Recent progress in oil-in-water-in-oil (O/W/O) double emulsions

Study on the foam properties of peanut oil body (POB)-based oil-in-water-in-oil (O/W/O) foamed emulsion gel: The key role played by the interface between the water phase and the outer oil phase

A novel POB-based O/W/O foamed emulsion gel was constructed. The mechanism by which POB strengthens the foamed emulsion gel was preliminarily explored by studying the microstructure and rheological properties, and the applications of POB in decoration and 3D printing were analyzed. The adsorption of POBs and their fragments might strengthen the interface between the water and internal oil phases, thereby increasing the yield stress of the system, which protected the O/W/O structure from being damaged during whipping, and formed a special foam structure where air-in-oil (A/O) structures and O/W/O structure coexist. Besides, adding POB promoted the overrun of the emulsion gel, and the maximum overrun rate was 68.6 %. Finally, POB-based O/W/O foamed emulsion gel exhibited good decoration and 3D printing performance and is expected to become a healthy and higher-quality foamed food in the future.

Engineering surfactant-free pickering double emulsions gels with different structures as low-calorie fat analogues: Tunable oral perception, inhibiting lipid digestion, and potent co-delivery for lycopene and epigallocatechin gallate

Structural design has been as a transformative strategy to create clean-label and well-nourished fat-based foods. Herin, surfactant-free, plant-based oil-in-water-in-oil (O/W/O) and water-in-oil-in-water (W/O/W) emulsions gels (EGs) were designed using protein microgels and fat crystals formed in situ, which achieved dual-interface Pickering stabilization. The suitability and difference of O/W/O and W/O/W EGs as fat analogues in maintaining fat texture, inhibiting lipid digestion, target release and bioactivity of co-loading epigallocatechin gallate (EGCG) and lycopene were examined. O/W/O and W/O/W EGs displayed own unique characteristics, and could be tailored to optimize their performance. O/W/O EGs provided smoother oral perception similar to butter. The multi-structure and interface modulation for double EGs achieved inhibiting lipid digestion, fat phase position mainly controlled the digestive process. Co-delivery systems exhibited synchronous release profiles, allowing a more obvious in-time sustained release of lycopene in O/W/O and EGCG in W/O/W EGs. Both co-delivery O/W/O and W/O/W showed anti-inflammatory bioactivity.

Interfacial mechanisms, environmental influences, and applications of polysaccharide-based emulsions: A review

To develop stable polysaccharide-based emulsions, many studies have focused on the interfacial behavior of adsorbed polysaccharides. This review first discussed the mechanism of polysaccharides self-assembly at the oil-water interface. It can be concluded that polysaccharides can form a thick and strong interfacial membrane that stabilizes emulsions through steric hindrance and electrostatic interactions. In particular, we also investigated the influence of various conditions (i.e., mechanical stress, heating, pH, enzymatic treatment, and ionic strength) on the architecture and properties of polysaccharide-based emulsions. Additionally, the interactions of polysaccharides with other molecules in the emulsion system were summarized, revealing that co-adsorption further changes their properties. Furthermore, current approaches for monitoring the behavior of adsorbed polysaccharides at the oil/water interface were reviewed, highlighting their advantages and limitations. Lastly, we emphasized the potential of polysaccharides for producing environmental-friendly emulsions in the food industry.

Capsaicin: pharmacological applications and prospects for drug designing

OBJECTIVES

A primary objective of this review is to summarize the evidence-based pharmacological applications of capsaicin, particularly its use to manage pain and treat various health conditions. A second goal of the review is to research how recent technological advances are improving the bioavailability and therapeutic index of capsaicin, as well as the development of novel capsaicin-mimetics that are able to enhance therapeutic responses in various human diseases.

METHODS

In the review, numerous human clinical trials and preclinical studies are examined to determine how effective, safe, and optimal dosages of capsaicin can be used in pain management and therapeutic applications. Furthermore, it discusses capsaicin's mechanisms of action, specifically its interactions with the transient receptor potential vanilloid 1 (TRPV1) channel. As a result of this review, the potential of nanotechnology systems for bypassing the limits of capsaicin's pungency is discussed. The review takes into account individual factors such as pain tolerance and skin sensitivity.

KEY FINDINGS

For topical applications, capsaicin is typically used in concentrations ranging from 0.025% to 0.1%, with higher concentrations being used under medical supervision for neuropathic pain. The formulation can come in the form of creams, gels, or patches, which provide sustained release over the course of time. A condition such as arthritis or neuropathy can be relieved with capsaicin as it depletes substance P from nerves. Neuropathy and osteoarthritis as well as musculoskeletal disorders have been treated successfully with this herbal medicine. A major mechanism through which capsaicin relieves pain is through activating TRPV1 channels, which induce calcium influx and neurotransmitter release. Additionally, it affects the transcription of genes related to pain modulation and inflammation, particularly when disease conditions or stress are present. There have been recent developments in technology to reduce capsaicin's pungency and improve its bioavailability, including nanotechnology.

CONCLUSIONS

It is proven that capsaicin is effective in pain management as well as a variety of therapeutic conditions because of its ability to deplete substance P and desensitize nerve endings. Although capsaicin is highly pungent and associated with discomfort, advancements in delivery technologies and the development of capsaicin-mimetics promise improved therapeutic outcomes. There is a great deal of complexity in the pharmacological action of capsaicin due to its interaction with TRPV1 channels and its ability to affect gene transcription. There is a need for further research and development in order to optimize capsaicin's clinical applications and to enhance its therapeutic index in a variety of human diseases.

Multi-Interface Electromagnetic Wave Absorbing Material Based on Liquid Marble Microstructures Anchored to SEBS

The direct application of liquid marbles in electromagnetic wave (EMW) absorption is challenging due to their poor stability, susceptibility to gravitational collapse, and shaping difficulties. To address this issue, a novel strategy is proposed to incorporate liquid marble microstructures (NaCl/nano-SiO2) encapsulated in organic phases (Octadecane) into the rubber-matrix (SEBS) using the ultrasound-assisted emulsion blending method. The resulting NaCl/SiO2/Octadecane microstructures anchored to SEBS offer a substantial solid-liquid interface consisting of NaCl solution and SiO2. When subjected to an alternating electromagnetic (EM) field, the water molecules and polysorbate within SiO2 exhibit heightened responsiveness to the EM field, and the movement of Na+ and Cl- within these microstructures leads to their accumulation at the solid-liquid interface, creating an asymmetric ion distribution. This phenomenon facilitates enhanced interfacial polarization, thereby contributing to the material's EMW absorption properties. Notably, the latex with 16 wt% SEBS (E-3), exhibiting a surface morphology similar to human cell tissues, achieves complete absorption of X-band (fE = 4.20 GHz, RLmin = -33.87 dB). Moreover, the latex demonstrates light density (0.78 g cm-3) and environmental stability. This study not only highlights the predominant loss mechanism in rubber-based wave-absorbing materials but also provides valuable insights into the design of multifunctional wave-absorbing materials.

One-Step Formation of Pickering Double Emulsion Costabilized by Hydrophobic Silica Nanoparticles and Sodium Alginate

Pickering double emulsions exhibit higher stability and biocompatibility compared with surfactant-stabilized double emulsions. However, tailored synthesis of particle stabilizers with appropriate wettability is time consuming and complicated and usually limits their large-scale adoption. Using binary stabilizers may be a simple and scalable strategy for Pickering double emulsion formation. Herein, commercially available hydrophobic silica nanoparticles (SNPs) and sodium alginate (SA) as binary stabilizers are used to prepare O/W/O Pickering double emulsions in one-step emulsification. The influence of system composition on double emulsion preparation is identified by optical microscopy, confocal laser scanning microscopy, and interfacial tension and water contact angle analyses. The formation of the O/W/O Pickering double emulsion depends critically on the aqueous phase viscosity and occurrence of emulsion inversion. Both hydrophobic SNPs and SA adsorb at the droplet surface to provide a steric barrier, while SA also reduces interfacial tension and increases aqueous phase viscosity, giving double emulsion long-term stability. Their microstructure and stability are controlled by adjusting the SA concentration, water-oil volume ratio, concentration and wettability of the particle stabilizer, and oil type. As a demonstration, the middle layer of the as-prepared O/W/O Pickering double emulsions can be cross-linked in situ with calcium ions to produce calcium alginate porous microspheres. We believe that our strategy for double emulsion formation holds great potential for practical applications in food, cosmetics, or pharmaceuticals.

O1/W/O2 double emulsion gels based on nanoemulsions and Pickering particles for co-encapsulating quercetin and cyanidin: A functional fat substitute

An O1/W/O2 double emulsion gel, as a functional fat substitute and based on nanoemulsions and hydrophobic Pickering particles, is prepared by two-step emulsification to co-encapsulate hydrophilic cyanidin and hydrophobic quercetin. Nanoemulsions loading quercetin are fabricated by Tween-80 and combining high-speed and high-pressure emulsification. Phytosterol nanoparticles stabilize the W-O2 interface of the secondary emulsion to load cyanidin in the W phase. The concentration of Tween-80 is optimized as 0.3% by the droplet size and viscosity of nanoemulsions. The structural stability of double emulsion gels will be weakened along with the increase of nanoemulsions, showing lower modulus and encapsulation efficiency (EE) and bigger droplets. In double emulsion gels, the EE of quercetin and cyanidin reaches 93% and 85.6%, respectively. Analysis of molecular interaction indicates that Tween-80 would decrease the in-situ hydrophobicity of phytosterol nanoparticles by hydrogen bonding adsorption, thereby weakening the emulsification. The pH-chromic 3D printing of double emulsion gels is designed according to the pH sensitivity of cyanidin. Texture profile analysis is performed to test the textural properties of 3D-printed objects. The simulated digestion is conducted on double emulsion gels. The double emulsion gel with fewer nanoemulsions is beneficial for protecting quercetin and improving the delivery due to the higher structural stability, while that with more nanoemulsions is conducive to the digestion of cyanidin and camellia oil due to weakened semi-solid properties. This double emulsion gel further simulates fat tissues by co-encapsulating hydrophilic and hydrophobic substances, promoting the application of fat substitutes in the food industry.

Biomimetic biphasic microsphere preparation based on the thermodynamic incompatibility of glycosaminoglycan with gelatin methacrylate for hair regeneration

Hair follicle (HF) tissue engineering is promising for hair loss treatment especially for androgenetic alopecia. Physiologically, the initiation of HF morphogenesis relies on the interactions between hair germ mesenchymal and epithelial layers. To simulate this intricate process, in this study, a co-flowing microfluidic-assisted technology was developed to produce dual aqueous microdroplets capturing growth factors and double-layer cells for subsequent use in hair regeneration. Microspheres, called G/HAD, were generated using glycosaminoglycan-based photo-crosslinkable biological macromolecule (HAD) shells and gelatin methacrylate (GelMA) cores to enclose mesenchymal cells (MSCs) and mouse epidermal cells (EPCs). The findings indicated that the glycosaminoglycan-based HAD shells display thermodynamic incompatibility with GelMA cores, resulting in the aqueous phase separation of G/HAD cell spheres. These G/HAD microspheres exhibited favorable characteristics, including sustained growth factor release and wet adhesion properties. After transplantation into the dorsal skin of BALB/c nude mice, G/HAD cell microspheres efficiently induced the regeneration of HFs. This approach enables the mass production of approximately 250 dual-layer microspheres per minute. Thus, this dual-layer microsphere fabrication method holds great potential in improving current hair regeneration techniques and can also be combined with other tissue engineering techniques for various regenerative purposes.

An Updated Comprehensive Overview of Different Food Applications of W1/O/W2 and O1/W/O2 Double Emulsions

Double emulsions (DEs) present promising applications as alternatives to conventional emulsions in the pharmaceutical, cosmetic, and food industries. However, most review articles have focused on the formulation, preparation approaches, physical stability, and release profile of encapsulants based on DEs, particularly water-in-oil-in-water (W1/O/W2), with less attention paid to specific food applications. Therefore, this review offers updated detailed research advances in potential food applications of both W1/O/W2 and oil-in-water-in-oil (O1/W/O2) DEs over the past decade. To this end, various food-relevant applications of DEs in the fortification; preservation (antioxidant and antimicrobial targets); encapsulation of enzymes; delivery and protection of probiotics; color stability; the masking of unpleasant tastes and odors; the development of healthy foods with low levels of fat, sugar, and salt; and design of novel edible packaging are discussed and their functional properties and release characteristics during storage and digestion are highlighted.

Membrane Emulsification as an Emerging Method for Lacticaseibacillus rhamnosus GG® Encapsulation

Techniques capable of producing small-sized probiotic microcapsules with high encapsulation yields are of industrial and scientific interest. In this study, an innovative membrane emulsification system was investigated in the production of microcapsules containing Lacticaseibacillus rhamnosus GG® (Lr), sodium alginate (ALG), and whey protein (WPI), rice protein (RPC), or pea protein (PPC) as encapsulating agents. The microcapsules were characterized by particle size distribution, optical microscopy, encapsulation yield, morphology, water activity, hygroscopicity, thermal properties, Fourier-transform infrared spectroscopy (FTIR), and probiotic survival during in vitro simulation of gastrointestinal conditions. The innovative encapsulation technique resulted in microcapsules with diameters varying between 18 and 29 μm, and encapsulation yields > 93%. Combining alginate and whey, rice, or pea protein improved encapsulation efficiency and thermal properties. The encapsulation provided resistance to gastrointestinal fluids, resulting in high probiotic viability at the end of the intestinal phase (> 7.18 log CFU g-1). The proposed encapsulation technology represents an attractive alternative to developing probiotic microcapsules for future food applications.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11947-023-03099-w.

The Influences of Emulsification Variables on Emulsion Characteristics Prepared through the Phase Inversion Temperature Method as Engine Fuel

The effects of emulsification variables, such as surfactant type and heating/cooling emulsion processes, on the emulsification characteristics of silicone oil’s emulsions prepared by the phase inversion temperature method were investigated in this study. The water-in-oil (W/O) emulsions have been widely applied to enhance burning efficiency and reduce both pollutant emissions and fuel consumption. The silicone oil was emulsified with de-ionized water with the assistance of nonionic surfactants to form oil-in-water (O/W) emulsions. The hydrophilic–lipophilic balance (HLB) value of the Span 80 and Tween 20 surfactant mixture was set equal to 10 based on their weight proportions and the respective HLB values of the two surfactants. The experimental results show that the emulsions with the Span 80/Tween 20 surfactant mixture appeared to have a higher phase inversion temperature and a larger electrical conductance. On the other hand, it has a lower emulsification stability and a narrower range of phase inversion temperature than the emulsions prepared with a Brij 30 surfactant (polyoxyethylene (4) lauryl ether). The increase in surfactant concentration from 1 wt.% to 10 wt.% decreased the electrical conductance and phase inversion temperature while increasing the suspensibility and absorbance value for the emulsions prepared with either Span 80/Tween 20 mixture or Brij 30.

One-step generation of core-shell biomimetic microspheres encapsulating double-layer cells using microfluidics for hair regeneration

Tissue engineering of hair follicles (HFs) has enormous potential in the treatment of hair loss. HF morphogenesis is triggered by reciprocal interactions between HF germ epithelial and mesenchymal layers. Here, a microfluidic-assisted technology is developed for the preparation of double aqueous microdroplets that entrap double-layer cells and growth factors to ultimately be used for hair regeneration. Mouse mesenchymal cells (MSCs) and epidermal cells (EPCs) are encapsulated in gelatin methacrylate (GelMA) cores and photo-curable catechol-grafted hyaluronic acid (HAD) shells to fabricate GelMA-MSC/HAD-EPC (G/HAD) microspheres. The findings show that the G/HAD microspheres exhibit ultrafast gelation, aqueous phase separation, superior biocompatibility, and favorable wet adhesion properties. G/HAD microspheres can also support cell proliferation and sustain growth factor release. These composite cell microspheres are capable of efficient HF generation upon transplantation into the dorsal dermis of nude mice. This finding facilitates the large-scale preparation of approximately 80 double-layer cell spheres per min. This simple double-layer cell sphere preparation approach is a promising strategy for improving current hair-regenerative medicine techniques and can potentially be applied along with other organoid techniques for extended applications.

Mannose-based surfactant as biofunctional nanoemulsion stabilizer

The development and implementation of new amphiphiles based on natural resources rather than petrochemical precursors is an essential requirement due to their feedstock depletion and adverse environmental impacts. In addition, the use of bio-based surfactants can provide unique characteristics and improve the properties and versatility of the colloidal systems in which they are applied, such as emulsions. Here, the emulsification properties of a synthesized biocompatible mannose-based surfactant were investigated. Its behavior was evaluated in the presence of four different natural oils (castor, sunflower, olive and soybean) as well as two different aqueous phases (pure water and phosphate-buffered saline). The results highlighted its interest as surfactant in O/W nanoemulsions for all tested oil and aqueous phases, using a low-energy preparation protocol and relatively low surfactant concentrations. Furthermore, the mannose groups present on the polar head of the surfactant and adsorbed on the surface of the emulsion droplets were shown to retain their native biological properties. The specific mannose-concanavalin A binding was observed in vitro by the designed nanoemulsions, revealing the biorecognition properties of the surfactant and its potential applicability as a nanocarrier.

Moisturizer in Patients with Inflammatory Skin Diseases

As interest in skin increases, the cosmetic market is also growing. It is difficult to choose between the numerous types of basic cosmetics on the market. This article aims to provide advice and guidance on which products to recommend according to a patient’s skin condition. Appropriate application of a moisturizer attempts not only to improve the dryness, but also improve the skin’s natural barrier function to protect the skin from internal and external irritants to keep the skin healthy. Moisturizers consist of various ingredients, including occlusive agents, emollients, humectants, lipid mixture, emulsifiers, and preservatives. Pathophysiology of dry skin is also discussed to provide readers with the background they need to choose the right moisturizer for themselves. As moisturizers play an important role as adjuvant in the treatment of common skin diseases, such as atopic dermatitis, contact dermatitis, psoriasis, acne and rosacea, which type of moisturizer is appropriate for each disease was also dealt with. Basic cosmetics, especially moisturizers, should be recommended in consideration of the ingredients, effectiveness and safety of each product, and the skin condition of each patient.

Contribution of Nanoscience Research in Antioxidants Delivery Used in Nutricosmetic Sector

Nanoscience applications in the food and cosmetic industry offer many potential benefits for consumers and society. Nanotechnologies permit the manipulation of matter at the nanoscale level, resulting in new properties and characteristics useful in food and cosmetic production, processing, packaging, and storage. Nanotechnology protects sensitive bioactive compounds, improves their bioavailability and water solubility, guarantees their release at a site of action, avoids contact with other constituents, and masks unpleasant taste. Biopolymeric nanoparticles, nanofibers, nanoemulsions, nanocapsules, and colloids are delivery systems used to produce food supplements and cosmetics. There are no barriers to nanoscience applications in food supplements and cosmetic industries, although the toxicity of nano-sized delivery systems is not clear. The physicochemical and toxicological characterization of nanoscale delivery systems used by the nutricosmeceutic industry is reviewed in this work.