Encapsulation of the peptide Ac–Glu–Thr–Lys–Thr–Tyr–Phe–Trp–Lys–NH2 into polyvinyl alcohol biodegradable formulations—Effect of calcium alginate

Stability and structural properties of bee pollen protein hydrolysate microencapsulated using maltodextrin and whey protein concentrate

In this research, the bee pollen protein hydrolysate was microencapsulated by spray drying using maltodextrin (MD), whey protein concentrate (WPC) and a mixture of both compounds. For this purpose, the bee pollen was hydrolysed by alcalase (enzyme concentration of 1.5%) at 50 °C and pH 8 during 3.95 h, and then freeze-dried. The hydrolysed protein and wall materials were used in ratio of 1:10 (w/w). The wall materials included maltodextrin 2%, WPC 2%, as well as maltodextrin and WPC mixtures with 3:1 ratio. The resulting capsules were exposed to UV radiation for 48 h to accelerate the oxidation. The results showed that the capsule prepared using maltodextrin and WPC mixture showed the highest DPPH radical scavenging during exposure to UV radiation. Based on the FTIR spectroscopy results, the wall containing maltodextrin and WPC mixture showed the best performance in maintaining the chemical structure of hydrolysed protein. The SEM results indicated that the microcapsules prepared with WPC and maltodextrin mixture as wall material showed uniform and smoother wall than those prepared with maltodextrin alone. Finally, it was found that the maltodextrin and WPC mixture was the best wall with an appropriate protective capability for the microencapsulation of hydrolysed proteins and their protection against UV radiation.

Novel poly(vinyl alcohol)-based amphiphilic nanogels by non-covalent boric acid crosslinking of polymeric micelles

In this work, we report a new type of poly(vinyl alcohol)-g-poly(N-isopropylacrylamide) (PVA-g-PNiPAAm) amphiphilic nanogel produced by the non-covalent crosslinking of PVA polyol domains in preformed polymeric micelles with boric acid. The nanomaterials showed sizes in the 100-250 nm range (DLS) and a spherical morphology (HR-SEM). We demonstrated that the size of the polymeric micelles could be fine-tuned by changing the concentration (and the aggregation pattern) of the polymeric amphiphile in water. Upon crosslinking, the polymeric micelles turned into physically stable amphiphilic nanogels that displayed both size and size distribution similar to the micellar precursor for up to two weeks, even under disfavored conditions of concentration and temperature that, in the case of non-crosslinked counterparts, resulted in quick disassembly. In addition, we show for the first time the feasibility of spray-drying technology to consolidate the 3D network formed between PVA and boric acid and to produce stable powders that can be reconstituted upon use at any desired concentration. Moreover, the formation of a borated surface conferred the nanogels with good mucoadhesiveness in vitro. Finally, these novel nanomaterials showed optimal cell compatibility in a model of the intestinal epithelium, the Caco2 cell line. Overall results demonstrate the unprecedented versatility of the proposed modular approach and opens completely new horizons in the application of polymeric micelles and other self-assembled polymeric nanomaterials in diagnostics and therapeutics.

Fe(0)-Fe3O4 nanocomposites embedded polyvinyl alcohol/sodium alginate beads for chromium (VI) removal

In this study, Fe(0)-Fe3O4 nanocomposites embedded polyvinyl alcohol (PVA)/sodium alginate (SA) beads were synthesized, which exhibited an excellent physical properties and catalytic reactivity, and a robust performance of post-separation (complete separation using a simple grille) and reusability (efficiency of 69.8% after four runs) in Cr(VI) removal. 5.0 wt% PVA with 1.5 wt% SA was the optimal proportion for beads molding, and the followed acidification and reduction treatments were critical to ensure high mechanical strength and high Cr(VI) removal ability of beads. Effects of Fe(0) and Fe3O4 mass fraction, initial pH and Cr(VI) concentration on final removal efficiency were also evaluated. Merely 0.075 wt% Fe(0) together with 0.30 wt% Fe3O4 was sufficient to deal with 20 mg L(-1) Cr(VI) solution. The efficiency decreased from 100 to 79.5% as initial Cr(VI) increased from 5 to 40 mg L(-1), while from 99.3 to 76.3% with increasing pH from 3.0 to 11.0. This work provides a practical and high-efficient method for heavy metal removal from water body, and simultaneously solves the problems in stabilization, separation and regeneration of Fe(0) nanoparticles.