Micelle Media Research Articles

Pyrylazo Dye: A Novel Azo Dye Structure with Photoinduced Proton Release and Highlighted Photophysical Properties in Biological Media.

A straightforward method for synthesizing a stable, photoreactive, and fluorescent-probe azo dye molecule is presented, highlighting the influence of azo and pyrylium groups within the electronic structure of the novel dye. This compound, named the pyrylazo molecule, is synthesized through the chemical reaction between 2,4,6-trimethylpyrylium and a 4-methoxybenzenediazonium species. The methyl group at the para position of the pyrylium readily reacts with the diazonium molecule, forming a stable protonated pyrylium-azo dye (N-protonated pyrylazo). The pyrylazo structure can easily change into its N-deprotonated form upon introduction of a weak base, such as an amine, promoting significant spectral shifts in the visible absorption and fluorescence bands. Because of that and other photochemical properties, this novel dye has shown significant potential for applications in photoinduced processes and biological contexts, particularly in Coulombic interactions with micelles and animal cells. In contrast to other nonfluorescent azo dyes, the singlet excited state of pyrylazo is deactivated through a radiative process in organized media, as evidenced by its behavior during micelle media, cell membrane permeation, and fluorescence emission in the cytoplasm. Nanosecond-transient absorption spectroscopy reveals a reversible photoinduced proton release process occurring in the excited singlet state, suggesting that the excited states of pyrylazo may play roles in transport through ion channels, artificial photosynthesis, and photoinduced protein folding. These promising applications underscore the pyrylium-azo structure as a novel dye with remarkable photochemical and photophysical properties not observed in other azo dye molecules reported before.

Tuning Sensing Efficacy of Oligo(phenylenevinylene) Based Chromogenic Probes: Effect of Alkyl Substituents on Metal Ion Detection at Micelle-Water Interface.

In this work, we conducted a comparative analysis of the metal ion sensing capabilities of two pyridine-end oligo p-phenylenevinylene compounds featuring different alkyl substituents (-C4H9 and -C16H33) within a micelle medium. Our findings revealed a correlation between the positioning of the probe molecules within the micelle and the length of the alkyl chains, impacting their self-assembly tendencies and optical characteristics. The compound with shorter alkyl chains demonstrated a superior affinity towards Hg2+ ions, whereas exposure to the compound with longer alkyl substituent resulted in a color-changing response with both Cu2+and Hg2+ ions. Intriguingly, the sensitivity towards Hg2+ ions heightened with increasing alkyl chain length. This trend persisted in non-polar solvents like THF. The capacity to modulate sensing efficacy solely by adjusting the length of the alkyl chains represents a relatively uncommon occurrence in the existing literature. This discovery suggests promising prospects for engineering sensory devices equipped with adaptable sensitivity.

Assorted designing of molecular logic gates and memory latch functionality descended from copper Ions-Triggered optical responses

The present letter showcases the designing of versatile inter-convertible logic circuits and molecular memory latch by exploiting the optical responses of a chromogenic probe (1) in a context-dependent manner. Different combinations of ionic and non-ionic analytes in specific ratios have been used as inputs, whereas the changes in absorption signals of 1 at different wavelengths have been considered as outputs. For instance, the changes in UV–visible spectra of 1 have been considered during interaction with specific analytes, such as Cu(I) and Cu(II) ions in anionic micelle medium. In addition, binding of 1 with Cu(I) or Cu(II) ions in the presence of suitable chelating ligands [ethylenediamine, neucouprine] or redox-reagents [H2O2, GSH] have also been scrutinized for the construction of diverse logic circuits. Beyond trivial logic gates (NOR, OR, AND, NAND), we have designed a series of non-trivial (IMPLICATION, INHIBIT, TRANSFER, NOT-TRANSFER) logic circuits. Additionally, we also designed dual-input PASS 1 and PASS 0 logic circuits with the specific sets in opto-chemical inputs and outputs. Here it's fascinating how easily optical toggling allows us to change the type of logic sense. Additionally, for the first time we are reporting here a dual-input-dual-output buffer logic gate. At long last, with Cu(I) and H2O2 we designed a rarest of molecular JK latch functionality.

Steady-State and Time-Resolved Fluorescence Study of Selected Tryptophan-Containing Peptides in an AOT Reverse Micelle Environment.

The aim of this study was to demonstrate the utility of time-resolved fluorescence spectroscopy in the detection of subtle changes in the local microenvironment of a tryptophan chromophore in a confined and crowded medium of AOT reverse micelles, which mimic biological membranes and cell compartmentalization. For this purpose, fluorescence properties of L-tryptophan and several newly synthesized tryptophan-containing peptides in buffer and in an AOT reverse micelle medium were determined. It was shown that insertion of tryptophan and its short di- and tripeptides inside micelles led to evident changes in both the steady-state emission spectra and in fluorescence decay kinetics. The observed differences in spectral characteristics, such as a blue shift in the emission maxima, changes in the average fluorescence lifetime, and the appearance of environmental-dependent fluorescent species, showed the utility of time-resolved fluorescence spectroscopy as a sensitive tool for detecting subtle conformational modifications in tryptophan and its peptides induced by changes in polarity, viscosity, and specific interactions between chromophores and water molecules/polar groups/ions that occur inside reverse micelles.

A Simple Live Cell Imaging "Turn-On" Fluorescence Probe for the Selective and Sensitive Detection of Aqueous Hg2+ Ions.

A simple, efficient, and reversible fluorescent sensor probe, PBA (2,6-dimethyl pyrone barbituric acid conjugate), comprised of a pro-aromatic donor conjugated with a barbituric acid, was developed for the detection of highly toxic mercuric ions. The probe showed high selectivity and "Turn-On" fluorescence response towards Hg2+ among various metal cations such as Na+, Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Ba2+, Hg2+, and Pb2+, in both homogeneous and microheterogeneous micelle medium sodium dodecyl sulphate (SDS). The binding stoichiometry, limit of detection (LOD), and binding constant for the PBA-Hg complex were determined. The mechanism of binding was ascertained using the N,N'-dimethylbarbituric acid conjugate of 2,6-dimethylpyran (PDMBA), where no binding interaction by deprotonation is possible. In the presence of cysteamine hydrochloride and trifluoroacetic acid (TFA), the complexation of Hg2+ with PBA was demonstrated to be reversible, indicating its potential for the development of reusable sensors. Moreover, the practical applicability of PBA in monitoring Hg2+ in living cells was also evaluated.

Comparative Spectrophotometric Determination of Neodymium (III), Praseodymium (III), Samarium (III) and Terbium (III) in Aqueous and Micelle Media

This research work titled comparative spectrophotometric determination of neodymium (III), praseodymium (III), samarium (III) and terbium (III)in aqueous and micelle media using schiff base was carried out with the aim to use a simple, rapid and sensitive spectrophotometric method for the determination of Nd (III), Pr (III), Sm(III) and Tb(III) using the Schiff base 2,2′-((1E,1′E)-(1,2-phenylenebis(azanlylidene)bis (methanylylidene))diphenol (BSOPD) as a ligand. Spectral and absorbance measurements were carried out using UV/Visible Spectrophotometer (Jenway model no.: 6305) with 1-cm matched quartz cells. This method of experiment was based on the formation of green coloured complexes, upon the reaction of Nd(III) and Pr(III) and a brown coloured complexes for Sm(III) and Tb(III) having a maximum absorbance of 376, 386, 384 and 380 nm respectively. The comparative analysis of the complexes formed in aqueous and in micellar media were investigated in this study. In the obtained results, it was discovered that, Beer’s law was obeyed in the concentration ranges of 0.001 - 0.02 ppm. The molar absorptivity was found to be in the range of 7,776- 23,197 and 27,087 dm³mol^-1cm^-1 and the Sandell’s sensitivity for the compounds analyzed were in the ranges of 6.13-19.34 g cm^-2. The increase in absorbance in the presence of the surfactants is due to micelle formation. The reactants were bound in a small volume of stern layer of the micelle leading to a greater increase in concentration effect. This effect in concentration reaches a maximum before decreasing due to dilution effect occasioned by increase in metal ion concentration.

Photocatalyst CdS for efficient cleavage of lignin C[sbnd]O bonds in micellar aqueous medium

Photocatalytic cleavage of lignin CO bonds is a promising way to depolymerize lignin into aromatic value-added chemicals. However, the dispersibility of lignin in solvents and photocatalytic efficiency still face great challenges. Here, a micelle aqueous medium (CTAB-15) composed of hexadecyl trimethyl ammonium bromide and water was successfully prepared. 2-phenoxy-1-phenylethanol (lignin model compounds, PPol) and dioxanesolv poplar lignin have a good dispersion in CTAB-15. Compared to the previous reports, the highest photocatalytic efficiency can be obtained under optimal conditions by using the photocatalyst CdS. The main products formed by photocatalytic cleavage of lignin CO bonds are phenols and ketones. Mechanism studies show that CTAB-15 can provide sufficient hydrogen by photo-driven dissociation of water for photocatalytic cleavage of lignin CO bonds, which is critical to rapidly improving photocatalytic efficiency. The hydrogen, which is used to form acetophenone, comes from H2O and PPol. However, the hydrogen needed to form phenol comes only from PPol itself. In addition, the photocatalytic reaction follows a photogenerated electron-hole coupled redox process. This work develops a new direction for promoting the high-value utilization of lignin.

Formulation Development of Nifedipine through Nanotechnology: A Comprehensive Review.

The therapeutic use of nifedipine, a dihydropyridine calcium channel blocker, is limited due to its poor solubility profile, rapid onset of its action, stability profile and short biological half-life. Many formulation techniques have been applied to improve physicochemical and pharmacological properties of the drug. The objective of the study is to summarize the nanotechnology approaches made to improve the therapeutic and pharmacokinetic properties of nifedipine till 2020. The searches for the related articles were done up to 28 March 2020 with the specific keywords in Pubmed and Google Scholar excluding review articles. The discussion showed that among the nano-carriers used to improve the pharmacological property of the drug, lipid nanoparticles, polymeric nanoparticles, crystalline nanoparticles, and nano-emulsions were prevalent. Nanotechnology has been efficient to improve the solubility profile of nifedipine, achieve sustained and controlled release by achieving targeted and local delivery and transdermal drug delivery. Exploiting nano-formulations, new windows of therapeutic applications have been achieved. Finally, micelle media, polymeric nanoparticles, and microcrystalline nanoparticles have been used to develop a photostable formulation. The technological innovations in the field of nanomedicine have paved many ways for the delivery of nifedipine and such sparingly water-soluble compounds.

Second order Derivative Spectrophotometric determination of Fe(II) using 3,4-DihydroxyBenzaldehydeTiosemicarbazone(DHBTSC) in presence of micelle medium

Second order Derivative Spectrophotometric determination of Fe(II) using 3,4-DihydroxyBenzaldehydeTiosemicarbazone(DHBTSC) in presence of micelle medium

Photochromism of Copper(I) and Silver (I) complexes of 1-alkyl-2-(arylazo)imidazoles in miceller media

Photochromism, a reversible structural change of distinctive absorption feature of each isomer upon irradiation of light, is largely influenced by external environment such as polarity of media, existence of noncovalent interactions, hydrogen bonding etc. In this work, the Photochromism of [Cu(RaaiR/)2]ClO4 and [Ag(RaaiR/)2]NO3 complexes (RaaiR/ = 1-alkyl-2-(arylazo)imidazole) have been examined in the micelle media in MeOH using Triton-X-100, CTAB and SDS. 1-Alkyl-2-(arylazo)imidazole undergoes trans-to-cis isomerization about –N=N- bond upon light irradiation. The quantum yield (ft®c) of the photoisomerization follows the sequence nonionic micelle (Triton-X-100) > Cationic micelle (CTAB) > no micelle > anioic micelle (SDS). Although the cis-to-trans isomerization is also carried out photochemically but thermal process is faster and is followed. The activation energy (Ea) of cis-to-trans isomerization is calculated by controlled temperature (298 – 313 K) experiment. Triton-X-100 and CTAB amplify the activation energy (Ea) of cis ® trans thermal isomerization while in presence of SDS it is decreased.

UV-VIS spectrophotometric determination of magnesium after complexing with 8-hydroxy quinoline in sodium dodecyl sulphate micellar medium

In this study, an alternatifive UV-VIS spectrophotometric method for determination of magnesium was proposed. The method is based on complexation with 8-hydoxyquinoline (oxin) in sodium dodecyl sulphate (SDS) micelle medium, the absorbance of the product was recorded at 390 nm. pH of the solution, the concentration of ligand and surfactant were critical parameters, which affect the absorbance measurements, and optimised. The molar absorptivitiy coefficient is 5×102 Lmol-1cm-1, the Sandell’s sensitivity is 0,052 µgcm-2, detection limit is 0,3 mgL-1, quantification limit is 1,1 mgL-1 and linear working range is 2-8 mgL-1 at pH 12 and 390 nm. The proposed method was applied for determination of magnesium to some drug and mineral water samples, nearly good accuracy and reproducible volues were obtained percent as recovery and relative standart deviation.

Kinetics of Micellar Effect of Non-Ionic Surfactant on Oxidative Degradation of Ciprofloxacin

Oxidative degradation kinetics of leading fluoroquinolone family drug ciprofloxacin (CIP) by chloramine-T (CAT) in TX-100 micelle media was studied spectrophotometrically at 275 nm and 298 K. In pseudo-first-order conditions the rate constant (kobs) decreased regularly with increasing [TX-100]. To understand the self-organizing activities of TX-100, CMC values in varying reaction conditions had been evaluated. The role of non-ionic surfactant in the oxidative degradation process of ciprofloxacin by chlorinating agent chloramine-T is explained in terms of mathematical model explained by Menger-Portnoy. The reaction showed first to zero order dependence on [CAT] and fractional order on [CIP]. Increasing [H+] decreased the rate of reaction. The effect of ionic strength and solvent polarity of the medium in reaction conditions were studied. The effects of added salts [HSO4Na], [KCl], [KNO3] and [K2SO4] had also been studied. The stoichiometry of the reaction determined was 1:2 and the oxidation products were identified by LC-EI-MS. The analysis of degradation product of ciprofloxacin evidently reveals that the piperazine moiety is active site for oxidation in the reaction. Activation parameters were studied to propose appropriate mechanism for the reaction.

Mononuclear Binary Complex Formation Equilibria of L-Ornithine with Biologically Essential Metals in TBAB Micellar Media

Investigation of mononuclear complex of L-ornithine in tetrabutylammonium bromide (TBAB, a cationinc surfactant) micelle media has been made pH metrically at constant temperature and ionic strength in different percentage of micellar solutions (0.0-2.5 %). Stability constants and best fit model for metal complexes were obtained by MINIQUAD75 computer program on the basis of the analysis of residues and other statistical parameters. Accordingly, ML, ML2, MLH and ML2H for both Co(II) and Cu(II) and ML2 and ML2H for Ni(II) mononuclear chemical models were obtained. The stabilization/destabilization equilibria of the binary system for the model species with percentage composition of micelles at constant ionic strength and temperature could be attributed to dielectric constant and other intrinsic interaction properties of tetrabutylammonium bromide micelle with ligands and metal ions. The plot of percentage of species against pH values has been generated from SIM refined data using origin85 software.

Study of energy transfer mechanism from CdS quantum dots to Rhodamine 101 in reverse micelle medium

In this study, fluorescence resonance energy transfer (FRET) between CdS quantum dots (QDs) and Rhodamine 101 was investigated in reverse micelles. CdS QDs as donor were synthesized by using reverse micelle method. The particle sizes of CdS QDs were found as 1.18 ± 0.05 for QD1 and 2.11 ± 0.25 nm for QD2 with TEM measurements. It was determined that the fluorescence intensity of the QDs quenched as the concentration of Rh101 increased. The effect of the concentration of dye on the quenching of the fluorescence intensity of QDs was evaluated by the Stern-Volmer approach and KSV and kq values were calculated. It was observed that the quenching was not diffusion controlled. The FRET parameters were also calculated by using fluorescence spectroscopy. The distances between donor-acceptor (r) were also calculated as 4.74 nm for QD1 and 2.26 nm for QD2. The steady-state transfer efficiencies were calculated as 0.24 and 0.53 for QD1 and QD2, respectively. The time-resolved transfer efficiencies were also determined as 0.11 for QD1 and 0.48 for QD2. The results demonstrated that the novel donor-acceptor pairs may play an important role in the applications of many research areas such as FRET-based nanosensors and light harvesting devices.

Harnessing carbazole based small molecules for the synthesis of the fluorescent gold nanoparticles: A unified experimental and theoretical approach to understand the mechanism of synthesis.

Six structurally different carbazoles (1-6) were explored as the green reducing agents for the synthesis of the fluorescent Au nanoparticles with tailor-made morphology in anionic (sodium dodecyl sulphate, SDS), cationic (cetyltrimethylammonium bromide, CTAB) and neutral (polyvinylpyrrolidone, PVP) micelle medium. Structure of the carbazoles played an important role in controlling the morphology, rate of formation and fluorescent activity of the Au nanoparticles. The Au nanoparticles formed in-situ also simultaneously catalyzed the intermolecular CC and NN couplings between the carbazoles, leading to the corresponding bis-carbazole derivatives. The free and bis-carbazole derivatives functionalized the surface of the synthesized Au nanoparticles and thereby controlling their morphology and fluorescence activity. A computational study was also made to determine the origin of the absorption and emission bands of the synthesized nanoparticles. The combined experimental and theoretical studies unraveled the nanoparticle formation process and mechanistic pathway of this green and easily implementable synthetic protocol of Au nanoparticles.

The effect of transglutaminase treatment on the physico-chemical properties of skim milk with added ethylenediaminetetraacetic acid

The influence of transglutaminase (TG) treatment on the changes in the physico-chemical properties of reconstituted skim milk (10 wt%) with different amounts of added ethylenediaminetetraacetic acid (EDTA) (0–50 mM) was studied. The partition of salts (Ca, Mg, K, Na and inorganic phosphate) was determined experimentally by atomic absorption and emission spectroscopy, colorimetry and 31P-nuclear magnetic resonance spectroscopy, and calculated with a model of the salt partition in milk based on equilibrium thermodynamics. Hydrodynamic radius, skim milk viscosity and casein micelle medium resolution substructure were measured by dynamic light scattering, rheology, and small-angle X-ray scattering (SAXS), respectively. TG treatment of milk did not influence the partition of salts upon the addition of EDTA as TG crosslinking is unlikely to disrupt the phosphate centre motifs on the short exon-encoded amino acid sequences on caseins. However, TG treatment prevented full dissociation of casein micelles when >15 mM EDTA was added, and induced higher viscosity increase than TG-untreated milk upon addition of EDTA. In accordance with the particle sizing results, SAXS demonstrated that TG treatment reduced the extent of EDTA-induced micellar disruption, as compared to milk without TG treatment.

Micellar oxidative transformation of ciprofloxacin: a kinetic investigation

Environmental contextPollution of the aquatic environment by drugs results not only during their manufacture, but also from the excretion of drug residues and the discharge of expired drugs by households and hospitals. The transformation of ciprofloxacin, one of the leading antibiotic drugs, in the presence of surfactants has been investigated. The results provide a better understanding of how ciprofloxacin degrades in aquatic environments by considering the effect of omnipresent surfactants. AbstractThe kinetics of the oxidative transformation, i.e. oxidative degradation, of ciprofloxacin (CIP) by chloramine-T (CAT) in cationic and anionic micelle media during the water chlorination process was studied spectrophotometrically at 275nm and 298K. The influence of added salts (1–10×10–4moldm–3) and solvent polarity of the medium on the reaction was studied. The orders with respect to substrate CIP and oxidant CAT were found to be first order in each. The variation of acid concentrations showed opposite effects in cationic and anionic micellar aggregates. Liquid chromatography–electrospray ionisation mass spectrometry was used to identify degradation products of CIP, which confirmed the full dealkylation of the piperazine ring in CIP as the major product. The piperazine moiety of CIP is the principal active site for the CAT during oxidation. Activation parameters for the CIP degradation in cationic and anionic micelles were evaluated by studying the reaction at different temperatures, which lent further support to the proposed degradation mechanism for CIP. The rate constants were evaluated to confirm the micellar effect from incorporating sodium dodecyl sulfate and cetyltrimethylammonium bromide in the reaction mixture and the intrinsic reactivity constants were determined in the aqueous as well as in the micellar pseudo-phases as 4.85 and 0.0083.

Effect of addition of iron on morphology and catalytic activity of PdCu nanoalloy thin film as catalyst in Sonogashira coupling reaction

Palladium‐supported catalysts are complex assemblies with a challenging preparation. Minor changes in their preparation conditions can affect the activity, selectivity and lifetime of these catalysts. PdCuFe nanoparticle (NP) thin films were supported on reduced graphene oxide (RGO) by the reduction of the organometallic complex [PdCl2‌(cod)] (cod = cis,cis‐1,5‐cyclooctadiene), and [Cu(acac)2] and [Fe(acac)3] (acac = acetylacetonate) complexes at a toluene–water interface. We have investigated the application of the liquid–liquid interface method for preparing ultrathin films of catalysts and have evaluated the catalytic activity of the prepared NPs for the Sonogashira coupling reaction in micelle media. Also, we have investigated the effect of the addition of iron on the morphology, size and catalytic activity of PdCu/RGO NPs. Our study shows that both of the prepared catalysts (PdCu/RGO and PdCuFe/RGO) are efficient and recoverable catalysts for the Sonogashira carbon–carbon coupling reaction. This method has advantages compared to other routes, such as short reaction times, high to excellent yields, facile and low‐cost method for the preparation of the catalysts, and easy separation and reusability of the catalysts.

Visible and fluorescence spectroscopic studies on interaction of water-soluble anionic azo dyes with Triton X-100 in reverse micelle media

A series of Triton X-100 (TX-100) reverse micelles was prepared in isooctane and characterized with respect to size, polarity, and electric conductivity. Three typical azo dyes including methyl orange (MO), Acid Black 234 (AB 234) and Reactive Red 195 (RR 195) were selected and solubilized in the water phase to investigate their interaction with TX-100 reverse micelles. Effect of water content on the spectra of these dyes in the micelles was also examined. It has been revealed from the experimental results that at low water content, MO and AB 234 may be located in the polar core but outside the water pool of the micelles. Increasing water content leads to their gradual movement towards the water pools. AB 234 may bind to the micelles more closely than MO, especially at high water content. Moreover, the stronger interaction between RR 195 and TX-100 result in the complex formation. Higher water content enhances the transition from bound RR 195 to free RR 195. It can be concluded that the spectral characteristics of the three dyes in the micelles are very different owing to the space limitation and the polarity evolution of the microenvironment of the micelles.

Determination of trace vanadium in sea cucumbers by ultrasound-assisted cloud point extraction and graphite furnace atomic absorption spectrometry

An ultrasound-assisted cloud point extraction (CPE) procedure was used for preconcentration and determination of vanadium by graphite furnace atomic absorption spectrometry. The vanadyl(IV) complex with ascorbic acid form a hydrophobic complex with 4-(2-pyridylazo) resorcinol (PAR) in a micelle medium, which is stable under our working conditions, and followed by its extraction into Triton X-100 surfactant-rich phase. The main factors affecting CPE efficiency, such as pH, concentrations of PAR, ascorbic acid and Triton X-100, incubation temperature, frequency and equilibration time of ultrasonic bath were investigated in detail. Under the optimum conditions, preconcentration of 10 mL sample gave a preconcentration factor of 36.4 and a detection limit of 4.0 µg kg−1. The proposed method was successfully applied to determination of vanadium in sea cucumbers with satisfactory results.