Physicochemical properties of whey protein, lactoferrin and Tween 20 stabilised nanoemulsions: Effect of temperature, pH and salt

Oil-in-water nanoemulsions were prepared by emulsification and solvent evaporation using whey protein isolate (WPI), lactoferrin and Tween 20 as emulsifiers. Protein-stabilised nanoemulsions showed a decrease in particle size with increasing protein concentration from 0.25% to 1% (w/w) level with Z-average diameter between 70 and 90 nm. However, larger droplets were produced by Tween 20 (120-450 nm) especially at concentration above 0.75% (w/w). The stability of nanoemulsions to temperature (30-90°C), pH (2-10) and ionic strength (0-500 mM NaCl or 0-90 mM CaCl2) was also tested. Tween 20 nanoemulsions were unstable to heat treatment at 90°C for 15 min. WPI-stabilised nanoemulsions exhibited droplet aggregation near the isoelectric point at pH 4.5 and 5 and they were also unstable at salt concentration above 30 mM CaCl2. These results indicated that stable nanoemulsions can be prepared by careful selection of emulsifiers.

Combined tween 20-stabilized gold nanoparticles and reduced graphite oxide-Fe3O4 nanoparticle composites for rapid and efficient removal of mercury species from a complex matrix

This study describes a simple method for removing mercuric ions (Hg(2+)) from a high-salt matrix based on the use of Tween-20-stabilized gold nanoparticles (Tween 20-Au NPs) as Hg(2+) adsorbents and composites of reduced graphite oxide and Fe3O4 NPs as NP collectors. Citrate ions adsorbed on the surface of the Tween 20-Au NPs reduced Hg(2+) to Hg(0), resulting in the deposition of Hg(0) on the surface of the NPs. To circumvent time-consuming centrifugation and transfer steps, the Hg(0)-containing gold NPs were collected using reduced graphite oxide-Fe3O4 NP composites. Compared with the reported NP-based methods for removing Hg(2+), Tween 20-Au NPs offered the rapid (within 30 min), efficient (>99% elimination efficiency), durable (>10 cycles), and selective removal of Hg(2+), CH3Hg(+), and C2H5Hg(+) in a high-salt matrix without the interference of other metal ions. This was attributed to the fact that the dispersed Tween 20-Au NPs exhibited large surface-area-to-volume ratio to bind Hg(2+) through Hg(2+)-Au(+) metallophilic interactions in a high-salt matrix. The formation of graphite oxide sheets and reduced graphite oxide-Fe3O4 NP composites was demonstrated using X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectrometry, and transmission electron microscopy. The mechanism of interaction between Tween 20-Au NPs and Hg(2+) was studied using visible spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy.

Microemulsions based on a sunflower lecithin-Tween 20 blend have high capacity for dissolving peppermint oil and stabilizing coenzyme Q10

The objectives of the present study were to improve the capability of microemulsions to dissolve peppermint oil by blending sunflower lecithin with Tween 20 and to study the possibility of codelivering lipophilic bioactive compounds. The oil loading in microemulsions with 20% (w/w) Tween 20 increased from 3% (w/w) to 20% (w/w) upon gradual supplementation of 6% (w/w) lecithin. All microemulsions had particles of <12 nm that did not change over 70 d of storage at 21 °C. They had relatively low Newtonian viscosities and were physically and chemically stable after 50-200-fold dilution in water, resulting from similar hydrophile-lipophile-balance values of the surfactant mixture and peppermint oil. Furthermore, the microemulsions were capable of dissolving coenzyme Q10 and preventing its degradation at UV 302 nm, more significant for the microemulsion with lecithin. Therefore, natural surfactant lecithin can reduce the use of synthetic Tween 20 to dissolve peppermint oil and protect the degradation of dissolved lipophilic bioactive components in transparent products.

Resveratrol proniosomes as a convenient nanoingredient for functional food

Proniosomes are free-flowing powders composed of water-soluble carriers blended with surfactants, which form niosomes upon hydration. In this work, proniosomal formulations containing the natural antioxidant resveratrol (RSV) were prepared and fully characterized. A pre-formulation study on RSV-loaded niosomes was carried out to determine the most promising ratio between the two surfactants, Tween 20 and Span 60, in terms of entrapment efficiency and antioxidant activity. The optimized formulae were subsequently adapted to be prepared as proniosomes by the slurry method, including lactose or maltodextrin as carriers. The impact of surfactants and carriers properties on size, entrapment efficiency and release kinetics of proniosomes were evaluated. In vitro release of RSV in simulated gastric and intestinal media was determined, as well as the vesicular stability. Moreover, the biocompatibility of the formulations was determined on intestinal cells in vitro. Overall, the developed proniosomes provide promising nanoingredient for functional food, improving resveratrol stability and bioavailability.

Polymer Molecules Adsorption-Induced Zincophilic-Hydrophobic Protective Layer Enables Highly Stable Zn Metal Anodes

Zn metal, as one of the most promising anode materials for aqueous batteries, suffers from uncontrollable dendrite growth and water-induced parasitic reactions, which drastically compromise its cycle life and Coulombic efficiency (CE). Herein, a nonionic amphipathic additive Tween-20 (TW20) is proposed that bears both zincophilic and hydrophobic units. The zincophilic segment of TW20 preferentially adsorbs on the Zn anode, while the hydrophobic segment is exposed on the electrolyte side, forming an electrolyte-facing hydrophobic layer that shields the anode from active water molecules. Moreover, theoretical calculation and experimental results reveal that the TW20 additive can induce the preferential growth of (002) plane by adsorbing on other facets, enabling dendrite-free Zn anodes. Benefitting from these advantages, the stability and reversibility of Zn anodes are substantially improved, reflected by stable cycling for over 2500 h at 1.0 mA cm-2/1.0 mAh cm-2 and 500 h at 5 mA cm-2/5 mAh cm-2 as well as an average CE of 99.4% at 1.0 mA cm-2/1.0 mAh cm-2. The full cells paired with MnO2 demonstrate a long lifespan for more than 700 cycles at 500 mA g-1. This work is expected to provide a new approach to modulate Zn electrode interface chemistry for highly stable Zn anodes.

Fluorescence Anisotropy-Based Signal-Off and Signal-On Aptamer Assays Using Lissamine Rhodamine B as a Label for Ochratoxin A

Ochratoxin A (OTA), a common mycotoxin, has attracted great concern as many foodstuffs can suffer from OTA contamination; OTA causes harmful effects on human and animals. Rapid and sensitive detection of OTA is demanded in many fields for agricultural product quality, food safety, and health. Aptamer fluorescence polarization/anisotropy (FP/FA) assays integrate advantages of nucleic acid aptamers (e.g., easy preparation, high stability, and low cost) and FP/FA analysis (e.g., high sensitivity, rapidity, simplicity, and robustness). Here, we report the preparation of lissamine rhodamine B labeled OTA and developed competitive aptamer fluorescence anisotropy (FA) assays for OTA with signal-off or signal-on responses by using this fluorescently labeled probe. In the signal-off FA assay, the binding between the fluorescent probe and aptamer gave a large FA signal due to molecular volume increase, and the fluorescent probe was displaced from the aptamer in the presence of OTA target, causing FA to decrease. To further enhance the FA change in the signal-off assay, large-sized streptavidin was conjugated on the aptamer, and this assay allowed for a detection limit of 2.5 nM and a more remarkable FA decrease. Furthermore, we found that the fluorescent probe could interact with Tween 20, which caused the fluorescent probe to show a higher FA value than that of the aptamer-fluorescent probe complex. A signal-on FA assay was achieved in the binding buffer containing 0.1% Tween 20, with a detection limit of 10 nM. Signal-off and signal-on FA methods both were selective and enabled detection of OTA spiked in red wine samples, showing capability for target analysis in complex sample matrix.

Physicochemical characterization of sodium stearoyl lactylate (SSL), polyoxyethylene sorbitan monolaurate (Tween 20) and κ-carrageenan

Surfactant-polymer mixtures are common in food, cosmetic and pharmaceutical products. These components can interact with each other. The interactions depend on the type of polymer and surfactant, the purity of the ingredients, the ionic content and their concentration. Therefore, the data presented here provide valuable information that could be useful for those working with these mixtures in different applications, particularly in blends with polyelectrolytes and their counterions. This article contains experimental data about the physicochemical characterization of sodium stearoyl lactylate (SSL), polyoxyethylene sorbitan monolaurate (Tween 20) and κ-carrageenan. Techniques included atomic absorption, DSC, FTIR-ATR, NMR, and surface tension.

Evaluation of biosurfactant obtained from Lactobacillus pentosus as foaming agent in froth flotation

This study analyzes the kinetics of sediment sorption on two chemical surfactants (Tween 20 and SDS) and a biotechnologically produced surfactant (obtained from Lactobacillus pentosus). Biosurfactants were produced by fermentation of hemicellulosic sugars from vineyard pruning waste supplied as a substrate to L. pentosus. Results obtained showed that almost no SDS was adsorbed onto the sediments, whereas Tween 20 and biosurfactants from L. pentosus were absorbed after a few minutes. Kinetic models revealed that adsorption of surfactant onto riverbed sediments is governed not only by an intra-particle diffusion model (evaluated by the Weber and Morris model), but also by surface reaction models (evaluated by first, second, third order equations and Elovich equation), showing the best fit when employing the Elovich model. The adsorption properties showed by biosurfactant from L. pentosus onto sediments present it as a potential foaming agent in froth flotation.

Oxidative stability of emulsions fortified with iron: the role of liposomal phospholipids

BACKGROUND

Interest in supplementing food with iron to counteract dietary deficiencies has been on the rise in recent years. A major challenge is the pro-oxidant activity of soluble iron, which compromises the chemical stability of the enriched food products. This problem could be mitigated by encapsulating iron, to physically keep it separated from oxidizable substrates, such as unsaturated fatty acids. In the present work, the physical and chemical stability of surfactant- or protein-stabilized oil-in-water emulsions fortified with iron was investigated.

RESULTS

Iron (ferrous sulfate) was successfully incorporated in liposomes at high encapsulation efficiency (89%). The liposomes obtained were added to emulsions stabilized with either Tween 20 or whey protein isolate (WPI), and its oxidative stability was monitored and compared with emulsions with free iron. Tween 20-stabilized emulsions were more stable against oxidation than WPI-stabilized emulsions, and furthermore lipid oxidation was substantially higher in emulsions containing iron (either free, or encapsulated in liposomes) than in blank emulsions. This shows that liposomal encapsulation did not inhibit the pro-oxidant activity of iron.

CONCLUSION

Despite the high encapsulation efficiency of iron in our liposomes, these systems are not suitable to supplement model foods with iron because of the associated deleterious chemical reactivity. This is most probably due to the phospholipids used as encapsulation material being prone to oxidation, which may actively contribute to the oxidative process. These aspects are normally not taken into account but we showed that they are of utmost importance, and should be taken as a starting point in the design of delivery systems. © 2018 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The preparation and evaluation of self-nanoemulsifying systems containing Swietenia oil and an examination of its anti-inflammatory effects

There is an increasing trend among pharmaceutical industries to use natural bioactive materials as medicinal agents and to use new technologies such as self-nanoemulsifying systems. The solubility and bioavailability of poorly soluble drugs can be enhanced by self-nanoemulsifying systems. Swietenia oil is frequently used because of its antimicrobial, antimutagenic, and anticancer bioactive medical properties. This study was conducted to develop self-nanoemulsifying systems for Swietenia oil that will enhance the anti-inflammatory activity of the oil. The self-emulsifying systems developed for Swietenia oil in this study were constructed using ternary phase diagrams and contained the nonionic surfactants Labrasol(®), Tween 20, Capmul(®), and Labrafil(®). The effect of these surfactants on the formulation was examined. The mean droplet size of Swietenia oil as well as their distribution, appearance, viscosity, and spreading times were studied to find the optimum formula, which contained droplets that were less than 200 nm. The next step was to test the anti-inflammatory properties of the optimum formula using a carrageenan-induced rat paw edema test. The results from this test were compared to the oil solution. Different oil/surfactants mixtures had various emulsification properties that were related to the size of their droplets. Tween 20 is a good surfactant to use in self-emulsifying systems because it produces droplets of nano-size. Mixtures of Capmul/Labrasol at a ratio of 2:1 and Labrafil/Tween 20 at a ratio of 1:2 were able to produce self-nanoemulsifying formulations containing Swietenia oil concentrations that ranged from 20%-50%. Nanoemulsion occurred when the size of the droplets fell below 200 nm with low size distribution (<0.3) after being gently mixed with water. It was found that the hydrophilic/lipophilic balance value affected the ternary phase diagram behavior of Swietenia oil and surfactants. In addition, the anti-inflammatory properties of Swietenia oil were greater in the self-nanoemulsifying systems than in the oil solution.

Deconvolution procedure of the UV-vis spectra. A powerful tool for the estimation of the binding of a model drug to specific solubilisation loci of bio-compatible aqueous surfactant-forming micelle

UV-vis-spectra evolution of Nile Red loaded into Tween 20 micelles with pH and [Tween 20] have been analysed in a non-conventional manner by exploiting the deconvolution method. The number of buried sub-bands has been found to depend on both pH and bio-surfactant concentration, whose positions have been associated to Nile Red confined in aqueous solution and in the three micellar solubilisation sites. For the first time, by using an extended classical two-pseudo-phases-model, the robust treatment of the spectrophotometric data allows the estimation of Nile Red binding constant to the available loci. Hosting capability towards Nile Red is exalted by the pH enhancement. Comparison between binding constant values classically evaluated and those estimated by the deconvolution protocol unveiled that overall binding values perfectly match with the mean values of the local binding sites. This result suggests that deconvolution procedure provides more precise and reliable values, which are more representative of drug confinement.

Citral stabilization and characterization of nanoemulsions stabilized by a mixture of gelatin and Tween 20 in an acidic system

BACKGROUND

Citral is one of the most important flavor compounds in fresh juice and lemon oil. Unfortunately, citral is chemically unstable and degrades over time in aqueous solutions. Here, citral nanoemulsions including a mixture of gelatin and Tween 20 as emulsifiers were produced in an effort to maintain the stability of citral in an acidic system.

RESULTS

The mean droplet size and polydispersity index of the citral nanoemulsion were 467.83 nm and 0.259 respectively when the mass ratio of gelatin/Tween 20 was 3:1 and the total emulsifier concentration of the emulsion system was 10 g kg^-1 . The citral nanoemulsion remained stable during storage for 14 days at 30 °C. Therefore this nanoemulsion system effectively protected citral from degradation and decreased the formation of off-flavor compounds (e.g. p-cymene, p-cresol and p-methylacetophenone) relative to a single emulsifier.

CONCLUSION

The mixture of gelatin and Tween 20 enhanced the stability of citral under acidic conditions and could be used as an effective emulsifier to protect citral from degradation under acidic environments in the food industry. © 2016 Society of Chemical Industry.

Interference from ordinarily used solvents in the outcomes of Artemia salina lethality test

Methanol, ethanol, Tween 20 and dimethyl sulfoxide (DMSO) are widely used as dissolving agents in Artemia salina lethality test (aka brine shrimp lethality test [BSLT]) to screen the pharmaceutical properties of natural products. Nevertheless, there is lack of toxicity level of these solvents against brine shrimp. High concentration of these organic solvent might be toxic for this zoology invertebrate and interfere in the experimental outcomes. To avoid this, permissible concentration of the solvents used in BSLT was identified. BSLT was performed to evaluate the toxicity effect of Tween 20, methanol, ethanol and DMSO at 24 h post-treatment time point against A. salina. The suggested maximum working concentration (v/v) for DMSO, methanol, ethanol was found to be 1.25% and that for Tween 20 was 0.16%. LC50 for the solvents were 8.5% (DMSO), 6.4% (methanol), 3.4% (ethanol) and 2.5% (Tween 20). The findings have shown a toxicity level among the solvents in descending order as Tween 20 > ethanol > methanol > DMSO. DMSO is a safer solvent to be used in BSLT compared with other tested solvents, whereas Tween 20 has been shown to be the most stringent solvent among the tested solvents. The findings are resourcefully useful to avoid interference of solvents in the assessment of natural products using BSLT.

Phytoremediation potential of Miscanthus sinensis And. in organochlorine pesticides contaminated soil amended by Tween 20 and Activated carbon

The organochlorine pesticides (OCPs) have raised concerns about being persistent and toxic to the environment. Phytoremediation techniques show promise for the revitalization of polluted soils. The current study focused on optimizing the phytoremediation potential of Miscanthus sinensis And. (M. sinensis), second-generation energy crop, by exploring two soil amendments: Tween 20 and activated carbon (AC). The results showed that when M. sinensis grew in OCP-polluted soil without amendments to it, the wide range of compounds, i.e., α-HCH, β-HCH, γ-HCH, 2.4-DDD, 4.4-DDE, 4.4-DDD, 4.4-DDT, aldrin, dieldrin, and endrin, was accumulated by the plant. The introduction of soil amendments improved the growth parameters of M. sinensis. The adding of Tween 20 enhanced the absorption and transmigration to aboveground biomass for some OCPs; i.e., for γ-HCH, the increase was by 1.2, for 4.4-DDE by 8.7 times; this effect was due to the reduction of the hydrophobicity which made pesticides more bioavailable for the plant. The adding of AC reduced OCPs absorption by plants, consequently, for γ-HCH by 2.1 times, 4.4-DDD by 20.5 times, 4.4-DDE by 1.4 times, 4.4-DDT by 8 times, α-HCH was not adsorbed at all, and decreased the translocation to the aboveground biomass: for 4.4-DDD by 31 times, 4.4-DDE by 2.8 times, and γ-HCH by 2 times; this effect was due to the decrease in the bioavailability of pesticides. Overall, the amendment of OCP-polluted soil by Tween 20 speeds the remediation process, and incorporation of AC permitted to produce the relatively clean biomass for energy.

Enhanced removal of mixed VOCs with different hydrophobicities by Tween 20 in a biotrickling filter: Kinetic analysis and biofilm characteristics

Mass transfer limitation usually causes the poor performance of biotrickling filters (BTFs) for the treatment of hydrophobic volatile organic compounds (VOCs) during long-term operation. In this study, two identical lab-scale BTFs were established to remove a mixture of n-hexane and dichloromethane (DCM) gases using non-ionic surfactant Tween 20 by Pseudomonas mendocina NX-1 and Methylobacterium rhodesianum H13. A low pressure drop (≤110 Pa) and a rapid biomass accumulation (17.1 mg g^-1) were observed in the presence of Tween 20 during the startup period (30 d). The removal efficiency (RE) of n-hexane was enhanced by 15.0%- 20.5% while DCM was completely removed with the inlet concentration (IC) of 300 mg·m^-3 at different empty bed residence times in the Tween 20 added BTF. The viable cells and the relative hydrophobicity of the biofilm were increased under the action of Tween 20, which facilitated the mass transfer and enhanced the metabolic utilization of pollutants by microbes. Besides, Tween 20 addition enhanced the biofilm formation processes including the increased extracellular polymeric substance (EPS) secretion, biofilm roughness and biofilm adhesion. The kinetic model simulated the removal performance of the BTF with Tween 20 for the mixed hydrophobic VOCs, and the goodness-of-fit was above 0.9.

Nanoemulsions (O/W) containing Cymbopogon pendulus essential oil: development, characterization, stability study, and evaluation of in vitro anti-bacterial, anti-inflammatory, anti-diabetic activities

Essential oil from Cymbopogon pendulus is immensely useful in various sectors like food, pharmaceutical, and cosmetic industries. Since this oil is hydrophobic, unstable, and volatile, hence encapsulation by using nanoemulsions technology is the best way to protect it. This study reports biosynthesis of O/W (oil/water) nanoemulsions based on essential oil from Cymbopogon pendulus and analysis of its biological activities. O/W nanoemulsions were prepared by using tween 20/80, sodium dodecyl sulphate as surfactants, and ethanol as co-surfactants. Fingerprinting of nanoemulsions using UV, fluorescent, and FT-IR was studied along with other parameters like pH and conductivity. Biological activities like antibacterial, anti-inflammatory, and anti-diabetic activities and drug release pharmokinetics were evaluated. Ethanol containing nanoemulsions was noticeably smaller than other nanoemulsions. Encapsulation efficiency of nanoemulsions was in the range from 41 to 60%. Nanoemulsions were spherical in shape and stable even after 50 days of storage. Appreciable biological activities like anti-bacterial, anti-inflammatory, and anti-diabetic activities were detected. Drug kinetic study revealed that nanoemulsions exhibited Korsmeyer-Peppas model. Based on this, the possible role of lemon grass oil-based nanoemulsions in cosmetic, food, and pharma sectors has been discussed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12668-022-00964-4.

Application of response surface methodology and spectroscopic approach for investigating of curcumin nanoencapsulation using natural biopolymers and nonionic surfactant

This study aimed at encapsulation of poor water-soluble curcumin so that it could be utilized in various food products as a functional ingredient. Biopolymer nanoparticles were assembled from sodium caseinate and gum arabic using electrostatic complexation in the presence of nonionic surfactant Tween 20. Fourier transform infrared spectroscopy was used to investigate the interactions of curcumin with protein, polysaccharide and surfactant. The effects of sodium caseinate (A), gum arabic (B), Tween 20 (C) and pH (D) on responses were studied using a three-level four-factor Box-Behnken design. For each response, a second-order polynomial model was developed. For optimum nanoencapsulation of curcumin, the variables concentration of sodium caseinate, concentration of gum arabic, pH and concentration of Tween 20 were 0.21, 0.5, 5 and 0.14 wt% respectively. The particles were characterized by ζ-potential measurement. Spectroscopic results and data modelling, showed interaction of curcumin with sodium caseinate, gum arabic and Tween 20. Also, the nonionic surfactant Tween 20, influenced the electrostatic interaction between sodium caseinate and gum arabic.

Efficient Extraction of Carotenoids from Sargassum muticum Using Aqueous Solutions of Tween 20

The replacement of synthetic compounds by natural products witnesses an increasing demand from the pharmaceutical, cosmetic, food and nutraceutical industries. Included in the set of natural raw materials that are poorly explored are the macroalgae. Despite the detailed characterization and identification of most relevant biomolecules that are present in the main macroalgae species, there remains a lack of efficient and economically viable processes available to meet the needs of the markets. In this work, an efficient and single-step process, based on aqueous solutions of Tween 20, to recover carotenoids from Sargassum muticum, an invasive brown macroalgae species present in the Portuguese coast, is proposed and optimized allowing an extraction yield of 2.78 ± 0.4 mgcarotenoids.gdried mass-1, which is shown to increase the extraction efficiency by 38% when compared with traditional methods.

Biotin biosynthesis affected by the NADPH oxidase and lipid metabolism is required for growth, sporulation and infectivity in the citrus fungal pathogen Alternaria alternata

The tangerine pathotype of Alternaria alternata affects many citrus cultivars, resulting in yield losses. The capability to produce the host-selective toxin and cell-wall-degrading enzymes and to mitigate toxic reactive oxygen species is crucial for A. alternata pathogenesis to citrus. Little is known about nutrient availability within citrus tissues to the fungal pathogen. In the present study, we assess the infectivity of a biotin deficiency mutant (ΔbioB) and a complementation strain (CP36) on citrus leaves to determine how biotin impacts A. alternata pathogenesis. Growth and sporulation of ΔbioB are highly dependent on biotin. ΔbioB retains its ability to acquire and transport biotin from the surrounding environment. Growth deficiency of ΔbioB can also be partially restored by the presence of oleic acid or Tween 20, suggesting the requirement of biotin in lipid metabolism. Experimental evidence indicates that de novo biotin biosynthesis is regulated by the NADPH oxidase, implicating in the production of H₂O₂, and is affected by the function of peroxisomes. Three genes involved in the biosynthesis of biotin are clustered and co-regulated by biotin indicating a transcriptional feedback loop activation. Infectivity assays using fungal mycelium reveal that ΔbioB cultured on medium without biotin fails to infect citrus leaves; co-inoculation with biotin fully restores infectivity. The CP36 strain re-expressing a functional copy of bioB displays wild-type growth, sporulation and virulence. Taken together, we conclude that the attainability or accessibility of biotin is extremely restricted in citrus cells. A. alternata must be able to synthesize biotin in order to utilize nutrients for growth, colonization and development within the host.

Translation attenuation via 3' terminal codon usage in bovine csn1s2 is responsible for the difference in αs2- and β-casein profile in milk

The rate of secretion of αs2-casein into bovine milk is approximately 25% of that of β-casein, yet mammary expression of their respective mRNA transcripts (csn1s2 and csn2) is not different. Our objective was to identify molecular mechanisms that explain the difference in translation efficiency between csn1s2 and csn2. Cell-free translational efficiency of csn2 was 5 times that of csn1s2. Transcripts of csn1s2 distributed into heavier polysomes than csn2 transcripts, indicating an attenuation of elongation and/or termination. Stimulatory and inhibitory effects of the 5' and 3' UTRs on translational efficiency were different with luciferase and casein sequences in the coding regions. Substituting the 5' and 3' UTRs from csn2 into csn1s2 did not improve csn1s2 translation, implicating the coding region itself in the translation difference. Deletion of a 28-codon fragment from the 3' terminus of the csn1s2 coding region, which displays codons with low correlations to cell fitness, increased translation to a par with csn2. We conclude that the usage of the last 28 codons of csn1s2 is the main regulatory element that attenuates its expression and is responsible for the differential translational expression of csn1s2 and csn2.

Synthesis of naproxen-imprinted polymer using Pickering emulsion polymerization

For the last decades, molecular imprinting is developing intensively, especially in the case of the application of new imprinting techniques. In this work, for the first time, a Pickering emulsion polymerization was used to synthesize the S-naproxen-imprinted polymer spheres following a noncovalent protocol. To enhance the knowledge about imprinting process using mentioned technique, thorough analysis of the synthesis process was performed. Optimization of polymerization conditions included the selection of functional monomer, cross-linking agent, type of porogen, surfactant, and the choice of appropriate amount of the template and porogen. Prepared materials were characterized using scanning electron microscopy and nitrogen adsorption. To study the binding properties, the sorption studies, including adsorption isotherms and competitive binding, were performed. Investigation of the effect of the functional monomer on the selective recognition of S-naproxen showed that the interactions between the template molecule and 4-vinylpyridine resulted in the best recognizing ability. Moreover, the synthesis with application of ethylene glycol dimethacrylae as a cross-linker, toluene as a porogen, and Tween 20 as an additional emulsion stabilizer gave the most desired result. The optimal ratio of the porogen to monomers mixture was 0.1, due to the fact that the increase of the porogen volume resulted in the significant increase of nonspecific uptake. In addition, the tenfold molar excess of functional monomer relative to the template turned out to be optimal. Subsequent binding studies demonstrated that the material synthesized using optimized polymerization conditions consists of imprinted sites that are sensitive for the S-naproxen.

Development of a Surfactant-Containing Process to Improve the Removal Efficiency of Phenol and Control the Molecular Weight of Synthetic Phenolic Polymers Using Horseradish Peroxidase in an Aqueous System

To reduce phenolic pollutants in the environment, many countries have imposed firm restrictions on industrial wastewater discharge. In addition, the current industrial process of phenolic resin production uses phenol and formaldehyde as the reactants to perform a polycondensation reaction. Due to the toxicity of formaldehyde and phenolic pollutants, the main purpose of this research was to design a green process using horseradish peroxidase (HRP) enzymatic polymerization to remove phenols and to produce formaldehyde-free phenolic polymers. In this study, the optimal reaction conditions, such as reaction temperature, pH, initial phenol concentration and initial ratio of phenol, and H₂O₂, were examined. Then, the parameters of the enzyme kinetics were determined. To solve the restriction of enzyme inactivation, several nonionic surfactants were selected to improve the phenol removal efficiency, and the optimal operation conditions in a surfactant-containing system were also confirmed. Importantly, the molecular weight of the synthetic phenolic polymers could be controlled by adjusting the ratio of phenol and H₂O_2. The content of biphenols in the products was almost undetectable. Collectively, a green chemistry process was proposed in this study and would benefit the treatment of phenol-containing wastewater and the production of formaldehyde-free phenolic resin in the future.

A modified precise analytical method for anti-malarial screening: Heme polymerization assay

Malarial parasite detoxifies the heme generated in its food vacuole in many ways one of which involves heme polymerization to hemozoin. The existing heme polymerization assays involve use of activators along with buffers for polymerization of heme leading to its precipitation. Such assays then involve special instruments and laborious work of isolating the precipitated polymer and its detection. Simple and precise spectrophotometric and HTS methods were developed for heme polymerization using tween 20 as the activator without isolation of polymerized heme.

Monitoring of particle sizes distribution during Valsartan precipitation in the presence of nonionic surfactant

Particle size is a key parameter when dealing with drug particle formation, delivery or dissolution. The correct measurement of particle size depends on various factors, such as sample preparation or dilution, but also on the choice of method for its characterization. In this work, we study the process of precipitation of poorly water-soluble drug Valsartan from supersaturated solution in the presence of nonionic surfactant Tween 20. Several techniques including dynamic light scattering (DLS) operated in several measuring modes, optical microscope (OM) and static light scattering (SLS) were used to analyze the kinetics of particle formation. As concluded by the results, the increase in turbidity of the solution seriously limits the application of classical DLS to properly measure the particle size and polydispersity. One way to get around this restriction is by dilution, which however results in a decrease in the size of Valsartan particles in the studied population. In contrast, here we present for a first time technique based on modulated 3D cross correlation DLS equipped with the sample goniometer to determine size of submicron particles of the drug in highly turbid solutions. Additionally, a modified OM was used to measure micron-sized particles for samples without any dilution in a continuous mode. Measured particle sizes combined with measured Valsartan concentration allowed us to identify mechanism responsible for the particle formation from supersaturated solutions. The main mechanism, as it is shown in this work, is covering surface of precipitate particles by the amount of used Tween 20.

Replacing Synperonic® N in the Physical Developer fingermark visualisation process: Reformulation

The Physical Developer solution currently recommended for use in the United Kingdom for fingermark visualisation uses two surfactants: n-dodecylamine acetate (nDDAA) and Synperonic® N. Synperonic® N is covered by the EU directive 82/242/EEC, which sought to phase out chemicals with degradation products more harmful than their precursor. This study explores the replacement of Synperonic® N with alternative detergents and examines their ability to produce clear, stable solutions that are effective at developing fingermarks. The critical properties of the detergents were investigated, such as the critical micelle concentration and the hydrophilic-lipophilic balance, and planted mark comparisons were performed on promising formulations. Tween® 20 was deemed unsuitable due to the production of cloudy solutions and the requirement to age the formulation to improve effectiveness. Brij® C10 produced clear formulations; however, these were too stable causing unacceptably long exhibit processing times, and an additional preparation stage was necessary. Brij® L23, Brij® S10, Igepal® CO-630, Polyoxyethylene (10) tridecyl ether and Tergitol™ 15-S-9 also proved to be unsuccessful alternatives. Decaethylene glycol monododecyl ether (DGME) was found to be a suitable alternative to Synperonic® N and depletion series experiments suggested that a range of DGME and nDDAA detergent quantities were effective at developing marks. The processing time using DGME was similar to Synperonic® N and the most favourable ratio of reagents is proposed in this paper as a reformulated Physical Developer solution.