Micellar Systems Research Articles

High-Yield Synthesis of Phosphatidylserine in a Well-Designed Mixed Micellar System.

A sustainable enzymatic system is essential for efficient phosphatidylserine (PS) synthesis in industrial production. Conventional biphasic systems face challenges such as excessive organic solvent usage, enzyme-intensive processes, and increased costs. This study introduces a novel approach using chitin nanofibrils (ChNFs) as an immobilization material for phospholipase D (PLD) in a mixed micellar system stabilized by the food-grade emulsifier sodium deoxycholate (SDC). The immobilized enzyme, ChNF-chiA1, was quickly prepared in a one-step process, eliminating the need for purification. By optimizing the reaction conditions, including l-Ser concentration (1.0 M), SDC concentration (10 mM), reaction time (8 h), and enzyme dosage (1.0 U), a remarkable PS yield of 96.74% was achieved in the solvent-free mixed micellar system. The catalytic efficiency of ChNF-chiA1 surpassed that of the free PLD-chiA1 biphasic system by 6.0-fold. This innovative and green biocatalytic technology offers a reusable solution for the high-value enzymatic synthesis of phospholipids, providing a promising avenue for industrial applications.

Reversing Ferroptosis Resistance in Breast Cancer via Tailored Lipid and Iron Presentation.

Ferroptotic cancer therapy is promising in many scenarios where traditional cancer therapies show a poor response. However, certain types of cancers lack the long-chain acyl-CoA synthetase 4 (ACSL4), a key modulator of ferroptosis, resulting in therapy resistance and tumor relapse. Because ACSL4 is in charge of the synthesis of ferroptotic lipids (e.g., arachidonoylphosphatidylethanolamine/PE-AA), we postulated that direct delivery of PE-AA may reverse ferroptosis resistance induced by ACSL4 deficiency. To further increase the ferroptosis sensitivity, we employed the ferrocene-bearing polymer micelles to co-load PE-AA with an FDA-approved redox modulator, auranofin (Aur), targeting the thioredoxin reductase. The presence of ferrocene enabled triggered cargo release and iron production, which can sensitize ferroptosis by boosting autoxidation-mediated PE-AA peroxidation. The micellar system could impair redox homeostasis and induce lipid peroxidation in ACSL4-deficient MCF-7 cells. Moreover, the tailored micelles potently induced ferroptosis in MCF-7 tumors in vivo, suppressed tumor growth, and increased the mice's survival rate. The current work provides a facile means for reversing the ferroptosis resistance in ACSL4-deficient tumors.

Behavior of Curcumin in micellar biomimetic systems and its protolytic and tautomeric equilibria elucidated by multivariate analysis

Curcumin (CUR), a natural compound originating from Asia, has found widespread application in the field of biomedicine. CUR shows significant results in its applications, despite its high hydrophobicity and low bioavailability. In general, success depends mainly on the interaction between CUR and the target cell, microbial membrane, cell wall, or protein capsule. Associated with this, solid tumors, gastric or stomach regions, as well as regions affected by wounds, have very different pH conditions. In this scenario, micellar biomimetic systems obtained from cationic (CTAB), anionic (SDS), zwitterionic (HPS), and non-ionic (TX-100) surfactants emerge as an interesting alternative within this type of investigation. Thus, in the present study, the interaction of CUR with CTAB, SDS, HPS, and TX-100 micelles was evaluated first under physiological conditions (pH 7.4). The results showed that CUR interacts very well with the most distinct environments, as demonstrated by experimental and computational analysis. The binding constant, Kb, was higher for TX-100 micelles and lower for SDS in the presence or absence of the ionic strength control, appointing the influence of hydrophobic and electrostatic effects. The spectral properties show the efficient incorporation of CUR in micelles, also confirmed by in-silico assays. Multivariate analysis based on Q-Imbrie's factor and the K-matrix method on the electronic absorption spectroscopy data in different pHs ranging from 0 to 14 allowed for the understanding of the complex protolytic/tautomeric equilibrium, and the influence of the microenvironment on the CUR at each pH. Thus, the CUR tends to prevail in the photolytic form of better interaction, a chemically explained fact here called the “chameleon effect”. So, in SDS the pKa values tend to increase to favor the interaction between CUR0 and SDS-. On the other hand, in CTAB the pKa values tend to decrease to favor the interaction between CUR-1/CUR-2 and CTA+. The multivariate analysis also allowed the pure spectra separation and the molar absorptivity determination of each species. These interactions were also confirmed by the estimated electrical potential ψo from ΔpKa-el determined using the Boltzmann equation.

A highly sensitive micelle-enhanced synchronous spectrofluorimetric determination of the recently approved co-formulated drugs, bilastine and montelukast in pharmaceuticals and human plasma at nanogram levels.

In this study, the simultaneous determination of bilastine and montelukast, two recently approved co-formulated antihistaminic medications, was accomplished using a quick, sensitive, environmentally friendly, and reasonably priced synchronous fluorescence spectroscopic approach for the first time. Enhancement of the method's sensitivity down to nanogram levels was achieved by the addition of sodium dodecyl sulfate (1.0% w/v) as a micellar system. According to the results, bilastine and montelukast's fluorescence was measured at 255.3 and 355.3nm, respectively, using Δλ of 40.0nm and distilled water as a green diluting solvent. With respect to the concentration ranges of bilastine (5.0-300.0ng/ml) and montelukast (50.0-1000.0ng/ml), the method showed excellent linearity (r ≥ 0.9998). The results showed that the suggested method is highly sensitive, with detection limits of 1.42 and 13.74 ng/ml for bilastine and montelukast, respectively. Within-run precisions (intra- and interday) per cent relative standard deviations (RSD) for both analytes were <0.59%. With high percentage recoveries and low percentage RSD values, the designed approach was successfully applied for the simultaneous estimation of the cited medications in their dosage form and human plasma samples. To evaluate the green profile of the suggested method, an analytical GREENNESS metric approach (AGREE) and green analytical procedure index (GAPI) metric tools were used. These two methods for evaluating greenness confirmed that the developed method met the highest number of green requirements, recommending its use as a green substitute for the routine analysis of the studied drugs. The proposed approach was validated according to ICHQ2 (R1) guidelines.

Study on rheology of a novel UV-light sensitive trimeric anionic–cationic surfactant/trans-o-methoxycinnamic acid micellar system

Abstract Two novel UV photosensitive micellar systems, trimeric dodecyl anionic–cationic surfactant (TDCC)/trans-OMCA, and trimeric cetyl anionic–cationic surfactant (TCCC)/trans-OMCA, were successfully synthesized by using two different carbon chain length trimeric anionic–cationic surfactants (TACS, including TDCC and TCCC) and the photosensitive additive trans-o-methoxycinnamic acid (trans-OMCA). The incorporation of trans-OMCA resulted in a peak in the zero shear viscosity (η 0) of the system at pH = 6.17–6.61. The flow behaviour of the TACS/OMCA system was well described by the Carreau-Yasuda model. Prior to UV irradiation, the TCCC/trans-OMCA system exhibited pronounced shear thinning, thixotropic, and viscoelastic properties. After UV irradiation at 365 nm, the isomerization of trans-OMCA to cis-OMCA caused the disruption of the network structures, leading to a significant decrease in the thixotropic and viscoelastic properties, resulting in a decrease in viscosity. The viscosity reduction rate of the TCCC/trans-OMCA system reached 99 %. The influence of the hydrophobic carbon chain length on the UV responsiveness was also investigated. The TDCC/trans-OMCA system exhibited an 86 % decrease in η 0 after UV irradiation, highlighting the favorable effect of longer hydrophobic tail chains in improving the UV responsiveness of the micellar system. The UV light kinetics of the TCCC/trans-OMCA solution were studied and a rheological model was developed to accurately describe the viscosity changes. The TCCC was found to predominantly exhibit cationic characteristics at pH = 6.17–6.61. In this pH range, the 2 wt% TCCC/0.12 wt% NaSal system exhibited excellent viscoelasticity, and the addition of trans-OMCA disrupted the network structure resulting in a decrease in viscosity. After UV irradiation, the viscosity of the system increased by 2.5 times, confirming the potential of the TCCC/NaSal/trans-OMCA micellar system as a UV thickener.

Unveiling the Role of Nonionic Surfactants in Enhancing Cefotaxime Drug Solubility: A UV-Visible Spectroscopic Investigation in Single and Mixed Micellar Formulations.

This study reports the interfacial phenomenon of cefotaxime in combination with nonionic surfactants, Triton X-100 (TX-100) and Tween-80 (TW-80), and their mixed micellar formulations. Cefotaxime was enclosed in a micellar system to improve its solubility and effectiveness. TX-100 and TW-80 were used in an amphiphilic self-assembly process to create the micellar formulation. The effect of the addition of TX-100, a nonionic surfactant, on the ability of TW-80 to solubilize the drug was examined. The values of the critical micelle concentration (CMC) were determined via UV-Visible spectroscopy. Gibbs free energies (ΔGp and ΔGb), the partition coefficient (Kx), and the binding constant (Kb) were also computed. In a single micellar system, the partition coefficient (Kx) was found to be 33.78 × 106 and 2.78 × 106 in the presence of TX-100 and TW-80, respectively. In a mixed micellar system, the value of the partition coefficient for the CEF/TW-80 system is maximum (5.48 × 106) in the presence of 0.0019 mM of TX-100, which shows that TX-100 significantly enhances the solubilizing power of micelles. It has been demonstrated that these surfactants are effective in enhancing the solubility and bioavailability of therapeutic compounds. This study elaborates on the physicochemical characteristics and solubilization of reactive drugs in single and mixed micellar media. This investigation, conducted in the presence of surfactants, shows a large contribution to the binding process via both hydrogen bonding and hydrophobic interactions.

Studies on anionic dye Eosin Y in mixed anionic micellar medium

Dye-Surfactant interactions in aqueous solution are important in industrial processes. Generally, dyes associate strongly with oppositely charged surfactants. But, similarly charged dye-surfactants are not preferred anticipating repulsion. To gain insight into the nature and extent of interaction between anionic dye Eosin Yellow (EY) and mixed anionic micellar system, this study was undertaken. Mixed micellar system comprised of anionic, Sodium dodecyl sulfate (SDS) and nonionic Pluronic L-35 (L-35). The characterizations employed were FTIR Spectroscopy, Conductivity, UV visible spectroscopy, Fluorescence spectroscopy and SEM studies. A red shift with enhancement of intensity was observed both in UV-absorption and emission spectra of EY when interacted with SDS + L-35 mixed micellar system. From the conductance measurements, the counter ion binding constant β was calculated. Subsequently, various thermodynamic parameters viz., ΔGm, ΔHm and ΔSm were evaluated using β. The Gibbs free energy of micellization, ΔGm was observed to be −4.56 kJ mol−1, −13.34 kJ mol−1 and −18.55 kJ mol−1 for SDS, SDS + L-35 and SDS + L-35 + EY respectively. The negative values of ΔGm are indicating the spontaneous binding occurring between EY and SDS + L-35. The SEM images revealed enlargement of grain size of the mixed micelle after encapsulation of EY. To the best of our knowledge this is the first report of anionic dye EY with an anionic mixed micellar system.

Dynamic Phosphorus: Thiolate Exchange Cascades with Higher Phosphorothioates

AbstractIn this study, we introduce phosphorus, a pnictogen, as an exchange center for dynamic covalent chemistry. Cascade exchange of neutral phosphorotri‐ and ‐tetrathioates with thiolates is demonstrated in organic solvents, aqueous micellar systems, and in living cells. Exchange rates increase with the pH value, electrophilicity of the exchange center, and nucleophilicity of the exchangers. Molecular walking of the dynamic phosphorus center along Hammett gradients is simulated by the sequential addition of thiolate exchangers. Compared to phosphorotrithioates, tetrathioates are better electrophiles with higher exchange rates. Dynamic phosphorotri‐ and ‐tetrathioates are non‐toxic to HeLa Kyoto cells and participate in the dynamic networks that account for thiol‐mediated uptake into living cells.

Dynamic Phosphorus: Thiolate Exchange Cascades with Higher Phosphorothioates.

In this study, we introduce phosphorus, a pnictogen, as an exchange center for dynamic covalent chemistry. Cascade exchange of neutral phosphorotri- and -tetrathioates with thiolates is demonstrated in organic solvents, aqueous micellar systems, and in living cells. Exchange rates increase with the pH value, electrophilicity of the exchange center, and nucleophilicity of the exchangers. Molecular walking of the dynamic phosphorus center along Hammett gradients is simulated by the sequential addition of thiolate exchangers. Compared to phosphorotrithioates, tetrathioates are better electrophiles with higher exchange rates. Dynamic phosphorotri- and -tetrathioates are non-toxic to HeLa Kyoto cells and participate in the dynamic networks that account for thiol-mediated uptake into living cells.

Stratification and film ripping induced by structural forces in granular micellar thin films

HypothesisInteractions across incredibly thin layers of fluids, known as thin films, underpin many important processes involving colloids, such as wetting-dewetting phenomena. Often in these systems, thin films are composed of complex fluids that contain dispersed components, such as spherical micelles, giving rise to oscillatory structural forces due to preferential layering under confinement. Modelling of thin film dynamics involving Derjaguin-Landau-Verwey-Overbeek (DLVO) type forces has been widely reported using the Stokes-Reynolds-Young-Laplace (SRYL) model, and we hypothesize that this theory can be extended to a concentrated micellar system by including an oscillatory structural force term in the disjoining pressure. ExperimentsWe study the drainage behaviour of thin films comprising sodium dodecyl sulfate (SDS) micelles across a range of concentrations and interaction conditions between an air bubble and a mica disk using a custom-built dual-wave interferometry apparatus. FindingsEarly-stage film behaviour is dominated by hydrodynamics, which can be well reproduced by the SRYL model. However, experimental profiles drain significantly faster than predicted, transitioning into a structural force dominated phase characterised by four types of film ripping instabilities that we term ‘waving’, ‘ridging’, ‘webbing’, and ‘hole-sheeting’. These instabilities were mapped according to SDS concentration and approach velocity, providing insight into the interplay between structural forces and hydrodynamic conditions.

Aptamer-based self-assembled nanomicelle enables efficient and targeted drug delivery

Nucleic acid aptamer-based nanomicelles have great potential for nanomedicine and nanotechnology applications. However, amphiphilic aptamer micelles are known to be inherently unstable upon interaction with cell membranes in the physiological environment, thus potentially compromising their specific targeting against cancer cells. This flaw is addressed in the present work which reports a superstable micellar nanodelivery system as an amphiphilic copolymer self-assembled micelle composed of nucleic acid aptamer and polyvalent hydrophobic poly(maleic anhydride-alt-1-octadecene) (C18PMH). Using Ce6 as a drug model, these C18-aptamer micelles exhibit efficient tumor-targeting and -binding ability, facilitating the entry of Ce6 into targeted cells for photodynamic therapy. In addition, they can be loaded with other hydrophobic drugs and still demonstrate favorable therapeutic effects. As such, these C18-aptamer micelles can serve as a universal platform for loading multiple drugs, providing a safer and more effective solution for treating cancer.

Binding and occupancy properties of gabapentin in mixed surfactant systems

AbstractThis research highlights the efficacy of mixed micellar systems as an innovative chemical formulation for improving the binding properties of active pharmaceutical drugs. The formulations based on the mole fraction were utilized for preparing mixed micelles with anionic sodium dioctyl sulfosuccinate (AOT) and sodium dodecyl sulphate (SDS). DLS measurements demonstrated the formation of small micelles and mixed micelles in SDS‐AOT combinations. A UV absorbance investigation demonstrated the effectiveness of the SDS‐AOT mixed micelles for determining the binding constant (Kb) and mean ion occupancy (i0) of the anticonvulsant gabapentin (GBP) drug. Kb values increased, but the occupancy (i) of GBP per micelle decreased by decreasing the mole fraction (α) of SDS from αSDS 0.9 to 0.1, predicting a shift in occupancy of drugs from the Palisade to the Stern layer. To get a better comprehension of micellization behavior and preferential interaction of the drugs under study, molecular docking studies were performed. According to the docking studies, the GBP displayed significant binding in the presence of SDS‐AOT when compared to pure SDS and AOT molecules. Ultimately, in pharmaceutical applications, mixed micelle played an important role in enhancing the binding and encapsulation efficiency of drugs.

Unraveling the impact of mono- or di-cationic ionic liquids on sodium deoxycholate aggregation and their interactions with ciprofloxacin

The interaction study between drugs and surfactants grasps significant attention in the field of pharmacology and for the advancement in pharmaceutical formulations. In this study, a mixed micellar system composed of sodium deoxycholate and either mono- or di-cationic ionic liquids was proposed. The main objective was to evaluate the aggregation behaviour of NaDC in the presence of mono or di-cationic ionic liquids and its ability to interact with ciprofloxacin. Although mixed micellar systems using imidazolium-based monocationic ionic liquids have been actively researched, the potential of di-cationic ionic liquid has not yet been explored. Therefore, in the present work imidazolium-based monocationic ionic liquid ([C10(mIm)]Br) and corresponding di-cationic ionic liquid ([C10(mIm)2]2Br) with bromide as a common anion were synthesized and evaluated their effect on the aggregation behavior of sodium deoxycholate. The aggregation behaviour of these micellar and mixed micellar systems was evaluated using conductivity and fluorescence experiments by determining the critical micellar concentration. Additionally, dynamic light scattering experiments were conducted to comprehend the size of the aggregates that are formed, and zeta potential was measured to determine the surface charge of the micelles which in turn helps to determine the stability of the aggregates formed. The interaction study between micellar or mixed micellar systems with ciprofloxacin was carried out using UV–visible spectroscopy. The Benesi-Hildebrand equation was employed to scrutinize the interaction parameters of micellar and mixed micellar systems with CIP, revealing that the mixed micellar system containing [C10(mIm)]Br exhibited the greatest binding affinity towards CIP.

Thermosensitive Micelles Gel to Deliver Quercetin Locally for Enhanced Antibreast Cancer Efficacy: An In Vitro Evaluation.

Although quercetin is low cytotoxicity to normal human cells, quercetin is effective against the growth of some tumors. Given the poor blood stability in vivo, insolubility, low delivery efficiency, and poor medicinal properties of quercetin, we developed a local drug delivery system comprising quercetin core's polymer micelles and F127 hydrogel stroma. In vitro evaluation revealed that quercetin core's polymer micelles have excellent antitumor activity and could inhibit the multiplication of 4T1 breast cancer cells through the apoptosis pathway. Meanwhile, a rheological study revealed that the quercetin core's micelles gel possessed excellent properties of hydrogel formation and injectability of liquid preparation as a local drug delivery system after the quercetin core's polymer micelles were loaded into the F127 hydrogel stroma. Our study findings indicated that the drug stability and stable release capacity of quercetin were vastly improved with the composite formulation of the micelles gel. This not only realized drug injectability but also drug storage in the semisolid form, which is a more comfortable and slower drug-releasing form that will eventually exert a proper therapeutic effect. In conclusion, quercetin micellar hydrogel system has better antitumor activity and excellent hydrogel properties.

Evaluating the binding ability of promethazine hydrochloride drug with sodium dodecylsulphate/sodium lauroylsarcosinate/sodium cholate in the company of uridine biomolecules: experimental and theoretical approach

The appraisal of drug–surfactant binding interactions is pharmacologically and pharmaceutically noteworthy. The simple model compounds of nucleic acids such as nucleic acid bases/nucleosides are key biologically active molecules useful for studying interactions of nucleic acids with other components in bio-fluids. Therefore, the binding studies of promethazine hydrochloride (PMT) drug with individual surfactants such as sodium dodecylsulphate (SDS, anionic surfactant), sodium lauroylsarcosinate (SLS, amino based-surfactant), and sodium cholate (NaC, trihydroxy bile salt), and their mixed systems (PMT + SDS/SLS/NaC) at mole fractions, α PMT = 0.02, 0.04, 0.06, and 0.08 have been accomplished in water and 0.025 mol kg−1 aqueous uridine (nucleoside) solutions at temperatures (298.15, 308.15, and 318.15) K. Thermodynamic characteristics of micellization have been obtained from the conductivity studies. Binding constants (K b, K f) and standard Gibbs free energies of binding (ΔG ο b, ΔG ο f) for pure PMT drug and its mixed systems with anionic surfactants were evaluated from UV–visible absorption and fluorescence emission studies. Further, the density functional theory (DFT) calculations for studied systems were carried out to get net stabilization energies for the drug–surfactant complexes. NBO and HOMO–LUMO analyses were also carried out in the absence/presence of uridine. Dynamic light scattering study was used to measure the hydrodynamic diameters in micellar systems. The major influences of hydrophobic–hydrophobic interactions among the hydrophobic groups and electrostatic (ionic and H-bond) interactions among the hydrophilic/ionic groups of PMT drug, SDS/SLS/NaC, and uridine have been depicted from the present investigations.

Catechin-Functionalized Cationic Lipopolymer Based Multicomponent Nanomicelles for Lung-Targeting Delivery.

Catechins from green tea are one of the most effective natural compounds for cancer chemoprevention and have attracted extensive research. Cancer cell-selective apoptosis-inducing properties of catechins depend on efficient intracellular delivery. However, the low bioavailability limits the application of catechins. Herein, a nano-scaled micellar composite composed of catechin-functionalized cationic lipopolymer and serum albumin is constructed. Cationic liposomes tend to accumulate in the pulmonary microvasculature due to electrostatic effects and are able to deliver the micellar system intracellularly, thus improving the bioavailability of catechins. Albumin in the system acts as a biocompatible anti-plasma absorbent, forming complexes with positively charged lipopolymer under electrostatic interactions, contributing to prolonged in vivo retention. The physicochemical properties of the nano-micellar complexes are characterized, and the antitumor properties of catechin-functionalized materials are confirmed by reactive oxygen species (ROS), caspase-3, and cell apoptosis measurements. The role of each functional module, cationic polymeric liposome, and albumin is revealed by cell penetration, in vivo animal assays, etc. This multicomponent micellar nanocomposite has the potential to become an effective vehicle for the treatment of lung diseases such as pneumonia, lung tumors, sepsis-induced lung injury, etc. This study also demonstrates that it is a great strategy to create a delivery system that is both tissue-targeted and biologically active by combining cationic liposomes with the native bioactive compound catechins.

Reverse Micellar Dyeing of Cotton Fabric with Reactive Dye Using Biodegradable Non-Ionic Surfactant as Nanoscale Carrier: An Optimisation Study by One-Factor-at-One-Time Approach.

This study investigates the feasibility of using biodegradable secondary alcohol ethoxylate (SAE) non-ionic surfactant as a building block for the formation of reverse micelles, functioning as reactive dye carriers for the dyeing of cotton fabric in non-aqueous octane medium. Ten dyeing parameters were optimised, by a one-factor-at-a-time approach, namely: (i) effect of colour fixation agent; (ii) surfactant-to-water mole ratio; (iii) surfactant-to-co-surfactant mole ratio; (iv) volume of soda ash; (v) volume of dye; (vi) solvent-to-cotton ratio; (vii) dyeing temperature; (viii) dyeing time; (ix) fixation time; (x) soda-ash-to-cotton ratio. The colour properties, fastness properties and physical properties of SAE-dyed samples were experimentally compared with the conventional water-dyed samples. The optimised condition was found when SAE samples were dyed as follows: (a) 1:20 surfactant-to-water ratio; (b) 1:8 surfactant-to-co-surfactant ratio; (c) 10:1 solvent ratio; (d) 40 min dyeing time; (e) 60 min fixation time; and (f) 70 °C dyeing and fixation temperature. The results showed that SAE-dyed samples have better colour strength, lower reflectance percentage and comparable levelness, fastness and physical properties than that of water-dyed samples. SEM images revealed that the dyed cotton fibres had no severe surface damage caused by an SAE-based reverse micellar dyeing system. The TEM image depicts that the reverse micelle was of nanoscale, spherical-shaped and had a core-shell structure, validating the presence of reverse micelle as a reactive dye carrier and the potential of an SAE-based reverse micellar system for dyeing of cotton fabrics.

Synthesis, Photophysical Properties, and Toxicity of o-Xylene-Bridged Porphyrin Dimers

In this work, a number of new porphyrin dimers coupled with spacers based on α,α’-dibromo-o-xylene were synthesized and characterized by 1H, 13C NMR, 1H-1H COSY NMR, UV-vis-spectroscopy, and MALDI-TOF mass spectrometry. The initial A3B-type hydroxy-substituted porphyrins form dimer structures with high yields of 80–85%, while the use of amino-substituted porphyrins as starting compounds leads to the heterocyclization and formation of N-heterocycle fused porphyrins. For porphyrin dimers, photophysical properties and quantum yields of singlet oxygen were investigated. The peripheral alkoxy-substituents increase fluorescence quantum yield in comparison with the unsubstituted compounds. Also, it was found that dimers are characterized by lower singlet oxygen quantum yields compared to the corresponding monomers. Model aggregation experiments in micellar systems demonstrate stabilization of the photoactive monomolecular form of all the porphyrins, using nonionic surfactant Triton X-100. Cytotoxicity of received dimers shows high inhibition against HEK293T cells in the absence of light.

CTAB induced growth and shrinkage of Pluronics® P103 micelles: Experimental and theoretical rationale

This study offers an insight into the concentration influence of a cationic surfactant- cetyltrimethylammonium bromide (CTAB) having a 16-carbon long alkyl side chain that influences the self-assembly and micellization behaviour of a linear triblock copolymer based on ethylene oxide (EO) and propylene oxide (PO) Pluronic® P103 in aqueous solution. The work makes an exclusive use of a variety of methodologies, such as high sensitivity differential scanning calorimetry (HSDSC), phase behaviour study, dynamic light scattering (DLS), and small-angle neutron scattering (SANS). The investigation on the clouding behaviour demonstrates that the cloud point value of 5 %w/v P103, which is typically in the vicinity of 90 °C, rises up to more than 100 °C with the addition on of very low concentration of CTAB. The DLS technique predicted the change in hydrodynamic diameter (Dh) of micelles with temperature and in varying CTAB concentration. The SANS results inferred the morphological changes in the micelles. A comprehensive approach revealing the relationship between the molecular orbital energies of the tested P103 and CTAB were assessed by utilising the computational simulation method with the Gaussian 09 calculation window and Gauss View 5.0.9 software. The perception of CTAB-stabilized Pluronics® micelles is predicted to be much improved from the evaluated optimised descriptors. Additionally, our examined micellar system revealed the solubilization enhancement of a model hydrophobic dye orange-OT utilizing UV–vis spectroscopy.

Micellar systems of the o/w type with essential oils of andiroba and lemon grass with applications for the elimination of bacterial activity

In this study, a promising microemulsion delivery system containing andiroba essential oil, lemongrass essential oil, and chitosan was developed and applied in 100% cotton fabrics to provide antibacterial functionality. The developed micellar systems were characterized by coloration, electrical conductivity, viscosity, zeta potential, particle size, temperature resistance, and microbial activity analyses. The microemulsions in the substrates were verified by FTIR analyses and microbial activity before and after the domestic washing of the functionalized fabrics. The microemulsions SMs_P1 and SMs_P4 showed more significant inhibitory action against Staphylococcus aureus, Escherichia coli, and Enterobacter sp. bacteria, observed in the functionalized samples before and after domestic washing. In this study, the microemulsions SMs_P1 and SMs_P4 developed and tested on 100% cotton fabrics have greater application viability because they showed inhibitory action against gram-positive and gram-negative bacteria Staphylococcus aureus, Escherichia coli, and Enterobacter sp. This antibacterial functionality of the microemulsions was also observed in 100% cotton fabrics treated with them (Ta_SMs_P1 and Ta_SMs_P4) before and after domestic washing, as demonstrated by FTIR and antimicrobial activity analyses, with greater emphasis on microemulsion SMs_P4, which has lower concentrations than SMs_P1 and showed significant values (halo size) in blocking the action of Escherichia coli bacteria.