Mixture Of Lecithin Research Articles

A taste for growth: Rapeseed lecithin improves the feed intake of post‐juvenile rainbow trout (Oncorhynchus mykiss)

AbstractFeed formulations low in fish meal and fish oil can decrease feed intake and nutrient digestibility. Dietary application of lecithins could improve growth performance and nutrient digestibility; however, knowledge about specific lecithins and their effects in post‐juvenile fish is lacking. This study evaluated the effects of a commercially available rapeseed lecithin mixture on growth performance, feed intake, and nutrient digestibility of post‐juvenile rainbow trout (77.1 ± 12.1 g). A commercially based diet low in fish meal served as the control, while in the remaining three diets, fish oil was replaced with lecithin by 50%, 100% with lecithin, or 100% with a mixture of equal amounts of lecithin and rapeseed oil. Fish were fed to apparent satiation twice per day for 56 days. At the end of the trial, growth parameters, health parameters, nutrient digestibility, and filet coloration were assessed. Overall growth and feed intake were significantly elevated in all lecithin diets compared with the control group. The nutrient digestibility of all diets containing lecithin was similar to the control, and no differences in health parameters were detected. Filet coloration was significantly improved in diets of 100% fish oil replacement. Rapeseed lecithin can act as a feed attractant in fish meal and fish oil‐reduced diets.

Effect of dietary phospholipid on the behavior in C57BL/6J mice

Nowadays phospholipids are widely used as hepatoprotective, neuroprotective and anti-stress drugs, as well as the dietary supplements. Besides, lecithin consisting up to 70% of the phospholipids mixture: phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidic acid, is the often component of food production as an emulsifier. Dose of these biologically active substances in the modern human diet could be quite high. Previously we have shown that chronic intestinal inflammation in Muc2-knockout mice induces behavioral changes along with the significant increase in the content of phospholipids in intestinal epithelial cells, particularly, phosphatidylcholine, phosphatidylserine and phosphatidic acid. Here we investigate the effects of long-term administration of a mixture of these phospholipids, as well as the effects of long-term administration of soy lecithin on the behavioral patterns in laboratory mice. Animals long-term taken a phospholipid mixture shows no normally observed preference towards females in the two intruders test (with female and male). In the social odor preference test, they also did not distinguish female and male odors, while non-social odors discrimination preserved. In addition, we identified a decrease in anxiety, obsessive traits, and schizophrenia-like behavior traits in these animals. Soy lecithin supplementation had similar effects on social behavior and compulsive traits, and increased aggression in males. Thus, long-term perinatal administration of either mixture of phospholipids (phosphatidylcholine, phosphatidylserine and phosphatidic acid) or soy lecithin can influence various aspects of behavior in mice.

Unveiling the formation capacity of multicomponent oleogels: Performance of lecithin interacting with monostearate derivatives

Oleogels have been explored as fat substitutes due to their healthier composition compared to trans and saturated fats, also presenting interesting technological perspectives. The aim of this study was to investigate the compositional perspective of multicomponent oleogels. Structuring ability of lecithin (LEC) (20 or 90 wt% of phosphatidylcholine – PC) combined with glycerol monostearate (GMS), sorbitan monostearate (SMS) or sucrose monostearate (SAC) in sunflower oil was evaluated from oleogels properties. The thermal and rheological properties, microstructure and stability of the oleogels were affected by the difference in the chemical composition of LEC and the ratio between LEC and different surfactants. Interestingly, low-phosphatidylcholine LEC (L20) performed better, although systems formed with reduced amounts of LEC tended to be softer (LEC-GMS) and present high oil holding capacity (LEC-SMS). The mixtures of LEC and monostearate-based surfactants showed different behaviors, depending on the surfactant polar head. In LEC-GMS systems, LEC hindered the self-assembly of GMS in sunflower oil, compromising mechanical properties and increasing oil release. When combined with SMS, LEC acted as a crystal habit modifier of SMS, forming a more homogeneous microstructure and producing stronger oleogels with greater oil binding capacity. However, above the threshold concentration, LEC prevented SMS self-assembly, resulting in a weaker gel. A positive interaction was found in LEC-SAC formulations in specific ratios, since SAC cannot act as a single oleogelator. Results show the impact of solubility balance played by LEC and fatty-acid derivatives surfactant when combined and used as oleogelators. This knowledge can contribute to a rational perspective in the preparation and modulation of the properties of edible oleogels.

Combinatorial effects of longan (Dimocarpus longan) peel extract and lecithin on stability of soybean oil and the oxidative stability of fried shrimp crackers during storage

Soybean oil contains relatively high polyunsaturated fatty acids (PUFAs) which present problems for storage, as they are not oxidatively stable. To solve this problem, the present study mixed a naturally hydrophilic antioxidant (longan peel extract, LP) with an amphiphilic compound (lecithin) to create a water-oil based interface with antioxidant properties and analyzed the effect on lipid oxidation. Pretreatments with LP, lecithin, and a combined mixture of LP and lecithin improved oxidative stability in refined soybean oil heated at 70 and 180 °C, by decreasing the resulting peroxide value (POV), conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS). Pretreatment with a combination of both LP and lecithin exhibited a synergistic effect in lowering TBARS and maintaining α-tocopherol, which is an endogenous antioxidant in soybean oil. The pretreatment helped to maintain PUFAs, which led to the prevention of POV, CD and TBARS formation in the oil. In deep-frying experiment, application of LP, lecithin, and a combined mixture of the two, improved the stability of the frying oil in addition to fried shrimp crackers that were cooked in the oil. Collectively, the results demonstrated the potential of LP, lecithin, and their combination in improving oxidative stability of vegetable oils under high-temperature conditions.

Aqueous dispersions of oleic acid nanodroplets for thymol encapsulation

This study focuses on the use of oleic acid to disperse thymol as nanodroplets, stabilized by a mixture of alkylpolyglucoside and lecithin, in an aqueous environment. This approach aims to develop innovative platforms for the encapsulation and release of poorly water-soluble molecules such as thymol, useful for drug delivery and insecticide systems. The results highlight the critical role of controlling the content and concentration of the oil phase (thymol-oleic acid mixture) in achieving optimal thymol dispersion and nanodispersion stability. The interplay between the ability of oleic acid to inhibit thymol crystallization and the maximum dispersible oil amount is crucial. It affects the dispersion of thymol within the nanodroplets and influences coalescence and Ostwald ripening phenomena. The balance between oleic acid and thymol content is key: while oleic acid stabilizes dispersions, higher thymol content increases droplet size, potentially triggering destabilization. The uneven distribution of thymol within the droplets, revealed by fluorescence spectroscopy, suggests that up to three different chemical environments exist. This investigation may pave the way for the development of efficient platforms to improve access to biologically relevant, poorly soluble molecules.

Lentil protein stabilized emulsion - Impact of lecithin addition on emulsions properties

Plant-based proteins are currently the focus of a lot of product development research, as they have proved to be a potential replacement of animal-based ingredients and safeguard environmental and human health. However, most of the studies focus on soy and pea based food whereas lentil proteins have received only little attention. The aim of this work is to elucidate the behavior of different lentil protein sources (isolate, concentrate and flour) in stabilizing emulsions and to study their interaction with food emulsifiers such as lecithin. We study the adsorption kinetics at the oil water interface of both, the different protein sources as well as their combination with lecithin. Lentil protein-based emulsions (with 1%wt protein content) reveal bimodal particle size distribution and the emulsion shows various dispersion states (aggregated or well dispersed) depending on the protein sources and processing conditions. The addition of lecithin (with 0.25%wt) reduces aggregation phenomenon and reduce the average droplet size for lentil flour based emulsion. The adsorption kinetic at the oil water interface, suggest the formation of a surface active protein-lecithin complex and a mixed interfaces. Moreover, the mixture of lentil proteins and lecithin can reduce the interfacial tension by up to 12 mN/m compared to lentil protein alone. This demonstrates the presence of synergistic effects at interfaces and potential interactions between lecithin and proteins.

The anti-spermatogenic activity of nanoliposomes loaded with Heracleum persicum phenolic compounds in Balb/C mice.

There are various types of bioactivities that have been reported for Heracleum persicum species, such as antioxidant, anti-inflammatory, and cytotoxicity properties. In the current study, the bio-accessibility of H. persicum bioactive compounds was improved by purifying its phenolic-enriched fractions (PEF) and encapsulating them into nanoliposomes to analyze its cytotoxic impacts on mice testicular tissue and their fertility status. Nano liposomal H. persicum PEF (NL-HPEF) was prepared by ultrasound-based encapsulation of HPEF and L-agranular lecithin mixture. The size, morphology, and stability of NL-HPEF were characterized by dynamic light scattering, field emission scanning electron microscopy, and zeta potential analysis. The 18 white male Balb/c mice (20-25g) at 3 treatment groups were provided to study the NL-HPPF cytotoxicity by measuring the mice liver enzyme including aspartate aminotransferase (AST), ALP and alanine aminotransferase (ALT), testis lipid peroxidation, and testicular tissue destruction levels. Moreover, the mice's fertility was evaluated by studying the Adam3, Prm1, Spata19, and Tnp2 gene expression in the testicular tissues. The obtained results manifested that the synthesized NL-HPEF was stable (193.7nm) and exhibited a notable cytotoxic impact on the mice's liver (ALT and AST enhancement levels) and testicular tissues. Moreover, their increasing treatment doses impaired the male mice's fertility by decreasing the sperm count, viability, and motility. In addition, fertility suppression was verified by decreasing serum testosterone and downregulating the Adam3, Prm1, Spata19, and Tnp2 gene expression in their testicular tissues. The male mice's fertility was significantly (p<0.05) suppressed by increasing treatment doses of NL-HPEF. Hence, the NL-HPEF could be considered a promising alternative to replace the male chemical contraceptives drugs.

Ultrasonic-Assisted Extraction of Astaxanthin from Shrimp By-Products Using Vegetable Oils.

The use of conventional astaxanthin extraction methods, typically involving organic solvents, leads to a heightened environmental impact. The aim of this study was to explore the potential use of environmentally friendly extraction solvents, such as vegetable oils, for recovering the shrimp by-product astaxanthin. Ultrasound-assisted extraction (UAE) in vegetable oils, including olive oil (OO), sunflower oil (SO), and flaxseed oil (FO), was employed to extract astaxanthin. The astaxanthin antioxidant activity was evaluated using an ABTS assay, and a mixture of gum Arabic and soy lecithin was used to form coacervates to produce astaxanthin encapsulation. A by-product-vegetable oil ratio of 1:60, extraction time of 210 min, 60% amplitude of the extraction process, and the use of OO as the extracting medium resulted in an astaxanthin yield of 235 ± 4.07 μg astaxanthin/g by-products. The astaxanthin encapsulation efficiency on day 0 and astaxanthin recovery on day 1 were recorded at 66.6 ± 2.7% and 94.4 ± 4.6%, respectively. The utilization of OO as an extraction solvent for astaxanthin from shrimp by-products in UAE represents a novel and promising approach to reducing the environmental impact of shrimp by-products. The effective astaxanthin encapsulation efficiency highlights its potential application in food industries.

Lecithin - Bifidobacterium probiotics interactions: a case study

Probiotic formulations containing lecithin phospholipids have been shown to extend their viability. However, the protective effect of lecithin and the properties of the mixtures of lecithin and probiotic cells in aqueous media have not been fully documented. The aim of this study was to investigate the interactions between Bifidobacterium animalis ssp. lactis (Bifido) probiotics and lecithin. The lecithin-Bifido interactions were dependent on lecithin concentration. FTIR and Raman spectroscopy suggested that Bifido cells interacted with lecithin molecules, mainly through hydrophobic interactions. At the lecithin concentration of 0.1%.w/v, Bifido lost only about 17% of their viability over 56 days, while free Bifido probiotics (without lecithin) lost about 66% of their viability in the same time period. Furthermore, flow cytometer side scatter plots also showed that Bifido-lecithin samples at 0.1.%w/v lecithin, showed the lowest side scatter, which is indicative of lower cellular stress and a more stable environment to preserve Bifido cells viability over time.

Caffeic acid phenethyl ester loaded in a targeted delivery system based on a solid-in-oil-in-water multilayer emulsion: Characterization, stability, and fate of the emulsion during in vivo digestion

Many studies have shown that caffeic acid phenethyl ester (CAPE) has various functions, such as antioxidant, anti-inflammatory and anticancer activity, but its low bioavailability and stability limit its application. In this study, the colorectal targeted delivery system for CAPE based on a solid-in-oil-in-water (S/O/W) multilayer emulsion was prepared using CAPE-loaded nanoparticles as the solid phase, coconut oil as the oil phase, and a mixture of lecithin and sodium caseinate as the aqueous phase. The stability of the O/W interfacial layer was improved by using a sodium casein-lecithin mixture as the aqueous surface layer in the preparation. This S/O/W emulsion is a spherical droplet with an S/O/W trilayer structure with a particle size of 155.5 ± 0.72 nm and a polydispersity index (PDI) of 0.24 ± 0.01. The Fourier transform infrared (FTIR) results confirmed that CAPE was successfully loaded into the S/O/W emulsion. This S/O/W emulsion was able to maintain a stable liquid state at pH 6.00–7.4 or cholate concentration of 0–50 mg/mL but showed a gel state at pH 2.0–3.0. The storage experiments demonstrated that the S/O/W emulsion was stable for 15 days at 4 °C, but was prone to agglomeration and emulsion breakage at 25 °C. The in vivo digestion process indicated that the S/O/W emulsion was gradually digested in the digestive tract and released solid phase nanoparticles in the large intestine. Therefore, this newly developed targeted delivery system can effectively deliver CAPE to the colorectum and achieve a 12-hour delayed release, which improved the bioavailability and activity of CAPE.

The Insecticidal Efficacy and Physiological Action Mechanism of a Novel Agent GC16 against Tetranychus pueraricola (Acari: Tetranychidae).

Simple SummarySpider mite is major pest in agriculture and have developed resistance to commonly used pesticides. Therefore, it is urgent to discover new pesticides to control the pest. In order to provide alternatives for its management, we evaluated the effectiveness of a new agent GC16 against the spider mite Tetranychus pueraricola. Then, we preliminarily revealed the its acaricidal mechanism of action based on the damage of cuticle and organelles of mites. We confirmed that GC16 has a good controlling effect on T. pueraricola and it is not harmful to Picromerus lewisi and Harmonia axyridis. Our research provides not only an alternative pesticide for the management of spider mites, but also guidance for the application of GC16 in sustainable agriculture.Chemical control plays a crucial role in pest management but has to face challenges due to insect resistance. It is important to discover alternatives to traditional pesticides. The spider mite Tetranychus pueraricola (Ehara & Gotoh) (Acari: Tetranychidae) is a major agricultural pest that causes severe damage to many crops. GC16 is a new agent that consists of a mixture of Calcium chloride (CaCl2) and lecithin. To explore the acaricidal effects and mode of action of GC16 against T. pueraricola, bioassays, cryogenic scanning electron microscopy (cryo-SEM) and transmission electron microscopy (TEM) were performed. GC16 had lethal effects on the eggs, larvae, nymphs, and adults of T. pueraricola, caused the mites to dehydrate and inactivate, and inhibited the development of eggs. GC16 displayed contact toxicity rather than stomach toxicity through the synergistic effects of CaCl2 with lecithin. Cryo-SEM analysis revealed that GC16 damaged T. pueraricola by disordering the array of the cuticle layer crest. Mitochondrial abnormalities were detected by TEM in mites treated by GC16. Overall, GC16 had the controlling efficacy on T. pueraricola by cuticle penetration and mitochondria dysfunction and had no effects on Picromerus lewisi and Harmonia axyridis, indicating that GC16 is likely a new eco-friendly acaricide.

The Acaricidal Potential of a New Agent GC16 for Tetranychus pueraricola (Acari: Tetranychidae) Based on Developmental Performance and Physiological Enzyme Activity.

The spider mite, Tetranychus pueraricola (Ehara & Gotoh; Acari: Tetranychidae), is a serious pest in agriculture and horticulture. Application of chemical pesticides is the main mode of this pest control. Due to pesticide residues and resistance-induced resurgence of pests, there is a need to discover alternatives for spider mite management. GC16 comprises a mixture of calcium chloride (CaCl2, 45%) and lecithin (55%), which was recently found to have acaricidal properties. We evaluated the sublethal effects of GC16 on T. pueraricola using life table and enzyme [catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), carboxylesterase (CarE), glutathione S-transferases (GST), and Ca2+-ATPase (Ca2+-ATP)] activity assays. The results showed that fecundity of T. pueraricola increased at LC30 but decreased at LC50 of GC16. The intrinsic rate of increase (r) of T. pueraricola decreased under the LC30 and LC50 of GC16. GC16 concentration and exposure time significantly influenced the activities of CAT, POD, CarE, GST, and Ca2+-ATP in adult mites. Twelve hours later after the treatment, GST and Ca2+-ATP activities were significantly inhibited by LC30 but enhanced by LC50. Moreover, the demographic parameter r and enzyme activities were negatively correlated. In sum, sublethal amounts of GC16 had an adverse effect on mites, and there was a trade-off between developmental performance and physiological enzyme activity of mites under GC16 stress, and GC16 showed an acaricidal potential for T. pueraricola. This work provides guidance for the application of GC16 to control T. pueraricola.

Aplikasi penggunaan Mono Di-Acyl Glycerol (MDAG) untuk meningkatkan stabilitas dan titik leleh dark chocolate [Application of Mono Di-Acyl Glycerol (MDAG) to Improve Stability and Melting Point of Dark Chocolate

Chocolate is one of the processed cocoa products in the form of a water-in-oil (w/o) emulsion. In its production, cocoa powder, sugar, and vanilla are evenly dispersed in cocoa butter by using lecithin as an emulsifier. Lecithin is an effective emulsifier used to w/o emulsions due to its HLB ranging (4-6). So far, by using a single emulsifier (lecithin), it will takes 8-12 hours of conching to produce dark chocolate with good quality and stability. Hence, the addition of MDAG which has an HLB ranging 3-5 as a co-emulsifier, is expected to reduce conching time and increase product stability and melting point. The study was aimed to determine the effect of adding MDAG as a co-emulsifier to increase the stability and melting point of dark chocolate and to determine the optimum concentration of MDAG addition. The study was arranged in a completely randomized design (CRD), the treatments were 6 levels of lecithin/MDAG ratio (%) in the dough, namely P0 (0.60:0), P1 (0.56:0.04), P2 (0.52 :0.08), P3 (0.48:0.12), P4 (0.44:0.16), and P5 (0.40:0.20). Each treatment level was repeated 3 times to obtain 18 experimental units. The parameters tested were melting point and fat-blooming. To see whether there was an effect of adding MDAG as a co-emulsifier, the data obtained were analyzed using ANOVA and followed by DNMRT at a 5% significance level. The results showed that the addition of MDAG as a co-emulsifier could increase the stability and melting point of dark chocolate. The best proportion of emulsifier mixture of lecithin and MDAG is the use of 0.44% lecithin and 0.16% MDAG which produces a melting point of 34oCwith a level of stability during storage at room temperature was quite high (not having fat-bloomduring storage up to 21 days).

Nanoplaform based on ultra-small Au regulating phototoxicity and fluorescence off–on function of Ag2S for multi-modal diagnosis and treatment of tumor

• Hydrophobic ultra-small (3 ∼ 5 nm) nano-Au particle (mAu) is synthesized. • ASAuDP probe greatly reduces the phototoxicity of Ag 2 S. • Ag 2 S in ASAuDP probe achieves off–on FL imaging at tumor site. • mAu has CT, PAI, PTT and SDT capabilities thus reducing the dosage of ASAuDP probe. • The synergistic effect of PTT and SDT presents better tumor killing ability. In this paper, a mixture of lecithin, polyethylene glycol monostearate, and polyethylene glycol phospholipid (DSPE-PEG 2000 ) is used to wrap hydrophobic nano silver sulfide (Ag 2 S) and 3 ∼ 5 nm ultra-small gold nanoparticle (mAu) to form ∼ 150 nm hydrophilic nanocomposite probe Ag 2 S/Au@DSPE-PEG 2000 (ASAuDP) with good stability and dispersion. The probe combines the functions of Ag 2 S and mAu, while mAu can significantly inhibit the fluorescence (FL) of Ag 2 S, thereby reducing the phototoxicity of probe when circulating in the body. When the ASAuDP probe is phagocytosed by tumor cell, Ag 2 S and mAu are separated due to the rupture of probe, thereby restoring the ability of FL imaging and ROS production. MTT test, blood analysis and organ pathology test prove that ASAuDP is a safe probe. In vitro and in vivo imaging experiments prove that the ASAuDP probe presents good FL, CT and photoacoustic imaging capabilities. In vitro and in vivo treatments prove that the ASAuDP probe has both photothermal and sonodynamic therapy abilities, and the synergy between them has the best therapeutic effect. Therefore, ASAuDP probe is a kind of integrated diagnostic and therapeutic probe with good safety, and it has a good application prospect in the treatment of tumor.

Structural transition of reverse cylindrical micelles to reverse vesicles by mixtures of lecithin and inorganic salts

HypothesisThe transformation from reverse micelles to reverse vesicles is influenced by electrostatic interactions between lecithin headgroups and inorganic salts. The electrostatic interactions are expected to influence molecular geometry of lecithin, resulting in a reduction in critical packing parameter (p). Hence, it should be possible to drive structural transitions of reverse self-assembled structures by addition of inorganic salts to lecithin solutions. ExperimentsStructural transitions of reverse micelles and reverse vesicles were formulated including lecithin and inorganic salts as a function of concentration in cyclohexane. A systematic study was performed using inorganic salts with the different valences of the cations such as Li+, Ca2+, and La3+. To probe the nanodomain structures from the lecithin/salt mixtures, small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) were used. FindingsAdding salts to lecithin solutions induced the systematic transformation of reverse self-assembled structures from reverse spherical micelles to reverse cylindrical micelles and finally to reverse vesicles. The transformation was also correlated with interactions between lecithin headgroups and salts, that is, Li+ < Ca2+ < La3+. In addition, a water-soluble dye such as rhodamine B (RB) can be readily encapsulated into reverse micelles and vesicles, indicating that they are potentially useful for controlled solute delivery.

Micellar catalysis beyond the hydrophobic effect: Efficient palladium catalyzed Suzuki-Miyaura coupling of water and organic solvent insoluble pigments with food grade surfactants

Micellar catalysis is having a dramatic impact in improving the sustainability of a wide variety of chemical transformations, including most of the popular palladium mediated carbon–carbon and carbon–nitrogen bond forming reactions. The Suzuki-Miyaura coupling is one of the earliest examples of micellar catalyzed reactions and it is still a very much active research field even at industrial scale. So far, micellar catalysis proved particularly efficient in enabling the high yield, low catalyst loading and mild reaction condition coupling of hydrophobic reagents in a water solution of selected surfactants. In this paper we show that the use of aqueous solutions of a mixture of food grade lecithin and the industrial surfactant Tween 80 not only enables efficient coupling in water of hydrophobic chemicals, but also provides a very resourceful tool for the functionalization of water and organic solvent insoluble pigments of interest for the dye and printed electronic industries.

Effect of temperature on the reverse self-assembly of lecithin and sugar alcohol mixtures in a nonpolar solvent

It has been shown that the addition of sugar alcohols to lecithin solutions induces a transformation from reverse spherical micelles into reverse cylindrical micelles, resulting in the formation of viscoelastic Maxwell fluids. Herein, we systematically investigated the effects of temperature on the rheological parameters, such as the plateau modulus (Gp), relaxation time (tR), and zero-shear viscosity (η0), of lecithin and sugar alcohol mixtures in decane. The rheological properties upon heating of mixtures of lecithin and sugar alcohols with different numbers (3–6) of hydroxyl (–OH) groups and concentrations were studied in detail. Gp, tR, and η0 for all reverse cylindrical micelles decreased with temperature. This decrease can be attributed to a reduction in the lengths of the reverse cylindrical micelles, as evidenced by the small-angle X-ray scattering results at different temperatures. More importantly, the decay rates of Gp, tR, and η0 upon heating decreased more rapidly when the hydrogen bonds between the lecithin and sugar alcohol molecules were weaker as the hydrogen bonds were closely associated with the formation of the reverse self-assembled structure. This indicates that the driving force for the formation of reverse cylindrical micelles can be weakened by increasing the temperature.

Polymer Dispersed Liquid Crystal Film as a Functional and Aesthetic Second Skin Barrier

Polymer films, which reproduce the functional properties of human skin, are emerging as innovative solutions to many skin problems. These films, referred to as second skins, not only serve as a physical barrier to environmental insults but also impart an aesthetic appearance to the skin. Despite being essential components in the cutaneous barrier, lipids have never been included in the second skin films. Here we show that wearable and transparent second skin can be prepared as a polymer dispersed liquid crystal (PDLC) film, where lipid materials are contained as a lamellar liquid crystalline (LC) phase. The lipid materials are mixtures of phytosterol, stearic acid, and lecithin or ceramide, which can be dispersed as lyotropic LC microdroplets in a polymer matrix. The PDLC film can be topically applied as a cosmetic cream (PDLC emulsion), and consequently forms on human skin as a substrate. Structural (X-ray diffraction, XRD), thermal (differential scanning calorimetry, DSC), and surface (atomic force microscopy, AFM) characterizations reveal that our PDLC film has human skin-like features. Notably, the PDLC film can act as an effective barrier against evaporative water loss and carbon pollutants. In a human study (n=10), we have demonstrated that the hydration, adhesion, mechanical, and aesthetic properties of the PDLC film are superior to those of control polymer films. We mainly attribute this in vivo performance to a unique hydration mechanism, whereby the lamellar LC dispersion generates a water concentration gradient and regulates the water content in the PDLC film. Taken together, our beauty film prepared by the PDLC approach is a highly functional cosmetic and potentially serves as a second skin barrier.

Spontaneous Formation of Stable Vesicles and Vesicle Gels in Polar Organic Solvents.

The self-assembly of lipids into nanoscale vesicles (liposomes) is routinely accomplished in water. However, reports of similar vesicles in polar organic solvents like glycerol, formamide, and ethylene glycol (EG) are scarce. Here, we demonstrate the formation of nanoscale vesicles in glycerol, formamide, and EG using the common phospholipid lecithin (derived from soy). The samples we study are simple binary mixtures of lecithin and the solvent, with no additional cosurfactants or salt. Lecithin dissolves readily in the solvents and spontaneously gives rise to viscous fluids at low lipid concentrations (∼2-4%), with structures ∼200 nm detected by dynamic light scattering. At higher concentrations (>10%), lecithin forms clear gels that are strongly birefringent at rest. Dynamic rheology confirms the elastic response of gels, with their elastic modulus being ∼20 Pa at ∼10% lipid. Images from cryo-scanning electron microscopy (cryo-SEM) indicate that concentrated samples are "vesicle gels," where multilamellar vesicles (MLVs, also called "onions"), with diameters between 50 and 600 nm, are close-packed across the sample volume. This structure can explain both the elastic rheology as well as the static birefringence of the samples. The discovery of vesicles and vesicle gels in polar solvents widens the scope of systems that can be created by self-assembly. Interestingly, it is much easier to form vesicles in polar solvents than in water, and the former are stable indefinitely, whereas the latter tend to aggregate or coalesce over time. The stability is attributed to refractive index-matching between lipid bilayers and the solvents, i.e., these vesicles are relatively "invisible" and thus experience only weak attractions. The ability to use lipids (which are "green" or eco-friendly molecules derived from renewable natural sources) to thicken and form gels in polar solvents could also prove useful in a variety of areas, including cosmetics, pharmaceuticals, and lubricants.

Spontaneous Formation of Cationic Vesicles in Aqueous DDAB-Lecithin Mixtures for Efficient Plasmid DNA Complexation and Gene Transfection.

Cationic liposomes have become an attractive tool to deliver genes and interfering RNA into cells. Herein, we report the application of spontaneously formed cationic vesicles in mixtures of lecithin and cationic amphiphiles for efficient transfection of plasmid DNA and siRNA into cells. The average hydrodynamic diameter of the phospholipid vesicles was modulated by changing the ratio of dihexadecyldimethylammonium bromide (DDAB) to phospholipid in the vesicles. The vesicles were characterized by dynamic light scattering, ζ potential, and small-angle X-ray scattering. Depending on the ratio of DDAB to phospholipid, the average size of the vesicles can be varied in the range of 150-300 nm with a ζ potential of +40 mV. The ability of these cationic vesicles to form lipoplexes upon binding with pDNA is demonstrated by ζ potential, isothermal titration calorimetry, gel retardation, and DNase I digestion assay. The enthalpy of binding between pDNA and cationic liposome was found to be -5.7 (±0.8) kJ/mol. The cellular uptake studies of lipoplexes observed by fluorescence microscopy confirmed good transfection efficiency of DDAB liposomes in MCF-7 and HeLa cells. The fluorescent imaging analysis showed effective gene delivery and expression of green fluorescent protein. In addition, the formulation has demonstrated an ability to deliver small interfering RNA (siBRD4) for efficient gene silencing as seen by a significant decrease in BRD4 protein level in siBRD4-treated cells. Comparison of the transfection efficiency of different formulations suggests that DDAB-rich mixed phospholipid vesicles with size <200 nm are better than large size vesicles for improved endocytosis and gene expression.