Surfactant Concentration Research Articles

Antimicrobial Activity of Formulated Origanum and Thyme Essential Oil Nanoemulsions - A Comparative Study

Introduction: This study focused on the formulation processing and antimicrobial activities of Origanum and Thyme essential oils (OEO) (TEO) and their nanoemulsions (OEON) (TEON) on gram-positive and gram-negative bacteria and yeast. Optimal nanoemulsion formulation and stability were achieved through balancing between requisite hydrophilic-lipophilic balance (rHLB) and surfactant concentration (Smix) of nanoemulsions. Methods: The smallest droplet sizes of OEON: (z -185.1 nm ± 0.85) and TEON (z -130.1 nm ± 0.60), were achieved by using 10 g/100 mL of OEO and TEO with 15 g/100 mL Smix at ultrasonication for 2 min with no phase separation. The size of nanoemulsion droplet and PDI was found to be influenced by HLB value, treatment time, and Smix concentration. Antimicrobial analyses, including a zone of inhibition, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill kinetics assay, were performed against Escherichia coli, Staphylococcus aureus, and Saccharomyces cerevisiae. Results: The antimicrobial findings demonstrated that OEO exhibited higher antimicrobial activity compared to TEO (P<0.05). Meanwhile, the OEON and TEON substantially reduced the MIC and MBC values, compared to OEO and TEO against all tested microorganisms (P<0.05). Throughout the time-kill assay, E. coli was reduced by 5 log CFU/ml within 120 minutes, while S. cerevisiae and S. aureus were eradicated after 60 and 120 minutes of incubation with OEON, respectively. Conclusion: In turn, TEON reduced E. coli by 5 log CFU/ml and S. cerevisiae by 4 log CFU/ml within 120 minutes, while S. aureus was inhibited within the same time of incubation with TEON. The nanoemulsion formulations of OEO and TEO considerably enhanced the antimicrobial properties, which provides a promising alternative plant-derived antimicrobial for pharmaceuticals and food applications.

Bead Size and Rheological Properties of SEBS-Based Elastic Beads

Abstract Styrene-ethylene-butylene-styrene, (SEBS), is a thermoplastic elastomer that has applications in robotics and shock absorption. While SEBS as a bulk material as well as an additive to solid composites has been extensively studied, this work focuses on developing SEBS-based beads to enhance material, particularly fluid, elasticity; the first time this has been seen in literature. SEBS bead mixtures were developed by mixing SEBS elastomer, water, and surfactant (Triton X-100) at high temperature. Stability, rheology, and microscopy of SEBS bead mixtures were studied as a function of neat SEBS concentration in SEBS elastomer, SEBS elastomer concentration, and surfactant concentration. Resulting bead mixtures were classified as creamed, homogenous and stable, or aggregated bead mixtures based on the mixture's tendency to separate into layers and ability to disperse in excess water. Microscopic studies suggest that while bead mixtures exhibit size polydispersity, the average bead size is a strong function of neat SEBS, SEBS elastomer, and surfactant concentrations. Rheological studies suggest that all the bead mixtures exhibit shear thinning behavior, and the overall viscosity of a given bead mixture is a function of both SEBS elastomer and surfactant concentration. The developed SEBS elastic beads can be used as additives to enhance the viscoelastic properties of fluid-based systems like magnetorheological and damping fluids.

New Cationic Gemini Surfactants and Their Use as Dispersants in Oil-in-Water (O/W) Emulsions

In the current research, two types of new cationic gemini surfactants with different spacers (aromatic and heterocyclic) derived from epichlorohydrine were prepared. The prepared compounds were characterized using FTIR and 1H-NMR spectroscopy. Then the value of critical micelle concentration CMC was calculated using the electrical conductivity and preparing a series of molar concentration of the new surfactants, as well as calculating the balance value between the hydrophilic and hydrophobic (lipophilic) HLB groups. Cationic gemini surfactants were tasted at different concentration 20-40 ppm by preparing dishes for oil-in-water emulsions determine their dispersion efficiency. It was observed that the dispersant containing the heterogeneous ring (MS1) was more efficiently dispersed than the surfactant containing the aromatic ring (MS2) in the presence of the same hydrocarbon chain and at a concentration of 40 ppm.

Facile Synthesis of Surface-Modified Hollow-Silica (SiO2) Aerogel Particles via Oil-Water-Oil Double Emulsion Method.

Due to their high surface area and low weight, silica aerogels are ideally suited for several uses, including drug delivery, catalysis, and insulation. Oil-water-oil (OWO) double emulsion is a simple and regulated technique for encasing a volatile oil phase in a silica shell to produce hollow silica (SiO2) aerogel particles by using hydrophilic and hydrophobic emulsifiers. In this study, the oil-water-oil (OWO) double emulsion method was implemented to synthesize surface-modified hollow silica (SiO2) aerogel particles in a facile and effective way. This investigation mainly focused on the influence of the N-hexane-to-water glass (OW) ratio (r) in the first emulsion, silica (water glass) content concentration (x), and surfactant concentration (s) variations. Furthermore, surface modification techniques were utilized to customize the aerogel's characteristics. The X-ray diffraction (XRD) patterns showed no imprints of impurities except SiO2. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images highlight the hollow microstructure of silica particles. Zeta potential was used to determine particle size analysis of hollow silica aerogel particles. The oil-water-oil (OWO) double emulsion approach was successfully employed to synthesize surface-modified hollow silica (SiO2) aerogel particles, providing precise control over the particle characteristics. By the influence of the optimization condition, this approach improves the aerogel's potential applications in drug delivery, catalysis, and insulation by enabling surface modifications.

More Biosurfactants and Fewer Synthetic Surfactants to Improve Alkali-Surfactant-Polymer Flooding: Feasibility Study and Large-Scale Field Application

Summary Alkali-surfactant-polymer (ASP) flooding has achieved highly enhanced oil recovery (EOR) in the Daqing Oil Field; however, there are concerns about synthetic surfactants owing to their high cost and difficulty in biodegradation. Cheap biosurfactants conform to human concepts of green circular economy; however, known biosurfactants, as well as their mixtures with alkali, cannot reduce water/oil interfacial tension (IFT) to ultralow values below 0.01 mN/m, which is necessary for ASP flooding to effectively mobilize residual oil. Therefore, we investigate the feasibility of partially replacing synthetic surfactants with biosurfactants rather than completely replacing them to improve ASP flooding. First, through a series of IFT tests, a blend of rhamnolipids (RLs) and alkylbenzene sulfonate (ABS) in a 1:1 mass ratio is determined to be the optimal mixed surfactant and labeled RL/ABS-opt. Second, the interfacial activities, phase behaviors, and wettability alteration capabilities of ASP solutions with RL/ABS-opt are studied. Then, 1.0 wt% NaOH and 0.2 wt% RL/ABS-opt are determined to construct a new ASP system. Subsequently, the waterflooded cores are displaced using the new and the classical ASP systems. Based on the promising experimental results, the new ASP system floods a test block of 56 wells for 3 years. The EOR and surfactant costs are calculated to determine the technical and economic effects. Finally, the concentrations of surfactants before and after activated sludge treatment (AST) are tested by spectrophotometry to verify the biodegradability of RLs better than that of ABS. The laboratory and field results indicate that more biosurfactants and fewer synthetic surfactants could improve ASP flooding to be more environmentally friendly and cost-effective with a higher EOR.

Preliminary study for Polycyclic aromatic Hydrocarbons mobilization from contaminated marine sediment using synthetic and natural surfactants

The persistent presence of Polycyclic Aromatic Hydrocarbons (PAHs) in soils and sediments due to their chemical properties requires new methods to mobilize and make them more available for remediation purposes. In this work, the evaluation of the abilities of eight different non-ionic sugar-based and totally biodegradable surfactants, such as synthetic alkyl polyglycosides (APGs), biological sophorolipids (SLs) and biological rhamnolipids (RLs), was conducted in order to provide a preliminary guideline for the selection of the surfactant and the technical approach for PAHs extraction from the sediment. The reference sample was a marine sediment collected from Bagnoli (Naples, Italy) that was characterized to evaluate the level of PAHs contamination, which resulted equal to 3.51 g Kg−1 of total PAHs in the sediment. By using surfactants solutions with a surfactant concentration five times greater than critical micelle concentration (Cs = 5x CMC), a preliminary washing test in batch configuration was conducted, then followed by multiple consecutive washes (MCW) of the sediment to assess the solubilization of PAHs from the sediment by the action of selected surfactants. The results show an evident advantage given by the employment of each studied surfactant in mobilizing PAHs, compared to distilled water as benchmark. In detail, the synthetic alkyl polyglycosides APG2 led to a 3.4 % of total PAHs mobilization in the preliminary washing test with a maximum peak of 9.8 % for a single compound. The MCW test demonstrates that more consecutive washes can increase the amount of total PAHs removed, with a similar contribution from each wash, and that biosurfactants can be more attractive after several washes thanks to the increased capacity of PAHs mobilization. Interestingly, the high efficiency of surfactant to mobilize PAHs makes the soil washing a more attractive technology for removing PAHs from the marine sediments.

Surfactant Partitioning Dynamics in Freshly Generated Aerosol Droplets.

Aerosol droplets are unique microcompartments with relevance to areas as diverse as materials and chemical synthesis, atmospheric chemistry, and cloud formation. Observations of highly accelerated and unusual chemistry taking place in such droplets have challenged our understanding of chemical kinetics in these microscopic systems. Due to their large surface-area-to-volume ratios, interfacial processes can play a dominant role in governing chemical reactivity and other processes in droplets. Quantitative knowledge about droplet surface properties is required to explain reaction mechanisms and product yields. However, our understanding of the compositions and properties of these dynamic, microscopic interfaces is poor compared to our understanding of bulk processes. Here, we measure the dynamic surface tensions of 14-25 μm radius (11-65 pL) droplets containing a strong surfactant (either sodium dodecyl sulfate or octyl-β-D-thioglucopyranoside) using a stroboscopic imaging approach, enabling observation of the dynamics of surfactant partitioning to the droplet-air interface on time scales of 10s to 100s of microseconds after droplet generation. The experimental results are interpreted with a state-of-the-art kinetic model accounting for the unique high surface-area-to-volume ratio inherent to aerosol droplets, providing insights into both the surfactant diffusion and adsorption kinetics as well as the time-dependence of the interfacial surfactant concentration. This study demonstrates that microscopic droplet interfaces can take up to many milliseconds to reach equilibrium. Such time scales should be considered when attempting to explain observations of accelerated chemistry in microcompartments.

Towards natural care products: Structural and deposition studies of bio-based polymer and surfactant mixtures

Oppositely charged polymer-surfactant systems are expected to interact with formation of coacervate complexes near composition of charge-neutrality. Such behaviour is widely used in formulated products (e.g. household and personal care), where the co-deposition of coacervates and active ingredients on various surfaces is triggered by dilution. A transition towards the use of more sustainable ingredients is currently ongoing as a response to the need of more environmentally conscious choices in production, albeit slowed down by the often more complex and not fully understood bulk and interfacial behaviour of new ingredients. In this work, mixtures of a medium-chain fatty acid (sodium decanoate) and two grades of bio-based cationic modified inulin were studied. The phase behaviour was determined in a wide composition matrix. The formation of coacervate complexes was observed for the mixture with the higher charge density polymer at a surfactant concentration of 1–3 wt%, close to the surfactant critical micellar concentration in pure water. Such behaviour was confirmed by DLS and SAXS data, suggesting surfactant-polymer complexation in a concentrated phase of packed micelles with a micelle-to-micelle distance of ∼4.5 nm. In situ ellipsometry and neutron reflectometry experiments were conducted to study the effect on surface deposition when diluting. The ellipsometry showed an adsorbed mass of ∼1.3–1.9 mg/m2, consistent with the deposition of a coacervate layer, and considerably higher than the neat, adsorbed polymer layer of ∼0.3 mg/m2. In the case of the neutron reflectometry experiments, dilution was performed before contact with the surface (pre-mixing), and no adsorption of coacervates was observed, but rather the adsorption of a polymer layer (0.49–0.85 mg/m2). The different results obtained with the different techniques highlight the kinetic nature of bulk coacervate formation and deposition, and the competition between these two phenomena. Maximal deposition can be achieved if one can control this time window either by tuning the composition of the system or the experimental set-up, to mimic the conditions of a specific application.

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.

Hydrothermal synthesized nickel tungstate (NiWO4) microflowers for supercapacitor and water-splitting

Herein, we have synthesized nickel tungstate microflowers (NWO MFs) using the hydrothermal route and used them as an electrode in electrochemical and electrocatalytic applications. In this article, we discuss the effects of the concentration of surfactant on the NWO MFs. Additionally, the resultant products are undergone to assess the energy storage and water-splitting phenomena. In addition, NWO-SM (steel mesh) electrode demonstrates the maximum specific capacitance (Cg) and specific capacity (Csp) of 712 F/g and 158 mAh/g at 5 mV/s with ∼95% capacitive retention over the 5000 cycles. Furthermore, the fabricated device reveals the maximum performance of the capacitance and capacity of 185 F/g and 75 mAh/g at 5 mV/s and 160 F/g and 53 mAh/g with the highest energy (Ed) and power densities (Pd) of 24 Wh/kg and 1600 W/kg at 5 mA/cm2 respectively. The hybrid device shows better capacitive properties with excellent stability (94% over 5000 cycles). The NWO-SM electrodes were tested for electrocatalytic activities using different techniques. The NWO-1 SM electrode exhibited strong electrocatalytic activity with a moderate overpotential value of 302 mV, a negligible Tafel slope (118 mV/dec), an acceptable electrochemical surface area (ECSA) value of 121 cm2, and exceptional stability over 10 hours.

Sensitive Voltammetric Detection of Acetaminophen on CuONPs-MWCNTs Modified Glassy Carbon Electrode with Enhancement Effect of Anionic Surfactant

In the present work, a voltammetric method using differential pulse voltammetric technique for the assessment of antipyretic and analgesic drug, acetaminophen was developed. The CuO nanoparticles were prepared and characterized. A glassy carbon electrode (GCE) fabricated with the suspension of CuO nanoparticles (CuONPs) and multi-walled carbon nanotubes (MWCNTs) were used. The modified electrode showed improved anodic peak current by introducing an anionic surfactant sodium dodecyl sulphate in phosphate buffer solution. The consequence of pH of supporting electrolyte, amount of nanoparticles suspension and surfactant concentration was investigated at a physiological pH of 7.4. Using differential pulse voltammetry, the fabricated electrode showed linear dynamic range from 9 to 160 nM of acetaminophen concentration. From the calibration plot, the computed detection limit was 5.06 nM and quantification limit was 16.88 nM. The developed method was checked for its reproducibility and assay during a day and intraday as well. The developed process was fruitfully applied to detect acetaminophen in pediatric oral suspensions administered to infants.

Rheology and surface active properties of sodium N-lauroyl sarcosinate in mixed surfactant system

Anionic surfactant sodium N-lauroyl sarcosinate (SNLS) forms elongated wormlike micelles with cocamide monoethanolamine (CMEA) and lauryl glucoside (LG) a nonionic surfactants in the pH range 5.5–6.0. The total surfactant concentration was examined between 10% and 20% wt/v, and the pH was lowered from 7.5 to 4.5. The presence of CMEA/LG diminishes electrostatic repulsion amid SNLS head groups and prompts micellar transition displaying moderate viscosity. The viscosity peak of each system occurred in the pH range 5.5–5.8, close to the system’s pKa. This might prove to be a novel approach for SNLS surfactant formulation which otherwise was difficult to thicken. Additionally, mixed surfactant systems of SNLS/CMEA/LG portrays high surface activity, enhanced foaming behavior and improved skin mildness. Further, this study demonstrated a cost-effective and thickener-free method for cleansing compositions with the desired viscosity.

Foam fractionation for the separation and enrichment of trace m-phenylenediamine and o-phenylenediamine in solution

In this study, a foam fractionation technique was developed for the separation and enrichment of the trace m-phenylenediamine (MPD) and o-phenylenediamine (OPD) in solution. Firstly, a self-designed foam fractionation device was assembled and built, followed by a comprehensive characterization on gas types, foam fractionation column parameters, and porous sieve plate material used in the apparatus. Subsequently, the most crucial parameters for the separation and enrichment, such as surfactant species, solution pH, electrolyte categories, and gas flow rate, were identified and optimized. The mechanisms of key processes during foam fractionation under the influence of these parameters were thoroughly discussed. Other influencing factors, such as surfactant concentration, foam collection time, and solution volume in the fractionation column, were optimized using response surface methodology (RSM). Under these optimal conditions, maximal enrichment ratios of 138.2 and 85.5 were achieved for MPD and OPD, respectively. Finally, foam fractionation coupled with high-performance liquid chromatography (HPLC) was employed to detect MPD and OPD in the solution. The results demonstrated limits of detection (LOD) of 1.5 × 10−2 μg/L and 1.5 μg/L for MPD and OPD, with relative standard deviation (RSD) values of 4.1 % and 3.9 %. When testing various actual samples, the recoveries were in the range from 92.0 % or greater in all cases. The method exhibited advantages of high sensitivity, precision, and accuracy, attributed to the high enrichment efficiency of foam fractionation. In conclusion, the foam fractionation method established in this study offers simplicity in apparatus, operational convenience, environmental friendliness (minimized use of organic solvents), and high enrichment efficiency. It proves valuable for the quantitative analysis of trace amounts of MPD and OPD in solution, presenting a novel approach for the detection of trace organic compounds in solutions.

Flexible, Photonic Films of Surfactant‐Functionalized Cellulose Nanocrystals for Pressure and Humidity Sensing

Most paints contain pigments that absorb light and fade over time. A robust alternative can be found in nature, where structural coloration arises from the interference of light with submicron features. Plant‐derived, cellulose nanocrystals (CNCs) mimic these features by self‐assembling into a cholesteric liquid crystal that exhibits structural coloration when dried. While much research has been done on CNCs in aqueous solutions, less is known about transferring CNCs to apolar solvents that are widely employed in paints. This study uses a common surfactant in agricultural and industrial products to suspend CNCs in toluene . Surprisingly, a stable liquid crystal phase is formed within hours, even with concentrations of up to 50 wt%. Evaporating the apolar CNC suspensions results in photonic films with peak wavelengths ranging from 660 to 920 nm. The resulting flexible films have variable mechanical properties with surfactant content, allowing for an optical response with applied force. The films also act as humidity sensors, with increasing relative humidity swelling the films, yielding a redshift in the reflected wavelength. With the addition of a single surfactant, CNCs can be made compatible with existing production methods of industrial coatings, while improving the strength and responsiveness of structurally colored films to external stimuli.

Epoxy/polymercaptan microcapsules composite: Synthesis, mechanics, and self-healing behavior

To enhance the longevity of materials, minimize maintenance expenses, and optimize material performance. The wall material employed in this study was urea-melamine-formaldehyde (UMF), and a dual microcapsule self-healing system was established by synthesizing two distinct microcapsules of epoxy resin and polymercaptan via an in situ polymerization technique. Moreover, the reaction conditions were optimized. The reaction parameters were as follows: core-shell ratio of 2:1, surfactant concentration of 0.6 g/L (sodium dodecyl benzene sulfonate (SDBS): Arabic gelatin (GA) = 2:1), polymerization pH = 3.5, stirring rate of 700r/min. Then, the two microcapsules (The mass ratio of the two microcapsules is 1:1) were added to the epoxy resin matrix at 0, 2.5, 5, 7.5, 10, and 12.5 wt% to prepare the resin matrix with self-healing properties. The conical double cantilever beam (TDCB) was used to test the mechanical properties of the matrix. The results showed that the matrix with microcapsule content of 10 wt% had relatively better comprehensive properties, and the self-healing rate was 49.87% at room temperature. These findings provide valuable insights and potential for advancing the development of self-healing materials.

Preparation of Surface-Wrinkled Silica-Polystyrene Colloidal Composite Particles.

In this work, we report a facile emulsion swelling route to prepare surface-wrinkled silica-polystyrene (SiO2-PS) composite particles. Submicrometer-sized, near-spherical SiO2-PS composite particles were first synthesized by dispersion polymerization of styrene in an ethanol/water mixture, and then, surface-wrinkled SiO2-PS particles were obtained by swelling the SiO2-PS particles with a toluene/water emulsion and subsequent drying. It is emphasized that no surface pretreatment on the SiO2-PS composite particles is required for the formation of the wrinkled surface, and the most striking feature is that the surface-wrinkled particle was not deformed from a single near-spherical SiO2-PS composite particle but from many ones. The influence of various swelling parameters including toluene/particle mass ratio, surfactant concentration, stirring rate, swelling temperature, swelling time, and silica size on the morphology of the composite particles was studied. This method represents a new paradigm for the preparation of concave polymer colloids.

Wetting permeability of surface active agent droplets impacting on a layer of coal dust

The wetting and penetration of the coal dust layer by liquid droplet is crucial for suppressing coal dust. A combination of experimental and simulation methods was employed to investigate the impact of surfactant concentration, droplet velocity, and particle size on the penetration properties and their underlying mechanisms. Droplet impact wetting experiments were employed to evaluate their dynamic wetting behavior on the coal dust layer. The experimental results show that increasing the impact velocity of droplets is advantageous for enhancing the maximum dimensionless wetting length. Increasing the surfactant concentration can expedite the droplet reaching maximum dimensionless wetting volume in the dust layer. The larger the particle size of coal dust, the shorter time required for droplet to reach maximum wetting volume. The research results provide a theoretical basis for selecting and efficiently applying surfactants in treating coal dust.

Comparison of Methods Used to Investigate Coalescence in Emulsions.

We present a study of moderately stable dilute emulsions. These emulsions are models for water contaminated by traces of oil encountered in many water treatment situations. The purification of water and the elimination of oil rely on the emulsion stability. Despite actively being studied, the topic of emulsion stability is still far from being fully understood. In particular, it is still unclear whether experimental methods accessing different length scales lead to the same conclusions. In the study presented in this paper, we have used different methods to characterize the emulsions, such as centrifugation and simple bottle tests, as well as investigations of the collision of single macroscopic oil drops at an oil-water interface. We studied different emulsions containing added polymer or surfactant. In the case of added polymer, centrifugation and single drop experiments led to opposite trends in stability when the polymer concentration is varied. In the case of added surfactant, both centrifugation and single drop experiments show a maximum stability when the surfactant concentration is increased, whereas bottle tests show a monotonous increase in stability. We propose tentative interpretations of these unexpected observations. The apparent contradictions are due to the fact that different methods require different drop sizes or different drop concentrations. The puzzling decrease in emulsion stability at a higher surfactant concentration observed with some methods, however, remains unclear. This coalescence study illustrates the fact that different results can be obtained when different experimental methods are used. It is therefore advisable not to rely on a single method, especially in the case of emulsions of limited stability for reasons explained in the paper.

Advancing SeNP synthesis: Innovative confined environments for enhanced stability and size control

Nanotechnology's exponential growth has spurred a demand for high-quality and safe nanomaterials, prompting increased interest in cost-effective and fast colloidal syntheses that must mitigate their irreversible aggregation, an issue particularly pertaining to spherical selenium nanoparticles (SeNPs), promising materials in a wide array of technological and biological fields.This study presents a novel approach to SeNP synthesis in confined environments developed from the highly biocompatible surfactant sodium oleate (NaOl) and the amino acid l-cysteine as a selenite-reducing agent. l-cysteine@NaOl (C@NaOl) confined environments were modulable as a function of the amino acid and surfactant concentrations and yielded high-quality spherical SeNPs with enhanced stability. This approach enables generating SeNPs even under alkaline conditions and improving up to 3-fold the final SeNP yield compared to other processes. Besides, we introduce a groundbreaking method for determining SeNP size by adapting Mie's scattering theory to metalloid NPs. This innovative technique proves effective for SeNPs in the 40–100 nm range, offering a reliable alternative to conventional sizing methods. These findings provide valuable insights regarding the generation of bio- and eco-compatible confined environments and SeNPs, paving the way for developing safe, cost-effective, and environmentally friendly strategies for their synthesis with broad applications in various scientific and technological domains.

Formulation and evaluation of Fluconazole Nanosuspensions: In vitro characterization and transcorneal permeability studies

The aim in this study was to develop and evaluate a nanofluconazole (FLZ) formulation with increased solubility and permeation rate using nanosuspensions. The FLZ nanosuspensions were stabilized using a variety of stabilizing agents and surfactants in various concentrations. The FLZ nanosuspension was characterized in vitro using particle size, zeta potential, X-ray powder diffraction (XRPD), and solubility. In addition, the ex vivo ocular permeation of FLZ through a goat cornea was analyzed. The results showed that the particle size of all nanosuspension formulations was in the nanometer range from 174.5 ± 1.9 to 720.2 ± 4.77 nm; that of the untreated drug was 18.34 μm. The zeta potential values were acceptable, which indicated suitable stability for formulations. The solubility of the nanosuspensions was up to 5.7-fold higher compared with that of the untreated drug. The results of the ex vivo ocular diffusion of the FLZ nanosuspensions showed the percentage of FLZ penetrating via the goat cornea increased after using Kollicoat to stabilize the nanosuspension formulation. Consequently, when using a nanosuspension formulation of Kollicoat, the antifungal activity of the drug strengthens.