We demonstrate the synthesis of phytosterol colloidal particles using a simple food grade method based on antisolvent precipitation in the presence of a non-ionic surfactant. The resulting colloidal particles have a rod-like shape with some degree of crystallinity. The colloidal dispersions display good stability assured by surface charge, due to the presence of water and hydroxyl groups on the particle surface, and by steric stabilisation, due to the presence of a non-ionic stabiliser. In vitro bioaccessibility experiments demonstrated that colloidal phytosterol can be effectively solubilised in model dietary mixed micelles and the micellar cholesterol concentration can be effectively reduced by 47% within two hours.

Colloidal phytosterols: synthesis, characterization and bioaccessibility

Following skin injury, the overproduction of reactive oxygen species (ROS) during the inflammatory phase can cause tissue damage and delay in wound healing. Methylene blue (MB) decreases mitochondrial ROS production and has antioxidant effects. The authors aimed to prepare MB-loaded niosomes using the ultra-sonication technique as a green formulation method. A Box–Behnken design was selected to optimize formulation variables. The emulsifier to cholesterol ratio, HLB of mixed surfactants (Span 60 and Tween 60), and sonication time were selected as independent variables. Vesicle size, zeta potential (ZP), and drug entrapment capacity percentage were studied as dependent variables. The optimized formulation of niosomes showed spherical shape with optimum vesicle size of 147.8 nm, ZP of − 18.0 and entrapment efficiency of 63.27%. FTIR study showed no observable interaction between MB and other ingredients. In vivo efficacy of optimized formulation was evaluated using an excision wound model in male Wistar rat. Superoxide dismutase (SOD, an endogenous antioxidant) and malondialdehyde (MDA, an end product of lipid peroxidation) levels in skin tissue samples were evaluated. After 3 days, MDA was significantly decreased in niosomal gel-treated group, whereas SOD level was increased. Histological results indicate rats that received niosomal MB were treated effectively faster than other ones.

/pdf/methylene-blue-loaded-niosome-preparation-physicochemical-kgp1ihfihg.pdf

Methylene blue-loaded niosome: preparation, physicochemical characterization, and in vivo wound healing assessment

We report the first observation of chiral colloidal liquid crystals of rod-like particles from a low molecular weight organic compound—phytosterols. Based on the particles shape and crystal structure, we attribute this phenomenon to chiral distribution of surface charge on the surface of neighbouring rods.

/pdf/cholesteric-colloidal-liquid-crystals-from-phytosterol-rod-3skmajtqd1.pdf

Cholesteric colloidal liquid crystals from phytosterol rod-like particles

We study the self-assembly of a food-grade glucose-β-sitosterol conjugate in bulk and in solution by small angle X-ray scattering (SAXS) and atomic force microscopy (AFM). The amphiphilic behavior of the glucose-β-sitosterol conjugate, combined with the chirality of both its moieties, leads in solutions to the aggregation into supramolecular chiral aggregates with plate-like, spherical and helical ribbon configurations, depending on concentration and solvent quality. Owing to the crucial role of phytosterols in replacing cholesterol content and the need for functional edible fibrils with enhanced nutritional value, this system shows great promise in the struggle for the design of new functional food building blocks with targeted properties.

Edible supramolecular chiral nanostructures by self-assembly of an amphiphilic phytosterol conjugate

Influence of counterion type and diffusion on the primary electroviscous effect

Cholesterol colloids stabilised by Tween 20 (Colloid I), SDS-Et4 NBr (Colloid II), and CTAB-Nac (Colloid III) were prepared. Moving boundary electrophoresis established Colloid III to be positively charged with a zeta potential of 12.2 mV. Addition of 5 mmol dm−3 Na2SO4 and 0.1 mmol dm−3 bilirubin dye (Na-salt) decreased the zeta potential to 9.7 mV and 9.5 mV, respectively, by screening the surface charge of the colloidal particles. Higher concentrations of Na2SO4 and bilirubin (Na-salt) made making electrophoretic measurements difficult, and such a situation was also faced in the case of Colloid II even without external addition of an electrolyte. Addition of several electrolytes revealed that Colloids II and II were coagulated by the neutralisation of their positive charge, but Colloid I was destabilised by salting-out effect. Measured intrinsic viscosity values and electron microscopic measurements supported overall spherical shape of the colloid particles. Colloid II exibited structural viscosity; higher concentration of NaSO4 decreased the viscosities of Colloid II and II by electroviscous effect which helped indirect determination of the electrokinetic potential (23.7 mV) of Colloid II.

A. R. Das

Papers

Surfactant stabilised colloidal cholesterol