Preparation of alginate hydrogel microparticles by gelation introducing cross-linkers using droplet-based microfluidics: a review of methods

This review examines the preparation of alginate hydrogel microparticles by using droplet-based microfluidics, a technique widely employed for its ease of use and excellent control of physicochemical properties, with narrow size distribution. The gelation of alginate is realized “on-chip” and/or “off-chip”, depending on where cross-linkers are introduced. Various strategies are described and compared. Microparticle properties such as size, shape, concentration, stability and mechanical properties are discussed. Finally, we consider future perspectives for the preparation of hydrogel microparticles and their potential applications.

Preparation and Characterization of Electrosprayed Nanoparticles containing Ethyl Maltol Flavor

In this study, electrospraying is used to prepare electrosprayed multicomponent nanoparticles of ethylcellulose and stearic acid entrapping ethyl maltol. Electrospraying nanoparticles produced were ≤100 nm diameter and narrow size distribution (polydispersity index 0.26) is achieved. The ethyl maltol entrapment efficiency and yield were approximately 88% and 76%, respectively. The presence of ethyl maltol flavor within the polymeric electrosprayed nanoparticles was shown by Fourier transform infrared spectroscopy. The morphology of the electrosprayed multicomponent nanoparticles generated was studied by transmission electron microscopy.

A new purification technique to obtain specific size distribution of giant lipid vesicles using dual filtration

A new purification technique is developed for obtaining distribution of giant unilamellar vesicles (GUVs) within a specific range of sizes using dual filtration. The GUVs were prepared using well known natural swelling method. For filtration, different combinations of polycarbonate membranes were implemented in filter holders. In our experiment, the combinations of membranes were selected with corresponding pore sizes–(i) 12 and 10 μm, (ii) 12 and 8 μm, and (iii) 10 and 8 μm. By these filtration arrangements, obtained GUVs size distribution were in the ranges of 6−26 μm, 5–38 μm and 5–30 μm, respectively. In comparison, the size distribution range was much higher for single filtration technique, for example, 6−59 μm GUVs found for a membrane with 12 μm pores. Using this technique, the water-soluble fluorescent probe, calcein, can be removed from the suspension of GUVs successfully. The size distributions were analyzed with lognormal distribution. The skewness became smaller (narrow size distribution) when a dual filtration was used instead of single filtration. The mode of the size distribution obtained in dual filtration was also smaller to that of single filtration. By continuing this process of purification for a second time, the GUVs size distribution became even narrower. After using an extra filtration with dual filtration, two different size distributions of GUVs were obtained at a time. This experimental observation suggests that different size specific distributions of GUVs can be obtained easily, even if GUVs are prepared by different other methods.

Influence of functionalized nanosilica with different functional groups in the properties of cementitious composites: A review

The use of supplementary nano cementitious material (SNCM) to improve the mechanical properties and durability performances of cementitious composites (cement paste, mortar and concrete) has received remarkable attention in recent studies. The use of nanosilica as SNCM is a consolidated practice in the scientific community. However, recent developments in the synthesis of monodisperse and narrow-size distribution of nanoparticles by functionalization methods provide a significant improvement to the development of silica-group nano composites (among the functional groups: amine, carboxyls and glycol groups), the so-called functionalized nanosilica (FNS). This article aims to raise a literature review on the properties of FNS in cementitious materials and the advanced techniques of nano/micro structural analysis used to characterize cementitious composites containing FNS’s.

Generation of Therapeutically Potent Spheroids from Human Endometrial Mesenchymal Stem/Stromal Cells

Endometrial mesenchymal stem/stromal cells (eMSCs) hold great promise in bioengineering and regenerative medicine due to their high expansion potential, unique immunosuppressive properties and multilineage differentiation capacity. Usually, eMSCs are maintained and applied as a monolayer culture. Recently, using animal models with endometrial and skin defects, we showed that formation of multicellular aggregates known as spheroids from eMSCs enhances their tissue repair capabilities. In this work, we refined a method of spheroid formation, which makes it possible to obtain well-formed aggregates with a narrow size distribution both at early eMSC passages and after prolonged cultivation. The use of serum-free media allows this method to be used for the production of spheroids for clinical purposes. Wound healing experiments on animals confirmed the high therapeutic potency of the produced eMSC spheroids in comparison to the monolayer eMSC culture.