The presented article reviews the studies of the stability of TiO ₂ nanomaterials' suspensions in the presence of different dispersants under a wide range of experimental conditions.

Microencapsulation of bioactive substances is a common strategy for their protection and release rate control. The use of chitosan (Ch) is particularly promising due to its abundance, biocompatibility, and interaction with anionic surfactants to form complexes of different characteristics with relevance for use in microcapsule wall design. In this study, Ch/sodium dodecyl sulfate (SDS) microcapsules, without and with cross-linking agent (formaldehyde (FA) or glutaraldehyde (GA)), were obtained by the spray drying of vitamin E loaded oil-in-water emulsion. All of the microcapsules had good stability during the drying process. Depending on the composition, their product yield, moisture content, and encapsulation efficiency varied between 11–34%, 1.14–1.62%, and 94–126%, respectively. SEM and FTIR analysis results indicate that SDS as well as cross-linkers significantly affected the microcapsule wall properties. The profiles of in vitro vitamin E release from the investigated microcapsules fit with the Korsmeyer-Peppas model (r² > 0.9). The chemical structure of the anionic surfactant was found to have a significant effect on the vitamin E release mechanism. Ch/SDS coacervates may build a microcapsule wall without toxic crosslinkers. This enabled the combined diffusion/swelling based release mechanism of the encapsulated lipophilic substance, which can be considered favorable for utilization in food and pharmaceutical products.

The aim of this work was to investigate a possibility of preparing composite zein/natural resin (shellac and rosin) nanoparticles by antisolvent co?precipitation from their aqueous ethanol solutions. Influence of zein/resin mass ratio (1/0, 0.8/0.2, 0.5/0.5, 0.4/0.6 and 0/1) and pH (2?12) on particle size, d, and zeta potential, ?, of the prepared particles was studied. The functional properties of zein/rosin composite nanoparticles were evaluated by studying carvacrol encapsulation. It was shown that the antisolvent precipitation can be successfully used to prepare the shellac and rosin nanoparticles, as well as the composite zein/shellac and the zein/rosin nanoparticles. Colloidal properties, d and ?, of the obtained nanoparticles are influenced by the zein/ /resin mass ratio and the pH of nanoparticles? dispersions. The isoelectric point of composite nanoparticles can be modulated by varying the zein/resin mass ratio. It was found that the zein/rosin nanoparticles are suitable for carvacrol encapsulation, where carvacrol release is enhanced by increasing the rosin share in the composite zein/rosin nanoparticles.

Water in oil (W/O) emulsions are dispersed systems which have very wide application as a carriers in the food, pharmaceutical and cosmetic industry products. The main problem with practical application of such systems is their low stability. The emulsifiers used to stabilize this type of emulsions are with low hydrophilic-lipophilic balance values. The present work examines the possibility of the application of mixtures of lipophilic emulsifiers polyglycerol polyricinoleate (PGPR) and polyglycerol fatty acid esters for stabilization of W/O emulsions. First of all, the adsorption properties of the used emulsifiers were examined by tensiometic measurements. Based on these results, two emulsifiers PGPR and decaglycerol decaoleate (Caprol 10G10O) were selected for the preparation of the emulsions, as well as their mass ratios and total concentrations. The results of the investigation of the emulsions properties (dispersion analysis and sedimentation stability) showed that more stable emulsions can be obtained by decreasing the Caprol 10G10O mass ratio and increasing the total concentration of emulsifiers.

Silk fibroin (SF) is a protein with many outstanding properties (superior biocompatibility, mechanical strength, etc.) and is often used in many advanced applications (epidermal sensors, tissue engineering, etc.). The properties of SF-based biomaterials may additionally be tuned by SF interactions with other (bio)polymers. Being a weak amphoteric polyelectrolyte, SF may form polyelectrolyte complexes (PECs) with other polyelectrolytes of opposite charge, such as poly(acrylic acid) (PAA). PAA is a widely used, biocompatible, synthetic polyanion. Here, we investigate PEC formation between SF and PAA of two different molecular weights (MWs), low and high, using various techniques (turbidimetry, zeta potential measurements, capillary viscometry, and tensiometry). The colloidal properties of SF isolated from Bombyx mori and of PAAs (MW, overlap concentration, the influence of pH on zeta potential, adsorption at air/water interface) were determined to identify conditions for the SF-PAA electrostatic interaction. It was shown that SF-PAA PEC formation takes place at different SF:PAA ratios, at pH 3, for both high and low MW PAA. SF-PAA PEC’s properties (phase separation, charge, and surface activity) are influenced by the SF:PAA mass ratio and/or the MW of PAA. The findings on the interactions contribute to the future development of SP-PAA PEC-based films and bioadhesives with tailored properties.