Search Results (407)

The preparation and use of iron oxide magnetic nanoparticles for water remediation is a widely investigated research field. To improve the efficacy of such nanomaterials, different synthetic processes and functionalization methods have been developed in the framework of green chemistry to exploit their magnetic properties and adsorption capacity in a sustainable way. In this work, iron oxide magnetic nanoparticles embedded in cross-linked sodium alginate beads designed to clean water from metal ions were magnetically characterized. In particular, the effect of copper adsorption on their magnetic properties was investigated. The magnetic characterization in a DC field of the beads before adsorption showed the presence of a superparamagnetic state at 300 K—a state that was also preserved after copper adsorption. The main differences in terms of magnetic properties before and after Cu²⁺ adsorption were the reduction of the magnetic signal (observed by comparing the saturation magnetization) and a different shape of the blocking temperature distribution obtained by magnetization versus temperature measurements. The evaluation of the reduction in magnetization can be important from the application perspective since it can affect the efficiency of the beads’ removal from the water medium after treatment. Full article

Infection control and bleeding management in deep wounds remain urgent and unmet clinical challenges that demand innovative, multifunctional, and sustainable solutions. Unlike previously reported sodium alginate and silk fibroin-based gel formulations, the present work introduces a dual-functional system combining antimicrobial and haemostatic activity in the form of conformable aerogel beads. This dual-functional formulation is designed to absorb exudate, promote clotting, and provide localized antimicrobial action, all essential for accelerating wound repair in high-risk scenarios within a single biocompatible system. Aerogel beads were obtained by supercritical drying of a silk fibroin–sodium alginate blend, resulting in highly porous, spherical structures measuring 3–4 mm in diameter. The formulations demonstrated efficient ciprofloxacin encapsulation (42.75–49.05%) and sustained drug release for up to 12 h. Fluid absorption reached up to four times their weight in simulated wound fluid and was accompanied by significantly enhanced blood clotting, outperforming a commercial haemostatic dressing. These findings highlight the potential of silk-based aerogel beads as a multifunctional wound healing platform that combines localized antimicrobial delivery, efficient fluid and exudate management, biodegradability, and superior haemostatic performance in a single formulation. This work also shows for the first time how the prilling encapsulation technique with supercritical drying is able to successfully produce silk fibroin and sodium alginate composite aerogel beads. Full article

Oral delivery of hydrophobic compounds remains challenging due to their poor aqueous solubility and the potential toxicity associated with conventional surfactant-based emulsions. To address these issues, we present a surfactant-free encapsulation strategy using electrosprayed alginate hydrogel beads for the stable and controlled delivery of hydrophobic oils. Hydrophobic compounds were dispersed in high-viscosity alginate solutions without surfactants via ultrasonication, forming kinetically stable oil-in-water dispersions. These mixtures were electrosprayed into calcium chloride baths, yielding monodisperse hydrogel beads. Higher alginate concentrations improved droplet sphericity and suppressed phase separation by enhancing matrix viscosity. The resulting beads exhibited stimuli-responsive degradation and controlled release behavior in response to physiological ionic strength. Dense alginate networks delayed ion exchange and prolonged structural integrity, while elevated external ionic conditions triggered rapid disintegration and immediate payload release. This simple and scalable system offers a biocompatible platform for the oral delivery of lipophilic active compounds without the need for surfactants or complex fabrication steps. Full article

This study aimed to microencapsulate Limosilactobacillus reuteri DSM 17938 to enrich soy yogurt flavored with peach jam. The effect of three concentrations of alginate and coating chitosan were evaluated in terms of probiotic viability, and the physicochemical and sensory properties of soy yogurt. Lim. reuteri was microencapsulated in alginate (1, 2, and 3%) and coated with chitosan (0, 0.4, and 0.8%). Soymilk was fermented using Lactobacillus bulgaricus and Streptococcus thermophilus. Soy yogurt was combined with probiotic beads and peach jam and stored for 27 days at 4 °C. The pH, titratable acidity, and probiotic viability of probiotic peach soy yogurt (PPSY) were determined during storage. Alginate at 3% and alginate (2%) coated with 0.4% chitosan maintained probiotic counts at 8 and 7.5 log CFU/g after 27 days. The pH of PPSY decreases rapidly and drastically during storage when probiotic-free cells are added. The PPSY containing alginate (3%) beads, alginate (2%) coated with chitosan (0.4%), and probiotic-free cells had a similar level of acceptance in color, texture, and odor (p > 0.05), while flavor and overall acceptability were significantly higher (p < 0.05) in PPSY with probiotic beads. These findings support the use of microencapsulation strategies in developing functional plant-based probiotic foods. Full article

Rice (Oryza sativa L.), a staple food for over half of the global population, plays a pivotal role in food security. Among its two primary groups, japonica and indica, temperate japonica varieties are particularly valued for their high-quality grain and culinary uses. Although some of these varieties are adapted to cooler climates, they often suffer from reduced productivity or increased disease susceptibility when cultivated in warmer productive environments. These limitations underscore the need for breeding programs to incorporate biotechnological tools that can enhance the adaptability and resilience of the plants. However, New Genomic Techniques (NGTs), including CRISPR-Cas9, require robust in vitro systems, which are still underdeveloped for temperate japonica genotypes. In this study, we developed a reproducible and adaptable protocol for protoplast isolation and regeneration from the temperate japonica cultivars ‘Ónix’ and ‘Platino’ using somatic embryos as the starting tissue. Protoplasts were isolated via enzymatic digestion (1.5% Cellulase Onozuka R-10 and 0.75% Macerozyme R-10) in 0.6 M AA medium over 18–20 h at 28 °C. Regeneration was achieved through encapsulation in alginate beads and coculture with feeder extracts in 2N6 medium, leading to embryogenic callus formation within 35 days. Seedlings were regenerated in N6R and N6F media and acclimatized under greenhouse conditions within three months. The isolated protoplast quality displayed viability rates of 70–99% within 48 h and supported transient PEG-mediated transfection with GFP. Additionally, the transient expression of a gene editing CRISPR-Cas9 construct targeting the DROUGHT AND SALT TOLERANCE (OsDST) gene confirmed genome editing capability. This protocol offers a scalable and genotype-adaptable system for protoplast-based regeneration and gene editing in temperate japonica rice, supporting the application of NGTs in the breeding of cold-adapted cultivars. Full article

The increasing frequency of Sargassum spp. blooms represents a global environmental challenge, impacting coastal ecosystems and requiring sustainable management strategies. This study evaluates the potential of Sargassum spp. extract as an encapsulating material for biological pest control, contributing to marine waste valorization. Pelagic Sargassum spp. collected from the Havana coast was processed to obtain an alginate-rich extract, which was used to encapsulate Beauveria bassiana conidia via ionic gelation. FTIR confirmed characteristic carboxylate absorption bands, indicating structural similarities with commercial alginate, while TGA demonstrated comparable thermal behavior. Beads exhibited consistent dimensions (0.5–3 mm) with irregular post-drying shapes. Encapsulation efficiency yielded a conidial concentration of 1.43 × 10⁸ conidia per mL, ensuring retention within the matrix. Long-term viability was confirmed as conidia remained viable and able to grow after six months, potentially benefiting from extract-derived compounds. These findings highlight the potential of repurposing Sargassum spp. for sustainable agricultural applications, advancing environmentally friendly pest management while addressing the ecological burden of excessive Sargassum accumulation. Full article

This research aims to synthesize a novel hydrogel bio-composite based on natural clay, sodium alginate (Na-AL), and iota-carrageenan as adsorbents to remove phosphate ions from aqueous solutions. The adsorbents were characterized by a variety of techniques, such as Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy coupled with energy dispersive X-rays (SEM-EDX), and the determination of point zero charge (PZC). This research investigated how the adsorption process is influenced by parameters such as adsorbent dose, contact time, solution pH, and temperature. In this study, we used four isotherms and four kinetic models to investigate phosphate ion removal on the prepared bio-composite. The results showed that the second-order kinetic (PSO) model is the best model for describing the adsorption process. The findings demonstrate that the R² values are highly significant in both the Langmuir and Freundlich models (very close to 1). This suggests that Langmuir and Freundlich models, with a diversity of adsorption sites, promote the adsorption of phosphate ions. The maximum adsorbed amounts of phosphate ions by the bio-composite used were 140.84 mg/g for H₂PO₄⁻ ions and 105.26 mg/g for HPO₄²⁻ ions from the batch system. The positive ∆H° confirms the endothermic and physical nature of adsorption, in agreement with experimental results. Negative ∆G° values indicate spontaneity, while the positive ∆S° reflects increased disorder at the solid–liquid interface during phosphate uptake. The main parameters, including adsorbent dosage (mg), contact time (min), and initial concentration (mg/L), were tuned using the Box–Behnken design of the response surface methodology (BBD-RSM) to achieve the optimum conditions. The reliability of the constructed models is demonstrated by their high correlation coefficients (R²). An R² value of 0.9714 suggests that the model explains 97.14% of the variability in adsorption efficiency (%), which reflects its strong predictive capability and reliability. Finally, the adsorption behavior of phosphate ions on the prepared bio-composite beads was analyzed using an artificial neural network (ANN) to predict the process efficiency. The ANN model accurately predicted the adsorption of phosphate ions onto the bio-composite, with a strong correlation (R² = 0.974) between the predicted and experimental results. Full article

Probiotics like Lactobacillus rhamnosus GG (LRGG) offer health benefits but face reduced viability under harsh gastrointestinal (GI) conditions. Encapsulation improves stability, yet most studies rely on static GI models with a simplified environment that may overestimate survival. This study assessed LRGG survival using chitosan-coated alginate beads under both static and dynamic GI models, including peristaltic flow and continuous juice replenishment. Food matrices (casein, corn starch, and soybean oil) were tested in static models. Beads were prepared via extrusion and subjected to simulated gastric and intestinal digestion. After 2 and 4 h of digestion, casein preserved LRGG viability at 8.50 ± 0.11 Log CFU/g, compared to 5.81 ± 0.44 with starch and undetectable levels with soybean oil. Casein’s protective effect was attributed to its pH-buffering capacity, raising gastric pH from 2.5 to 4.6. Starch offered moderate protection, while soybean oil led to bead dissolution due to destabilization of the egg-box structure. Dynamic GI models showed greater reductions in LRGG viability than static models, emphasizing the need for physiologically relevant simulations. The results highlight the importance of selecting appropriate food matrices and digestion models for accurate probiotic assessment, supporting improved encapsulation strategies in functional food development. Full article

Probiotics and phenolic compounds provide benefits to humans when they are consumed in adequate amounts. However, these materials are not very stable and can easily be degraded during processing and storage; so, they must be protected. This study evaluated the encapsulation of Lactiplantibacillus fabifermentans BAL-27 ITTG and phenolic compounds from coffee husks via alginate beads. The research considered variables such as alginate concentration (1.5% and 3%), crosslinking time (8 and 20 min), and the inclusion of chitosan. A 2³ factorial design was employed, and the effects were analyzed via ANOVA (p < 0.05). The encapsulation efficiency of the probiotic exceeded 80%, and its viability following gastrointestinal simulation ranged from 73.65% to 85.34%. The phenolic compounds achieved encapsulation efficiencies of up to 20%. In yogurt, the alginate beads maintained probiotic viability at approximately 9 Log₁₀ CFU/g and preserved the stability of the antioxidant compounds over 28 days. Moreover, the incorporation of beads did not adversely affect the physicochemical properties or sensory acceptance of the yogurt, supporting their potential application in functional foods. Full article

Alginate hydrogels offer distinct advantages as ionically crosslinked, biocompatible networks that can be shaped into spherical beads with high compositional flexibility. These spherical architectures provide isotropic geometry, modularity and the capacity for encapsulation, making them ideal platforms for scalable, stimuli-responsive actuation. Their ability to respond to thermal, magnetic, electrical, optical and chemical stimuli has enabled applications in targeted delivery, artificial muscles, microrobotics and environmental interfaces. This review examines recent advances in alginate sphere-based actuators, focusing on fabrication methods such as droplet microfluidics, coaxial flow and functional surface patterning, and strategies for introducing multi-stimuli responsiveness using smart polymers, nanoparticles and biologically active components. Actuation behaviours are understood and correlated with physical mechanisms including swelling kinetics, photothermal effects and the field-induced torque, supported by analytical and multiphysics models. Their demonstrated functionalities include shape transformation, locomotion and mechano-optical feedback. The review concludes with an outlook on the existing limitations, such as the material stability, cyclic durability and integration complexity, and proposes future directions toward the development of autonomous, multifunctional soft systems. Full article

Alginate is one of the most utilized biopolymers for the encapsulation of polyphenols throughout ionic gelation. For improvement in the encapsulation of polyphenols, other biopolymers and/or fillers can be employed. The purpose of this study was to include pullulan and/or disaccharides in an alginate encapsulation mixture to monitor whether we would achieve higher encapsulation of chokeberry juice polyphenols. Alginate hydrogel beads were used as controls, and through the results for total polyphenol and proanthocyanidin contents, concentrations of individual polyphenols, and antioxidant activities, it can be observed that pullulan and/or disaccharides had an impact on the encapsulation of these bioactives. Alginate/pullulan hydrogel beads had the highest contents of total polyphenols and proanthocyanidins (8.60 g/kg and 2.37 g/kg, respectively), whereas alginate/trehalose hydrogel beads had the lowest (5.50 g/kg and 1.16 g/kg, respectively). All hydrogel beads, except alginate/pullulan/sucrose, had higher anthocyanin (cyanidin-3-galactoside and cyanidin-3-arabinoside) contents than alginate beads (404.37 mg/kg and 89.97 mg/kg, respectively), but the most efficient combination for encapsulation of chokeberry anthocyanins was alginate/pullulan (477.32 mg/kg and 109.60 mg/kg, respectively). The highest concentration of neochlorogenic acid was determined in controls (260.14 mg/kg), while the highest concentration of chlorogenic acid in alginate/pullulan/sucrose beads (229.51 mg/kg). Quercetin-3-glucoside was evaluated as having the highest concentration in alginate/pullulan hydrogel beads (35.45 mg/kg). The data obtained through this study highlight the importance of the composition of an encapsulation mixture in order to achieve high encapsulation of chokeberry juice polyphenols. High encapsulation efficiency was obtained for anthocyanins, especially when pullulan was used in combination with alginate. Full article

This study evaluated two techniques for encapsulating Lactiplantibacillus plantarum using bovine lactoferrin and sodium alginate. The first method involved a layer-by-layer (LbL) coating of lactoferrin and alginate directly onto individual cells, using three layers of these electrolytes. The second method focused on encapsulating the probiotics in calcium alginate miniaturized beads, followed by a lactoferrin coating (AAcL). Encapsulation efficiency was measured at 52.7% for the LbL method and 32.6% for AAcL. Encapsulation was confirmed through zeta potential changes and scanning electron microscopy (SEM) micrographs. After freeze drying, the LbL technique showed a 2.67 log CFU decrease in survival rates, whereas the AAcL method resulted in a 3.77 log CFU decline. Nonencapsulated probiotics experienced a reduction of 5.8 log CFU. In storage at −20 °C, the LbL method led to a 32% decrease in survival after 30 days and 41% after 90 days, while the AAcL method showed a decline of 15% after 30 days and 28% after 90 days. Both techniques preserved 75% of the initial L. plantarum population under simulated gastrointestinal conditions. Overall, these methods effectively protected the probiotic from environmental stress. Full article

Low-temperature dried alginate/silica hybrid aerogel beads with a large specific surface area (160.8 m²/g), low density (0.160 m²/g), and high degree of sphericity were successfully fabricated. Single networks of silica aerogels beads were synthesized via by calcining hybrid aerogel beads in air. Moreover, alginate-derived carbon/silica aerogel beads were also obtained by the thermal treatment of the hybrid aerogel beads in nitrogen, which were indicative of the double networks of the as-synthesized crack-free hybrid aerogel beads for the first time. The adsorption performances of above aerogel beads were also investigated. Meanwhile, using a common silane coupling agent as a modifying agent, a series of hybrid aerogel beads with tunable functional surfaces were obtained. The results showed that the obtained samples adsorbed Pb²⁺ well, and the hybrid aerogel beads modified with KH-590 exhibited an experimental maximum adsorption capacity of Pb²⁺ of 193.73 mg·g⁻¹. Full article

Peanut (Arachis hypogaea L.) is one of the most important oilseeds crops worldwide. Through symbiosis with the bacterium Bradyrhizobium sp., peanuts can assimilate atmospheric nitrogen, reducing the need for chemical fertilizers. However, this nitrogen fixation process is highly sensitive to environmental factors that can inhibit the early stages of symbiotic interaction. In this study, we propose the encapsulation of Bradyrhizobium sp. SEMIA6144 and the flavonoid naringin (Nar) in alginate beads to improve flavonoid stability and promote nodulation kinetics in peanuts. Three types of beads were synthesized: A (control, SEMIA6144 only); B (SEMIA6144 induced with 10 µM Nar); and C (SEMIA6144 co-entrapped with 1 mM Nar). Although Nar increased cell mortality (2-fold compared to control) and reduced metabolic activity—particularly at 1 mM—cells in beads B and C responded by altering their membrane fatty acid profile (30% and 55.5% of 18:1, respectively) leading to a reduction in saturated fatty acids (5.8% and 13.1% for 16:0 and 18:0 in B; 11.8% and 21.2% in C). Bacterial release kinetics followed a primarily Fickian diffusion model, with minor matrix–bacteria interactions in Nar-treated beads. Notably, bacterial release in peanut root exudates was 6%, 10%, and 11% higher for beads A, B, and C, respectively, compared to release in physiological solutions. Nar-beads enhanced the formation of curved root hairs, promoted bacterial colonization in root hair zones, and stimulated the appearance of rosette-like structures associated with nodule initiation. In conclusion, encapsulating Bradyrhizobium sp. SEMIA6144 with Nar in beads represents a promising strategy to improve symbiotic nitrogen fixation in peanuts. Full article

Addressing the removal of hazardous phenolic pollutants from water, this study introduces an eco-friendly adsorbent composed of waste-derived hydrochar immobilized in alginate beads (Alg/HC). The physicochemical properties of the Alg/HC beads were characterized using SEM, XRD, and FTIR, confirming hydrochar encapsulation and partial structural preservation. Batch studies revealed a maximum 2-nitrophenol (2-NP) adsorption capacity of 15.80 ± 0.62 mg/g at 30 mg/L of 2-NP, with kinetics best described by the Elovich and pseudo-second-order models. Freundlich isotherm fitting indicated multilayer adsorption on heterogeneous surfaces, likely governed by hydrogen bonding and π–π interactions. In a fixed-bed column system, Alg/HC beads demonstrated a continuous adsorption capacity of 6.84 ± 0.45 mg/g at 10 mg/L of 2-NP, with breakthrough behavior modeled by the Yoon–Nelson and Thomas equations. The beads maintained stable performance across four regeneration cycles using a mild water/ethanol desorption method. This work represents the first study to explore Alg/HC composites for 2-NP removal in both batch and continuous modes, demonstrating their potential as low-cost, regenerable adsorbents for tertiary treatment of phenolic industrial wastewater. Full article