Nanoparticle Stabilized Pickering Emulsion Research Articles

Rice husk derived lignin/silica hybrid nanoparticles stabilized pickering emulsion for phytosterol ester biosynthesis

This study investigates the production of lignin/silica hybrid nanoparticles (LSNPs) from rice husks, an abundant agricultural waste, and their capacity to stabilize Pickering emulsions for biocatalysis. Lignin extracted from rice husks under alkaline conditions was co-precipitated with silica to produce LSNPs in the presence or absence of ethanol as a co-solvent. Characterization of LSNPs revealed that ethanol played a key role in forming uniform, spherical nanoparticles and minimizing aggregation. Lignin imparted amphiphilicity to the LSNPs, which significantly improved their capacity to form stable Pickering emulsions. LSNPs were able to form stable oil-in-water Pickering emulsions while droplet size and emulsion stability were influenced by LSNPs concentration, oil/water ratio, temperature and pH. LSNPs-stabilized Pickering emulsions were evaluated for lipase-mediated biosynthesis of phytosterol esters, which are plant bioactive compounds that can reduce dietary cholesterol uptake. LSNPs-stabilized emulsions provided 1.915 × 106 times larger interfacial areas compared to conventional biphasic systems which facilitated improved mass transfer and lipase activity. Under optimal conditions, LSNPs-stabilized Pickering emulsion systems delivered 90.6 % phytosterol ester conversion in 4 h, compared to 10 h in biphasic systems. This research highlights the potential of sustainable, biomass-derived nanoparticles in Pickering emulsion applications and offers an environmentally friendly approach to produce bioactive compounds.

Enhancing Vaccine Efficacy with Polyethylenimine-Modified Lovastatin-Loaded Nanoparticle Pickering Emulsion Adjuvant.

Despite the potent immunoadjuvant properties of mevalonate pathway inhibitors, their application is constrained by poor solubility and instability. In this study, we developed a cationic nanoparticle-stabilized Pickering emulsion loaded with lovastatin (Lov-PPE), using polyethylenimine (PEI)-modified PLGA nanoparticles and squalene as carriers. The system was prepared and tested by evaluating the physicochemical properties and adjuvant efficacy of the Lov-PPE. Lov-PPE/O demonstrated good particle size distribution and zeta potential, with an adsorption efficiency of up to 73.07%. The immunization results showed that Lov-PPE/O significantly promoted the production of OVA-specific IgG antibodies, activated CD4+ and CD8+ T cells, and induced a strong mixed Th1/2 immune response. Additionally, safety assessments indicated that Lov-PPE/O has good in vivo safety. This study demonstrates that the PEI-modified lovastatin PLGA nanoparticle Pickering emulsion (Lov-PPE) is an effective vaccine adjuvant capable of significantly enhancing humoral and cellular immune responses while possessing good safety, offering a new strategy for vaccine formulation development.

Hierarchical bio-inspired design and fabrication of all-dimensional superhydrophobic ultra-lightweight high-volume fly ash cement foams using novel ultrasonic-assisted siloxane-encapsulated pickering emulsions

Ultra-lightweight foamed cement (ULFC) exhibits super-high porosity and excellent thermal-insulation capabilities. However, the thermodynamic instability and high water-absorptivity of ULFC with high-volume fly ash have restricted its large-scale application. Superhydrophobic technology can significantly improve the substrates’ hydrophobicity, among which the nanocoating is a popular option but the water-repellent layer may be easily destroyed due to the mechanical damage. Therefore, the intrinsic superhydrophobization becomes a promising alternative to the coating scheme. Here, the internal superhydrophobic ULFC was formulated through introducing the ultrasonic-assisted siloxane-encapsulated Pickering emulsions, in which two Pickering structures containing n-dodecyltrimethoxysilane were stabilized by hydrophobic SiO2 and C–S–H nanoparticles, respectively. Compared with the SiO2 nanoparticles-stabilized dispersion, the droplets of C–S–H nanoparticles-stabilized Pickering emulsion were more stable and controlled-release in cement hydration environment. As such, the incorporation of the latter showed no negative impact on the setting times and static yield stress of the interstitial matrix, optimizing the homogeneity, mechanical strength and heat conductivity of ULFC. The combination of nanoscale foam stabilizer and Pickering emulsions could form the hierarchical waterproof structure with low surface free energy at the gas-solid interfaces, and the multiscale siloxane-grafted intertwined hydration products were responsible for the inner superhydrophobicity of ULFC. Therefore, under the water vapor-saturated environment, the water absorption of superhydrophobic samples showed only a slight increase as a function of time and the ULFC was still hydrophobic with a reduction of apparent water contact angle from 154.6° to 137.8°. From energy consumption analysis, the all-dimensional superhydrophobic ULFC had a potential application in heat-insulation building.

Enzymatically green-produced bacterial cellulose nanoparticle-stabilized Pickering emulsion for enhancing anthocyanin colorimetric performance of versatile films

To enhance the colorimetric performance of anthocyanin (Ant), a konjac glucomannan (KGM)-based multifunctional pH-responsive indicator film was fabricated by introducing enzymatically prepared bacterial nanocellulose (EBNC) stabilized camellia oil/camellia essential oil Pickering emulsion (BCCE). Specifically, optimized enzymatic hydrolysis time (36 h) was determined based on the particle size and microstructure. Then BCCE (containing 0.4% EBNC) was incorporated into Ant-containing KGM, and the novel active indicator film (KGM-Ant-BCCE) was constructed. Films with varying BCCE concentrations (3%–11%) exhibited enhanced UV shielding, thermal stability, mechanical strength, water vapor and oxygen permeability, hydrophobicity, and antioxidant performance. The pronounced color change of KGM-Ant-BCCE indicated its potential for visually detecting shrimp freshness. Moreover, the biodegradability (25 days) confirmed the environmentally benign property of the film. In summary, incorporating green-produced EBNC nanoparticle-stabilized BCCE offers an innovative pathway to improve the color indication capability of polysaccharide-based smart packaging.

Konjac glucomannan-based highly antibacterial active films loaded with thyme essential oil through bacterial cellulose nanofibers/Ag nanoparticles stabilized Pickering emulsions

The aim of this study was to develop novel konjac glucomannan (KGM)-based highly antibacterial active films, where five types of films were prepared and compared. The microstructure results showed that KGM-based films loaded with thyme essential oil (TEO) through bacterial cellulose nanofibers/Ag nanoparticles (BCNs/Ag nanoparticles) stabilized Pickering emulsions (Type V films) displayed the smoothest surface and the most evenly dispersed TEO droplets as compared with the other four types of films. Moreover, Type V films showed the highest contact angle value (86.28°), the best thermal stability and mechanical properties. Furthermore, Type V films presented the highest total phenol content (13.23 mg gallic acid equivalent/g film) and the best antioxidant activity (33.96 %) as well as the best sustained-release property, thus showing the best antibacterial activity, which was probably due to that BCNs/Ag nanoparticles and TEO displayed a synergistic effect to some extent. Consequently, Type V film-forming solutions were used as coatings for tangerines. The results showed that the tangerines treated with Type V coatings displayed excellent fresh-keeping properties. Therefore, the coatings, KGM-based film-forming solutions loaded with TEO through BCNs/Ag nanoparticles stabilized Pickering emulsions, have great potential for the preservation of fruits and vegetables.

The soybean lecithin-cyclodextrin-vitamin E complex nanoparticles stabilized Pickering emulsions for the delivery of β-carotene: Physicochemical properties and in vitro digestion

In this work, soybean lecithin (LC) was used to modify β-cyclodextrin (β-CD) with hydrophobic fat chains to become amphiphilic (LC-CD), and vitamin E (VE) was encapsulated in former modified β-CD complexes (LC-CD-VE), the new Pickering emulsions stabilized by LC-CD-VE and LC-CD complexes for the delivery of β-carotene (BC) were created. The surface tension, contact angle, zeta potential, and particle size were used to assess the changes in complexes nanoparticles at various pH values. Furthermore, LC-CD-VE has more promise as Pickering emulsion stabilizer than LC-CD because of the smaller particle size (271.11 nm), proper contact angle (58.02°), and lower surface tension (42.49 mN/m). The interactions between β-cyclodextrin, soybean lecithin, and vitamin E were confirmed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and thermogravimetric analysis (TGA). The durability of Pickering emulsions was examined at various volume fractions of the oil phase and concentrations of nanoparticles. Compared to the emulsion stabilized by LC-CD, the one stabilized by LC-CD-VE showed superior storage stability. Moreover, for the delivery of BC, Pickering emulsions stabilized by LC-CD and LC-CD-VE can outperform bulk oil and Tween 80 stabilized emulsions in terms of UV light stability, storage stability, and bioaccessibility. This work could offer fresh perspectives on stabilizer alternatives for Pickering emulsion delivery systems.

Deformation and rupture of Janus nanoparticle-stabilized Pickering emulsion in confined channel

The interaction between Pickering emulsions and confined channels is vital for their industrial applications. However, how solid particle shells modulate the deformation stability and rupture limit of Pickering emulsions in contact with wall remains poorly understood. In this work, mechanical deformation and rupture of Janus nanoparticles (JNP)-stabilized Pickering emulsions on solid surfaces are elaborated by molecular dynamics (MD) simulations. A universal master-type predictive model is developed for the first time to describe the contact behavior of Pickering emulsions against surfaces with distinct wettability. The contact stress of an emulsion is determined by the equivalent elastic modulus of the emulsion, geometric deformation function, and the influence of the JNP shell and its interactions. Moreover, hydrophobic surfaces lead to the rupture of Pickering emulsions in compression. The rupture can be delayed by increasing JNP surface coverage (ϕ). Especially, once ϕ reaches a critical value, the JNP shell can form an ordered quasi-solid structure, significantly enhancing the emulsion stability. These results can aid in the design or screening of specific Pickering emulsions to manage their deformation and rupture on the solid surface, in applications ranging from water treatment and drug delivery to environmental remediation and mobility control in oil recovery.

Cinnabaris modified with SiO2 nanoparticles stabilized Pickering emulsion to improve the photostability of volatile oil: A Lingzhu San case study

The pharmacological activity of volatile oils (VOs) is significant, but they can generate peroxides under light conditions, reducing the VO content and affecting their stability. This study aims to introduce Pickering emulsion technology to enhance the antioxidant activity of VOs and improve the photostability and efficacy of solid formulations. In this work, Cinnabaris was used as a stabilizer in the formulation of Lingzhu San to prepare Pickering emulsions using high-speed shearing. By controlling the duration of light exposure, the retention rate, degree of oxidation, and changes in volatile components of the volatile oil of Acorus tatarinowii Schott (AT-VO) were compared between the crude oil group and the Pickering emulsion group. Compared with the crude oil group, the Pickering emulsion group significantly improved the retention rate, reduced the degree of oxidation, and mitigated the changes in volatile components. GC–MS analysis of the quantitative and qualitative changes showed that the volatile components of the oil retained by the Pickering emulsion were closer to the untreated AT-VO in the light environment. In addition, the Pickering emulsion with water as the outer phase and oil as the inner phase retarded the formation of peroxides in the VOs and achieved the goal of maintaining the photostability of the VOs.

Interfacial properties and structure of Pickering emulsions co-stabilized by different charge emulsifiers and zein nanoparticles

The stability of Pickering emulsions can be improved by the synergistic action of colloidal particles and small molecule emulsifiers. In addition, the interaction between particles and different charge emulsifiers at the interface may result in different interfacial film structures, thus affecting the stability of Pickering emulsions. However, little is currently known about the impact of emulsifier charge on the fabrication and characteristics of these co-stabilized Pickering emulsions. Herein, we investigated the influence of Pickering emulsions co-stabilized by zein nanoparticles and anionic (quillaja saponin, QS), non-ionic (Tween 80), or cationic (lauroyl arginate ethyl hydrochloride) emulsifiers on the interfacial properties. The adsorption kinetics and rheological behavior of the molecular emulsifiers at oil/water interfaces were studied. Changes in interfacial structure and adsorption behavior were studied by confocal laser scanning microscopy (CLSM), and quartz crystal microbalance-dissipation (QCM-D) analysis. The dynamic interface characteristics showed that QS has good emulsification performance. The CLSM images indicated that the emulsifier charge impacted the interfacial structure of the Pickering emulsions. The combination of QS and zein nanoparticles formed a coating at the oil/water interface that was denser than for the other two emulsifiers, which improved the stability of the Pickering emulsions. QCM-D revealed that the interfacial film formed by anionic emulsifiers and zein nanoparticles was the thickest (about 6.6 nm). Moreover, anionic emulsifiers and zein nanoparticles stabilized Pickering emulsions provided the best protection against curcumin. These results may be important for optimizing the performance of Pickering emulsions in the food and pharmaceutical industries.

Temperature-sensitive and amphiphilic silica nanoparticle-stabilized Pickering emulsion for water shutoff

Due to the shale matrix's low permeability and narrow pore throats, conventional Pickering emulsion plugging agents are unable to effectively seal the formation, making it challenging to create a reliable mud cake that prevents fluid penetration. To address this issue, SiO2 nanoparticles (PEG200-SiO2-OTES) with amphiphilic and temperature-sensitive properties were synthesized for this study. These modified particles were used to prepare temperature-sensitive Pickering emulsions. The aim was to use the emulsion as a carrier to transport the nanoparticles to the specified stratum to release and seal the pore throat. This temperature-sensitive smart Pickering emulsion-based plugging agent (POOP) is used to water shutoff. The produced material had a particle size of around 20 nm, according to structural studies, and had a sensitive temperature response (response temperature of 80 °C). Furthermore, laboratory tests and characterizations revealed that the average diameter of the POOP emulsion droplets was measured to be 1.62 µm, with the emulsion exhibiting a response temperature for breakage at approximately 80 °C.The plugging agent could release PEG200-SiO2-OTES particles at the response temperature of the formation. At this temperature, the plugging agent particles undergo a transition from hydrophilic to hydrophobic, effectively sealing the low permeability (100 mD) and high permeability (1000 mD) formations with sealing efficiencies of up to 83.56% and 75.07% respectively.

Fabrication and characterization of food-grade pea protein-ascorbic acid nanoparticles-stabilized Pickering emulsion

In this study, modified pea proteins (PP) were prepared by heat treatment, ultrasound, adjusting the pH to 9, and the addition of ascorbic acid (AA) to stabilize the Pickering emulsion (PE) with a 50% volume fraction of corn oil. The solubility of PP after different treatments was higher in all treatments than in the native state. FTIR and SDS-PAGE results confirmed that a covalent bond (Maillard reaction) was formed between PP and AA, which occurred more strongly in the heat-treated suspensions. The nanoparticles produced from ultrasonication of PP and the PP/AA complexes were able to stabilize the emulsion with a high volume fraction of oil as novel Pickering emulsifiers. In ultrasonicated PP and PP/AA complexes, the reduction of interfacial tension and particle size and increase of contact angle caused a significant improvement in the physical stability of the PE, which can be the result of regular placement of protein particles at the water-oil interface. The treatment corresponds to highly stable PE, heat-treated PP in the presence of AA in alkaline conditions (HPP.AA.pH), increased the contact angle of PP from ∼ 42 to 77, and decreased interfacial tension from ∼ 25 to 14. These PEs showed high physical and oxidative stability. According to CLSM images, the type of PE was oil in water, and PP particles surrounded the oil droplets. The results of this research could be effective in developing PP-based low-fat formulations with improved oxidative stability by utilizing different treatments, including ultrasonic treatment and/or complex formation between PP and AA.

Acetalized starch-based nanoparticles stabilized acid-sensitive Pickering emulsion as a potential antitumor drug carrier

Pickering emulsions are attracting increased attention owing to their therapeutic applications. However, the slow-release property of Pickering emulsions and the in vivo solid particle accumulation caused by the solid particle stabilizer film limit their applications in therapeutic delivery. In this study, drug-loaded, acid-sensitive Pickering emulsions were prepared using acetal-modified starch-based nanoparticles as stabilizers. The acetalized starch-based nanoparticles (Ace-SNPs) not only act as a solid-particle emulsifier to stabilize Pickering emulsions but also exhibit acid sensitivity and degradability, conducive to the destabilization of Pickering emulsions to release the drug and reduce the effect of particle accumulation in an acidic therapeutic environment. In vitro drug release profiles show that 50 % of curcumin was released in 12 h in an acidic medium (pH 5.4), whereas only 14 % of curcumin was released in 12 h at higher pH (7.4), indicating that the Ace-SNP stabilized Pickering emulsion possess good acid-responsive release characteristics in acidic environments. Moreover, acetalized starch-based nanoparticles and their degradation products showed good biocompatibility, and the resulting curcumin-loaded Pickering emulsions exhibited significant anticancer activity. These features suggest that the acetalized starch-based nanoparticle-stabilized Pickering emulsion has the potential for application as an antitumor drug carrier to enhance therapeutic effects.

Optimized hydrophobic magnetic nanoparticles stabilized pickering emulsion for enhanced oil recovery in complex porous media of reservoir

With an extensive application of flooding technologies in oil recovery, traditional emulsion flooding has seen many limits due to its poor stability and easy demulsification. Pursuing a new robust emulsion plays a fundamental role in developing highly effective emulsion flooding technology. In this work, a novel Pickering emulsion with special magnetic nanoparticles Fe3O4@PDA@Si was designed and prepared. To disclose the flooding mechanism from magnetic nanoparticles, the physico-chemical characterization of Fe3O4@PDA@Si was systematically examined. Meanwhile, the flooding property of the constructed Pickering emulsion was evaluated on the basis of certain downhole conditions. The results showed that the synthesis of Fe3O4@PDA@Si nanoparticles was found to have a hydrophobic core-shell structure with a diameter of 30 nm. Pickering emulsions based on Fe3O4@PDA@Si nanoparticles at an oil-to-water ratio of 5:5, 50°C, the water separation rate was only 6% and the droplet diameter of the emulsion was approximately 15 μm in the ultra-depth-of-field microscope image. This demonstrates the excellent stability of Pickering emulsions and improves the problem of easy demulsification. We further discussed the oil displacement mechanism and enhanced oil recovery effect of this type of emulsion. The microscopic flooding experiment demonstrated that profile control of the Pickering emulsion played a more important role in enhanced recovery than emulsification denudation, with the emulsion system increasing oil recovery by 10.18% in the micro model. Core flooding experiments have established that the incremental oil recovery of the Pickering emulsion increases with decreasing core permeability, from 12.36% to 17.39% as permeability drops from 834.86 to 219.34 × 10−3 μm2. This new Pickering emulsion flooding system stabilized by Fe3O4@PDA@Si nanoparticles offers an option for enhanced oil recovery (EOR).

Acid-Responsive Immune-Enhancing Chitosan Formulation Capable of Transforming from Particle Stabilization to Polymer Chain Stabilization.

Chitosan with pH sensitivity and biocompatibility was selected to prepare chitosan nanoparticle-stabilized Pickering emulsion (CSPE). The flexibility of CSPE enables stress deformation when in contact with cell membranes, thereby mimicking the deformability of natural pathogens and facilitating their efficient uptake by cells. In the acidic environment of lysosomes, the amino groups of chitosan molecules are protonated, and the water solubility increases. CSPE transforms from particle-stabilized to polymer chain-stabilized, its subsequent swelling and proton accumulation lead to lysosome rupture. The experimental results evaluating CSPE as an adjuvant shows that CSPE could efficiently load antigens, promote endocytosis and antigen cross-presentation, recruit antigen-presenting cells at the injection site, boost T-cell activation, and enhance both humoral and cellular immune responses. In the prophylactic and therapeutic tumor models of E.G7-OVA lymphoma and B16-MUC1 melanoma, CSPE significantly inhibited tumor growth and prolonged the survival of mice. In summary, antigenic lysosomal escape resulted from the chitosan molecular state transition is the key to the enhancement of cellular immunity by CSPE, and CSPE is a promising vaccine adjuvant.

Cationic Nanoparticle-Stabilized Vaccine Delivery System for the H9N2 Vaccine to Promote Immune Response in Chickens.

Chinese yam polysaccharides (CYPs) have received wide attention for their immunomodulatory activity. Our previous studies had discovered that the Chinese yam polysaccharide PLGA-stabilized Pickering emulsion (CYP-PPAS) can serve as an efficient adjuvant to trigger powerful humoral and cellular immunity. Recently, positively charged nano-adjuvants are easily taken up by antigen-presenting cells, potentially resulting in lysosomal escape, the promotion of antigen cross-presentation, and the induction of CD8 T-cell response. However, reports on the practical application of cationic Pickering emulsions as adjuvants are very limited. Considering the economic damage and public-health risks caused by the H9N2 influenza virus, it is urgent to develop an effective adjuvant for boosting humoral and cellular immunity against influenza virus infection. Here, we applied polyethyleneimine-modified Chinese yam polysaccharide PLGA nanoparticles as particle stabilizers and squalene as the oil core to fabricate a positively charged nanoparticle-stabilized Pickering emulsion adjuvant system (PEI-CYP-PPAS). The cationic Pickering emulsion of PEI-CYP-PPAS was utilized as an adjuvant for the H9N2 Avian influenza vaccine, and the adjuvant activity was compared with the Pickering emulsion of CYP-PPAS and the commercial adjuvant (aluminum adjuvant). The PEI-CYP-PPAS, with a size of about 1164.66 nm and a ζ potential of 33.23 mV, could increase the H9N2 antigen loading efficiency by 83.99%. After vaccination with Pickering emulsions based on H9N2 vaccines, PEI-CYP-PPAS generated higher HI titers and stronger IgG antibodies than CYP-PPAS and Alum and increased the immune organ index of the spleen and bursa of Fabricius without immune organ injury. Moreover, treatment with PEI-CYP-PPAS/H9N2 induced CD4+ and CD8+ T-cell activation, a high lymphocyte proliferation index, and increased cytokine expression of IL-4, IL-6, and IFN-γ. Thus, compared with the CYP-PPAS and aluminum adjuvant, the cationic nanoparticle-stabilized vaccine delivery system of PEI-CYP-PPAS was an effective adjuvant for H9N2 vaccination to elicit powerful humoral and cellular immune responses.

Cellular Affinity of Particle-Stabilized Emulsion to Boost Antigen Internalization.

The cellular affinity of micro-/nanoparticles is the precondition for cellular recognition, cellular uptake, and activation, which are essential for drug delivery and immune response. The present study stemmed from the observation that the effects of charge, size, and shape of solid particles on cell affinity are usually considered, but we seldom realize the essential role of softness, dynamic restructuring phenomenon, and complex interface interaction in cellular affinity. Here, we developed poly-lactic-co-glycolic acid (PLGA) nanoparticle-stabilized Pickering emulsion (PNPE) that overcame the shortcomings of rigid forms and simulated the flexibility and fluidity of pathogens. A method was set up to test the affinity of PNPE to cell surfaces and elaborate on the subsequent internalization by immune cells. The affinity of PNPE to bio-mimetic extracellular vesicles (bEVs)-the replacement for bone marrow dendritic cells (BMDCs)-was determined using a quartz crystal microbalance with dissipation monitoring (QCM-D), which allowed real-time monitoring of cell-emulsion adhesion. Subsequently, the PNPE was used to deliver the antigen (ovalbumin, OVA) and the uptake of the antigens by BMDCs was observed using confocal laser scanning microscope (CLSM). Representative results showed that the PNPE immediately decreased frequency (ΔF) when it encountered the bEVs, indicating rapid adhesion and high affinity of the PNPE to the BMDCs. PNPE showed significantly stronger binding to the cell membrane than PLGA microparticles (PMPs) and AddaVax adjuvant (denoted as surfactant-stabilized nano-emulsion [SSE]). Furthermore, owing to the enhanced cellular affinity to the immunocytes through dynamic curvature changes and lateral diffusions, antigen uptake was subsequently boosted compared with PMPs and SSE. This protocol provides insights for designing novel formulations with high cell affinity and efficient antigen internalization, providing a platform for the development of efficient vaccines.

The synthesis of novel amphiphilic GOJS-Cn nanoparticles and their further application in stabilizing pickering emulsion and enhancing oil recovery

Mixed nanoparticle stabilized Pickering emulsion is a novel research topic, which has been attracted more attention. In the present study, the novel amphiphilic GO-Janus SiO2-Cn nanoparticles (GOJS-Cn, n represents the number of carbon atoms in the modified alkyl chain) were successfully fabricated for the first time and investigated their ability in stabilizing Pickering emulsions for enhancing oil recovery. Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were employed to determine the successful fabrication of the GOJS-Cn. The optical microscopy was utilized to directly observe the GOJS-Cn (n = 0, 3, 8, and 12) stabilized emulsions and the static multiple light scattering was employed to further evaluate its stability quantitatively. It was found that the GOJS-C12 displayed the greatest ability to stabilize emulsions, even in high salinity (104 mg/L NaCl/MgCl2/CaCl2/AlCl3) and temperature (90 °C). Then, the interfacial tension, water contact angle, and dilatational measurements were conducted to reveal the mechanism of the GOJS-C12 superior emulsifying ability. The amphiphilic GOJS-C12 with great amphiphilicity spontaneously adsorbed at oil-water interface to promote the formation of rigid interfacial film, which was essential for the long-term stability of emulsion. Moreover, the core flooding tests reflected the GOJS-C12 stabilized emulsion could significantly enhance oil recovery (∼14.8%), then based on microscopic visualization experiments the potential EOR mechanism was proposed.

Fabrication and characterization of Chinese yam polysaccharides PLGA nanoparticles stabilized Pickering emulsion as an efficient adjuvant

The Chinese yam polysaccharides PLGA nanoparticles were applied as stabilizers in this study to prepare O/W Pickering emulsion. The optimized preparation conditions were PLGA concentration of 5 mg/mL, ultrasonic power of 50 %, and ultrasonic time of 2 min. The CYP-PPAS emulsion exhibits a raspberry-like morphology with a large number of nanoparticles surrounding the oil droplets. The CYP-PPAS emulsion exhibited outstanding stability at 4 °C and 37 °C for 28 days with high antigen loading efficiency and provided a controlled and sustained release of Chinese yam polysaccharides and OVA antigen in vitro. CYP-PPAS/OVA elicited robust antigen-specific immune response and induced a mixed Th1/Th2 immune response after immunization. Furthermore, CYP-PPAS/OVA caused a high CD4+/CD8+ ratio leading in increased activation of splenic T lymphocytes subpopulations. Moreover, CYP-PPAS is a safe vaccination adjuvant with high safety profile in vivo. Thus, the novel designed Pickering emulsion CYP-PPAS was a safe and effective adjuvant for inducing the strong and long-term immune response.

THE ABILITY OF BREADFRUIT STARCH NANOPARTICLE-STABILIZED PICKERING EMULSION FOR ENCAPSULATING CINNAMON ESSENTIAL OIL

Cinnamon essential oil (CO) is susceptible to decreased stability during storage, limiting its application in food products. Pickering emulsion stabilized by starch nanoparticles becomes a potential encapsulating method that can improve CO stability. This study aimed to investigate the ability of breadfruit starch nanoparticles-stabilized Pickering emulsion to encapsulate CO with various concentrations. Encapsulation process was carried out using the high-energy emulsification method with dispersing CO (0.05%; 0.1%; 0.5%; 1% w/w) in emulsion. The loading efficiency of CO and emulsion properties were evaluated. Retention of CO was also observed in 7 days-storage. Results showed that 0.5% and 1% CO were encapsulated effectively and stable in Pickering emulsion, with loading efficiency and CO retention ranging from 79.49-81.13% and 78.86-79.20%, respectively. The addition of 0.5% and 1% CO increased yellowness (+a*: 7.45-8.99) as well as decreased whiteness (+L*: 85.77-86.06) and viscosity (629.9-721.8 cP) of Pickering emulsion. However, differences in CO concentrations did not affect the emulsion index of Pickering emulsion. These findings concluded that breadfruit starch nanoparticles-stabilized Pickering emulsion could encapsulate up to 0.5% and 1% CO with the best properties among other treatments. Therefore, breadfruit starch nanoparticles-stabilized Pickering emulsion can be an alternative as encapsulation method, which can later expand the application of CO in food products.

Enhancing the physicochemical performance of myofibrillar gels using Pickering emulsion fillers: Rheology, microstructure and stability

Water loss and lipid oxidation of meat products during processing and storage compromise their sensory qualities, such as flavor, tenderness, juiciness. Herein, surfactant-stabilized emulsions and Pickering emulsions were employed as particulate fillers and fat substitutes in myofibrillar protein-based gels (MPGs). Relatively weak MPGs were formed with the addition of NaCl, which were further enhanced via filling with soy protein isolate nanoparticle-stabilized Pickering emulsions (SNPE) or soy protein isolate nanoparticle-stabilized Pickering emulsions with cinnamaldehyde (SNPE-CA). After thermal treatment at 80 °C, incorporation of SNPE-CA contributed to a highly compact gel network and the highest gel strength, but the minimum moisture content. SNPE resulted in a moderately compact network and the maximum moisture content, MPGs without fillers possessed a looser network and similar gel strength with those containing SNPE. While Tween 80 hindered the aggregation of myofibrillar proteins, causing the presence of Tween 80-stabilized emulsions (TWE) in MPGs generated the loosest network and the lowest gel strength. After further centrifugation or cooking, MPGs with SNPE showed the highest water holding stability, TWE conduced to the moisture stability of MPGs against centrifugation, MPGs with TWE or SNPE-CA or without fillers had a similar water holding stability index during cooking at 100 °C. Additionally, the ability of the three emulsion fillers for improving lipid oxidation stability of MPGs decreased in the following order: SNPE-CA > SNPE > TWE. These findings indicate that Pickering emulsions are potential particulate fillers to enhance moisture stability in meat gels, as well as fat substitutes to protect lipid from oxidation.