Search Results (115)

Unlike many biopolymers, α-1,3-glucan (α-1,3-GLU) is water-insoluble, making it a promising candidate for the production of moisture-resistant films with applications in biodegradable packaging, biomedicine, and cosmetics. This study aimed to characterize the structural, physicochemical (water affinity, optical, mechanical), and biodegradation properties of a film made from α-1,3-GLU extracted from Laetiporus sulphureus. The film was fabricated through alkaline dissolution, casting, drying, washing to remove residual NaOH, and re-plasticization with a glycerol solution. FTIR and Raman spectroscopy confirmed the polysaccharide nature of the film, with predominant α-glycosidic linkages. The film exhibited a semi-crystalline structure and high opacity due to surface roughness resulting from polymer coagulation. Owing to re-plasticization, the film showed a high moisture content (~47%), high water solubility (81.95% after 24 h), and weak mechanical properties (tensile strength = 1.28 MPa, elongation at break ≈ 10%). Its water vapor permeability (53.69 g mm m⁻² d⁻¹ kPa⁻¹) was comparable to other glycerol-plasticized polysaccharide films reported in the literature. The film supported the adhesion of soil microorganisms and target bacteria and was susceptible to degradation by Trichoderma harzianum and endo- and exo-α-1,3-glucanases, indicating its biodegradability. The limitations in its mechanical strength and excessive hydration indicate the need for improvements in the composition and methods of producing α-1,3-GLU films. Full article

Background/Objectives: The oral delivery of large-molecule drugs remains challenging due to poor solubility, perdemeability, and stability in the gastrointestinal tract, resulting in low bioavailability. In this study, hot melt extrusion (HME) was investigated as a solvent-free manufacturing technique for mucoadhesive bilayer films to improve drug absorption. Methods: Polyvinyl alcohol (PVA) and polyethylene oxide (PEO) were evaluated as mucoadhesive film-forming polymers, in conjunction with Eudragit^® RS as a water-insoluble backing layer. Paracetamol and lactase were utilized as small and large molecule APIs, respectively. The resulting films were assembled into bilayer film samples and examined for mechanical properties, mucoadhesion, and dissolution behavior. A novel dissolution model was developed to evaluate unidirectional drug transport. Results: The results showed that bilayer films could be successfully fabricated using HME, with different mechanical properties depending on the polymer and drug content. Tests with the newly developed dissolution model showed a unidirectional drug release. The model also confirmed the need for biorelevant dissolution test systems because of a better differentiation between polymers compared to standard test methods such as the paddle-over-disk method. Furthermore, the investigation revealed that the activity of enzymes was retained after extrusion, thus indicating the feasibility of processing biologics. Conclusions: This study highlights the potential of HME to produce bilayer films as an innovative drug delivery platform offering improved bioavailability for both small and large molecules. Full article

Sodium tungstate (Na₂WO₄) was filled into the micropores and onto the surface of a magnesium alloy microarc oxidation (MAO) coating by means of vacuum impregnation. Subsequently, the coating was sealed through silane treatment to synergistically boost its corrosion resistance. The phase composition of the coating was inspected using XRD. FTIR was utilized to analyze the functional groups in the coating. XPS was employed to study the chemical composition and valence state of the coating. The surface and cross-sectional morphology of the coating, along with its elemental composition and distribution, were investigated by SEM and EDS. Meanwhile, the thickness of the coating was analyzed using Image J software. Electrochemical impedance spectroscopy (EIS) was employed to determine the corrosion resistance of the coating. The results show that compared with an MAO coating, M-0.125W composite coating (only filled with sodium tungstate on the surface of the MAO coating), and M-SG composite coating (only receiving silanization treatment applied to the surface of the MAO coating), the corrosion resistance of the M-nW-SG composite coating (loaded with sodium tungstate on the surface of the MAO coating and then treated with silane) is significantly improved. This is mainly attributed to the fact that sodium tungstate can be combined with Mg²⁺ to form insoluble magnesium tungstate protective film, which blocks corrosion media. At the same time, silanization treatment further seals the MAO coating and increases the compactness of the coating. In addition, with the increase in the impregnation concentration of sodium tungstate, the content of sodium tungstate in the M-nW-SG composite coating improves, and the sealing effect of silanization treatment is better. When the impregnation concentration of sodium tungstate is 0.1 mol/L or above, the MAO coating with sodium tungstate can be completely sealed. When the impregnation concentration of sodium tungstate is 0.125 mol/L, M-0.125W-SG composite coating has the best corrosion resistance, and its impedance modulus value can be maintained at 8.06 × 10⁶ Ω·cm² after soaking in 3.5 wt.% NaCl solution for 144 h, which is about three orders of magnitude higher than those of MAO coating and M-0.125W and M-SG composite coatings. Full article

Orodispersible thin film (ODF) is an innovative dosage form that allows for adjustable dosing and improved patient compliance. It is administered by mouth, where it dissolves, making it suitable for children. Objectives: The aim of the study was to develop and characterize an optimal ODF formulation containing equivalent hydrocortisone at 0.5 mg/cm² using the solvent-casting method. A stability-indicating assay for the simultaneous quantification of hydrocortisone and hydrocortisone 21-hemissucinate (HMS) was developed. ODFs were characterized by organoleptic properties and by testing for uniformity of mass, content, stability, thickness, and dissolution. Results: When optimized, ODF is thin, flexible, and transparent, making it suitable for production in hospital pharmacies using standard equipment. In contrast to the water-insoluble hydrocortisone, the HMS-loaded cast gel successfully satisfied the tests, including content uniformity. Disintegration appeared acceptable as compared to the commercial grade ondansetron ODF (Setofilm^®). The physicochemical stability of the active ingredients (i.e., HMS, hydrocortisone) contained in the ODF at 0.5 mg/cm² is demonstrated for at least 84 days at 23 °C. Conclusion: The ODF formulated with the water-soluble hydrocortisone prodrug HMS allows accurate drug level to be achieved, thus opening up new opportunities for use in pediatric patients. Full article

Synthetic packaging is being replaced by biodegradable packaging through the revalorization of food industry by-products. The olive oil (OO) industry, known for producing large quantities of antioxidant-rich by-products, can be a major supplier for sustainable packaging materials. This study aims to valorize a food-grade by-product (defatted flour, DF) from OO extraction produced using a zero-waste strategy that combines expeller press technology and supercritical CO₂ extraction. DF and its aqueous extract (DFE) were combined with carboxymethylcellulose (CMC) to create biodegradable bioactive packaging films. DF contains a high content of insoluble dietary fiber (28.4%) and total phenolic compounds (35,000 ppm), including oleuropein, elenolic acid, hydroxytyrosol, and tyrosol (4324, 3603, 1525, and 157 ppm, respectively). This study examined the effects of DF and DFE on the physicochemical and barrier properties of the films, as well as their capacity to delay oxidation in polyunsaturated fatty acid-rich oil. Films with DF and DFE contained high phenolic content (1500 and 1200 ppm, respectively), and their inclusion improved ultraviolet visible barrier capacity. Additionally, oil oxidation was slower when protected by DF- and DFE-based films than when protected with CMC film alone. This allows their use as protective packaging and potential carriers of bioactive oils to enhance the nutritional and functional qualities of packaged foods. Full article

Mucilages are valuable to the food industry, but the solvents used to extract and concentrate them are detrimental to the environment. Therefore, environmentally friendly technologies that preserve the properties of biopolymers and reduce the use of solvents are being sought. In this work, the mucilage of Opuntia ficus-indica (mesocarp–endocarp) was extracted by two methods: In the first one, the pulp from the mesocarp–endocarp was extracted by ethanol precipitation and centrifugation cycles, then dried at room temperature. For the second, the pulp was processed in a three-step tangential microfiltration process: microfiltration (separation), diafiltration (purification), and concentration. The mucilages obtained differed significantly (p < 0.05) in color, betalains, total sugars, and proteins. The proportions of insoluble and soluble dietary fiber were similar. GC/MS analysis identified seven neutral sugars and a high content of uronic acids (31.3% in the microfiltered mucilage and 47.5% in the ethanol-precipitated mucilage). These show a low degree of esterification, which gives them a polar and hydrophilic character and the possibility of interacting with divalent ions through the carboxylic acid groups, which could form gels stabilized by an egg-box mechanism, with application as a thickening, stabilizing, gelling, or film-forming agent for foods with low sugar content. Full article

Metathesis homo- and copolymerization of bifunctional monomers bearing two norbornene moieties was studied. The monomers were synthesized from cis-5-norbornene-exo-2,3-dicarboxylic anhydride and various diamines (hexamethylenediamine, decamethylenediamine, 1R,3S-isophoronediamine). The metathesis homopolymerization of these bis(nadimides) in the presence of the second-generation Grubbs catalyst afforded glassy cross-linked polymers in more than 90% yields. The metathesis copolymerization of the bis(nadimides) and a monofunctional norbornene derivative containing the β-pinene fragment also resulted in insoluble cross-linked polymers in nearly quantitative yields. The structures and purity of the synthesized polymers were confirmed via IR spectroscopy and CP/MAS NMR spectroscopy. Conditions for the fabrication of mechanically strong solution-cast thin films based on copolymers synthesized from the comonomers mentioned above were determined by varying the content of the cross-linking agent. It was shown that the films made in this way are stable in a range of organic solvents and could be useful as semipermeable or membrane materials for use in liquid organic media. The permeability of the polymer films in question to 1-phenylethanol and mandelic acid was studied. The results obtained are discussed along with the data from the DSC, TGA, and powder X-ray diffraction studies of the properties of the synthesized metathesis homo- and copolymers. Full article

Electrically conductive polymeric materials have recently garnered significant interest from researchers due to their potential applications in the biomedical field, including medical implants, tissue engineering, flexible electronic devices, and biosensors. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is considered the most successful conducting polymer due to its higher electrical conductivity and chemical stability, but it suffers from limited solubility in common organic solvents, poor mechanical properties, and low biocompatibility. An area of tremendous interest is in combining PEDOT:PSS with another polymer to form a blend or composite material in order to access the beneficial properties of both materials. However, the hydrophilic nature of PEDOT:PSS makes it difficult to produce composites with non-polar polymers. In order to overcome these problems, we have specifically designed and synthesized two new sulfonated polyurethanes (PUS) with high sulfonic acid functionality. The two polyurethanes, one water-soluble (PUS1) and one water-insoluble (PUS2), were used to make blends with two commercially available PEDOT:PSS formulations (Clevios^TM FET and PH1000). Solvent cast films on glass substrates were made from water-soluble PEDOT:PSS/PUS1 blends while free-standing films of PEDOT:PSS/PUS2 blends were fabricated by compression-moulding. Ethylene glycol was used as conductivity enhancer, which showed an increase in the conductivity by several orders of magnitude in most of the compositions investigated. The highest conductivity of 438 S cm⁻¹ was achieved for the blend with 80 wt% of PEDOT:PSS (PH1000) in PUS1. Full article

Efficient catalytic reduction of 4-nitrophenol (4-NP) is one focus of industry and practical engineering, because 4-NP is one of the most important sources of pollution of the ecological environment and human health. Here, coassembled hybrid composites of pillar[5]arene (P5A) and gold nanoparticles (Au NPs) were successfully developed by a one-step synthetic method as a type of water-insoluble catalyst for the reduction of 4-NP. The geometric and topological structures, as well as physiochemical properties of Au NPs/P5A composite catalyst, were fully characterized and analyzed through various tests such as transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR), indicating that Au NPs were well dispersed on the surface of the two-dimensional film of assembled P5A. The influence factors of the catalytic reduction of 4-NP were further investigated and discussed, confirming that the content of Au NPs and the concentration of 4-NP were very significant during the catalysis. The catalytic reaction was carried out at the catalyst concentration of 100 mg·L⁻¹ and an initial 4-NP concentration of 90 mg·L⁻¹ under 30 °C. The calculated reaction rate constant was 0.3959 min⁻¹ and the reduction rate of 4-NP was more than 95% in 20 min. In addition, the as-prepared catalyst can maintain a high catalytic efficiency after five cycles. Thus, the easily recyclable composite catalyst with poor aqueous solution can exhibit prospective application to the treatment of 4-NP in water. Full article

In recent years, astaxanthin as a natural substance has received widespread attention for its potential to replace traditional synthetic antioxidants and because its antioxidant activity exceeds that of similar substances. Based on this, this review introduces the specific forms of astaxanthin currently used as an antioxidant in foods, both in its naturally occurring forms and in artificially added forms involving technologies such as emulsion, microcapsule, film, nano liposome and nano particle, aiming to improve its stability, dispersion and bioavailability in complex food systems. In addition, research progress on the application of astaxanthin in various food products, such as whole grains, seafood and poultry products, is summarized. In view of the characteristics of astaxanthin, such as insolubility in water and sensitivity to light, heat, oxygen and humidity, the main research trends of astaxanthin-loaded systems with high encapsulation efficiency, good stability, good taste masking effect and cost-effectiveness are also pointed out. Finally, the possible sensory effects of adding astaxanthin to food aresummarized, providing theoretical support for the development of astaxanthin-related food. Full article

Silicone rubber (SR) is a kind of polymer insulation material with excellent performance. With the service life of silicone rubber products reaching the limit, how to dispose of waste silicone rubber is an urgent problem to be solved. In this paper, silicone rubber-modified asphalt binder (SRMA) was prepared by SR and 90# base asphalt binder. The simulated short-term aging and long-term aging tests of SRMA were carried out using the thin film oven aging test (TFOT) and pressure aging vessel test (PAV). The rotary viscosity test and dynamic shear rheological test (DSR) were applied to the rheological properties of SRMA before and after aging. The degradation degree and chemical composition changes of SR were explored by the toluene insoluble matter test, Fourier transform infrared spectroscopy (FTIR), and a Fluorescence microscope (FM). The results demonstrate that SR can significantly affect the aging resistance, fatigue life, and high-temperature stability of SRMA. As the content of SR rose, the elastic component in SRMA increased, leading to a nice performance in stability at high temperatures and fatigue resistance. However, excessive content (14%wt and 16%wt) had a negative influence on the performance of SRMA. So, the optimal content was speculated to be between 12% and 14%. Furthermore, SR and asphalt binder would be aged and degraded together in the aging process, and this phenomenon was more obvious during long-term aging. Full article

Non-biodegradable plastic materials pose environmental hazards and contribute to pollution. Arabinoxylan (AX) films have been created for applications in food packaging to replace these materials. The water interaction characteristics of biodegradable AX films were assessed following the extraction of AX from dry-milled corn bran (DCB), wet-milled corn bran (WCB), and dried distiller’s grains with solubles (DDGS). Films were prepared with laccase and sorbitol before surface modification with lipase–vinyl acetate. Water solubility of the modified DCB films was significantly reduced (p < 0.05); however, the water solubility of modified WCB films decreased insignificantly (p > 0.05) compared to unmodified films. Water vapor permeability of the modified AX films from WCB and DDGS was significantly reduced (p < 0.05), unlike their unmodified counterparts. The biodegradation rates of the modified WCB AX and DDGS films increased after 63 and 99 days, respectively, compared to the unmodified films. The hydrophilic nature of AX polymers from WCB and DDGS enhances the biodegradability of the films. This study found that the modified WCB AX film was more hydrophobic, and the modified DDGS AX film was more biodegradable than the modified DCB AX film. Overall, surface modifications have potential for improving hydrophobicity of biopolymer films. Full article

Electrospun/sprayed fiber films and nanoparticles were broadly studied as encapsulation techniques for bioactive compounds. Nevertheless, many of them involved using non-volatile toxic solvents or non-biodegradable polymers that were not suitable for oral consumption, thus rather limiting their application. In this research, a novel electrospun lipid–polymer composite (ELPC) was fabricated with whole generally recognized as safe (GRAS) materials including gelatin, medium chain triglyceride (MCT) and lecithin. A water-insoluble bioactive compound, tetrahydrocurcumin (TC), was encapsulated in the ELPC to enhance its delivery. Confocal laser scanning microscopy (CLSM) was utilized to examine the morphology of this ELPC and found that it was in a status between electrospun fibers and electrosprayed particles. It was able to form self-assembled emulsions (droplets visualized by CLSM) to deliver active compounds. In addition, this gelatin-based ELPC self-assembled emulsion was able to form a special emulsion gel. CLSM observation of this gel displayed that the lipophilic contents of the ELPC were encapsulated within the cluster of the hydrophilic gelatin gel network. The FTIR spectrum of the TC-loaded ELPC did not show the fingerprint pattern of crystalline TC, while it displayed the aliphatic hydrocarbon stretches from MCT and lecithin. The dissolution experiment demonstrated a relatively linear release profile of TC from the ELPC. The lipid digestion assay displayed a rapid digestion of triglycerides in the first 3–6 min, with a high extent of lipolysis. A Caco-2 intestinal monolayer transport study was performed. The ELPC delivered more TC in the upward direction than downwards. MTT study results did not report cytotoxicity for both pure TC and the ELPC-encapsulated TC under 15 μg/mL. Caco-2 cellular uptake was visualized by CLSM and semi-quantified to estimate the accumulation rate of TC in the cells over time. Full article

In this work, a water-soluble (hydrophilic) polymer was used to form a hydrophobic coating on silicon substrates (Si) in a two-step process comprising (i) the transformation of the polymer into an insoluble material and (ii) the structuring of this coating at nanometric and micrometric scales to achieve the desired hydrophobic behavior. Polyvinylpyrrolidone (PVP), a water-soluble commodity polymer, was crosslinked using benzophenone and UV irradiation to produce a water-insoluble PVP coating. The nanometric scale roughness of the coating was achieved by the addition of silica nanoparticles (NPs) in the coating. The micrometric scale roughness was achieved by forming vertical pillars of PVP/NP coating. To prepare these pillars, a perforated polystyrene (PS) template was filled with a PVP/NP suspension. Micrometer scale vertical pillars of PVP/silica NPs were produced by this method, which allowed us to tune the wettability of the surface, by combining the micrometric scale roughness of the pillars to the nanometric scale roughness provided by the nanoparticles at the surface. By adjusting the various experimental parameters, a hydrophobic PVP coating was prepared with a water contact angle of 110°, resulting in an improvement of more than 80% compared to the bare flat film with an equal amount of nanoparticles. This study paves the way for the development of a more simplified experimental approach, relying on a blend of polymers containing PVP and NPs, to form the micro/nano-structured PVP pillars directly after the deposition step and the selective etching of the sacrificial major phase. Full article

The forest environment is exposed to a number of harmful factors that significantly reduce the resistance of forest stands, often leading to their extinction. In addition to abiotic and anthropogenic factors, biotic factors pose a significant threat to forests, among which insect pests are at the top of the list. Until now, the use of chemical insecticides has been considered the most effective method of pest control, resulting in pesticide residue in the environment. In an effort to minimize the harmful effects of insecticides, the European Union (EU), through EU Commission Implementing Regulations 2022/94, 2021/2081, 2021/795, and 2020/1643, has decided to withdraw from use a number of preparations containing compounds such as phosmet, indoxacarb, alpha-cypermethrin, and imidacloprid, among others. Botanical insecticides appear to be a promising alternative. Among them, plant oils and essential oils have become an innovative solution for controlling pests not only of forests but also of agricultural crops. The purpose of this literature review was to select oilseed plants with great biological potential. The rich chemical compositions of the seeds of Brassica carinata (A.) Braun and Camelina sativa (L.) Cranz predispose them to use as raw materials for the production of biopesticides with broad mechanisms of action. On the one hand, the oil will provide a physical action of covering pests feeding on a plant with a thin film, which will consequently lead to a reduction in gas exchange processes. On the other hand, the bioactive compounds in it or extracts of fat-insoluble compounds suspended in it and derived from the pomace fraction may have deterrent or lethal effects. This paper presents evidence of the potential action of these raw materials. Preparations based on these oils will not pose a threat to living beings and will not negatively affect the environment, thus allowing them to gain social acceptance. Full article