Monodisperse nanoparticles of biodegradable polyhydroxyalkanoates (PHAs) polymers, copolymers of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB), are synthesized using a membrane-assisted emulsion encapsulation and evaporation process for biomedical resorbable adhesives. The precise control over the diameter of these PHA particles, ranging from 100 nm to 8 μm, is achieved by adjusting the diameter of emulsion or the PHA concentration. Mechanical properties of the particles can be tailored based on the 3HB to 4HB ratio and molecular weight, primarily influenced by the level of crystallinity. These monodisperse PHA particles in solution serve as adhesives for hydrogel systems, specifically those based on poly(N, N-dimethylacrylamide) (PDMA). Semi-crystalline PHA nanoparticles exhibit stronger adhesion energy than their amorphous counterparts. Due to their self-adhesiveness, adhesion energy increases even when those PHA nanoparticles form multilayers between hydrogels. Furthermore, as they degrade and are resorbed into the body, the PHA nanoparticles demonstrate efficacy in in vivo wound closure, underscoring their considerable impact on biomedical applications.

Membrane emulsification technology has garnered increasing interest in emulsion preparation due to controllable droplet size, narrower droplet size distribution, low energy consumption, simple process design and excellent reproducibility. Nevertheless, the pore structure and surface engineering in membrane materials design play a crucial role in achieving high-quality emulsions with high throughput simultaneously. In this work, an oriented interpenetrating capillary network composed of highly aligned and interconnected wood cell lumens has been utilized to fabricate an emulsion membrane. A novel honeycomb porous ZnO layer obtained by a seed prefabrication-hydrothermal growth method was designed to reconstruct wood channel surfaces for enhanced microfluid mixing. The results show that through the unique capillary mesh microstructure of wood, the emulsion droplets were smaller in size, had narrower pore-size distribution, and were easy to obtain under high throughput conditions. Meanwhile, a well-designed ZnO layer could further improve the emulsion quality of a wood membrane, while the emulsifying throughput is still maintained at a higher level. This demonstrates that the convection process of the microfluid in these wood capillary channels was intensified markedly. This study not only develops advanced membrane materials in emulsion preparation, but also introduces a brand-new field for functional applications of wood.

Chocolate is a worldwide consumed food. This study investigated the fortification of sugar-free white chocolate with Lacticaseibacillus rhamnosus GG microcapsule co-encapsulated with beet residue extract. The chocolates were evaluated for moisture, water activity, texture, color properties, melting, physicochemical, and probiotic stability during storage. Furthermore, the survival of L. rhamnosus GG and the bioaccessibility of phenolic compounds were investigated under in vitro simulated gastrointestinal conditions. Regarding the characterization of probiotic microcapsules, the encapsulation efficiency of L. rhamnosus GG was > 89 % while the encapsulation efficiency of phenolic compounds was > 62 %. Chocolates containing probiotic microcapsules were less hard and resistant to breakage. All chocolates had a similar melting behavior (endothermic peaks between 32.80 and 34.40 °C). After 120 days of storage at 4 °C, probiotic populations > 6.77 log CFU/g were detected in chocolate samples. This result demonstrates the potential of this matrix to carry L. rhamnosus GG cells. Regarding the resistance of probiotic strains during gastric simulation, the co-encapsulation of L. rhamnosus GG with beet extract contributed to high counts during gastrointestinal transit, reaching the colon (48 h) with viable cell counts equal to 11.80 log CFU/g. Finally, one of our main findings was that probiotics used phenolic compounds as a substrate source, which may be an observed prebiotic effect.

Fenofibrate has shown therapeutic effects on diabetic retinopathy. However, fenofibrate can be rapidly cleared from the eye after a single intravitreal injection. Here, we aim to develop fenofibrate loaded PLGA microparticles (Feno-MP) with high drug loading and sustained in vitro release up to 6 months suitable for intravitreal injection. First, orthogonal array experimental design was applied for formulation optimization. The selected formulation parameters were used to formulate Feno-MP using homogenization method and direct membrane emulsification method. Both methods generated Feno-MP with high drug loading and sustained in vitro drug release more than 140 days. Unlike the polydisperse Feno-MP prepared using homogenization method, membrane emulsification method generated Feno-MP with uniform size distribution. By controlling the membrane pore size, 1.5 µm, 8 µm and 16 µm Feno-MP were formulated and we found that larger Feno-MP demonstrated higher drug loading, more sustained drug release in vitro with less burst drug release than the smaller Feno-MP. In conclusion, we developed Feno-MP with high drug loading and sustained release profile, and elucidated that changing the particle size could have notable impacts on drug loading and release kinetics. Formulating Feno-MP with uniform size distribution by membrane emulsification method would benefit the batch-to-batch repeatability.

We studied the encapsulation of iohexol (Ihex), a nonionic contrast agent used for X-ray computational tomography, into lipid vesicles using the multiple emulsification-solvent evaporation method to formulate a nanosized contrast agent. This lipid vesicle preparation method consists of three steps: (1) primary emulsification for producing water-in-oil (W/O) emulsions containing fine water droplets that will be converted to the internal water phase of the lipid vesicles, (2) secondary emulsification for formulating multiple water-in-oil-in-water (W/O/W) emulsions encapsulating the fine water droplets containing Ihex, and (3) solvent evaporation to remove the oil phase solvent (n-hexane) and to form lipid bilayers surrounding the fine inner droplets, resulting in the formation of lipid vesicles encapsulating Ihex. As the diameter and Ihex concentration of the primary W/O emulsion droplets decreased, a higher Ihex encapsulation yield was obtained for the final lipid vesicles. The entrapment yield of Ihex in the final lipid vesicles varied significantly with the emulsifier (Pluronic® F-68) concentration in the external water phase of W/O/W emulsion, and the highest yield (65%) was obtained when the emulsifier concentration was 0.1 wt%. We also investigated the powderization of lipid vesicles encapsulating Ihex via lyophilization. The powderized vesicles were dispersed in water after rehydration and maintained their controlled diameters. The entrapment yield of Ihex in powderized lipid vesicles was maintained for over 1 month at 25 ˚C, while significant leakage of Ihex was observed in the lipid vesicles suspended in the aqueous phase.

Produced water (PW) is, by volume, the largest waste product of the oil- and gas-exploration industry and contains pollutants such as hydrocarbons and heavy metals. To meet the stringent environmental regulations, PW must be treated before discharging into the environment. The current study proposes a novel treatment method where PW is used to prepare oil-in-water emulsion with potential applications within the oil-exploration industry. The emulsions are prepared by applying hollow fiber membrane emulsification (ME) on PW, which inherently contains oil, as to-be-dispersed phase. The results demonstrate that the average droplet size of the emulsions is a function of pressure applied on to-be-dispersed phase and could be customized from 0.24 to 0.65 µm by varying the pressure from 0.25 to 1 bar, respectively. Stability of the emulsions was verified under high pressure and a temperature and storage period of more than 24 h. The calculations showed that an ME unit with <100 kg weight and <1 m3 volume is appropriate to transform the daily average volume of PW from the Danish part of the North Sea into the emulsions. The study provides a novel route, which also complies well with the requirements (low-weight and small spatial footprints) of the offshore oil rigs, to treat and reuse PW within the oil production process and, therefore, eliminates its environmental footprint.

The improvement in the stability of solid-in-oil-in-water (S/O/W) emulsions, which are used as carriers for protein delivery, was investigated. For this purpose, emulsions were prepared using trimyristin, a solid fat, as the oil phase, and using the membrane emulsification and solvent evaporation methods. The samples were made into stable fine emulsions using polyvinyl alcohol, a hydrophilic polymer, as an emulsifier, and by controlling the particle size uniformly. The S/O/W emulsions prepared by this method showed almost no leakage of encapsulated proteins and exhibited controlled release in an intestinal environment.

Membrane-based gas separation is a promising unit operation in a low-carbon economy due to its simplicity, ease of operation, reduced energy consumption and portability. A methodology is proposed to immobilise enzymes in stable water-in-oil (W/O) emulsions produced by direct membrane emulsification systems and thereafter impregnated them in the pores of a membrane producing emulsion-based supported liquid membranes. The selected case-study was for biogas (CO2 and CH4) purification. Upon initial CO2 sorption studies, corn oil was chosen as a low-cost and non-toxic bulk phase (oil phase). The emulsions were prepared with Nadir® UP150 P flat-sheet polymeric membranes. The optimised emulsions consisted of 2% Tween 80 (w/w) in corn oil as the continuous phase and 0.5 g.L-1 carbonic anhydrase enzyme with 5% PEG 300 (w/w) in aqueous solution as the dispersed phase. These emulsions were impregnated onto a porous hydrophobic PVDF membrane to prepare a supported liquid membrane for gas separation. Lastly, gas permeability studies indicated that the permeability of CO2 increased by ~15% and that of CH4 decreased by ~60% when compared to the membrane without carbonic anhydrase. Thus, a proof-of-concept for enhancement of CO2 capture using emulsion-based supported liquid membrane was established.

We present combined experimental and modelling evidence that β-lactoglobulin proteins employed as stabilizers of oil/water emulsions undergo minor but significant conformational changes during premix membrane emulsification processes. Circular Dichroism spectroscopy and Molecular Dynamics simulations reveal that the native protein structure is preserved as a metastable state after adsorption at stress-free oil/water interfaces. However, the shear stress applied to the oil droplets during their fragmentation in narrow membrane pores causes a transition into a more stable, partially unfolded interfacial state. The protein\'s β-sheet content is reduced by up to 8% in a way that is largely independent of the pressure applied during emulsification, and is driven by an increase of contacts between the oil and hydrophobic residues at the expense of structural order within the protein core.

The treatment of neuropathic pain (NPP) is considered challenging, while the search for alternative medication is striving. NPP pathology is related with the expression of both the purinergic 2X7 (P2X7) receptor and the transient receptor potential vanilloid 1 receptor (TRPV1). Bufalin is a traditional Chinese medication derived from toad venom with pronounced antitumor, analgesic, and anti-inflammatory properties. However, poor solubility, rapid metabolism, and the knowledge gap on its pain alleviation mechanism have limited the clinical application of bufalin. Hence, the purpose of this study is to illustrate the NPP alleviation mechanism of bufalin via chronic constriction injury (CCI). To address the concern on fast metabolism, bufalin-PLGA microspheres (MS) were prepared via membrane emulsification to achieve prolonged pain-relieving effects. Western blot, real-time PCR, immunofluorescence, and molecular docking were employed to demonstrate the therapeutic action of bufalin on NPP. The results showed enhanced thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) after the administration of both bufalin and bufalin-PLGA MS in the CCI rats. Prolonged pain-relieving effects for up to 3 days with reduced dose frequency was achieved via bufalin-PLGA MS. In the CCI rats treated with bufalin-PLGA MS, the expression levels of protein and mRNA in TRPV1 and P2X7, both localized in the dorsal root ganglion (DRG), were reduced. Moreover, bufalin-PLGA MS effectively reduced the levels of IL-1β, IL-18, IL-6, and TNF-α in the CCI group. The results from molecular docking suggested a possible mechanism of NPP alleviation of bufalin through binding to P2X7 receptors directly. The administration of bufalin-PLGA MS prepared by membrane emulsification demonstrated promising applications for sustained effect on the alleviation of NPP.