Stability Of Nanoemulsions Research Articles

Synthesis and characterization of acetamiprid nanoemulsion by high-energy methods

Nanotechnology's application in agriculture has opened up new options for generating nanosized agrochemicals that have the potential to improve efficiency, improve stability, extend the effective duration, and reduce environmental impacts 1 . One of the most pressing difficulties in the agricultural industry is the need to handle pesticide-related issues such as environmental contamination, bioaccumulation, and increases in insect resistance, which necessitates reducing the amount of pesticide sprayed on crops and protecting stored products. Nanotechnology is proving to be an appealing tool for achieving this goal since it provides new ways to synthesize and transport active ingredients known as nanopesticides 1 . Nanoemulsions are particularly well suited to creating lipophilic functional agent delivery systems 2 . The current study uses a high-energy (ultrasound) emulsification approach to create oil-in-water (O/W) acetamiprid nanoemulsions with synthetic and natural additives. The acetamiprid nanoemulsions were spontaneously formed by adding a mixture of acetamiprid and solvent in an aqueous solution containing a surfactant (tween) with continuous stirring. The nanoemulsions were then formed by ultra-sonication. Various characterization techniques for acetamiprid nanoemulsions include particle size analysis (DLS), Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). Acetamiprid nanoemulsions are further evaluated by studying thermodynamic stability. This includes a Centrifugation assay, Freezethaw cycle nanoemulsions, Heating-cooling test, stability at room temperature of 25°C, pH measurement, and viscosity measurement. The droplet size and morphology of the acetamiprid nanoemulsions were measured by dynamic light scattering (DLS) and transmission electron microscopy (TEM). DLS and TEM measurements showed that acetamiprid nanoemulsions had an almost droplet size distribution (PDI < 200 nm). On this basis, an insecticide acetamiprid was incorporated into an optimized nanoemulsion system to demonstrate potential applications in pest control. Keywords: Acetamiprid nanoemulsion, nanoemulsion characterization, nanoemulsion stability.

Analysis of bioactive compounds in cinnamon leaves and preparation of nanoemulsion and byproducts for improving Parkinson's disease in rats.

Cinnamomum osmophloeum Kanehira (C. osmophloeum), a broad-leaved tree species of Taiwan, contains phenolic acids, flavonoids, and phenylpropanoids such as cinnamaldehyde and cinnamic acid in leaves. Many reports have shown that the cinnamon leaf extract possesses anti-inflammatory, hypoglycemic, hypolipidemic and neuroprotective functions. This study aims to analyze bioactive compounds in C. osmophloeum (cinnamon leaves) by UPLC-MS/MS and prepare hydrosol, cinnamon leaf extract and cinnamon leaf nanoemulsion for comparison in improving Parkinson's disease (PD) in rats. After extraction and determination of total phenolic and total flavonoid contents, cinnamaldehyde and the other bioactive compounds were analyzed in cinnamon leaves and hydrosol by UPLC-MS/MS. Cinnamon leaf nanoemulsion was prepared by mixing a suitable proportion of cinnamon leaf extract, soybean oil, lecithin, Tween 80 and deionized water, followed by characterization of particle size and polydispersity index by dynamic light scattering analyzer, particle size and shape by transmission electron microscope, encapsulation efficiency, as well as storage and heating stability. Fifty-six male Sprague-Dawley rats aged 8 weeks were divided into seven groups with group 1 as control (sunflower oil) and group 2 as induction (2 mg/kg bw rotenone in sunflower oil plus 10 mL/kg bw saline), while the other groups including rotenone injection (2 mg/kg bw) followed by high-dose of 60 mg/kg bw (group 3) or low-dose of 20 mg/kg bw (group 4) for tube feeding of cinnamon leaf extract or cinnamon leaf nanoemulsion at the same doses (groups 5 and 6) every day for 5 weeks as well as group 7 with rotenone plus hydrosol containing 0.5 g cinnamon leaf powder at a dose of 10 mL/kg bw. Biochemical analysis of brain tissue (striatum and midbrain) was done to determine dopamine, α-synuclein, tyrosine hydroxylase, superoxide dismutase, catalase, glutathione peroxidase and malondialdehyde contents by using commercial kits, while catalepsy performed by bar test. An extraction solvent of 80% ethanol was found to be the most optimal with a high yield of 15 bioactive compounds being obtained following UPLC analysis. A triple quadrupole tandem mass spectrometer with electrospray ionization mode was used for identification and quantitation, with cinnamaldehyde present at the highest amount (17985.2 µg/g). The cinnamon leaf nanoemulsion was successfully prepared with the mean particle size, zeta potential, polydispersity index and encapsulation efficiency being 30.1 nm, -43.1 mV, 0.149 and 91.6%, respectively. A high stability of cinnamon leaf nanoemulsion was shown over a 90-day storage period at 4 and heating at 100 for 2 h. Animal experiments revealed that the treatments of cinnamon leaf extract, nanoemulsion and hydrosol increased the dopamine contents from 17.08% to 49.39% and tyrosine hydroxylase levels from 17.07% to 25.59%, while reduced the α-synuclein levels from 17.56% to 15.95% in the striatum of rats. Additionally, in the midbrain of rats, an elevation of activities of superoxide dismutase (6.69-16.82%), catalase (8.56-16.94%), and glutathione peroxidase (2.09-16.94%) was shown, while the malondialdehyde content declined by 15.47-22.47%. Comparatively, the high-dose nanoemulsion exerted the most pronounced effect in improving PD in rats and may be a promising candidate for the development of health food or botanic drug.

Characterization and utilization of soy protein isolate-(-)-epigallocatechin gallate-maltose ternary conjugate as an emulsifier for nanoemulsions: Enhanced physicochemical stability of the β-carotene nanoemulsion.

In this study, a ternary conjugate was prepared by covalent bonding of protein, polysaccharide, and polyphenol via ultrasound and the Maillard reaction. Subsequently, the β-carotene nanoemulsion was prepared with the soy protein isolate-(-)-epigallocatechin gallate-maltose (SPI-EGCG-maltose) conjugate as the emulsifiers via ultrasound. The SPI-EGCG-maltose conjugate showed superior solubility, emulsification and foaming properties at 4h reaction time. Meanwhile, the retention rates of β-carotene in the nanoemulsion after 30 d of storage, 8h of light, and 55°C of heat were >60%, >75%, and >60%, respectively. Furthermore, ultrasound treatment at 500W for 10min produced an inhibitory effect on the degradation of β-carotene. This study indicates that the nanoemulsion based on the ternary conjugate can effectively inhibit the β-carotene degradation by the external environment and prevent the oxidation and degradation of β-carotene in the nanoemulsion.

Nanoemulsions as medicinal components in insoluble medicines

Background: Medicine’s success relies on solubility, which is the process of dissolving a solid substance in a fluid phase to create a uniform molecular dispersion. However, hydrophobic active medicinal components exhibit poor solubility in water, limiting their effectiveness and incorporation into medications. Aim: This review explores the potential of nanoemulsions as a solution for delivering hydrophobic medicinal components with low solubility. The study investigates the benefits of nanoemulsions, including enhanced absorption, effective targeting, controlled release, and protection of encapsulated bioactive ingredients. Materials and methods: Nanoemulsions are formulated by combining two immiscible liquids with emulsifying agents within a thermodynamically stable colloidal dispersion system. The review categorizes various preparation techniques into high-energy and low-energy spontaneous emulsification methods. The choice of preparation procedures and materials used significantly affects the stability of nanoemulsions over time. Evaluation of nanoemulsions includes studying medication release in vitro, in vitro permeation, stability and thermodynamic stability, shelf life, viscosity, interfacial tension, pH, and osmolarity. Results: Nanoemulsions, such as Celecoxib (Phase Inversion), acetylsalicylic acid (Ultrasonication), and Flurbiprofen (Homogenization and Ultrasonication), offer distinct advantages for medications with low solubility compared to conventional emulsions. These nanoemulsions comprise small droplets with a larger surface area, promoting enhanced absorption. They demonstrate effective targeting, controlled release, and protection of encapsulated bioactive ingredients. Moreover, the diminutive droplet sizes of nanoemulsions contribute to their reduced susceptibility to issues like flocculation, coalescence, sedimentation, or creaming. Conclusion: Nanoemulsions hold great promise in overcoming the solubility limitations of hydrophobic medicinal components. They provide enhanced absorption, effective targeting, controlled release, and protection of bioactive ingredients. The choice of preparation techniques and materials plays a crucial role in ensuring the stability of nanoemulsions over time. Further studies are warranted to optimize their use and explore their potential applications in drug delivery systems.

Hyaluronic Acid Poly(glyceryl)10-Stearate Derivatives: Novel Emulsifiers for Improving the Gastrointestinal Stability and Bioaccessibility of Coenzyme Q10 Nanoemulsions.

Fish oils are a rich source of polyunsaturated fatty acids, including eicosapentaenoic acid and docosahexaenoic acid, which are reported to exhibit therapeutic effects in a variety of human diseases. However, these oils are highly susceptible to degradation due to oxidation, leading to rancidity and the formation of potentially toxic reaction products. The aim of this study was to synthesize a novel emulsifier (HA-PG10-C18) by esterifying hyaluronic acid with poly(glyceryl)10-stearate (PG10-C18). This emulsifier was then used to formulate nanoemulsion-based delivery systems to co-deliver fish oil and coenzyme Q10 (Q10). Q10-loaded fish oil-in-water nanoemulsions were fabricated, and then their physicochemical properties, digestibility, and bioaccessibility were measured. The results indicated that the environmental stability and antioxidant activity of oil droplets coated with HA-PG10-C18 surpassed those coated with PG10-C18 due to the formation of a denser interfacial layer that blocked metal ions, oxygen, and lipase. Meanwhile, the lipid digestibility and Q10 bioaccessibility of nanoemulsions formulated with HA-PG10-C18 (94.9 and 69.2%) were higher than those formulated with PG10-C18 (86.2 and 57.8%), respectively. These results demonstrated that the novel emulsifier synthesized in this study could be used to protect chemically labile fat-soluble substances from oxidative damage, while still retaining their nutritional value.

Okra Mucilage Extract as A Co-Surfactant Increased the Curcumin Nanoemulsion Stability and Encapsulation Efficiency

Okra Mucilage Extract as A Co-Surfactant Increased the Curcumin Nanoemulsion Stability and Encapsulation Efficiency

Development and characterization of antimicrobial alginate hydrogel beads filled with cinnamon essential oil nanoemulsion

The aim of the present study was to investigate the characteristics of alginate beads filled with cinnamon essential oil nanoemulsions (CEONs). The influence of the alginate and CaCl2 concentrations on their physical, antimicrobial and antioxidant properties was studied. The droplet size of CEON was 146.20 ± 39.28 nm and the zeta potential was −33.8 ± 0.72 mV demonstrating proper nanoemulsions stability. Decreasing the alginate and CaCl2 concentrations resulted in higher EOs release due to the increased pore size of the alginate beads. The scavenging activity of DPPH of beads was found to be dependent on the alginate and calcium ion concentrations which affected the pore size of the fabricated beads. The FT-IR results declared the new bands in the spectra of filled hydrogel beads, which verified the encapsulation of EOs in the beads. The surface morphology of beads was studied using SEM images which showed the spherical shape and porous structure of alginate beads. In addition, the alginate beads filled with CEO nanoemulsion demonstrated strong antibacterial activity.

Improving the Stability and Effectiveness of Immunotropic Squalene Nanoemulsion by Adding Turpentine Oil.

Turpentine oil, owing to the presence of 7-50 terpenes, has analgesic, anti-inflammatory, immunomodulatory, antibacterial, anticoagulant, antioxidant, and antitumor properties, which are important for medical emulsion preparation. The addition of turpentine oil to squalene emulsions can increase their effectiveness, thereby reducing the concentration of expensive and possibly deficient squalene, and increasing its stability and shelf life. In this study, squalene emulsions were obtained by adding various concentrations of turpentine oil via high-pressure homogenization, and the safety and effectiveness of the obtained emulsions were studied in vitro and in vivo. All emulsions showed high safety profiles, regardless of the concentration of turpentine oil used. However, these emulsions exhibited dose-dependent effects in terms of both efficiency and storage stability, and the squalene emulsion with 1.0% turpentine oil had the most pronounced adjuvant and cytokine-stimulating activity as well as the most pronounced stability indicators when stored at room temperature. Thus, it can be concluded that the squalene emulsion with 1% turpentine oil is a stable, monomodal, and reliably safe ultradispersed emulsion and may have pleiotropic effects with pronounced immunopotentiating properties.

The evaluation of stability and bioactivity of xanthone nanoemulsion

The α-mangostin, a lipophilic xanthone derivative, has a low bioavailability. It was, however, isolated from mangosteen rind, which has antioxidant and antimicrobial activity. Oil in water (O/W) Nanoemulsion as drug delivery can stabilize lipophilic drug into core and increase bioavailability. The α-mangostin nanoemulsion (MN) was formulated with various surfactant (Tween 20, Tween 80, Span 20 and Span 80), co-surfactant (Span 20 and Span 80) and oil (Jojoba oil (JO), as well as evening primrose oil (EO), EMOGREENTM19 (E19) and EMOGREENTM15 (E15)). It was found that at 7.5–10% by weight of Tween 80 as surfactant was appropriate for MN formulation. The type of oil influenced droplet size and pH value of MN. The result showed that MN droplet size is bigger in vegetable oil than in hydrocarbon oil. However, its pH value is lower in vegetable oil than that in hydrocarbon oil. For three months, all MN droplet sizes were increased. Interestingly, MN using tween 80 as surfactant can provide good stability during that time. Moreover, MN exhibits anti-oxidant (SC50, 23.07 ± 0.84 μg/mL) and anti-inflammatory (IC50, 12.06 ± 0.99 μg/mL) bioactivities.

Performance of alkyl β-D-maltosides in molecular self-assembly and formation of oil-in-water nanoemulsions as drug delivery systems

Alkyl β-D-maltosides are nonionic sugar-based surfactants that can be used as excipients in lipid-based nanoparticles because of their physiological functions and biocompatibility. The self-assembly of alkyl β-D-maltosides (C8-C12) was studied to investigate the effects of alkyl chain length in the binary and ternary systems. Surface tension measurements in the binary systems revealed a synergistic effect on the stability of mixed surfactants with Tween 80 (T80) in the critical aggregation concentration (CAC). Subsequently, formulations of 10:90 wt% oil-in-water (O/W) nanoemulsions (ternary systems) containing T80/alkyl β-D-maltosides with and without cyclosporine (CsA) as the hydrophobic model drug were characterised by particle size, polydispersity index (PDI), morphology, rheology, and physical stability. The formulations of all nanoemulsion systems were found to be stable against phase separation for 28 days at room temperature. The hydrophobic effect of n-dodecyl-β-D-maltoside (DDM, C12) was stronger by enhancing the stability of T80 nanoemulsion in molecular self-assembly compared to the shorter chains of the maltosides. The in vitro drug release study showed that T80/DDM nanoemulsion improved the cumulative release of CsA in 24 h by 98.33 ± 7.72% compared to T80 nanoemulsion at 83.75 ± 4.05%. The release of CsA has the highest fit with the Korsmeyer-Peppas kinetic model (R2 > 0.9), suggesting that CsA is released slowly from the oily core of nanoemulsions to the dissolution medium due to its hydrophobic nature. The cytotoxicity study against 3T3 cells showed that all formulations had no cytotoxicity effect (IC50) up to 500 μg/mL. The findings demonstrated that T80/DDM nanoemulsion holds great promise as a drug delivery system for the treatment of psoriasis.

Surface protection of wood using cerium oxide nanoparticles dispersed paraffin wax nanoemulsion

Exposure to solar UV radiation and other environmental factors promotes the degradation and reduces the serviceability of the wood material under outdoor use. Oils and waxes have been found to be promising solutions for wood protection. This study elucidates the use of paraffin wax based emulsions incorporated with cerium oxide nanoparticles to improve weathering performance of wood. For this purpose, paraffin wax nanoemulsions were prepared by ultrasonication method using tween 80 as surfactant. Cerium oxide nanoparticles (conc. 0.5- to 2%) were added to provide protection against degradation caused by solar UV radiation. The storage stability of nano emulsion was assessed over a period of 30 days by measuring effective particle size and zeta potential. The microstructure of nanoemulsions was observed by optical microscopy and distribution of CeO2 nanoparticles on coated wood was observed through scanning electron microscopy (SEM). The chemical changes were analyzed by Fourier Transform Infrared spectroscopy (FTIR). Wood specimens of Pinus radiata coated with nanoemulsions were subjected to the accelerated weathering tests for 500h. The time dependent changes in surface color of uncoated and coated wood samples were examined. Moreover, the chemical changes on exposed wood surfaces were analyzed by ATR-FTIR spectroscopy. Stable and homogenous nanoemulsions with particle diameter between 200 and 400 nm were formed and exhibited excellent storage stability. Results of color changes showed that maximum degradation was observed in uncoated wood whereas wood coated with paraffin wax nanoemulsion alone could not improve the UV resistance. However, the addition of cerium oxide nanoparticles proved to be efficient in controlling the color changes on wood surfaces. The degradation of wood components reduced significantly in cerium oxide coated wood which was confirmed by FTIR results.

Preparation, characterization and properties of cinnamon essential oil nano-emulsion formed by different emulsifiers

Essential oil has unstable properties and low bioavailability. In order to improve these problems, with the help of ultrasonic wave, stable nano-emulsions were prepared with different emulsifiers. In this experiment, the formation of nano-emulsions with different emulsifiers at different concentrations was studied, including sodium caseinate (SC), whey glycoprotein (WGP), soy protein isolate (SPI) and Tween 80. Meanwhile, we studied the effect of ultrasonic cell disruption apparatus and homogenizer on the particle size of nano-emulsions. Cinnamon essential oil nano-emulsion prepared under the optimum emulsifier and its concentration has good microstructure and rheological properties. The stability of cinnamon essential oil nano-emulsion in different environments was studied, including centrifugation, freeze-thaw, heating-freezing and long-term (30 d) stability. The nano-emulsion of cinnamon essential oil is stable in emulsifiers. The nano-emulsions prepared by different emulsifiers has different particle sizes in different environments and their advantages and disadvantages are compared. Finally, how different nano-emulsion were digested in vitro was also studied. The in vitro digestion of nano-emulsion by different emulsifiers was simulated. Its properties include particle size, zeta potential and polymer dispersion index (PDI).

Study of nanoemulsions using carvacrol/MCT-(Oleic acid-potassium oleate)/ Tween 80 ®- water system by low energy method

Carvacrol is studied in different fields due to its microbial and antioxidant properties. Its use is limited because of the water insolubility and its strong taste. To overcome these problems, carvacrol has been successfully loaded into nanoemulsions. The low-energy emulsification method Phase Inversion Composition (PIC) is used to prepare oil-in-water nanoemulsions in the carvacrol/medium chain triglycerides (MCT)-(oleic acid-potassium oleate/Tween 80 ®)-water system. Oleic acid acts as a co-surfactant when it is neutralized with KOH along the emulsification path changing the spontaneous curvature of the interface when increasing the HLB number from 1 for the oleic acid to 20 for the potassium oleate and, therefore, changing the HLB number of the surfactant mixture. The phases diagrams are studied in order to understand the behaviour of the system and to establish the composition range where nanoemulsions can be obtained. Nanoemulsions are formed when the emulsification path crosses a region of direct or planar structure without excess of oil. Experimental design is performed in order to study the influence of composition variables as carvacrol/MCT ratio and (oleic-oleate)/Tween 80 ® ratio (OL-OT/T80 ratio) on the diameter of the nanoemulsions and their stability. It has been observed the importance of the HLB number of the surfactants mixture in order to obtain small-sized stable nanoemulsions. Surface response graphic shows that (OL-OT)/T80 ratio is a significant parameter in the mean diameter of the nanoemulsions. A minimum diameter is obtained for a (OL-OT)/T80 ratio 45/55 due to the fact that ratio is near the preferred HLB of the oil mixture and the emulsification path contains a wide liquid crystal monophasic region with all the oil incorporated in the structure.Diameters of 19 nm for carvacrol/MCT ratio of 30/70 or diameters of 30 nm for ratios of 45/55 with high stability values presented a good potential to be incorporated into edible films in the future.Regarding nanoemulsions stability an optimum value is also observed for a carvacrol/MCT ratio.The addition of another carrier oil as olive oil instead of MCT showed an improvement of the nanoemulsions stability against Ostwald ripening, probably due to the smaller solubility of olive oil. The use of olive oil does not significantly change the diameter of the nanoemulsion.

Preparation of lutein nanoemulsion by ultrasonic homogenization method: Stability and in vitro anti-inflammatory activity

Lutein is a natural antioxidant that has anti-inflammatory activity; thus, lutein-enriched anti-inflammatory agents have the potential for development. Nanoemulsions represent an effective molecular liquid for improving the solubility and stability of lutein. The oil and surfactant components, preparation method and preparation conditions are highly related to the stability and biological activity of nanoemulsions. In this study, lutein nanoemulsions were prepared by the ultrasonic homogenization method, the components and preparation conditions were optimized by the response surface methodology, and the final preparation conditions were confirmed. The contents of medium chain triglyceride (MCT) and Tween 80 were 1.5 wt% and 11 wt%, respectively, and the ultrasonic time was 8.5 min. The anti-inflammatory activities and long-term stability of the prepared lutein nanoemulsion were then evaluated. Lutein affected the secretion levels of interleukin-6 (IL-6), interleukin-10 (IL-10) and monocyte chemotactic and activating factor (MCAF), especially IL-6 and MCAF. On Day 28, the lutein retention rates of lutein nanoemulsion with Propyl gallate (PG) at 4 °C, 25 °C and 37 °C were 97.75 ± 0.43 %, 75.77 ± 0.45 % and 47.72 ± 0.19 %, respectively. The addition of PG greatly improved the retention rate of lutein and the particle size stability of the lutein nanoemulsion at high temperature (37 °C). The current results demonstrated the potential utilization of lutein emulsion as anti-inflammatory agents.

Host-Guest Assembly-Crosslinked Nanoemulsions with Dual-Antimicrobial Mechanism for Treating Multidrug-Resistant Bacterial Biofilms.

Plant essential oils have good antimicrobial properties, but their poor stability and compatibility in aqueous solutions greatly limit their practical application. To address this issue, a dynamically crosslinked nanoemulsion based on host-guest assembly was developed in this study. First, a β-cyclodextrin-functionalized quaternary ammonium surfactant (β-CD-QA) and adamantane-terminated polyethylene glycol (APA) crosslinker were first synthesized. Then, the oil-in-water host-guest crosslinked nanoemulsions (HGCTNs) were formed by incorporating tea tree essential oils (TTO) as a natural antimicrobial agent. The results showed that HGCTNs significantly improved the stability of the essential oil nanoemulsions and extended their shelf life. Furthermore, HGCTNs demonstrated effective antimicrobial properties against both Gram-negative/positive bacterioplankton and bacterial biofilms. The results of antibacterial experiments showed that the dynamically crosslinked HGCTNs exhibit superior antibacterial efficacy, with a minimum inhibitory concentration (MIC) of 12.5 v/v % (0.13 μL/mL TTO) and could eradicate the biofilms. The electrical conductivity of the bacterial solution gradually increased within 5 h of treatment with the nanoemulsions, indicating that the HGCTNs have a slow-release effect of TTO and sustainable antibacterial ability. The antimicrobial mechanism can be attributed to the synergistic antibacterial action of the β-CD-QA surfactant containing a quaternary ammonium moiety and TTO, which are stabilized by nanoemulsions.

Enzyme-assisted polysaccharides extraction from Calocybe indica: Synergistic antibiofilm and oxidative stability of essential oil nanoemulsion

Recently, mushroom polysaccharides have been explored to attribute to vital biologically important functions, and several extraction techniques can be employed, therefore, polysaccharides were extracted from the edible mushroom Calocybe indica to explore its functionality. Multiple enzymes viz., cellulase, pectinase, and protease (1:1:1) at temperature 47 °C and pH 4.64 with an extraction time of 2 h yielded 7.24 % polysaccharide content. The thermograph curve of polysaccharides showed two-stage decomposition at a different temperature range and decomposition of polysaccharides initiated with an onset temperature of 226.77 °C and a maximum peak at 248.90 °C. Hydrodistillation processed Eucalyptus globulus leaf oil was characterized using the chromatography technique and eucalyptol, p-cymene, Γ-terpinene, 4-epi-cubebol, spathulenol, viridiflorol, and p-mentha-1,5-dien-8-ol was observed as major components. As well, we formulated nanoemulsion using mushroom polysaccharide and eucalyptus leaf oil with 140.8 nm and evaluated synergistic antimicrobial and antibiofilm activity. MIC and MBC values for Pseudomonas aeruginosa, E. coli, and S. typhi were 12.50–3.12 and 6.25–1.56, and for S. aureus were 6.25, 6.25, 3.12, and 3.12, 3.12, 1.56 and for C. albicans the values were 12.50, 12.50, 6.250 and 6.25, 6.25, and 3.12 μL/mL respectively. The polysaccharides, essential oil, and nanoemulsion showed remarkable antibiofilm activity against S. aureus with inhibition of 57.42 ± 0.19, 59.62 ± 0.15, and 69.34 ± 0.19 %, while E. coli showed the least antibiofilm activity. However, all three tested samples showed significant (p < 0.05) differences against tested pathogenic microorganisms with inhibition of biofilm formation. Therefore, it could be inferred that the synergistic properties of essential oils with mushroom polysaccharides are a promising strategy to enhance antimicrobial efficacy and control foodborne pathogens.

Enhanced stability, formulations, and rheological properties of nanoemulsions produced with microfludization for eco-friendly process

HypothesisEco-friendly processes that are emerging around the world require mass production of low-energy, low-cost nanoemulsions. The process involving the high-concentrated nanoemulsions and diluting them with a large amount of solvent can certainly save the cost; however, not much detailed research has been conducted on the stability mechanism and rheological characteristics of high-concentrated nanoemulsions. ExperimentsIn this study, we produced nanoemulsions via the microfluidization (MF) process, comparing their dispersion stability and rheological characteristics with macroemulsions across various oil and surfactant concentrations. Droplet mobility and dispersion stability depended on these concentrations, with Asakura-Osawa-type attractive depletion considering interparticle interaction's role in stability changes. We investigated nanoemulsions' long-term stability based on turbidity and droplet size changes over four weeks, proposing a stability diagram showing four different states depending on emulsification conditions. FindingsWe explored the microstructure of emulsions under varying mixing conditions, observing their effects on droplet mobility and rheological properties. We monitored changes in rheology, turbidity, and droplet size over 4 weeks, establishing stability diagrams for macro- and nanoemulsions. The stability diagrams revealed that the stability of emulsions are sensitively dependent on the droplet size, concentrations, surfactant cocentrations and the strcture of coexistent phases in case of macroscopic segregation are significantly different depending on the droplet sizes. We identified their respective stability mechanisms and discovered the relationship between stability and rheological properties for highly concentrated nanoemulsion.

Preparation of cinnamaldehyde nanoemulsions: Formula optimization, antifungal activity, leaf adhesion, and safety assessment

Plant essential oils have become an increasingly popular topic in agriculture due to their outstanding fungicidal activity, good biocompatibility and abundance of sources. Cinnamaldehyde is found in cinnamon essential oil and has good antifungal activity, but cinnamaldehyde also has negative characteristics such as high volatility, poor water solubility and easy oxidative degradation, which seriously hinder the potential of its antimicrobial properties and its application in agriculture. In this study, the effects of the surfactant ratio, concentration and emulsification method on the stability of cinnamaldehyde nanoemulsions were systematically investigated by observing the sample appearance, mean droplet size and differential scanning calorimetry (DSC) analysis. The results showed that the optimal formula of cinnamaldehyde nanoemulsion was a surfactant (R5:848) ratio of 1:1 and a concentration of 7%, and the emulsification method was E1: adding dropwise aqueous phase (deionized water) to the oil phase (cinnamaldehyde + surfactant). Cinnamaldehyde nanoemulsions showed good antifungal activity against rice sheath blight (Rhizoctonia solani), wheat sheath blight (Rhizoctonia cerealis) and wheat take-all (Gaeumannomyces graminis). The nanoemulsions also had excellent wetting properties on rice and wheat leaves, higher biosafety for nontarget environmental organisms such as zebrafish and earthworms, low cytotoxicity to human BASE-2B cells, and no inhibition of germination and growth of wheat and rice. The results of this research provide important ideas for the design of efficient, safe and environmentally friendly plant-derived fungicides.

Characteristics and Physical Stability of Nanoemulsion as a Vehicle for Anti-Aging Cosmetics: A Systematic Review

Background: Skin aging can be overcome by applying anti-aging cosmetics. Many active ingredients that have anti-aging potential are derived from plants, and these materials must be delivered with a sound skin delivery system, namely nanoemulsion. The characteristics of nanoemulsion are closely related to physical stability. Objective: This study aims to conduct a systematic review of in vivo and in vitro study designs to examine the characteristics and physical stability of nanoemulsions used in topical anti-aging cosmetics. Methods: A systematic literature review based on the PRISMA statement was used to review the articles regarding nanoemulsions’ characteristics and physical stability. The article search was accessed from an internet search database: Scopus, Pubmed, and Web of Science, published between January 2012 and June 2022. Results: Of the 244 articles, 44 were found to be related to the characteristics and physical stability of nanoemulsions in anti-aging cosmetics. These showed that active ingredients with antioxidant activity, filter UV rays, moisturizing agents, and cell-repairing agents are delivered by a nanoemulsion system with various types and ratios of surfactants, cosurfactants, and oil phases. Tween 80, Span 80, Transcutol HP, and Caprylic/capric triglyceride are the most widely used nanoemulsion compositions. Conclusion: The type and composition of the oil phase, surfactant, and cosurfactant affect the characteristics of the nanoemulsion (droplet size, polydispersity index, viscosity, zeta potential) and the physical stability of the nanoemulsion so that it can deliver active ingredients that have the potential as anti-aging well.

On the Stability of Pickering and Classical Nanoemulsions: Theory and Experiments

Emulsification is a crucial technique for mixing immiscible liquids into droplets in various industries, such as food, cosmetics, biomedicine, agrochemistry, and petrochemistry. Quantitative analysis of the stability is pivotal before the utilization of these emulsions. Differences in X-ray attenuation for emulsion components and surface relaxation of the droplets may contribute to X-ray CT imaging and low-field NMR spectroscopy as viable techniques to quantify emulsion stability. In this study, Pickering (stabilized solely by nanoparticles) and Classical (stabilized solely by low molecular weight polymers) nanoemulsions were prepared with a high-energy method. NMR and X-ray CT were employed to constantly monitor the two types of nanoemulsions until phase separation. The creaming rates calculated from NMR match well with the results obtained from X-ray CT. Furthermore, we show that Stokes' law coupled with the classical Lifshitz-Slyozov-Wagner theory underestimates the creaming rate of the nanoemulsions compared to the experimental results from NMR and X-ray CT imaging. A new theory is proposed by fully incorporating the effects of Pickering nanoparticles, hydrocarbon types, volume fraction, size distribution, and flocculation on the droplet coarsening. The theoretical results agree well with the experimentally measured creaming rates. It reveals that the attachment of nanoparticles onto a droplet surface decreases the mass transfer for hydrocarbon molecules to move from the bulk aqueous phase into other droplets, thus slowing the Ostwald ripening. Therefore, Pickering nanoemulsions show a better stability behavior compared to Classical nanoemulsions. The impacts of hydrocarbon and emulsification energy on the stability of nanoemulsions are reported. These findings demonstrate that the stability of the nanoemulsions can be manipulated and optimized for a specific application, setting the stage for subsequent investigations of these nanodroplets.