Cellulose-starch Hybrid Films Plasticized by Aqueous ZnCl₂ Solution

Ecological Repellent Preparations Based on Natural Polymers with the Addition of Essential Oils Acting on Ticks

BACKGROUND

Ticks (Acari: Ixodida) pose a serious medical and veterinary threat as vectors of tick-borne pathogens. The wide variety of tick repellents available on the market primarily consist of synthetic preparations that may disrupt the ecological balance and accumulate in the environment, leading to harmful effects on humans and animals. The aim of the study was to develop an ecological preparation based on natural raw materials (biopolymers) with the addition of a mixture of essential oils that act as tick repellents.

METHODS

The preparations were acquired through the emulsification method, specifically the oil-in-water emulsion technique. The assessment encompassed an analysis of their physicochemical properties, including centrifugal and thermal stability, dynamic viscosity, wetting angle, and conductivity. Additionally, their biodegradation and ecotoxicity profiles were evaluated, as well as their impact on tick behavior.

RESULTS

The preparations exhibited stability, rapid biodegradation, and absence of ecotoxicity. Additionally, they had repellent properties against the two tested species of ticks (Ixodes ricinus and Dermacentor reticulatus).

CONCLUSIONS

Emulsion formulations comprising natural ingredients have significant research potential for combating ticks, thus mitigating the risk of tick-borne diseases in both human and animal populations.

Lutein encapsulation into dual-layered starch/zein gels using 3D food printing: Improved storage stability and in vitro bioaccessibility

The ability of 3D printing to encapsulate, protect, and enhance lutein bioaccessibility was investigated under various printing conditions. A spiral-cube-shaped geometry was used to investigate the effects of printing parameters, namely zein concentration (Z; 20, 40, and 60 %) and printing speed (PS; 4, 8, 14, and 20 mm/s). Coaxial extrusion 3D printing was used with lutein-loaded zein as the internal flow material, and corn starch paste as the external flow material. The viscosities of the inks, microstructural properties, storage stability, and bioaccessibility of encapsulated lutein were determined. The sample printed with a zein concentration of 40 % at a printing speed of 14 mm/s (Z-40/PS-14) exhibited the best shape integrity. When lutein was entrapped in starch/zein gels (Z-40/PS-14), only 39 % of lutein degraded after 21 days at 25 °C, whereas 78 % degraded at the same time when crude lutein was studied. Similar improvements were also observed after storing at 50 °C for 21 days. Furthermore, after simulated digestion, the bioaccessibility of encapsulated lutein (9.8 %) was substantially higher than that of crude lutein (1.5 %). As a result, the developed delivery system using 3D printing could be an effective strategy for enhancing the chemical stability and bioaccessibility of bioactive compounds (BCs).

Construction of Supramolecular Polymers and Covalent Polymers via the Same Monomers

Nature owns the ability to construct structurally different polymers from the same monomers. While polymers can be classified as covalent polymers (CPs) and supramolecular polymers (SPs), it is still difficult to synthesize CPs and SPs using same monomers like nature do. Herein, M1 with two diazo salts on both the ends was designed. Additionally, hydroquinone was chosen to be M2 for the existence of two hydroxyl groups. When mixing at room temperature, M1 and M2 self-assembled to SPs via N…H hydrogen bonds. In another way, upon the exposure to ultraviolet irradiation when blending M1 with M2, CPs were fabricated in the presence of covalent bonds. The excellent thermal stability of CPs was determined by TGA and DSC, while the great corrosion resistance of covalent polymers was detected by acid or alkali immersion. In this way, constructing two kinds of polymers using the same monomers was successfully achieved. This shows tremendous potential in fields of polymer science, supramolecular chemistry, which would boom the development of polymers.

Preparation, characteristics, and soil-biodegradable analysis of corn starch/nanofibrillated cellulose (CS/NFC) and corn starch/nanofibrillated lignocellulose (CS/NFLC) films

The objective of this study was to produce high-performance and biodegradable starch nanocomposites through film casting by using corn starch/nanofibrillated cellulose (CS/NFC) and corn starch/nanofibrillated lignocellulose (CS/NFLC). NFC and NFLC were obtained by super grinding process and added to fibrogenic solutions (1, 3, and 5 g/100 g of starch). The addition of NFC and NFLC from 1 to 5 % was verified to be influential in enhancing mechanical properties (tensile, burst, and tear index) and reducing WVTR, air permeability, and essential properties in food packaging materials. But, in comparison to control samples, the addition of NFC and NFLC from 1 to 5 % decreased the opacity, transparency, and tear index of films. In acidic solutions, produced films were more soluble than in alkaline or water solutions. The soil-biodegradability analysis showed that after 30 days of exposure to soil, the control film lost 79.5 % of its weight. The weight loss of all films was >81 % after 40 days. The results of this study may contribute to expanding the industrial applications of both NFC and NFLC by laying a basis for preparing high-performance CS/NFC or CS/NFLC.

Valorization of Starch to Biobased Materials: A Review

Many concerns are being expressed about the biodegradability, biocompatibility, and long-term viability of polymer-based substances. This prompted the quest for an alternative source of material that could be utilized for various purposes. Starch is widely used as a thickener, emulsifier, and binder in many food and non-food sectors, but research focuses on increasing its application beyond these areas. Due to its biodegradability, low cost, renewability, and abundance, starch is considered a "green path" raw material for generating porous substances such as aerogels, biofoams, and bioplastics, which have sparked an academic interest. Existing research has focused on strategies for developing biomaterials from organic polymers (e.g., cellulose), but there has been little research on its polysaccharide counterpart (starch). This review paper highlighted the structure of starch, the context of amylose and amylopectin, and the extraction and modification of starch with their processes and limitations. Moreover, this paper describes nanofillers, intelligent pH-sensitive films, biofoams, aerogels of various types, bioplastics, and their precursors, including drying and manufacturing. The perspectives reveal the great potential of starch-based biomaterials in food, pharmaceuticals, biomedicine, and non-food applications.

Effect of hybridization composition and glycerin content on novel corn starch/nata de coco plastic film: Thermal, mechanical, and degradation study

The objective of this work was to develop a plastic film from food sources with excellent thermal, mechanical, and degradability performance. Corn starch (CS)/nata de coco (NDC) were hybridized with addition of glycerin as plasticizer at different weight ratio and weight percent, respectively. Sample analysis found that the hybridization of CS with NDC improved the film forming properties, mechanical and thermal, degradation properties, as well as hydrophobicity and solubility of the film up to 0.5:0.5 wt hybrid ratio. The properties of the films were highly affected by the homogeneity of the sample during hybridization, with high NDC amount (0.3:0.7 wt CS:NDC) showing poor hydrophobicity, and mechanical and thermal properties. The glycerin content, however, did not significantly affect the hydrophobicity, water solubility, and degradability properties of CS/NDC film. Hybridization of 0.5:0.5 wt CS/NDC with 2 phr glycerin provided the optimum Young's modulus (15.67 MPa) and tensile strength (1.67 MPa) properties.

Cellulose aerogel micro fibers for drug delivery applications

Textile engineering can offer a multi-scale toolbox via various fiber or textile fabrication methods to obtain woven or nonwoven aerogels with different structural and mechanical properties to overcome the current limitations of polysaccharide-based aerogels, such as poor mechanical properties and undeveloped shaping techniques. Hereby, a high viscous solution of microcrystalline cellulose and zinc chloride hydrate was wet spun to produce mono and multi-filament alcogel microfibers. Subsequently, cellulose aerogel fibers (CAF) were produced and impregnated with model drugs using supercritical CO₂ processes. Fibers were characterized in terms of morphology and textural properties, thermal stability, mechanical properties, and in vitro biological and drug release assessments. Loaded and non-loaded CAFs proved to have a macro-porous outer shell and a nano-porous inner core with interconnected pore structure and a specific area in the range of 100-180 m²/g. The CAFs with larger diameter (d ~ 235 μm) were able to form knitted mesh while lower diameter fibers (d ~ 70 μm) formed needle punched nonwoven textiles. Humidity and water uptake assessments indicated that the fibrous structures were highly moisture absorbable and non-toxic with immediate drug release profiles due to the highly open interconnected porous structure of the fibers. Finally, CAFs are propitious to be further developed for biomedical applications such as drug delivery and wound care.

Chitosan Hydrogel Beads Supported with Ceria for Boron Removal

In this study, a chitosan hydrogel supported with ceria (labelled Ce-CTS) was prepared by an encapsulation technique and used for the efficient removal of excess B(III) from aqueous solutions. The functionalisation of chitosan with Ce(IV) and the improvement in the adsorptive behaviour of the hydrogel were determined by SEM-EDS, FTIR, XRD, and inductively coupled plasma optical emission spectrometer (ICP-OES) analyses and discussed. The results demonstrate that Ce-CTS removes boric acid from aqueous solutions more efficiently than either cerium dioxide hydrate or raw chitosan beads, the precursors of the Ce-CTS biosorbent. The maximum adsorption capacity of 13.5 ± 0.9 mg/g was achieved at pH 7 after 24 h. The equilibrium data of boron adsorption on Ce-CTS fitted the Freundlich isotherm model, while the kinetic data followed the Elovich pseudo-second-order model, which indicated that the process was non-homogeneous. The dominant mechanism of removal was the reaction between boric acid molecules and hydroxyl groups bound to the ceria chelated by chitosan active centres. Due to its high efficiency in removing boron, good regeneration capacity and convenient form, Ce-CTS may be considered a promising biosorbent in water purification.

Starch/microcrystalline cellulose hybrid gels as gastric-floating drug delivery systems

We report hybrid gels based on a high-amylose starch and microcrystalline cellulose with demonstrated properties for gastric-floating drug delivery purposes. The starch/cellulose gels were prepared by ionic liquid dissolution and regeneration, resulting in a continuous surface and a porous interior and a type-II crystalline structure of cellulose. These polysaccharide gels displayed satisfactory elasticity (0.88), recovery (0.26-0.36) and equilibrium swelling (1013-1369%). The hybrid gels were loaded with ranitidine hydrochloride as a model drug and subsequently, low-density starch/cellulose tablets were fabricated by vacuum-freeze-drying. In vitro tests in a simulated gastric fluid indicate that the 3:7 (wt./wt.) starch/cellulose system could maintain the buoyancy for up to 24 h with a release of 45.87% for the first 1 h and a sustained release for up to 10 h. Therefore, our results have demonstrated the excellent gastric-floating ability and sustainable drug release behavior of the starch/cellulose hybrid gels.