Investigating swelling-breakdown in double emulsions

Robust Double Emulsions for Multicolor Fluorescence-Activated Cell Sorting

Cell-cell interactions are essential for the proper functioning of multicellular organisms. For example, T cells interact with antigen-presenting cells (APCs) through specific T-cell receptor (TCR)-antigen interactions during an immune response. Fluorescence-activated droplet sorting (FADS) is a high-throughput technique for efficiently screening cellular interaction events. Unfortunately, current droplet sorting instruments have significant limitations, most notably related to analytical throughput and complex operation. In contrast, commercial fluorescence-activated cell sorters offer superior speed, sensitivity, and multiplexing capabilities, although their use as droplet sorters is poorly defined and underutilized. Herein, we present a universally applicable and simple-to-implement workflow for generating double emulsions and performing multicolor cell sorting using a commercial FACS instrument. This workflow achieves a double emulsion detection rate exceeding 90%, enabling multicellular encapsulation and high-throughput immune cell activation sorting for the first time. We anticipate that the presented droplet sorting strategy will benefit cell biology laboratories by providing access to an advanced microfluidic toolbox with minimal effort and cost investment.

Optimization and characterization of high internal phase double emulsion (HIPDE) stabilized by with soybean protein isolate, gallic acid and xanthan gum

This study aims to formulate a stable high internal phase double emulsion (HIPDE) using soybean protein isolate (SPI), gallic acid (GA), and xanthan gum (XG). To prepare HIPDE, W1/O was formulated with the water phase dispersed in the oil phase using polyglycerol polyricinoleate (PGPR) as a stabilizer. Thereafter, W1/O dispersed in W2 (SPI solution) was used. To stabilize the HIPDE, GA was added in W1 (0 or 1 %), XG was added in W2 (0 or 1 %), and the pH of the W phases was adjusted to acidic, neutral, and basic. The samples containing GA in W1 and XG in W2 did not phase out during the storage periods and maintained a higher ζ-potential value, a higher apparent viscosity, and a more sustainable droplet compared to others. These results were derived by the interaction between SPI and XG, SPI and GA, or GA and PGPR. Physicochemical crosslinks were formed, such as gallate-derived groups, SPI-GA complexation (Michael addition, Shiff base reaction), and hydrogen bonding. In conclusion, applying the SPI, GA, and XG to HIPDE would contribute to various industries such as food, medicine, and cosmetics.

Optimization of Self-Double Emulsifying Drug Delivery System Using Design of Experiments for Enhanced Oral Bioavailability of Gentamicin: In-vitro, Ex-vivo and In-vivo Studies

Water-in-oil-in-water (w/o/w) double emulsions have shown excellent capability in augmenting the enteral bioavailability of BCS class III drugs, besides being effective controlled-release formulations. However, the problem of thermodynamic instability has restrained their industrial applicability. The self-double emulsifying drug delivery system (SDEDDS) is one of several approaches used to improve the stability of double emulsions. SDEDDS is a mixture of primary emulsion and secondary surfactant that can spontaneously emulsify into double emulsions in an external aqueous environment with mild agitation. Here, we prepared SDEDDS of gentamicin sulfate by response surface methodology. Selected optimized formulations (ODS1 and ODS2) were evaluated for zeta potential (Y1), optical clarity (Y2), release at 420 min (Y3), emulsion stability index (Y4) and self-emulsification time (Y5). For ODS1, Y1=-35.45 (±1.06)mV, Y2=53.19 (±0.35)%, Y3=75.79 (±0.60)%, Y4=93.97(±0.15)% and Y5=0.631 (±0.014)min, whereas for ODS2, Y1=-35.70 (±0.56)mV, Y2=48.09 (±0.64)%, Y3=76.61 (±0.99)%, Y4=93.00(±0.94)% and Y5=0.687(±0.02)min. Furthermore, ex-vivo studies on intestinal permeability revealed that SDEDDS improved membrane permeability compared to drug solution. Histopathology investigations revealed that SDEDDS promoted permeation without causing significant local membrane distortion. In addition, in-vivo studies revealed a 2.84 -fold increase in AUC0-∞ of optimized SDEDD compared to pure drug oral solution.

Fabrication of anthocyanin–rich W1/O/W2 emulsion gels based on pectin–GDL complexes: 3D printing performance

The stability of anthocyanin-rich W₁/O/W₂ double emulsions prepared with Nicandra physalodes (Linn.) Gaertn. Seeds pectin was investigated, including droplet sizes, ζ-potential, viscosity, color, microstructures and encapsulation efficiency. Furthermore, the gelation behavior, rheological behavior, texture behavior and three-dimensional (3D) printing effects of the W₁/O/W₂ emulsion gels induced with Glucono-delta-lactone (GDL) were studied. The L*, b*, ΔE, droplet sizes and ζ-potential of the emulsions were gradually increased, while other indicators were gradually decreased during 28 days of storage under 4 ℃. The storage stability of sample under storage at 4 ℃ was higher than 25 ℃. The G' of W₁/O/W₂ emulsion gels gradually boosted with increased GDL addition, and reached the highest after the addition of 1.6 % GDL. In creep-recovery sweep, the minimum strain of 1.68 % and the highest recovery rate of 86 % were also found for the emulsion gels with 1.6 % GDL. Accordingly, the models "KUST", hearts, flowers printed by emulsion gels after 60 min addition of 1.6 % GDL had the best printing effects. The W₁/O/W₂ emulsion gels based on pectin-GDL complexes exhibited good performance in protecting anthocyanins and suggested as a potential ink for food 3D printing.

Determination of the Dominating Coalescence Pathways in Double Emulsion Formulations by Use of Microfluidic Emulsions

In water-in-oil-in-water (W1/O/W2) double emulsions several irreversible instability phenomena lead to changes. Besides diffusive processes, coalescence of droplets is the main cause of structural changes. In double emulsions, inner droplets can coalesce with each other (W1–W1 coalescence), inner droplets can be released via coalescence (W1–W2 coalescence) and oil droplets can coalesce with each other (O–O coalescence). Which of the coalescence pathways contributes most to the failure of the double emulsion structure cannot be determined by common measurement techniques. With monodisperse double emulsions produced with microfluidic techniques, each coalescence path can be observed and quantified simultaneously. By comparing the occurrence of all possible coalescence events, different hydrophilic surfactants in combination with PGPR are evaluated and discussed with regard to their applicability in double emulsion formulations. When variating the hydrophilic surfactant, the stability against all three coalescence mechanisms changes. This shows that measuring only one of the coalescence mechanisms is not sufficient to describe the stability of a double emulsion. While some surfactants are able to stabilize against all three possible coalescence mechanisms, some display mainly one of the coalescence mechanisms or in some cases all three mechanisms are observed simultaneously.

Exploring Various Techniques for the Chemical and Biological Synthesis of Polymeric Nanoparticles

Nanoparticles (NPs) have remarkable properties for delivering therapeutic drugs to the body's targeted cells. NPs have shown to be significantly more efficient as drug delivery carriers than micron-sized particles, which are quickly eliminated by the immune system. Biopolymer-based polymeric nanoparticles (PNPs) are colloidal systems composed of either natural or synthetic polymers and can be synthesized by the direct polymerization of monomers (e.g., emulsion polymerization, surfactant-free emulsion polymerization, mini-emulsion polymerization, micro-emulsion polymerization, and microbial polymerization) or by the dispersion of preformed polymers (e.g., nanoprecipitation, emulsification solvent evaporation, emulsification solvent diffusion, and salting-out). The desired characteristics of NPs and their target applications are determining factors in the choice of method used for their production. This review article aims to shed light on the different methods employed for the production of PNPs and to discuss the effect of experimental parameters on the physicochemical properties of PNPs. Thus, this review highlights specific properties of PNPs that can be tailored to be employed as drug carriers, especially in hospitals for point-of-care diagnostics for targeted therapies.

Encapsulation of Pomegranate Peel Extract (Punica granatum L.) by Double Emulsions: Effect of the Encapsulation Method and Oil Phase

Pomegranate peel is an agro-industrial waste that can be used as source of punicalagin, a polyphenolic compound with several beneficial effects on health. Since, once extracted, punicalagin is prone to degradation, its encapsulation by double emulsions can be an alternative to protect the active compound and control its release. The aim of this investigation was to evaluate the feasibility of encapsulating pomegranate peel extract (PPE) in double emulsions using different types of oils (castor, soybean, sunflower, Miglyol and orange) in a ratio of 70:30 (oil:PPE) and emulsification methods (direct membrane emulsification and mechanical agitation), using polyglycerol polyricinoleate (PGPR) and Tween 80 as lipophilic and hydrophilic emulsifiers, respectively. Direct membrane emulsification (DME) led to more stable emulsions during storage. Droplet size, span values, morphology and encapsulation efficiency (EE) were better for double emulsions (DEs) prepared by DME than for mechanical agitation (MA). DEs formulated using Miglyol or sunflower oil as the oily phase could be considered as suitable food grade systems to encapsulate punicalagin with concentrations up to 11,000 mg/L of PPE.

Simultaneous encapsulation of trans-resveratrol and vitamin D3 in highly concentrated double emulsions

BACKGROUND

Encapsulation of biocompounds is essential to protect them from environmental factors that could enhance their oxidation or cause them to lose their beneficial properties due to extreme photosensitivity, among other factors. The main goal of this work was to study the feasibility of preparing concentrated double emulsions with a high loading capacity containing simultaneously trans-resveratrol (RSV) and vitamin D₃ (VitD₃ ). Such emulsions could be used for food fortification or pharmaceutical formulations or as vehicles for targeted controlled release.

RESULTS

In order to achieve large concentrations of the encapsulated compounds, all the double emulsions were formulated using a W₁ /O in W₂ ratio of 80/20, while the ratios tested for W₁ in O where 20/80 and 30/70. All the emulsions were characterized by droplet size, morphology, colloidal stability and encapsulation efficiency (EE) over a period of 6 weeks. VitD₃ and RSV concentration were determined by a technique based on reverse-phase high-performance liquid chromatography. The viability of preparing concentrated W₁ /O/W₂ emulsions containing both biocompounds has been demonstrated with satisfactory results. Initial RSV concentrations in the concentrated double emulsions formulated varied from 5.0 to 8.3 mg L^-1 , while for VitD₃ values of 28-32 mg L^-1 were obtained. The presence of VitD₃ retarded RSV release in the formulated emulsions. It was observed that after 1 week of storage RSV EE increased around 10-50% when VitD₃ was simultaneously encapsulated.

CONCLUSION

Simultaneous encapsulation of RSV and VitD₃ was possible in high internal phase emulsions. The emulsions presented high colloidal stability, being suitable for food fortification applications. © 2020 Society of Chemical Industry.