Complex Dispersions Research Articles

Bio-Based Interpolyelectrolyte Complexes for the Stabilization of Pickering-like Emulsions

This work studies the stabilization of Pickering-like emulsions using dispersions of interpolyelectrolyte complexes (IPECs) formed by chitosan (CS) and sodium alginate (ALG), two polymers from natural resources, as the aqueous phase and soybean oil as the oil phase. The ability of these bio-based IPECs to form stable emulsions was evaluated by varying the compositional ratio of CS to ALG (Z-ratio) and the oil volume fraction (ϕo). Turbidity, zeta potential, and dynamic light scattering measurements revealed the dependence of IPEC properties on the Z-ratio, with phase separation observed near stoichiometric ratios. Phase diagram analysis showed that stable oil-in-water (O/W) and water-in-oil (W/O) emulsions could be obtained under certain combinations of the Z-ratio and ϕo. Emulsion stability increased with higher Z-ratios due to increased interfacial activity of the complexes and reduced coalescence. Emulsions with high ϕo exhibited transitions from discrete droplets to bicontinuous interfacially jammed emulsion gels (bijels), suggesting tunable morphologies. These results highlight the potential of CHI-ALG IPECs as eco-friendly and efficient stabilizers of Pickering-like emulsions for applications in food, cosmetics and pharmaceuticals.

Revealing the Structural Intricacies of Biomembrane-Interfaced Emulsions with Small- and Ultra-Small-Angle Neutron Scattering.

Utilizing cell membranes from diverse cell types for biointerfacing has demonstrated significant advantages in enhancing colloidal stability and incorporating biological properties, tailored specifically for various biomedical applications. However, the structures of these materials, particularly emulsions interfaced with red blood cell (RBC) or platelet (PLT) membranes, remain an underexplored area. This study systematically employs small- and ultra-small-angle neutron scattering (SANS and USANS) with contrast variation to investigate the structure of emulsions containing perfluorohexane within RBC (RBC/PFH) and PLT membranes (PLT/PFH). The findings reveal that the scattering length density of RBC and PLT membranes is 1.5 × 10-6Å-2, similar to 30% (w/w) deuterium oxide. Using this solvent as a cell membrane-matching medium, estimated droplet diameters are 770nm (RBC/PFH) and 1.5µm (PLT/PFH), based on polydispersed sphere model fitting. Intriguingly, calculated patterns and invariant analysis reveal native droplet architectures featuring entirely liquid PFH cores, differing significantly from the observed bubble-droplet core system in electron microscopy. This highlights the advantage of SANS and USANS in differentiating genuine colloidal structures in complex dispersions. In summary, this work underscores the pivotal role of SANS and USANS in characterizing biointerfaced colloids and in uncovering novel colloidal structures with significant potential for biomedical applications and clinical translation.

Cyclodextrin inclusion complex and amorphous solid dispersions as formulation approaches for enhancement of curcumin’s solubility and nasal epithelial membrane permeation

BackgroundCurcumin is a compound that occurs in the rhizomes of the turmeric plant (Curcuma longa) and has shown potential for the treatment of illnesses including certain neurodegenerative diseases. The bioavailability of curcumin is hindered by its extremely poor aqueous solubility.ResultsThis study aimed to apply formulation strategies such as inclusion complex formation with hydroxypropyl-β-cyclodextrin (HPβCD), as well as amorphous solid dispersion (ASD) formation with poly(vinylpyrrolidone-co-vinyl acetate) (PVP VA64) and hydroxypropyl methylcellulose (HPMC) to increase curcumin’s solubility and thereby its nasal epithelial membrane permeation. The curcumin formulations were evaluated by means of DSC, TGA, FT-IR, XRPD, microscopic imaging, aqueous solubility and membrane permeation across nasal respiratory and olfactory epithelial membranes. The solubility of curcumin was substantially increased by the formulations from 8.4 µg/ml for the curcumin raw material to 79.0 µg/ml for the HPβCD inclusion complex, 256.4 µg/ml for the HPMC ASD and 314.9 µg/ml for the PVP VA64 ASD. The HPMC ASD only slightly changed the membrane permeation of curcumin, while the PVP VA64 ASD decreased the membrane permeation of curcumin. The HPβCD inclusion complex enhanced the nasal epithelial membrane permeation of curcumin statistically significantly across the olfactory epithelial tissue and extensively across the respiratory epithelial tissue.ConclusionComplexation of curcumin with HPβCD enhanced the solubility of curcumin and thereby also increased its permeation across excised nasal respiratory and olfactory epithelial tissue. This indicated high potential of the curcumin-HPβCD complex for nose-to-brain delivery of curcumin for treatment of neurodegenerative diseases by means of intranasal administration.Graphical abstract

Drug dialysis through a semipermeable membrane as a preliminary efficacy assessment of a promising parasitocidal drug

The purpose of the research is to analyze the dynamics of fenbendazole (FBZ) and niclozamide (NZM) release from their solid dispersions (SD) of various compositions by dialysis through various semipermeable membranes in model systems that correspond to stomach and intestine environments. To evaluate the parasitocidal activity of experimental mixture compositions.Materials and methods. The study used substances of FBZ and NZM, and the polymer, polyvinylpyrrolidone (PVP). Mechanical processes were carried out in a LE-101 roller mill and an AGO-2 orbital centrifugal mill at different power density levels. The resulting SD of various compositions were studied for solubility. The dynamics of FBZ and NZM substance release from the SD were studied in a laboratory setup consisting of a temperature controlled glass with buffer solutions with pH = 9.18 (intestinal environment) and pH = 1.0 (stomach environment). The substance concentration in the dialysate was determined by HPLC and UV spectroscopy. The resulting complex SD of FBZ and NZM were studied for cestodocidal activity in a laboratory model of hymenolepiosis of white mice.Results and discussion. It was found that the substances release into a buffer solution with pH = 9.18 from the SD obtained in the roller mill is higher than that of the SD obtained in the AGO activator. The dialysis of the experimental compounds in a model system with a gastric juice medium observed only FBZ substance penetration through the membrane, which can be explained by protonation of the FBZ molecule which is a weak base. The NZM molecule, being a neutral molecule, does not penetrate through the semi-permeable partition into the hydrochloric acid environment; it remains entirely inside the dialysis bag. High anthelmintic efficacy rates (up to 100%) of SD complex FBZ : NZM : PVP obtained in the AGO activator and in the roller mill were recorded for the SD of composition 2 : 20 : 78 in the mice with hymenolepiosis. The activity of the base drug, the niclozamide substance, was 27.69%, which is 3 times lower than the activity of the resulting complex dispersions.

Solid dispersion complex triclabendazole preparations with succinic acid and their fasciolocidal activity

The purpose of the research is to test the efficacy of triclafascid and two solid dispersion complex preparations based on the triclabendazole substance against fasciolosis in cattle and sheep. Materials and methods. Complex preparations of triclabendazole (TCB) formulations: Succinic Acid (SA): Polyvinylpyrrolidone (PVP) (1: 1 : 8) and TCB: SA: Arabinogalactan (AG) (1: 1 : 8) were obtained by combined solid-stategrinding of the components in a fiber drum on an LE-101 ball mill at a roll rotation speed of 60 rpm with a process module of 1: 17 for 1 to 6 hours with sampling for analysis (HPLC) for changes in the TCB solubility. A comparative test of the efficacy of triclafascid and new solid dispersions (SD) of TCB complexes with SA against fascioliasis of sheep and cattle was conducted in the North-Eastern Federal District of the Caucasus in March-April 2023. To determine the Fasciola infection rate in animals, fecal samples were individually taken and examined by the Fülleborn methods using saturated aqueous NaCL solution and sequential washing. The drug efficacy was recorded at 25-30 days after deworming in analogy with "critical test". The results were statistically processed by the Student-Fisher method using Microsoft Excel 2007. Results and discussion. The resulting TCB and SA complexes with polymers had an increased solubility (up to 59–70 times) that depended on the polymer nature. The efficacy of new TCB dosage forms against fascioliasis in sheep at a dose of 1.5 mg/kg, i.e. 0.5 mg/kg less than the therapeutic dose as compared with oral triclafascid was 90.0 and 100%, respectively, and 85.7% in cattle at a dose of 2.0 mg/kg for the active substance.

Capillary Flow-MRI: Quantifying Micron-Scale Cooperativity in Complex Dispersions.

Strongly confined flow of particulate fluids is encountered in applications ranging from three-dimensional (3D) printing to the spreading of foods and cosmetics into thin layers. When flowing in constrictions with gap sizes, w, within 102 times the mean size of particles or aggregates, d, structured fluids experience enhanced bulk velocities and inhomogeneous viscosities, as a result of so-called cooperative, or nonlocal, particle interactions. Correctly predicting cooperative flow for a wide range of complex fluids requires high-resolution flow imaging modalities applicable in situ to even optically opaque fluids. To this goal, we here developed a pressure-driven high-field magnetic resonance imaging (MRI) velocimetry platform, comprising a pressure controller connected to a capillary. Wall properties and diameter could be modified respectively as hydrophobic/hydrophilic, or within w ∼ 100-540 μm. By achieving a high spatial resolution of 9 μm, flow cooperativity length scales, ξ, down to 15 μm in Carbopol with d ∼ 2 μm could be quantified by means of established physical models with an accuracy of 13%. The same approach was adopted for a heterogeneous fat crystal dispersion (FCD) with d and ξ values up to an order of magnitude higher than those for Carbopol. We found that for strongly confined flow of Carbopol in the 100 μm capillary, ξ is independent of flow conditions. For the FCD, ξ increases with gap size and applied pressures over 0.25-1 bar. In both samples, nonlocal interactions span domains up to about 5-8 particles but, at the highest confinement degree explored, ∼8% for FCD, domains of only ∼2 particles contribute to cooperative flow. The developed flow-MRI platform is easily scalable to ultrahigh field MRI conditions for chemically resolved velocimetric measurements of, e.g., complex fluids with anisotropic particles undergoing alignment. Future potential applications of the platform encompass imaging extrusion under confinement during the 3D printing of complex dispersions or in in vitro vascular and perfusion studies.

Effect of blending ratio on the compatibility and stability of konjac glucomannan/starch composite systems

A series of complex dispersions and films combining Konjac glucomannan (KGM) and starch in different ratios were prepared. The compatibility and stability of KGM/Starch composite (KS) systems were evaluated using a new horizontal casting device coupled with CCD camera system and Near-infrared (NIR) spectrometer and multiple conventional characterization techniques. The findings from the casting device revealed that when the KGM and starch were combined in a 7∶3 ratio, the dispersion demonstrated isotropic behavior, flowing and diffusing at a consistent speed from the central point to the surrounding area on the casting disc. Additionally, the scattered particles in the NIR reflectance spectrum were evenly distributed at every point, indicating excellent compatibility and uniformity within the dispersion. FTIR and XRD analyses indicated the existence of molecular interactions between the film components, and showed good compatibility between KGM and starch when the KGM content was greater than 50%. The best compatibility was obtained when the KGM content was 70%. The SEM results showed that the increase of KGM content contributed to a smoother and denser microstructure in the cross-section of the KS composite films, especially when the KGM content was 70% (w/w). The rheological results of the KS dispersion further confirmed the formation of a hybrid network structure between KGM and starch. Higher KGM content led to more hydrogen bonds and provided more opportunities for macromolecular chain entanglement. This work will contribute to a better understanding of the interaction mechanism between polysaccharides and starch, as well as provide a new perspective and novel characterization methods to deconstruct the compatibility and assembly structure stability between KGM and starch. It is beneficial for facilitate the application of KGM in the development of denatured food or starch materials, including food texture properties and emulsion stability, and establish a foundation for the diversification of food design tools.

Raman analyses of Al and Fe/Mg‐rich clays: Challenges and possibilities for planetary missions

AbstractClays are fine‐grained rocks that form in the presence of water. Their occurrence typically depends on a combination of geological setting and geochemical conditions. The widespread and diverse clay deposits identified on Mars indicate that the planet experienced multiple episodes of water activity, especially in the early period. The characterisation of Martian clays will reveal key information on geological history, the past climatic conditions and the overall habitability of Mars. Among the analytical techniques typically utilised for such mineralogical characterisation, Raman spectroscopy will be applied for the first time during several robotic exploration missions of Mars in the 2020s. In this study, various clay‐rich samples from Westerwald, Germany were analysed to help inform mission operations and interpretation of data returned by the miniaturised Raman instruments. The samples, as verified by infrared spectroscopy, constitute kaolinites, Al‐rich smectites and Fe/Mg‐rich smectites, which are relevant to the clay mineralogy expected at Martian landing sites (Jezero crater and Oxia Planum). Despite the levels of fluorescence experienced during Raman measurements of the clay‐rich powder samples when using a 532 nm laser, the Raman signatures of phyllosilicates were identified for kaolinite and several different types of smectite (e.g. montmorillonite, nontronite, saponite) in these complex dispersions. Following these measurements, identification of various accessory minerals disseminated in the clay matrix was also achieved using the micro‐Raman system. Finally, a brief discussion concerning the analytical strategies for successful clay analyses using miniaturised Raman instruments is provided.

Spectrum of the Hole Excitation in Spin-Orbit Mott Insulator Na2IrO3

We study the motion of a hole with internal degrees of freedom, introduced to the zigzag magnetic ground state of Na2IrO3, by using the self-consistent Born approximation. We find that the low-, intermediate-, and high-energy spectra are primarily attributed to the singlet, triplet, and quintet hole contributions, respectively. The spectral functions exhibit distinct features such as the electron-like dispersion of low-energy states near the Γ point, the maximum M-point intensity of mid-energy states, and the hole-like dispersion of high-energy states. These features are robust and almost insensitive to the exchange model and Hund’s coupling, and are in qualitative agreement with the angular-resolved photoemission spectra observed in Na2IrO3. Our results reveal that the interference between internal degrees of freedom in different sublattices plays an important role in inducing the complex dispersions.

Dynamic Raman Scattering: Molecular-Selective Correlation Spectroscopy for Diffusion Dynamics in Complex Systems

Diffusion dynamics of polymers and colloidal dispersions at high concentrations have been widely studied using dynamic light scattering (DLS), a correlation spectroscopic method based on Rayleigh scattering. However, DLS has not been applied to complex systems such as biological cells because of its lack of molecular selectivity. Here, we propose dynamic Raman scattering (DRS), a novel molecular-selective correlation spectroscopic technique based on Raman scattering. We theoretically demonstrate that molecular-selective diffusion dynamics can be monitored by measuring the intensity fluctuation of coherent anti-Stokes Raman scattering in a phase-mismatching condition. We then experimentally prove the molecular selectivity of the DRS by extracting the polystyrene diffusion dynamics in a mixture of polystyrene and silica nanoparticles. We believe that DRS will be applicable for monitoring diffusion dynamics in complex dispersions without any pretreatment.

The efficacy of complex solid dispersions of anthelmintics against experimental trichinellosis

The purpose of the research is to study the influence of various technological factors on obtaining of complex solid dispersions of anthelmintics with polyvinylpyrrolidone and licorice extract on anthelmintic efficacy in experimental trichinellosis of white mice.Materials and methods. The study of the nematodocidal activity of complex solid dispersions samples based on fenbendazole (FBZ), fenasal (FNS) and praziquantel (PZQ) with polyvinylpyrrolidone (PVP) and licorice extract (LE) obtained by mechanochemical technology at different ratios of components and different exposure times was carried out on 130 white mice experimentally infected with Trichinella spiralis in two experiments. On the 3rd day after infection, the animals were divided into experimental groups of 10 animals each. Samples of various complex solid dispersions of anthelmintics were administered intragastrically to the mice of the experimental groups at a dose of 2 mg/kg according to the active substance. FBZ substance was used as the basic drug at a dose of 2 mg/kg according to the active substance. Animals of the control groups did not receive the drugs. The animals were killed by decapitation on the 4th day after experimental drug samples administration, and the activity of the drugs was counted according to the results of helminthological necropsy of the intestine, the efficacy was calculated by the type of control test.Results and discussion. The efficacy of complex solid dispersions of FBZ and FNS with PVP polymer was higher in comparison with the activity of complexes with LE at the same duration of mechanochemical treatment in a roller mill. The FBZ activity decreased from 67.05 to 37.77% with a decrease in the duration of mechanochemical treatment from 24 h to 5 h and the efficacy of the FBZ : FNS complex with LE turned out to be almost at the level of the basic drug when treated for 1 h. The use of mechanochemical technology for obtaining of a solid dispersion of FBZ : FNS with PVP for targeted delivery makes it possible to increase the anthelmintic efficacy by 2.7 times compared with the activity of the FBZ substance, and with LE by 2.2 times. It was noted that complex solid dispersions of PBZ with PZQ have lower biological activity in comparison with compositions of FBZ with FNS.

Electrostatically Complexed Natural Polysaccharides as Aqueous Barrier Coatings for Sustainable and Recyclable Fiber-Based Packaging.

Driven by the ever-growing awareness of sustainability and circular economy, renewable, biodegradable, and recyclable fiber-based packaging materials are emerging as alternatives to fossil-derived, nonbiodegradable single-use plastics for the packaging industry. However, without functional barrier coatings, the water/moisture vulnerability and high permeability of fiber-based packaging significantly restrain its broader application as primary packaging for food, beverages, and drugs. Herein, we develop waterborne complex dispersion barrier coatings consisting of natural, biodegradable polysaccharides (i.e., chitosan and carboxymethyl cellulose) through a scalable, one-pot mechanochemical pathway. By tailoring the electrostatic complexation, the key element to form a highly crosslinked and interpenetrated polymer network structure, we formulate complex dispersion barrier coatings with excellent film-forming property and adaptable solid-viscosity profiles suitable for paperboard and molded pulp substrates. Our complex dispersions enable the formation of a uniform, defect-free, and integrated coating layer, leading to a remarkable oil and grease barrier and efficient water/moisture sensitivity reduction while still exhibiting excellent recyclability profile of the resulting fiber-based substrates. This natural, biorenewable, and repulpable barrier coating is a promising candidate to serve as a sustainable option for fiber-based packaging intended for the food and food service packaging industry.

Colloidal latex / liquid crystal coatings for thermochromic textiles

Latex is a colloidal dispersion of polymeric particles dispersed in water. They can be used to make complex dispersions of a complex mixture of pigments, surfactants etc. that are stable for long periods of time. In this paper we report cholesteric liquid crystals (CLCs) dispersed in a commercial water-based latex varnishes coated on fibers and fabrics. The CLC-latex coatings displayed bright, stable colors that change with temperature. The optical and stability properties of CLC-latex coated polyester fibers and fabrics are compared with previously reported LC materials. We find that the enhanced brightness of the latex coated materials is a result of the flattening of the phase separated CLC droplets during water evaporation from the latex varnishes. Owing to the stability of the commercial latex varnishes to UV irradiation and water exposure, these CLC-latex coatings are durable, environmentally friendly, inexpensive, and easy to coat on fibers and fabrics. The resulting smart textiles could be used for numerous biosensing, medical and decorative applications.

Complex dispersions of poloxamers and mesoporous carriers with ibrutinib

Ibrutinib is an anticancer drug, a Bruton's tyrosine kinase inhibitor with poor solubility in aqueous media. This study reports on the study of the effectiveness of mesoporous carriers based on magnesium aluminometasilicate and poloxamers to improve the solubility and bioavailability of ibrutinib in the form of amorphous solid dispersions. The choice of the most effective composition was made on a parallel study of (a) a physical mixture of ibrutinib with a mesoporous carrier, (b) a solid dispersion with a poloxamer on a non-porous carrier, (c) a dispersion with a poloxamer deposited on a mesoporous carrier. Sample mixtures and dispersions with ibrutinib were tested to establish amorphism by various methods and to determine the solubility in aqueous media. The composition of ibrutinib-poloxamer P407-mesoporous carrier showed the best results in three standard media regarding the solubility of ibrutinib (increase in solubility at pH 1.2 - 129.6%, pH 4.5 - 300.2%, pH 6.8 - 363.3%). This composition became the basis for the tablet formulation and showed the best results in the Dissolution test (the dosage was dissolved in only 10 min of the test in pH 1.2 medium by 98.3%, pH 4.5 - 95.4%, pH 6.8 – 57.3%). These results were superior to those of the original Imbruvica capsules at all points in the study. In conclusion, the resulting formulation was stable under accelerated conditions according to the ICH Q1 Quality Guideline (40 °C, 75% relative humidity, 6 months).

Non-Hermitian skin effect in a phononic beam based on piezoelectric feedback control

Non-Hermitian systems have gained a great deal of interest in various wave problems due their ability of exhibiting unprecedented phenomena such as invisibility, cloaking, enhanced sensing, or the skin effect. The latter manifests itself by the localization of all bulk modes in a specific frequency range at a given boundary, with an unconventional bulk-boundary correspondence. In this work, we propose to realize the skin effect for flexural waves in a non-Hermitian piezoelectric phononic beam with feedback control between a sensor and an actuator in each unit cell. By implementing a non-Hermitian parameter, effective gain and loss can be achieved in the phononic beam characterized by complex eigen frequencies, and non-reciprocal pass bands are obtained. We highlight that the split point separating the gain and loss areas can occur not only at the edges of the Brillouin zones but also inside the same Brillouin zone. We further analyze the influence of the geometric and non-Hermitian parameters on the complex dispersions and the split point. The topology of the complex bands is characterized by the winding number, which supports the skin effect together with the non-reciprocity. The localization degree of the skin mode manifested by the enhanced beam's vibration energy at one boundary is related to the strength of the non-reciprocity, and the skin mode can be always excited regardless of the source position. Our results provide a potential platform to introduce non-Hermiticity into phononic or metamaterial systems with novel functions for elastic waves such as topological insulators, vibration attenuation or amplification, and energy harvesting.

(Invited, Digital Presentation) Chemical Insights into Perovskite Ink Stability

Metal halide perovskite (MHP) semiconductors are excellent candidates for contemporary optoelectronics innovation, particularly for photovoltaics.1 The advantages of this class of materials derive from their hybrid nature, allowing for straightforward fabrication processes, and from their unique optoelectronic properties.A typical 3D organic-inorganic perovskite has a chemical formula of ABX3, where A is an organic cation (such as MA [methylammonium] or FA [formamidinium]), B is a metal cation (such as Pb2+), and X is a halogen anion (such as I or Br).2 However, recent advances have also explored more complex compositions embedding diverse cations/anions.3 These materials are prepared by simple and straightforward solution processing, the material precursors dissolved in a solvent undergoes self-assembly into a perovskite structure during spin-coating onto a substrate under mild thermal annealing.As the technology continues to mature, this still is a key advantage, allowing for affordable and scalable processing. Understanding perovskite ink properties is therefore a fundamental requirement towards industrialization, with special regards to their evolution over time.It has been demonstrated that even for the simplest system, the precursor solution is a complex – and dynamic – dispersion which contains not only solvated ions but also lead halide complexes, colloids and aggregates of different natures and dimensions. In these complex dispersions, multiple chemical species are present and can interact – or react – between each other or with the solvent.We have proved the existence of a reactivity between two of the perovskite components – methylammonium and formamidinium – in the precursors solutions, that leads to ink variations over time, which in turn means variation in the final polycrystalline material properties. In fact, the characteristics of precursor solution eventually dictate the optoelectronic quality of resulting perovskite films that proceed with the solution aging and determine undesirable decrease of solar cells performances. We have studied different parameters that affects such reactions kinetics and proposed solutions to overcome these issues.4 Starting from the known reactivity of the chemical species present in ink solutions, we outline the directions towards which future research efforts should be directed.5

Water-based dispersions of luminescent metal complexes for wet-processed multilayer organic light-emitting diodes

Tris(8-quinolinolato)aluminum (Alq3) and related luminescent metal complexes were dispersed in water by bead milling with poly(ethylene glycol)-based surfactants bearing aromatic hydrophobic moieties. Spin-coating of these dispersions afforded relatively smooth thin films. Especially, the average surface roughness of the film obtained from the Alq3 dispersion was 8.1 nm. We successfully fabricated a multilayer OLED consisting of a stack of ITO/poly(9-vinylcarbazole)/emitting layer/CsF/Al, where the emitting layer was formed by spin-coating of the Alq3 dispersion on the water-insoluble poly(9-vinylcarbazole) layer. The device exhibited green electroluminescence based on Alq3 with the maximum luminance greater than 500 cd m−2.

Synthesis of antibacterial polymer metal hybrids in irradiated poly‐1‐vinyl‐1,2,4‐triazole complexes with silver ions: pH tuning of nanoparticle sizes

AbstractPoly‐1‐vinyl‐1,2,4‐triazole (PVT)‐based materials with silver nanoparticles are promising antibacterial products. The metal nanoparticles with controllable sizes were obtained by radiation‐induced reduction of the dispersions of complexes of PVT with silver ions. Formation of the silver nanoparticles in aqueous suspensions irradiated at pH 6.0, 2.5, and 2.0 was studied using methods of UV–VIS spectroscopy and transmission electron microscopy. UV–VIS spectroscopy has detected a change in the efficiency of interaction between protonated or non‐protonated PVT units and the surface of silver nanoparticles. The interaction of macromolecules with the metal surface under different degrees of protonation of PVT functional groups afforded the nanoparticles with a narrow size distribution and an average size from 3 to 10 nm. An increase in the acidity also leads to a decrease in the ratio of the generation/growth of nanoparticles. The radiation approaches both provide the synthesis of the nanoparticles of controlled sizes and permits to obtain the nanocomposites containing no impurities of chemical reducing agents. The nanocomposites obtained exhibit high antibacterial activity against various bacterial strains, which depends on the size of silver nanoparticles.

Magnesium Aluminium Silicate-Metformin Hydrochloride Complexes - The Use of Isothermal Calorimetry for Probing Clay and Drug Nanocomplexations.

Studying complexation between a wide variety of drugs and clay is of high importance in expanding the knowledge about controlled drug delivery and its exploitation. This study reports the use of isothermal calorimetry (ITC) in understanding the complexation process occurring between magnesium aluminium silicate (MAS) and metformin hydrochloride (MET), as a potentially controlled release drug delivery system. To fully characterise and understand the complexes formed between MAS and MET and how that might impact on controlled release systems. MAS and MET complex dispersions and particles were formulated and analysed using ITC, DSC, XRPD, ATR-FTIR, SEM/EDX, digital microscopy and 2D-SAXS. The calorimetric results confirmed the binding between MET and MAS at various pHs (5, 7 and 9) and temperatures (25 ºC and 37 ºC). The overall change in enthalpy was found to be exothermic with a comparatively small entropic contribution to the total change in Gibbs free energy, implying that the binding was an enthalpically driven process. These findings suggest that the binding process was dominated by hydrogen bonding and electrostatic interactions. pH and temperature variation did not have a great impact on the binding, as observed from the similarity in enthalpy (ΔH), entropy (ΔS) or Gibbs free energy (ΔG), with the reaction being only slightly more exothermic at pH 5 and at 37 ºC. 2D-SAXS was able to differentiate between MAS particulates and MAS-MET complexes when analysed in their liquid form suggesting the importance of appropriate methodology and instrumentation used in characterisation. ITC was successfully used in understanding the complexation process occurring between MAS and MET. Care and consideration however should thus be taken in the accurate determination and characterisation techniques for the formation of complexes for controlled release using MAS.

The science of plant-based foods: Approaches to create nutritious and sustainable plant-based cheese analogs

There has been a growing interest in consumers around the world in adopting a more plant-based diet for health, sustainability, and ethical reasons. Many commercially successful products have already been developed, including plant-based meat and milk analogs. However, the production of plant-based cheese analogs that consumers find desirable and acceptable has proved extremely challenging. This is mainly due to the compositional and structural complexity of real cheese products, which is difficult to mimic using plant-derived ingredients. In this review article, we start by providing a brief overview of the production and properties of real dairy cheese. We then describe the plant-based ingredients and processing operations that can be used to assemble cheese analogs that mimic the composition, structure, physicochemical properties, sensory, and nutritional attributes of real cheese. We also consider in this review the potential impact of switching from animal-based to plant-based cheese on the environment and human health. Plant-based cheeses can be produced from plant proteins obtained using fractionation or tissue disruption routes. These products are typically complex colloidal dispersions consisting of lipid droplets embedded within a viscoelastic polysaccharide and/or protein network. These plant-based cheeses are likely to be more environmentally sustainable and better for animal welfare than their regular counterparts. More research is needed to identify appropriate ingredients and processing methods, including understanding the changes in texture and flavor as well as creating appropriate melting behaviors. Moreover, further research is required to improve the nutritional profile and test the health effects of plant-based cheeses. • Plant-based cheeses are produced by fractionation or tissue disruption route. • The network is stabilized by starch, fat, and/or protein phase transitions. • Many different mechanisms are used to induce curd formation ( e.g. ionic, thermal). • Current data suggest that plant-based cheeses have lower greenhouse gas emissions.