the thermodynamic parameters ΔG0, ΔH0, and ΔS0 demonstrated an endothermic and nearly spontaneous process of adsorption. The small valuation of ΔH0 specifies that the process is physical. FTIR spectroscopy and SEM imaging were used to confirm that the BG dye had been adsorbing on the adsorbent surface. The study concludes that NICSS is an effective adsorbent to extract BG dye from wastewater solutions, offers insights into numerous dye and adsorbent interaction possibilities and indicates that the process can be scaled to fit into the concept of circular economy.

Small-Molecule:Polymer Composites for Transparent Films with Visible Emission.

The analysis of the shift in photoluminescence emission for a blend of polyvinylcarbazole and acrylonitrile derivative compounds is reported. The small-molecule compounds have different functional groups, phenyl, pyridine, or methyl phenyl, attached to an acrylonitrile group. According to the functional group, the blue emission for pure dye shifts to green or yellowish in the blend film. Several PVK:dye ratios from 0:100 to 20:80 were used for film deposition. The film morphology was analyzed by atomic force microscopy; for low dye content, homogeneous films were achieved. However, aggregates of several micrometers are formed on the surface of films with higher dye concentrations. The shift in emission occurs only with PVK, and for a non-conjugated matrix such as polystyrene, the emission remains unchanged. The interaction of dyes with PVK leading to change in emission was also achieved by grinding dye and polymer. Results showed that shifts in emission could come from exciplex formation along with changes in dye intermolecular interactions. The blend films were highly transparent in the visible spectra due to the absorption in the UV region for dye and matrix. The films with ratio PVK: dye ratio 80:20 was used as active layer in OLEDs.

Bio- colouration of nylon fabric using natural dyes and mordants

ABSTRACT Natural dyes offer a harmless alternative to synthetic counterparts, minimizing the release of toxic chemicals associated with synthetic dyes. In this investigation, nylon fabrics underwent dyeing with neem leaf extract under acidic, neutral and alkaline conditions along with lemon juice mordant. The study revealed that colour strength exhibited an increase with decreasing pH levels, with the mordanted fabric dyed in an acidic medium demonstrating the highest value. Analysis of colour coordinates indicated that the mordanted fabric dyed in an acidic medium exhibited superior colour pickup compared to the other samples. Enhanced fastness properties were achieved under acidic pH conditions when a mordant was used. The FTIR test result ensured the nylon-lemon juice-neem leaves extracted dye interaction. The EDX analysis also confirmed the elemental composition of neem leaves extracted dye in nylon assisted by lemon juice. The SEM test results validated the dyeing process empirically.

Dyeing of Mixed Cotton and Polyester Fabrics with New Dyes—Complexes of Collagen with Transition Metal Ions

Uniform, stable, one-step dyeing of textile fabrics made from a mixture of natural and synthetic fibers using traditional methods remains problematic to this day. As an alternative to traditional methods, a one-step method for dyeing mixed cotton and polyester fabrics with a new natural dye—a complex of collagen and [Formula: see text] and [Formula: see text] ions—was proposed for the first time. Dyeing of pre-prepared cotton, polyester, and cotton–polyester fabrics is carried out by dipping in an aqueous dye solution, squeezing, drying, and heat setting. The influence of the mass ratio of dye components, fixation temperature, and pH of the solution on the degree of dye fixation was determined. A degree of sorption of dyes (14–25%) from the solution onto the surface of fabrics was established, which after heat fixation decreases slightly (1–3%). During washing processes, the copper complex is almost completely washed out from polyester and blended fabrics and remains in small quantities (2.4–3.8%) on the surface of cotton fabrics. After water washing, the degree of fixation of the collagen–chrome complex in fabrics is as follows: in cotton—8–10%, in polyester—10–12%, and in cotton–polyester—8–9%. The color coordinates of cotton and cotton–polyester fabrics hardly change before and after washing, but for polyester fabric, the changes are significant. The mechanism of interaction of the complex dye with the fibers was studied using the Fourier transform infrared method, and the morphology and distribution of the dye on the surface of the samples using the SEM-EDS method. The dye binds to cellulose through ionic and coordination bonds, and to polyester through joint melting. Therefore, unlike pure polyester fabric, cotton and cotton–polyester fabrics demonstrated high color fastness to washing and light fastness. The use of production waste, the exclusion of synthetic dyes and harmful chemicals, and single-stage dyeing of the material reduce the environmental burden.

Experimental exploration and DFT analysis of the kinetics and mechanism of malachite green photodegradation catalyzed by polyaniline-copper oxide nanocomposite.

A nanocomposite photocatalyst consisting of polyaniline (PANI) and copper oxide (CuO) was successfully synthesized through an in-situ polymerization approach using aniline as the precursor. The synthesized nanocomposite was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy (UV-Vis), determination of the point of zero charge (pHPZC), and scanning electron microscopy (SEM). The photocatalytic efficiency of the PANI-CuO nanocomposite was evaluated in the context of photodegrading Malachite Green (MG) dye under visible light. Malachite Green, a synthetic dye commonly used in the textile and aquaculture industries, is a significant contaminant due to its toxic, mutagenic, and carcinogenic properties, making its removal from water resources crucial for environmental and human health. Distilled water artificially contaminated with MG dye was used as the medium for testing. The parameters influencing the photodegradation efficiency were comprehensively investigated. These parameters included catalyst dosage, reaction time, initial dye concentration, and pH. The results of this study indicate that the degradation efficiency of MG dye displayed an upward trend with time, catalyst dosage, and pH while exhibiting a converse relationship with the initial dye concentration. A degradation rate of 97% was achieved with an initial concentration of 20mgL-1, employing a catalyst dose of 1.6gL-1 at pH 6 for a reaction time of 180min. Furthermore, the reusability of the catalyst was assessed, revealing consistent performance over five consecutive cycles. Density functional theory (DFT) was employed to optimize the structures of PANI, PANI-CuO, and their respective complexes formed through dye interaction, employing Gaussian software. These calculations employed the B3LYP/6-311G + + (d,p) basis set in an aqueous environment with water serving as the solvent. The kinetics of Malachite Green degradation were analyzed using both first and second-order kinetic models.

Interaction of anionic dye ethyl orange and cationic CnTAC surfactants: A multi technique investigation

This research presents the application of electrical conductivity measurements to ascertain the critical micelle concentration (CMC) values for N-alkyltrimethylammonium chloride surfactants (CnTAC; with alkyl chain lengths of n = 12, 14, 16, and 18). Complementary spectrophotometric analysis was conducted to probe the interactions between CnTAC series and Ethyl Orange (ETO), an anionic dye. Applying the Benesi-Hildebrand and Scott equations, we evaluated the binding constant (Kb) of the cationic micelles’ interaction with ETO, which in turn facilitated calculations of Gibb’s free energy (ΔG°) changes. These calculations provided insight into the binding affinity of ETO to the micelles. Our findings suggest that the interaction between ETO and CnTAC is contingent on the surfactant concentration, with higher concentrations leading to a disassociation of the ETO-CnTAC complex and a reduction in ETO adsorption. Notably, the alkyl chain length within CnTAC molecules critically affects various properties, including ΔG°, CMC, and other thermodynamic parameters that determine the surfactant’s energetic behavior. The study underscores the importance of the alkyl chain length in dictating the interaction dynamics and properties of CnTAC surfactants. A trend was observed where longer alkyl chains lead to increased Kb values and reductions in both CMC and ΔG°, enhancing dye solubilization and interaction spontaneity. The affinity sequence of ETO to the micelles, influenced by alkyl chain length, was found to be C12TAC < C14TAC < C16TAC < C18TAC.

A multi-scale computational investigation of cationic dye interaction with rutile TiO2: An interconnected simulation approach

Metal oxides have increasingly been employed for water pollution remediation. In the present investigation, the adsorptive characteristics of three cationic dyes, rhodamine B (RB), safranin O (SO), and methylene blue (MB), on the (110) surface of rutile titanium dioxide in an aqueous milieu were scrutinized. Utilizing Density Functional Theory (DFT), the reactivity of these organic compounds was evaluated by computing parameters such as molecular frontier orbital energies, energy gap (ΔEgap), electronegativity (χ), chemical hardness (η), chemical softness (σ), electrophilicity (ω), nucleophilicity, electron transfer fraction (ΔN), and Fukui indices. Findings demonstrated that RB exhibited superior reactivity and adsorptive capacity in comparison to MB and SO. Self-Consistent Charge Density-Functional Tight-Binding (SCC-DFTB) simulations revealed that RB engaged in the most potent interactions with the TiO2(110) surface, with interaction energies following the sequence RB (−1.12 eV) > MB (−1.07 eV) > SO (−1.01 eV). Furthermore, the most energetically favorable adsorption configurations for these dyes were elucidated through Molecular Dynamics (MD) simulations. Adsorption energies calculated via MD simulations corroborated that the TiO2 (110) surface possessed high adsorptive capabilities for these cationic dyes, particularly a stronger affinity for RB. The study provides comprehensive insights into the molecular-level interactions between cationic dyes and rutile TiO2, thereby contributing valuable information for the optimization of metal oxide-based water pollution treatment technologies.

Fundamental kinetic modeling of dye sensitization photocatalysis by oxygen vacancy enriched ZnO for the quantification of degradation by catalyst or dye sensitizer

Dye sensitization enhances catalyst reactivity using dye molecules to amplify light absorption. Researchers debate using dyes as model compounds due to uncertainty about whether degradation is driven by dye or the catalyst. Instead of avoiding this question, our approach involves understanding and quantifying the distinct roles of each component in the degradation process. This study investigated methylene blue (MB) sensitization of ZnO using a binary dye mixture of MB and methyl orange. A comprehensive kinetic model was developed to account for the function of MB sensitizer by simultaneously tracking the interaction of dyes across the catalyst surface and solution in pH range of 3 to 11. The effects of pH on dye adsorption were incorporated using dye speciation (pKa). The dye removal was kinetically modeled considering reversible adsorption/desorption and surface/aqueous degradation by the interaction between active radicals (in the solution) and electron-holes (on the catalyst surface). Additionally, the source of the generated electron hole (i.e., ZnO or MB sensitizer) was considered separately. Oxygen vacancy effects on dye adsorption and sensitization were explored through hydrogen reduction of ZnO at 500 °C. Characterization techniques assessed oxygen vacancy presence, while quantum yield calculations quantified MB sensitization's contribution to dye degradation versus the catalyst.

Binding interaction of cationic acridine dyes with glucose oxidase to enhance mediated bioelectrocatalysis

Cationic acridine dyes enhanced mediated bioelectrocatalysis of glucose oxidase, and their binding interactions were analyzed using fluorescence quenching and docking simulation.

Shedding light on thermally-activated delayed fluorescence.

Thermally activated delayed fluorescence (TADF) is a hot research topic in view of its impressive applications in a wide variety of fields from organic LEDs to photodynamic therapy and metal-free photocatalysis. TADF is a rare and fragile phenomenon that requires a delicate equilibrium between tiny singlet-triplet gaps, sizable spin-orbit couplings, conformational flexibility and a balanced contribution of charge transfer and local excited states. To make the picture more complex, this precarious equilibrium is non-trivially affected by the interaction of the TADF dye with its local environment. The concurrent optimization of the dye and of the embedding medium is therefore of paramount importance to boost practical applications of TADF. Towards this aim, refined theoretical and computational approaches must be cleverly exploited, paying attention to the reliability of adopted approximations. In this perspective, we will address some of the most important issues in the field. Specifically, we will critically review theoretical and computational approaches to TADF rates, highlighting the limits of widespread approaches. Environmental effects on the TADF photophysics are discussed in detail, focusing on the major role played by dielectric and conformational disorder in liquid solutions and amorphous matrices.

Nucleic acid-binding bis-acridine orange dyes with improved properties for bioimaging and PCR applications.

Understanding the intricate interactions of molecular dyes with nucleic acids is pivotal for advancing medical and biochemical applications. In this work, we present a comprehensive study of the interplay between a novel series of bis-acridine orange (BAO) dyes and double-stranded DNA (dsDNA). These BAO dyes were intentionally designed as two acridine orange units connected by neutral linkers featuring a 2,5-disubstituted thiophene moiety. Comparative analysis of BAO compounds with the widely utilized DNA-binding dye EvaGreen (EG) was carried out for fibroblast staining and qPCR analysis. The results show that BAO dyes outperform EG by supporting PCR amplification over a broader concentration range (0.5-5.0 μM). Furthermore, they exhibit an exceptional capability to generate consistent DNA melting curves regardless of DNA concentration fluctuations. Molecular dynamics simulations showed that BAO dyes when interacting with dsDNA unfold from the stacked conformation to the elongated one. The difference in the energy between the conformations is shown to be concomitant with fluorescence enhancement. This study enriches our understanding of the intricate interplay between innovative BAO dyes and dsDNA, fostering their applications in medical and biochemical research, particularly in qPCR methodologies and bioimaging techniques.

New insights into the photophysical properties and interaction mechanisms of Janus green blue dye with polyanions and its applications in colorimetric visualization of loop-mediated isothermal amplification and polymerase chain reaction.

In this investigation, the photophysical properties and interaction mechanisms of Janus green blue (JGB) dye with polyanions were systematically studied using spectroscopic techniques. The absorption spectral analysis revealed that JGB binds cooperatively to sodium alginate, leading to dye stacking along the polymer chain. The interaction of JGB dye with DNA was characterized by the emergence of a metachromatic peak at 564 nm, indicating the formation of dye aggregates. The analysis of absorption data reveals that JGB dye interacts with DNA at multiple binding sites, including at least one high-affinity site. The AutoDock Vina based blind docking approach was used to analyze the most probable binding location of JGB dye in DNA. By making use of the DNA-induced metachromasia, a colorimetric approach was developed for the visualization of loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR). The LAMP-colorimetric assay, targeting the Streptococcus pneumoniae gene, demonstrated a noticeable colour change with a detection limit of 1 pg μL-1. The practical applicability was validated by detecting S. pneumoniae in artificial urine. In addition to LAMP, we tested the JGB dye based colorimetric assay for applicability in PCR reactions. The colorimetric PCR assay using the metal-responsive transcription factor (MTF-1) gene achieved a detection limit as low as 0.1 pg μL-1. The study highlights the potential of DNA binding metachromic dye to significantly enhance colorimetric assays, offering a robust and sensitive tool for molecular diagnostics.

Effect of ions added by mordant and brightener on the signal structure and energy storage properties of natural dye-based DSSCs

It has been observed experimentally that the output voltage profiles are exponential of two types: rising or decaying; the structure of these profiles is controlled by the mobility of charges: ions and electrons. A comparison between the arrival times of electrons at electrode τe, and ions at double-layer τi, allows determining the shape of these signals. The electrons produced by the photon–dye interaction reach the cathode increasing the output voltage. The ions in the electrolyte are moved by the charge on the electrodes forming the electrical double layer; these ions reduce the output voltage: electrons and ions produce opposite effects. These two charge accumulations produce double layers on both sides of the electrode–electrolyte interface forming double-layer capacitors. The numerical values of several cell parameters (energy, electric field, charge density, capacitance) were estimated, and it was found that they depend on κ; the inverse of the thickness of the double layer λ = κ−1; because κ is a large number, double-layer capacitors are suitable for storing large amounts of energy which is associated with chemical capacitance Cμ. Two dyes were used: brazilwood and cochineal, Al3+ as a mordant, and Na+-metasilicate as brightener. A model was included to describe and fit oscillations in the voltage profiles that appear due to an abrupt illumination. An expression was obtained for Cμ as a function of the voltage.