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The purpose of this work is to establish the influence of the nature of solid alginate gels (alginic acid, AAG; calcium alginate, CAG) and the conditions of methylene blue (MB) introduction to alginate matrices upon its release into aqueous media. MB is an active photosensitizer, which is used in the photodynamic therapy of tumors and purulent wounds. Solid alginate gels based on AAG and CAG were obtained by adding hydrochloric acid and calcium chloride to sodium alginate. The dye was introduced into the matrix either at the stage of gelation or by immersing the gel in an aqueous solution of the dye. It has been shown that the strength of the dye's attachment to AAG is higher than that of CAG, which leads to a higher rate of MB release from CAG into aqueous media. It has also been shown that, when introduced at the stage of gel formation, MB is released into both the water and buffer solutions. When MB is introduced by gel immersion into an MB solution, the dye may be released only into salt solutions. An alginate gel with immobilized MB can be used as a solid photosensitizing system with the controlled release of the photoactive agent into the wound cavity for photodynamic treatment. [ABSTRACT FROM AUTHOR]

Calcium alginate spheres with a volume of about 5 mL can be used for important purposes. Those that incorporate oolong tea give, in addition to the recreational aspect, the possibility of drinking small quantities of this tea, because oolong tea can be used as a compound with antioxidant properties. This incorporation can be achieved by reverse spherification (5 mL). Six types of spheres have been made, all of them with calcium alginate and the presence or absence of agar-agar and xanthan gum—XG—in two concentrations. The weight loss of the spheres, the release of bioactive compounds over time (a total of 48 h), the surface (internal and external) of the membranes, and the physical characteristics of these membranes have been analyzed. The data obtained indicate that the presence of XG prevents the formation of precipitates inside the spheres and slows down weight loss. It also provides opacity to the spheres. However, the incorporation of agar-agar does not have a significant influence on the different parameters analyzed. The release of catechins reaches a maximum of 80% of what could be achieved under ideal conditions, and it reaches 90% in the first 3 h. The incorporation of XG increases the shelf life of the spheres, slows down the release of chelate, and decreases weight loss over time, allowing for a new perspective on the spherification process. [ABSTRACT FROM AUTHOR]

Hydrophobized soils have functional hydrophobic coatings to delay or restrict water infiltration and thus prevent infrastructure failure and long-term degradation. Over time, hydrophobized soils will be subjected to degradation under the action of external stresses, leading to the loss of its functional properties. Microencapsulation approaches, initially developed for self-healing applications emerge as a potential solution to enhance, switch (from hydrophilic) or prolong the longevity of hydrophobized soils. The aim of this study is to produce and investigate the effectiveness of microencapsulation to impart hydrophobicity in granular materials in response to external stimuli. In this research, polydimethylsiloxane (PDMS), with hydrophobic properties, is encapsulated in calcium alginate microcapsules with the ionic gelation method. The effectiveness of the microcapsules to induce hydrophobicity is investigated by mixing sand with microcapsules and quantifying the change of the contact angle and water drop penetration time (measures of hydrophobicity) under an external trigger, i.e., under drying and consecutive wetting–drying cycles. The results show that microcapsules release the hydrophobic cargo (PDMS) during shrinkage. After drying, the PDMS content in sand increased to 0.1–0.8% by mass of sand. The released hydrophobic cargo (PDMS) induced hydrophobicity in sands, reflected by a contact angle increase from 29.7° to at least 87.7°. The amount of polydimethylsiloxane encapsulated is a key parameter controlling the release of hydrophobic cargo. In addition, 4% capsule content in sands is identified as an effective microcapsule content in inducing hydrophobicity. [ABSTRACT FROM AUTHOR]

The utilization of lignocellulosic materials for second-generation ethanol production via enzymatic catalysts is primarily hindered by enzyme cost. Enzymatic immobilization emerges as a viable solution, enabling enzyme reuse. This study investigated the immobilization of an enzymatic extract obtained from Moniliophthora perniciosa fermentation in calcium alginate spheres using the direct trapping method. Initial tests assessed β-glucosidase activity, showing that a higher concentration of calcium chloride (1 M) alongside larger diameter spheres yielded improved results. The immobilized enzyme was reused for up to 17 cycles without significant loss of activity. The percentage of reducing sugars after 48-h hydrolysis with the supplemented enzymatic extract was 226%, doubling the value achieved with only the free enzymatic extract. The immobilized enzyme retained 50% of its initial activity after 1 h at 80 °C, demonstrating higher activity at pH 6 and 60 °C. These findings suggest that this immobilization technique is simple, economically viable, and effective for the hydrolysis of pretreated sugarcane bagasse. Successful immobilization of M. perniciosa enzymatic extract achieved through direct entrapment in calcium alginate. Immobilized β-glucosidase demonstrates sustained activity over 16 reuse cycles, showcasing the potential for cost-effective bioconversion processes. Enhanced hydrolysis of sugarcane bagasse observed with immobilized enzymatic extract, indicating a promising approach for improved biomass utilization. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the presence of residual Plus Moist HS-W (PM), a novel calcium alginate packing material, during the initial postoperative visit following endoscopic sinus surgery. The research aims to identify factors that influence the quantity of remaining PM. A retrospective review of medical records was conducted for patients who underwent middle meatus packing with PM. A total of fifty-two patients (representing 92 sides of paranasal sinuses) were included in the analysis. The remaining PM was classified as follows: absent (0) in 41 out of 92 cases, minimal (1) in 22 out of 92 cases, moderate (2) in 15 out of 92 cases, and substantial (3) in 14 out of 92 cases. Notably, all three patients who underwent Draf III surgery exhibited a significant amount of PM during their initial visit, with two patients classified as grade 2 and one patient as grade 3. Other factors investigated were found to be unrelated to the persistence of PM. Removal of all PM was achieved effortlessly using suction under flexible endoscopy. This study highlights the efficacy of PM in post-endoscopic sinus surgery care. It is important to limit an amount of PM, particularly in Draf III procedures. [ABSTRACT FROM AUTHOR]

A synthesis strategy of calcium alginate/silver nanosheet microencapsulated phase change material (Alg/Ag-MEPCM) with controlled morphology was proposed, which is assisted with calcium carbonate microencapsulated phase change material (CaCO3-MEPCM) as a template. After successively adsorbing alginate and Ag+ on the template surface, the addition of l-ascorbic acid dissolved CaCO3 in the template to synthesize calcium alginate, while Ag+ was reduced to silver nanosheets by controlling the concentrations of the alginate and Ag+. The Alg/Ag-MEPCM exhibited a satisfactory latent heat storage capacity of 99.51 J/g, which enabled the PVA hydrogels containing Alg/Ag-MEPCM to have favorable temperature regulation ability. Moreover, the abundant silver nanosheets in Alg/Ag-MEPCM provided the PVA hydrogel containing Alg/Ag-MEPCM with a favorable antimicrobial capacity. Thus, the Alg/Ag-MEPCM prepared in this work has a promising application in the fields of thermal energy storage, thermoregulation, and antimicrobials, specifically as wound dressings and food packaging. [ABSTRACT FROM AUTHOR]

ZIF-8, a metal–organic framework that has significant benefits such as a substantial specific surface area, abundant active sites, and high porosity, has extensive application in environmental remediation. However, ZIF-8 is powdery and easily agglomerated, making it difficult to separate ZIF-8 from aqueous solutions and thus limiting its practical application in wastewater treatment. In this work, sodium alginate was chosen as a gel matrix, and CaCl2 as a cross-linking agent to form a calcium cross-linked MOF gel material (ZIF-8/SA). The batch adsorption investigations demonstrated that the saturated adsorption capacities of ZIF-8/SA in single Mn2+ pollution solution and Mn–Cu–Cd composite pollution solution are 179.86 mg g−1 and 101.86 mg g−1, respectively. Specifically, the adsorption of Mn2+ followed the Langmuir model and exhibited monomolecular layer adsorption. Furthermore, the adsorption of Cu2+ and Cd2+ followed the quasi-first-order kinetic model, which is primarily physical adsorption. The adsorption order of ZIF-8/SA for contaminants in the adsorption process is as follows: Cu2+ > Cd2+ > Mn2+. The SEM-EDS, FT-IR, and XPS studies revealed that the adsorption mechanism of ZIF-8/SA mostly involves ion exchange, coordination of carboxyl/hydroxyl/amino groups, and electrostatic attraction. To summarize, the experimental findings of this study demonstrate that the synthetic ZIF-8/SA hydrogel has promising applications for practical pollution treatment. [ABSTRACT FROM AUTHOR]

Conductive hydrogels play a crucial role in advancing technologies like implantable bioelectronics and wearable electronic devices, owing to their favorable conductivity and appropriate mechanical properties. Here, a novel bottom‐up approach is reported for crafting conductive nanocomposite hydrogels to achieve enhancing conductive and mechanical properties. In this approach, new poly(ɛ‐caprolactone)‐based block copolymers with sulfonic groups are first synthesized and self‐assembled into uniform polyanionic nanoplatelets. Subsequently, these negatively charged nanoplatelets, with sulfonic groups on the surface, are employed as nanoadditives for the polymerization of 3,4‐ethylenedioxythiophene (EDOT), resulting in poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/nanoplatelet complex with 3.8 times enhanced electrical conductivity compared with their counterparts prepared using block copolymers (BCPs). Blending the (PEDOT:PSS)/nanoplatelet complex with calcium alginate, nanocomposite hydrogels are successfully prepared. In comparison with hydrogels with (PEDOT:PSS)/BCP complexes prepared by a top‐down method, the nanocomposite hydrogels are found to show twice as strong mechanical strength and 1.6 times higher conductivity. This work provides valuable insights into the bottom‐up construction of conductive hydrogels for bioelectronics using well‐controlled polymeric nanoplatelets. [ABSTRACT FROM AUTHOR]

Di-n-butyl phthalate (DBP) is a prevalent phthalate ester widely used as a plasticizer, leading to its widespread presence in various environmental matrices. This study presents an innovative microbial immobilization strategy utilizing biochar, calcium alginate (alginate-Ca, (C12H14CaO12)n), and waterborne polyurethane (WPU) composites to enhance the biodegradation efficiency of DBP. The results revealed that rice husk biochar, pyrolyzed at 300 °C, exhibits relatively safer and more stable physical and chemical properties, making it an effective immobilization matrix. Additionally, the optimal cultural conditions for Bacillus aquimaris in DBP biodegradation were identified as incubation at 30 °C and pH 7, with the supplementation of 0.15 g of yeast extract, 0.0625 g of glucose, and 1 CMC of Triton X-100. Algal biotoxicity results indicated a significant decrease in biotoxicity, as evidenced by an increase in chlorophyll a content in Chlorella vulgaris following DBP removal from the culture medium. Finally, microbial community analysis demonstrated that encapsulating B. aquimaris within alginate-Ca and WPU layers not only enhanced DBP degradation, but also prevented ecological competition from indigenous microorganisms. This novel approach showcases the potential of agricultural waste utilization and microbial immobilization techniques for the remediation of DBP-contaminated environments. [ABSTRACT FROM AUTHOR]

Liquid beads are core–shell particles with a liquid core and a solid shell. Calcium alginate liquid beads have been emerging as a promising platform for cell encapsulation. These beads have demonstrated their capability of encapsulating and culturing a wide range of human cells for tissue engineering. However, a significant research gap remains in the application of alginate liquid beads for encapsulating photosynthetic microorganisms. Herein, fast‐growing microalgae strain Chlorella vulgaris is encapsulated into calcium alginate liquid beads to facilitate the removal of nutrients from wastewater, minimizing the risk of eutrophication. Liquid bead‐microalgae systems are prepared, using different calcium ion concentrations as crosslinking ions. It has been thoroughly characterized for their morphologies, cell growth patterns, nutrient removal capabilities, and overall stability throughout the wastewater treatment process, with upflow anaerobic sludge blanket effluent as the wastewater model. The results indicate that the liquid bead‐microalgae system with the highest calcium ion concentration (5%) performs more efficiently, exhibiting a well‐formed crosslinking structure, leading to rapid cell growth with the highest cell density and the most effective removal of nutrients. The findings from this study provide valuable insights for future optimization and upscaling efforts in wastewater treatment systems based on calcium alginate liquid beads. [ABSTRACT FROM AUTHOR]

This study compared free and immobilized cells with palm oil and hexanol as an extractant in a large volume ratio of extractant to the broth. Fermentation was conducted using TYA (Tryptone-Yeast-Acetate) media, glucose as the substrate and the palm oil, hexanol, and a mixture of hexanol and palm oil with a composition of 1:1 v/v as an extractant in the fermentation with a large volume ratio of extractant to broth of 5. The strain was inoculated as free-suspended cells of C. saccharoperbutylacetonicum N1-4 and immobilized cells in calcium alginate. The best extractant results for the acetone fermentation process in the ratio of extractive fermentation of free cells and immobilized cells were using palm oil as extractants. This extractant harvested acetone well, with the acetone concentration in the extractant at 18.41 g/L in free cell fermentation and 17.07 g/L in immobilized cell fermentation. The maximum total acetone concentration was up to 93.72 g/L broth. Using palm oil as an extractant in a large extractant volume combined with immobilization is an alternative to enhance bioacetone production by effectively reducing the toxicity effect of the products and minimizing nutrient requirements. [ABSTRACT FROM AUTHOR]

Polymer microspheres (PMs), such as polyacrylamide, have been widely applied for enhanced oil recovery (EOR), yet with environmental concerns. Here, we report a microfluid displacement technology containing a bio-based eco-friendly material, i.e., calcium alginate (CaAlg) microspheres for EOR. Two dominant mechanisms responsible for EOR over CaAlg fluid have been verified, including the microscopic oil displacement efficacy augmented by regulating capillary force (determined by the joint action of interfacial tension and wettability between different phases) and macroscopic sweep volume increment through profile control and mobility ratio reduction. This comprehensive effectiveness can be further impacted when the CaAlg microsphere is embellished ulteriorly by using appropriate amount of sodium dodecyl sulfonate (SDS). The core flooding and nuclear magnetic resonance (NMR) tests demonstrate that CaAlg-SDS microsphere can balance the interphase property regulation (wettability alteration and IFT reduction) and rheology properties, enabling simultaneous profile control and oil displacement. Excessive introduction of SDS will have a negative impact on rheological properties, which is not favored for EOR. Our results show that the involvement of 4-mM SDS will provide the best behavior, with an EOR rate of 34.38%. This cost-effective and environmentally-friendly bio-microspherebased microfluidic displacement technology is expected to achieve "green" oil recovery in future oilfield exploitation. [ABSTRACT FROM AUTHOR]

Purpose: Removal of the current calcium alginate packing materials to the middle meatus in endoscopic sinus surgery (ESS) is usually accompanied by discomfort or pain owing to the hard and brittle nature of these materials. Plus moist HS-W® is a new calcium alginate packing material released in 2022 developed to overcome this issue by changing the uronic acid component. We aimed to compare the discomfort/pain during the removal of Plus moist HS-W® with Kaltostat®, as well as their suitability as packing materials in ESS. Methods: Kaltostat® and Plus moist HS-W® were used as packing materials in 22 and 21 patients who underwent ESS in 2021 and 2022, respectively. Patients were asked to rate the pain during the packing removal 10 days after ESS using the Numerical Rating Scale (NRS). The ratio of residual packing materials, number of suctions (insertions/extractions of the suction cannula), and time required to remove packing materials were measured. Postoperative complications such as hemorrhage, local infection, lateralization of the middle turbinate, and synechia of the middle meatus were also evaluated. Results: The Plus moist HS-W® group exhibited significantly lower NRS pain scores, a lower ratio of residual packing materials, a reduced number of suctions, and a shorter time required to remove the packing. No obvious postoperative complications occurred in both groups except for one suspicious case of a slight infection in the Kaltostat® group. Conclusion: Compared with Kaltostat®, Plus moist HS-W®, characterized by better gelatinization than Kaltostat®, benefits patients by minimizing discomfort/pain during removal. Level of evidence: Level 3. [ABSTRACT FROM AUTHOR]

In this brief report, omitting the step of dissolving sodium alginate with water, directly mixing sodium alginate powder with calcium chloride powder sufficiently, and gelatinizing sodium alginate by the impregnation method improve the characteristics of sodium alginate gel which is in the form of jelly and has poor mechanical properties. In this paper, micron-sized gel particles were prepared by slow impregnation method using mixed powder of sodium alginate and calcium chloride. The preparation method is simple and low-cost, and can be used for the recovery of rare earth ions from aqueous solutions. The SAG-2 gel prepared at a mass ratio of sodium alginate to calcium chloride of 1:1 showed the best adsorption performance; the particle size varies from 50 to 200 µm. The adsorption capacities of SAG-2 for La(III), Ce(III), Pr(III), and Nd(III) were 334.1, 349.8, 360.1, and 364.5 mg g−1 at pH = 5. The adsorption equilibrium was reached in 35 min. The kinetic study showed that the adsorption process was chemisorption and the adsorption isotherm was well fitted with the Freundlich model. The adsorption mechanism was explored using FTIR and XPS characterization, indicating that both -OH and -COOH functional groups were involved in adsorption. The desorption of rare earths by different eluents was explored and the recyclability of the adsorbent was examined. [ABSTRACT FROM AUTHOR]

Contamination with cadmium (Cd) is a prominent issue in agricultural non-point source pollution in China. With the deposition and activation of numerous Cd metal elements in farmland, the problem of excessive pollution of agricultural produce can no longer be disregarded. Considering the issue of Cd pollution in farmland, this study proposes the utilization of cross-linked modified biochar (prepared from pine wood) and calcium alginate hydrogels to fabricate a composite material which is called MB-CA for short. The aim is to investigate the adsorption and passivation mechanism of soil Cd by this innovative composite. The MB-CA exhibits a higher heavy metal adsorption capacity compared to traditional biochar and hydrogel due to its increased oxygen-containing functional groups and heavy metal adsorption sites. In the Cd solution adsorption experiment, the highest Cd2+ removal rate reached 85.48%. In addition, it was found that the material also has an excellent pH improvement effect. Through the adsorption kinetics experiment and the soil culture experiments, it was determined that MB-CA adheres to the quasi-second-order kinetic model and is capable of adsorbing 35.94% of Cd2+ in soil. This study validates the efficacy of MB-CA in the adsorption and passivation of Cd in soil, offering a novel approach for managing Cd-contaminated cultivated land. [ABSTRACT FROM AUTHOR]

Textile effluents containing toxic dyes must be treated effectively before discharge to prevent adverse environmental impacts. Traditional physical and chemical treatment methods are costly and generate secondary pollutants. In contrast, biological treatment is a more suitable, clean, versatile, eco-friendly, and cost-effective technique for treating textile effluent. It is well established that indigenous microbial populations present in effluents can effectively degrade toxic dyes. In this regard, Achromobacter xylosoxidans DDB6 was isolated from the effluent sample to decolorize crystal violet (CV), Coomassie brilliant blue (CBB), and alizarin red (AR) by 67.20%, 28.58%, and 20.41%, respectively. The growth parameters of A. xylosoxidans DDB6 in media supplemented with 100 ppm of various dyes were determined using the modified Gompertz growth model. The immobilized cells in calcium alginate beads showed apparent decolorization rate constant of 0.27, 0.18, and 0.13 h−1 for CV, CBB, and AR, respectively. The immobilized cells in a packed bed reactor with an optimum flow rate of 0.5 mL/min were used to treat 100 ppm of CV with a percentage decolorization of 79.47% after three cycles. Based on the findings, A. xylosoxidans DDB6 could be effectively used for decolorization of various dyes. [ABSTRACT FROM AUTHOR]

The flotation behavior of apatite, a main mineral source of phosphorus, is strongly affected by the dissolved ionic species from gangue minerals. In this study, the effect of calcium ions on the fluorapatite flotation using the extracted sodium alginate E.SA depressant was investigated through microflotation tests, adsorption experiments, zeta potential measurements, and FTIR analyses. Although the amount of NaOL collector adsorbed on fluorapatite increased with increasing calcium concentrations, microflotation results reveal that adding calcium ions could deteriorate the fluorapatite recovery. More significant depression of fluorapatite could be achieved when Ca2+ and E.SA co-existed in the system. Zeta potential measurements and FTIR analyses showed that the addition of Ca2+ hardly affected the adsorption of E.SA onto fluorapatite surface, which can be due to the formation and precipitation of calcium alginate. In contrast, NaOL remained weakly adsorbed on the fluorapatite surface even the presence of Ca2+ and E.SA. [ABSTRACT FROM AUTHOR]

A rapid and mild coating strategy was applied on the millimeter scale calcium alginate capsules (Ca‐SA caps) by in situ interfacial polymerization of ethyl cyanoacrylate (ECA). The generated poly(ethyl cyanoacrylate) (PECA) coating was initiated by trace water in the surface of the Ca‐SA caps. The effects of ECA content, reaction time, and type of aromatic solvent on the morphology and control‐release property of the resulting PECA‐coated Ca‐SA caps (Ca‐SA caps@PECA) were investigated. The results demonstrated a white PECA layer successfully coated on the surface of Ca‐SA caps. Notably, the Ca‐SA caps@PECA remained consistently pleasing spherical shape as prepared in methylbenzene and ethylbenzene. When the ECA was 6 mL, the thickness of PECA layer of the Ca‐SA caps@PECA was 43.52 μm. Compared with the Ca‐SA caps, the weight retention ratio of water in the Ca‐SA caps@PECA increased by 254.61%, indicating the effective delay of water diffusion from core of the Ca‐SA caps@PECA. Moreover, the PECA coating improved the stability of the Ca‐SA caps@PECA, which achieved release‐controlling of dye at different pH. This method provides solution for surface modification of fragile hydrogel capsules to effectively control the releasing of liquid core, which is highly valuable in the field of food, cosmetic, and medical delivery. [ABSTRACT FROM AUTHOR]

Driven by climate change and human activity, Sargassum blooming rates have intensified, producing copious amount of the invasive, pelagic seaweed across the Caribbean and Latin America. Battery recycling and lead-smelter wastes have heavily polluted the environment and resulted in acute lead poisoning in children through widespread heavy metal contamination particular in East Trinidad. Our study details a comprehensive investigation into the use of Sargassum (S. natans), as a potential resource-circular feedstock for the synthesis of calcium alginate beads utilized in heavy metal adsorption, both in batch and column experiments. Here, ionic cross-linking of extracted sodium alginate with calcium chloride was utilized to create functional ion-exchange beads. Given the low quality of alginates extracted from Sargassum which produce poor morphological beads, composite beads in conjunction with graphene oxide and acrylamide were used to improve fabrication. Stand-alone calcium alginate beads exhibited superior Pb2+ adsorption, with a capacity of 213 mg g−1 at 20 °C and pH 3.5, surpassing composite and commercial resins. Additives like acrylamide and graphene oxide in composite alginate resins led to a 21–40% decrease in Pb2+ adsorption due to reduced active sites. Column operations confirmed Alginate systems' practicality, with 20–24% longer operating times, 15 times lower adsorbent mass on scale-up and 206% smaller column diameters compared to commercial counterparts. Ultimately, this study advocates for Sargassum-based Alginate ion-exchange beads as a bio-based alternative in Trinidad and developing nations for dealing with heavy metal ion waste, offering superior heavy metal adsorption performance and supporting resource circularity. [ABSTRACT FROM AUTHOR]

Microencapsulation facilitates incorporating bioactive volatile compounds into products throughout the food, health, and cosmetics industries. To minimize the number of ingredients when microencapsulating volatile oils, we examined surfactant-free encapsulation of d-limonene in cross-linked alginate microcapsules (CLAMs) via in situ cross-linking during spray drying. Surfactant-free CLAMs (SF-CLAMs) were prepared by forming a Pickering d-limonene emulsion stabilized by calcium carbonate nanoparticles (CaCO3-NPs), combining with alginates, and then spray drying. CaCO3-NPs served as both the emulsifier and the reservoir of alginate cross-linking agent. SF-CLAMs, with a volatile retention of 73.1 ± 4.7% and total limonene content of 13.6 ± 8.6% (w/w, d.b.), exhibited core-shell morphology where CaCO3-NPs surrounded large emulsion cores (∼5 μm) encased in densely cross-linked alginate shells. Limonene was fully retained for up to 4 h in SF-CLAMs in water at 37 °C. Moreover, microencapsulation in SF-CLAMs minimized release in simulated gastric fluid (2.2 ± 0.3% in 2 h) while fully releasing in simulated gastric fluid at 37 °C.

In this study, an efficient nanocomposite based on calcium alginate-carboxymethyl cellulose/iron oxide-copper oxide (CA-CMC/Fe2O3-CuO) is developed in beads form and utilized as nanoadsorbent and nanocatalyst. Further, the beads were coated with chitosan, resulting in Cs@CA-CMC/Fe2O3-CuO beads. The prepared beads exhibited exceptional adsorption capabilities for selected heavy metal ions. Notably, the Cs@CA-CMC/Fe2O3-CuO beads displayed remarkable adsorption among the other beads toward the three selected metal ions. Ag(I) was highly adsorbed by Cs@CA-CMC/Fe2O3-CuO beads, and the adsorption capacity of beads was 4.91 mgg−1, while 4.5 mgg−1 and 3.0 mgg−1 for Co(II) and Ni(II), respectively. Beads’ ability to adsorb Ag(I) varied depending on several factors. It was observed that the adsorption capacity of Ag(I) ions increased as the interaction time and metal concentration rose. However, increasing the beads dose led to a decrease in the Ag(I) ion adsorption. Further, the waste beads after Ag(I) adsorption were treated with reducing agent to form beads supported Ag nanoparticles (Ag/Cs@CA-CMC/Fe2O3-CuO) and used as effective catalyst for reducing 4-nitrophenol in the presence of NaBH4 as a reducing agent. Ag/Cs@CA-CMC/Fe2O3-CuO achieved reduction up to 93% for 4-NP within 30 min. The designed nanocomposite beads displayed several desirable attributes, including eco-friendliness and robust catalytic performance, making them highly promising for useful reduction of 4-NP.

Tetracycline (TC) is a common antibiotic; when untreated TC enters the environment, it will cause a negative impact on the human body through the food chain. In the present study, MnO2/MCM-41@Fe3O4 (FeMnMCM) prepared using a hydrothermal and redox method and Camellia oleifera shell-activated carbon (COFAC) prepared through alkali activation were encapsulated using alginate (ALG) and calcium chloride as a cross-linking matrix to give the composite beads COFAC–FeMnMCM–ALG. The resultant COFAC–FeMnMCM–ALG composite beads were then carefully characterized, showing a high immobilization of MnO2/MCM-41@Fe3O4, with porous COFAC as an effective bioadsorbent for enriching the pollutants in the treated samples. These bead catalysts were subsequently applied to the oxidative degradation of TC in a Fenton oxidation system. Several parameters affecting the degradation were investigated, including the H2O2 concentration, catalyst dosage, initial TC concentration, and temperature. A very high catalytic activity towards the degradation of TC was demonstrated. The electron paramagnetic resonance (EPR) and quenching results showed that ·OH and ·O2− were generated in the system, with ·OH as the main radical species. In addition, the COFAC–FeMnMCM–ALG catalyst exhibited excellent recyclability/reusability. We conclude that the as-prepared COFAC–FeMnMCM–ALG composite beads, which integrate MnO2 and Fe3O4 with bioadsorbents, provide a new idea for the design of catalysts for advanced oxidation processes (AOPs) and have great potential in the Fenton oxidation system to degrade toxic pollutants. [ABSTRACT FROM AUTHOR]

Fennel essential oil (EO) is well known for its biological activities and wide potential for use in the food, cosmetic, and pharmaceutical industries, where the main challenge is to achieve higher stability of EO. This study aimed to evaluate the potential of electrostatic extrusion for encapsulation of fennel EO by examining the effects of alginate (1%, 1.5%, and 2%) and whey protein (0%, 0.75%, and 1.5%) concentrations and drying methods on the encapsulation efficiency, loading capacity, bead characteristics, and swelling behavior of the produced fennel EO microbeads. Results revealed that electrostatic extrusion proved to be effective for encapsulating fennel EO, with whey protein addition enhancing the examined characteristics of the obtained microbeads. Freeze-drying exhibited superior performance compared to air-drying. Optimal encapsulation efficiency (51.95%) and loading capacity (78.28%) were achieved by using 1.5% alginate and 0.75% whey protein, followed by freeze-drying. GC-MS analysis revealed no differences in the qualitative aspect of the encapsulated and initial EO, with the encapsulated EO retaining 58.95% of volatile compounds. This study highlighted the potential of electrostatic extrusion using alginate and whey protein as a promising technique for fennel EO encapsulation while also emphasizing the need for further exploration into varied carrier materials and process parameters to optimize the encapsulation process and enhance product quality. [ABSTRACT FROM AUTHOR]

Double‐network hydrogels based on calcium alginate are extensively exploited. Unfortunately, their low strength and unstable constitution to open environments limit their application potential. Herein, a new type of double‐network organohydrogel (OHG) is proposed. By solvent exchange, a stable physical network is established based on dimethyl sulfoxide (DMSO)‐alginate in the presence of a polyacrylamide network. The DMSO content endows tunable mechanical properties, with a maximum tensile strength of ≈1.7 MPa. Importantly, the OHG shows much better environmental stability compared to the conventional double‐network hydrogels. Due to the reversible association of hydrogen bonds, the OHG possesses some unique properties, including free‐shapeability, shape‐memory, and self‐adhesion, that offers several promising ways to utilize alginate‐based gels for wide applications. [ABSTRACT FROM AUTHOR]

To combat climate change, one approach is to manufacture products from biomass-fungi composite materials instead of petroleum-based plastics. These products can be used in packaging, furniture, and construction industries. A 3D printing-based manufacturing method was developed for these biomass-fungi composite materials, eliminating the need for molds, and enabling customized product design. However, previous studies on the 3D printing-based method showed significant shrinkage of printed samples. In this paper, an approach is proposed to reduce the shrinkage by incorporating ionic crosslinking into biomass-fungi composite materials. This paper reports two sets of experiments regarding the effects of sodium alginate (SA) and calcium chloride (CaCl2) on fungal growth and fungal viability. The first set of experiments was conducted using Petri dishes with fungi isolated from colonized biomass-fungi material and different concentrations of SA and CaCl2. Fungal growth was measured by the circumference of fungal colonies. The results showed that concentrations of SA and CaCl2 had significant effects on fungal growth and no fungal growth was observed on Petri dishes with 15% CaCl2. Some of these Petri dishes were also observed under confocal microscopy. The results confirmed the differences obtained by measuring the circumference of fungal colonies. The second set of experiments was conducted using Petri dishes with biomass-fungi mixtures that were treated with different concentrations of SA and exposure times in a CaCl2 (crosslinking) solution. Fungal viability was measured by counting colony-forming units. The results showed that the addition of the SA solution and exposure times in the crosslinking solution had statistically significant effects on fungal viability. The 2SA solution was prepared by dissolving 2 g of SA in 100 mL of water, the 5SA solution was prepared by dissolving 5 g of SA in 100 mL of water, and the crosslinking solution was prepared by dissolving 5 g of CaCl2 in 100 mL of water. The results also showed that fungal viability was not too low in biomass-fungi mixtures that included 2SA solution and were exposed to the crosslinking solution for 1 min. [ABSTRACT FROM AUTHOR]

A microfluidic strategy of smart calcium alginate (CA) capsules is presented to immobilize Pseudomonas aeruginosa to treat oil slicks effectively. The capsule wall is embedded with poly (N‐isopropyl acrylamide) sub‐microspheres as thermo‐responsive switches. CA capsules, with a diameter of 3.26 mm and a thin wall thickness about 12.8 μm, have satisfying monodispersity, cavity structure, and dense surface structures. The capsules possess excellent encapsulation of bacteria, which are fixed in a restricted space and become more aggregated. It overcomes the disadvantages of a long fermentation production cycle, easy loss of bacteria, and susceptibility to shear effect. The smart CA capsules immobilized with bacteria treat model wastewater containing soybean oil or diesel and display favorable fermentation ability. The capsules can effectively treat oil slicks with high concentration, and it is an economical way for processing oily wastewater. Practitioner Points: A thermo‐responsive calcium alginate capsule was prepared by microfluidic strategy.Pseudomonas aeruginosa is environmentally friendly in treating oil slicks.The capsules, immobilized bacteria, treat oil slicks effectively.This study provides an economical way for processing different oily water. [ABSTRACT FROM AUTHOR]

BACKGROUND: Calcium alginate gels are widely used to encapsulate active compounds. Some characteristic parameters of these gels are necessary to describe the release of active compounds through mechanistic mathematical models. In this work, transport and kinetics properties of calcium alginate gels were determined through simple experimental techniques. RESULTS: The weight‐average molecular weight (M¯w = 192 × 103 Da) and the fraction of residues of α‐l‐guluronic acid (FG = 0.356) of sodium alginate were determined by capillary viscometry and 1H‐nuclear magnetic resonance at 25 °C, respectively. Considering the half egg‐box model, both values were used to estimate the molecular weight of calcium alginate as Mg = 2.02 × 105 Da. An effective diffusion coefficient of water (Deff,w = 2.256 × 10−9 m2 s−1) in calcium alginate was determined using a diffusion cell at 37 °C. Finally, a kinetics constant of depolymerization (km = 9.72 × 10−9 m3 mol−1 s−1) of calcium alginate was obtained considering dissolution of calcium to a medium under intestinal conditions. CONCLUSION: The experimental techniques used are simple and easily reproducible. The obtained values may be useful in the design, production, and optimization of the alginate‐based delivery systems that require specific release kinetics of the encapsulated active compounds. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Calcium alginate gel microspheres exhibiting pH response release characteristics were prepared, and utilizing Bovine serum albumin (BSA) to evaluate drug release performance. Hydrogels composed of gelatin (GL) and sodium alginate oxide (NALO), with varying ratios (7:3; 4:1; 3:2) were prepared by controlling their composition. Scanning electron microscopy (SEM) and a microplate reader (ELIASA) were used to characterize the microspheres' microstructure and in vitro BSA release behavior, respectively. The results demonstrated that, under acidic conditions, the BSA release was slower than in neutral conditions. The hydrogels' physical and chemical properties were analyzed using optical microscopy, Fourier transform infrared spectroscopy (FTIR), swelling experiments and mechanical testing of the hydrogels and microsphere loaded hydrogels. The results showed that a GL to NALO ratio of 7:3 increased the swelling degree, while a 4:1 ratio optimized the mechanical characteristics. The study concluded that the microsphere-loaded hydrogels exhibited significant potential for human drug delivery applications. [ABSTRACT FROM AUTHOR]

Rugulopteryx okamurae (RO) is an invasive brown seaweed that causes severe environmental problems in the Mediterranean Sea. This work proposed an extraction method that enables their use as a raw material for producing sodium alginate. Alginate was successfully extracted from this invasive seaweed, with its gelling performance in the presence of Ca2+ ions comparable to existing commercial alginates. The mannuronic acid (M)-to-guluronic (G) acid ratio in the 1H-NMR profile indicated a higher percentage of G in the RO-extracted alginate, which implies a greater formation of so-called egg box structures. These differences resulted in their different rheological behaviour, as sodium alginate aqueous solutions exhibited a greater viscosity ( η at 1 s−1 = 3.8 ± 0.052 Pa·s) than commercial alginate (2.8 ± 0.024 Pa·s), which is related to the egg box structure developed. When gelled in the presence of calcium, an increase in the value of the elastic modulus was observed. However, the value of the tan δ for the extracted alginate was lower than that of commercial alginate gels, confirming a structure more densely packed, which implies a different restructuring of the alginate chain when gelling. These results confirm the suitability of using invasive Rugulopteryx okamurae as a source of calcium alginate gels. In this way, sustainable bio-based materials may be produced from undesired biomass that currently poses a threat to the ecosystem. [ABSTRACT FROM AUTHOR]

Purpose: Sodium alginate (Na-Alg) is a natural polysaccharide with a rich and renewable production that is widely used in the food, pharmaceutical and daily necessities industries, among other fields. The purpose of this study is to obtain a green and degradable shape memory material, calcium alginate (Ca-Alg) film was prepared and the mechanical properties, the shape memory effect of the film were investigated and confirmed. Design/methodology/approach: The Ca-Alg films were prepared by Na-Alg, calcium chloride (CaCl2) solution, and flow extension method. Dissolve sodium alginate powder, remove bubbles, pour into petri dish, dry at 60°C, add calcium chloride solution cross-linking and finally dry naturally. The effect of CaCl2 solution concentration on the mechanical properties of the films were investigated and discussed by universal tensile tester. The shape memory behavior and degradation performance of thin films were verified and studied by the fold-deploy shape memory test and soil embedding method, respectively. Findings: The Ca-Alg films exhibited good mechanical and shape memory properties, with a 72.2% shape memory fixity ratio and a 92.3% shape memory recovery ratio, respectively. For a period of 120 days, the film treated with a 6 wt% CaCl2 solution degraded at a rate of approximately 53%. Research limitations/implications: Shape memory polymers (SMPs) as intelligent materials are an important research direction for the development of modern high-tech materials. On the other hand, plastic pollution is a major problem today; as a result, preparing green degradable SMPs is essential. Originality/value: This study synthesized transparent and degradable shape memory Ca-Alg films using Na-Alg and CaCl2 solution and the flow extension method. [ABSTRACT FROM AUTHOR]

This work proposes a novel drying method suitable for probiotic bacteria, called flash freeze-drying (FFD), which consists of a cyclic variation in pressure (up-down) in a very short time and is applied during primary drying. The effects of three FFD temperatures (−25 °C, −15 °C, and −3 °C) on the bacterial survival and water activity of Lactobacillus acidophilus LA5 (LA), previously microencapsulated with calcium alginate and chitosan, were evaluated. The total process time was 900 min, which is 68.75% less than the usual freeze-drying (FD) time of 2880 min. After FFD, LA treated at −25 °C reached a cell viability of 89.94%, which is 2.74% higher than that obtained by FD, as well as a water activity of 0.0522, which is 55% significantly lower than that observed using FD. Likewise, this freezing temperature showed 64.72% cell viability at the end of storage (28 days/20 °C/34% relative humidity). With the experimental data, a useful mathematical model was developed to obtain the optimal FFD operating parameters to achieve the target water content in the final drying. [ABSTRACT FROM AUTHOR]

Maize starch, polyvinyl alcohol, glucose, and magnesium stearate are used as tablet excipients, acetylsalicylic acid as probe, polyvinyl acetate, and calcium alginate as protective membranes. By changing the proportions of the excipients, the nature and the thickness of the protective membrane, it was possible to optimize the formulation of a controlled release tablet. The mechanism and the kinetics of release of the active ingredient are evaluated using kinetic models: zero order, Higuchi, first order, Hixson–Crowell and Krosmeyer–Peppas. The representation of the released quantities using Krosmeyer–Peppas seems to be the most appropriate to describe the release mechanism (R2 ~ 1). The k and n values, Krosmeyer–Peppas, indicate that drug release is complex. The release rate of the AI is controlled by the erosion of the membrane and the relaxation of the chains of polymers constituting it. The solubility parameters (δ), according to Hansen, of the hydroxylated ingredients, predict compatibility and stability. [ABSTRACT FROM AUTHOR]

Calcium alginate fiber has become an ideal raw material for wound dressing preparation due to its excellent moisture absorption and biological compatibility. There are still some problems such as bacterial contamination of wounds and difficult observation of wound healing in the actual use process. To avoid bacterial contamination of the wound and visually observe the wound healing situation, a calcium alginate fiber with pH‐responsive and antibacterial properties has been developed by the facile and eco‐friendly one‐step method. In order to make the calcium alginate fiber can be used intelligently to continuously monitor wound changeable pH, the fiber is originally solution dyed by alizarin dye. And the antibacterial property of this calcium alginate fiber is mainly from silver nanoparticles (AgNPs) which are in situ reduced by alginate in the spinning solution. This one‐step wet spinning method can avoid the subsequent complicated process required for calcium alginate fiber functionalization while ensuring the material properties. Owing to the existence of AgNPs, the calcium alginate fiber prepared has a significant antibacterial effect on two kinds of gram bacteria. Therefore, this calcium alginate fiber exhibits good pH‐responsive and antibacterial properties performance and is an improvement upon the current flexible pH sensor to indicate wound healing. [ABSTRACT FROM AUTHOR]

A significant part of research in environmentally friendly agroindustrial production is aimed at immobilized bacterial preparations with retained capacity for active growth without loss of metabolic activity both during immobilization and after long-term storage and biotechnological use. In the present work, immobilization of members of the genus Azospirillum on natural and synthetic carriers was investigated. Efficiency of immobilization of the cells of A. brasilense strain SR80 in alginate hydrogel and vermiculite was investigated. Proliferative and metabolic activities of immobilized preparations were investigated. The prospects of using vermiculite and calcium alginate as matrices for Azospirillum immobilization are shown. [ABSTRACT FROM AUTHOR]

Objective: To compare the intervention effects and pharmacoeconomic advantages of Fufang Huangbai Fluid (FFHB) hydropathic compress versus Antimicrobial Calcium Alginate Wound Dressing (ACAWD) in the treatment of diabetic foot infections (DFI). Methods: Patients with DF who were hospitalized in the peripheral vascular Department of Dongzhimen Hospital of Beijing University of Chinese Medicine from December 2020 to February 2022 and met the inclusion and excluding criteria were allocated into the experimental group and control group through minimization randomization. The experimental group was treated with FFHB hydropathic compress for 2 weeks, while the control group was treated with ACAWD for the same duration. The wound healing of both groups was monitored for 1 month post-discharge. Clinical data from all eligible patients were collected, and differences in various indices between cohorts were analyzed. Results: 22 in the experimental group (including two fell off) and 20 in the control group. After the treatment, the negative rate of wound culture in the experimental group was 30% and that in the control group was 10%, There was no significant difference in the negative rate of wound culture and change trend of minimum inhibitory concentration (MIC) value of drug sensitivity (p > 0.05). The infection control rate of the experimental groupwas 60%, and that of the control group was 25%. The difference between the two groups was statistically significant (χ² = 5.013, p = 0.025). The median wound healing rate of the experimental group was 34.4% and that of the control group was 33.3%. There was no significant difference between the two groups (p > 0.05). During the follow-up 1month later, the wound healing rate in the experimental group was higher, and the difference was statistically significant (p = 0.047). Pharmacoeconomic evaluations indicated that the experimental group had greater cost-effectiveness compared to the control group. Conclusion: In the preliminary study, FFHB demonstrated comparable pathogenic and clinical efficacy to ACAWD in the treatment of mild DF infection, and exhibited superior pharmacoeconomic advantages. With the aid of infection control, the wound healing rate in the FFHB group showed notable improvement. Nevertheless, due to the limited sample size, larger-scale studies are warranted to further validate these findings. [ABSTRACT FROM AUTHOR]

Enzyme replacement therapy for hyperuricemia treatment has been proven effective for critical state hyperuricemia patients. Still, direct administration of recombinant uricase can induce several fatal side effects. To circumvent this drawback, hydrogel protein carriers can be used in platforms for extracorporeal treatment such as microscale‐based devices. In this work, calcium alginate and poly‐(vinyl alcohol) hydrogel films were studied for their urate oxidase immobilization and uric acid reduction, which could be implemented in microscale‐based extracorporeal devices. A mathematical model was developed in conjunction with uric acid reduction experiments to evaluate the influence of mass transfer and reaction parameters in the Michaelis–Menten kinetic expression. Alginate hydrogels prepared with crosslinker 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide and N‐(hydroxysuccinimide) offered superior diffusivity of uric acid in the gel matrix at the maximum value of Dg,UA≈$$ {D}_{\mathrm{g},\mathrm{UA}}\approx $$1.98 × 10−11 m2/s compared with alginate prepared solely from ionic crosslinking with Dg,UA≈$$ {D}_{\mathrm{g},\mathrm{UA}}\approx $$ 5.31 × 10−12 m2/s at the same alginate concentration. The maximum value of νmax was experimentally determined at 7.78 × 10−5 mol/(m3s). A 3% sodium alginate hydrogel with crosslinkers yielded the highest reduction of uric acid at 92.70%. The mathematical model demonstrated an excellent prediction of uric acid conversion suggesting potential use of the model for formulation and maximizing the therapeutic performance of functionalized hydrogels. [ABSTRACT FROM AUTHOR]

Liquid beads are core–shell particles with a liquid core and a solid shell. Calcium alginate liquid beads have been emerging as a promising platform for cell encapsulation. These beads have demonstrated their capability of encapsulating and culturing a wide range of human cells for tissue engineering. However, a significant research gap remains in the application of alginate liquid beads for encapsulating photosynthetic microorganisms. Herein, fast‐growing microalgae strain Chlorella vulgaris is encapsulated into calcium alginate liquid beads to facilitate the removal of nutrients from wastewater, minimizing the risk of eutrophication. Liquid bead‐microalgae systems are prepared, using different calcium ion concentrations as crosslinking ions. It has been thoroughly characterized for their morphologies, cell growth patterns, nutrient removal capabilities, and overall stability throughout the wastewater treatment process, with upflow anaerobic sludge blanket effluent as the wastewater model. The results indicate that the liquid bead‐microalgae system with the highest calcium ion concentration (5%) performs more efficiently, exhibiting a well‐formed crosslinking structure, leading to rapid cell growth with the highest cell density and the most effective removal of nutrients. The findings from this study provide valuable insights for future optimization and upscaling efforts in wastewater treatment systems based on calcium alginate liquid beads.

The purpose of this work is to establish the influence of the nature of solid alginate gels (alginic acid, AAG; calcium alginate, CAG) and the conditions of methylene blue (MB) introduction to alginate matrices upon its release into aqueous media. MB is an active photosensitizer, which is used in the photodynamic therapy of tumors and purulent wounds. Solid alginate gels based on AAG and CAG were obtained by adding hydrochloric acid and calcium chloride to sodium alginate. The dye was introduced into the matrix either at the stage of gelation or by immersing the gel in an aqueous solution of the dye. It has been shown that the strength of the dye’s attachment to AAG is higher than that of CAG, which leads to a higher rate of MB release from CAG into aqueous media. It has also been shown that, when introduced at the stage of gel formation, MB is released into both the water and buffer solutions. When MB is introduced by gel immersion into an MB solution, the dye may be released only into salt solutions. An alginate gel with immobilized MB can be used as a solid photosensitizing system with the controlled release of the photoactive agent into the wound cavity for photodynamic treatment.

Calcium alginate spheres with a volume of about 5 mL can be used for important purposes. Those that incorporate oolong tea give, in addition to the recreational aspect, the possibility of drinking small quantities of this tea, because oolong tea can be used as a compound with antioxidant properties. This incorporation can be achieved by reverse spherification (5 mL). Six types of spheres have been made, all of them with calcium alginate and the presence or absence of agar-agar and xanthan gum—XG—in two concentrations. The weight loss of the spheres, the release of bioactive compounds over time (a total of 48 h), the surface (internal and external) of the membranes, and the physical characteristics of these membranes have been analyzed. The data obtained indicate that the presence of XG prevents the formation of precipitates inside the spheres and slows down weight loss. It also provides opacity to the spheres. However, the incorporation of agar-agar does not have a significant influence on the different parameters analyzed. The release of catechins reaches a maximum of 80% of what could be achieved under ideal conditions, and it reaches 90% in the first 3 h. The incorporation of XG increases the shelf life of the spheres, slows down the release of chelate, and decreases weight loss over time, allowing for a new perspective on the spherification process.

Hydrogels have been widely used for adsorbing heavy metal ions in wastewater treatment. Herein, a calcium alginate/poly‐N‐isopropylacrylamide double‐network hydrogel with photothermal responsiveness was prepared for adsorbing heavy metal ions in aqueous solution. The chemical composition, micromorphology, swelling properties, photothermal responsiveness, adsorption properties, and adsorption mechanism of gel microspheres were studied, respectively. The gel microspheres had an interpenetrating three‐dimensional porous structure, and their high porosity morphology and high specific surface area could ensure the adequate exposure of active adsorption sites. The gel microspheres showed excellent selective adsorption of Cr(III), and the theoretical maximum adsorption capacity of 146.16 mg/g was calculated according to the Langmuir model. Besides, its excellent photothermal conversion ability enhanced the resistance to external interference after the adsorption. Our work has provided an innovative approach to solar water purification while optimizing the preparation process. [ABSTRACT FROM AUTHOR]

In this research, the vorinostat‐loaded alginate microparticles were created and their characterization was performed using scanning electron microscopy (SEM), energy‐dispersive X‐ray mapping (EDX‐mapping), and transmission electron microscopy (TEM). Differential scanning calorimetry (DSC) was used to assess the drug state and thermal behavior of vorinostat within the microparticles. The encapsulation efficiency and loading efficiency were determined, and the solubility of vorinostat in the microparticles was investigated. In vitro drug release studies demonstrated sustained release of vorinostat from the microparticles. The cytotoxicity of vorinostat‐loaded alginate microparticles was evaluated using HepG2, MCF‐7, and SK‐LU‐1 cell lines. The results indicated significant inhibition of cell growth, and the IC50 values were estimated. Overall, this study successfully demonstrated the fabrication of vorinostat‐loaded alginate microparticles using a microfluidic approach, suggesting a simple and effective delivery system for vorinostat with improved physicochemical and pharmacological properties. [ABSTRACT FROM AUTHOR]

In this article, the effectiveness of two different application methods (photocatalytic degradation and adsorption) onto the created solid nanomaterials for the removal of malachite green (MG) was investigated. Copper ferrite nanoparticles (CF) and copper ferrite/calcium alginate composite (CG) were synthesized as two studied solid samples. By using XRD, TGA, FTIR, DRS, nitrogen adsorption/desorption isotherm, pHPZC, SEM, and TEM, the physicochemical and morphological properties of the solid samples were tested. Sample dose, pH, initial MG concentration, shaking time, ionic strength, UV light power, and temperature were the key experimental parameters that were established. The obtained results demonstrated that at 40 °C, CG reached a greater adsorption capacity (297.62 mg/g). The spontaneous, endothermic, and advantageous adsorption process of MG was proved by the best fitting of pseudo-second order, Elovich, intra-particle diffusion, Langmuir, Dubinin-Radushkevich, and Temkin models onto all the produced materials. The maximum percentage of MG degradation by CG (89.9%) was accomplished by utilizing 1.0 g/L of catalyst mass, an initial MG concentration of 10 mg/L, and 33 W. Arrhenius and Eyring–Polanyi models well applied the MG photodegradation onto the catalyst surface. [ABSTRACT FROM AUTHOR]

The widespread use of highly complex synthetic dyes like reactive dyes in the textile industry has some adverse environmental impacts and deserves close attention. Biological treatment of these effluents utilizing various species of bacteria with remarkable efficiency in dye removal is still considered promising. Our current study deals with immobilizing an isolated bacterial strain into calcium alginate (Ca/Alg) gel beads and using it to treat pernicious pollutants like synthetic dyes. A potential Reactive Blue 19 (RB19)‐degrading Enterobacter cloacae strain A1 was isolated from the Kashan textile industry and was characterized by 16S rDNA gene sequencing. The decolorization ability of strain A1 was assessed by time‐based studies using free bacterial cells/immobilized in Ca/Alg. Based on the results of the 16S rDNA gene sequencing, it appears that strain A1 belonged to E. cloacae, with a 99.74% similarity. The findings suggest that immobilized strain A1 accomplished maximum decolorization activity compared with the free cells. The immobilized strain could utterly decompose and decolorize 0.05 mg/mL of RB19 within 48 h, while the free bacterial strain decolorized RB19 within 5 days. Moreover, Ca/Alg gel beads can maintain their efficiency for over three decolorization cycles. Further infrared spectroscopy (FTIR) and gas chromatograph mass spectrometer (GC/MS) investigation declared complete RB19 decomposition on reaction products. Artemia salina was used to investigate the toxicity of dye and its degraded metabolites. The LC50 values signified the pure dye as very toxic with 0.01 mg/mL concentration, while after‐treatment products showed no toxic effect on larvae. This immobilization technique increased the applicability of bacterial strain for dye removal. It was beneficial for the decolorization of RB19 from textile wastewater due to a remarkable reduction in time. Notably, strain A1‐immobilized beads can maintain their activity for three consecutive decolorization cycles without a considerable decrease in efficiency. Practitioner Points: The remarkable capacity of immobilized Enterobacter cloacae strain A1 for Reactive Blue 19 (RB19) removalImmobilized A1 strain showed two‐fold higher removal than free one over 48 hA promising method for enhancing RB19 decolorizationDecolorization was due to degradation based on UV–Vis, FTIR, and GC/MS analysisNon‐toxic posttreatment products for Artemia [ABSTRACT FROM AUTHOR]

Magnetic composite adsorbents using iron oxide nanoparticles have been produced in the past for glyphosate removal; however, the effect of the magnetic iron oxide content in the chitosan/calcium alginate hydrogel matrix on glyphosate removal efficiency has not been investigated. In this study, magnetic chitosan/calcium alginate hydrogel (MCAH) beads were synthesized according to our previous study with the same methodology with a magnetic iron oxide nanoparticle (MIONP) content of 33%, 50%, and 60% (w/w). Iron content was analyzed by characterization study. The increasing iron weight percentage was detected at the magnetic beads with the FESEM-EDX analysis. The magnetism of the MCAH beads increased with the higher MIONP content according to VSM analysis. The surface area and porosity of MCAH beads decreased with MIONP content increase according to the BET analysis. The results showed that the higher MIONP content increases the reaction rate by 13 percent but does not change the resultant removal efficiency significantly. [ABSTRACT FROM AUTHOR]

This study focuses on investigating a novel category of paper actuators, aiming to attain a favorable equilibrium between substantial electrically actuated force and extended service lifetime (Ts) for the soft electric-responsive artificial muscle. Consequently, the present research has developed an Electro-responsive Biomass Paper Actuator (ERBPA) utilizing calcium alginate hydrogel, employing absolute ethanol (CH3CH2OH) as the slow-release agent, through a straightforward and viable preparation procedure. Moreover, a comprehensive investigation was carried out on the electro-mechano-chemical behaviors and strengthening mechanism of the ERBPA with varying volume fractions of CH3CH2OH, under the electrical actuation of 4 V DC voltage. The experimental findings revealed a gradual decrease in the density of electrically actuated force, elastic modulus, and yield strength with the increasing volume fraction of CH3CH2OH. Specifically, at a volume fraction of 30%, these properties reached their respective minimum values of approximately 15.152 mN/g, 6.5 MPa, and 0.0999 MPa. In contrast to the internal resistance (Rg) of the ERBPA, the specific capacitance (Cp) and the Ts exhibited an initial improvement followed by a reduction, while the rise time (Tr) demonstrated a positive correlation with the volume fraction of CH3CH2OH but a negative correlation with the reaction velocity (Vf). Specifically, at a volume fraction of 25%, Cp, Ts and Tr reached their maximum values of 96.2 mF/g, 1287 s, and 170 s, respectively, whereas Rg and Vf attained their minimum values of 2.39 Ω and 0.044 mN/g·s, respectively. The slow-release effect of CH3CH2OH inherently contributed to the protection of certain free Ca2+ ions, thereby causing a gradual and consistent coordination process with sodium alginate molecules. This, in turn, greatly enhanced the internal structure of ERBPA, resulting in exceptional Ts stability and operational performance. [ABSTRACT FROM AUTHOR]

Initial research was focused on the production of calcium-based alginate-chitosan membranes from coral skeletons collected from the Gulf of Prigi. The coral skeleton's composition was analyzed using XRF, revealing a calcium oxide content ranging from 90.86% to 93.41%. These membranes showed the significant potential for salt adsorption, as evidenced by FTIR analysis, which showed the presence of functional groups such as -OH, C=O, C-O, and N-H involved in the NaCl binding process. SEM analysis showed the particle size diameter of 185.96 nm, indicating a relatively rough and porous morphology. Under optimized conditions, the resulting calcium-based alginatechitosan membrane achieved 40.5% Na+ and 48.39% Cl-adsorptions, using 13.3 mL of 2% (w/v) chitosan and 26.6 mL of 2% (w/v) alginate with a 40-minutes contact time. The subsequent we applied for the desalination potential of calcium alginate, revealing the efficient reduction of NaCl levels in seawater. The calcium of coral skeletons collected was 90.86% and 93.41% before and after calcination, respectively, affirming the dominant calcium composition suitable for calcium alginate production. We identified an optimal 8-minute contact time for calcium alginate to effectively absorb NaCl, resulting in an 88.17% and 50% for Na+ and Cl-absorptions. We applied the addition of chitosan into calciumalginate membranes and its impact on enhancing salt adsorption efficiency for seawater desalination. [ABSTRACT FROM AUTHOR]

The stability of black rice anthocyanin microcapsules at high temperature, light and pH, and their release in simulated gastroenteric fluid were studied by emulsification and gelation of black rice anthocyanin microcapsules with calcium alginate as wall material. The stability of black rice anthocyanin in microcapsules prepared under the process parameters of sodium alginate concentration of 15 g/L, water oil volume ratio of 1:3, wall to core ratio M (C3G):M (NaAlg) of 2:1, and solution pH of 4.5 was significantly higher than that of uncoated free black ones under different pH, temperature, and light conditions. The microencapsulated anthocyanin could be kept for 4 hours in simulated gastric fluid, and the wall material was slowly decomposed and released in simulated intestinal fluid. The microencapsulation technology based on emulsified gel can improve the stability of anthocyanins, and achieve their intestinal delivery and sustained release in vivo. [ABSTRACT FROM AUTHOR]

The acetylcholinesterase (AChE) is involved in termination of synaptic transmission at cholinergic synapses and plays a vital role in the insecticide detection and inhibitor screening. Here, we report the heterologous expression of an AChE from Tetronarce californica (TcA) in Escherichia coli (E. coli) as a soluble active protein. TcA was immobilized in calcium alginate beads; the morphology, biochemical properties, and insecticide detection performance of free and immobilized TcA were characterized. Moreover, we used sequence, structure-based approaches, and molecular docking to investigate structural and functional characterization of TcA. The results showed that TcA exhibited a specific activity of 102 U/mg, with optimal activity at pH 8.0 and 30 °C. Immobilized TcA demonstrated superior thermal stability, pH stability, and storage stability compared to the free enzyme. The highest sensitivity of free TcA was observed with trichlorfon, whereas immobilized TcA showed reduced IC50 values towards tested insecticides by 3 to 180-fold. Molecular docking analysis revealed the interaction of trichlorfon, acephate, isoprocarb, λ-cyhalothrin, and fenpropathrin in the active site gorge of TcA, particularly mediated through the formation of hydrogen bonds and π-π stacking. Therefore, TcA expressed heterologously in E. coli is a promising candidate for applications in food safety and environmental analysis. Key points: • T. californica AChE was expressed solubly in prokaryotic system. • The biochemical properties of free/immobilized enzyme were characterized. • The sensitivity of enzyme to insecticides was evaluated in vitro and in silico. [ABSTRACT FROM AUTHOR]

Nanoparticles of Al2O3, ZrO2, Fe3O4 and their mixed oxides are synthesized adopting new green methods. Aloe-vera gel is identified as a capping agent for controlling the size of particles. The slow generation of precipitating agent, NH3, and increase in viscosity of medium, assist the synthesis. The mixed nanoparticles are found to be very effective in the simultaneous extraction of phosphate (qe:112.14 mg/g) and chromate (qe:122.6 mg/g) from water atpH: 4, equilibration time: 60 min and dosage: 0.12 g/150 mL. These particles when doped in calcium alginate beads to make the filtration easy, the effective pH is increased to 10 for the simultaneous removal of both the pollutants with enhancement in adsorption capacities for phosphate (qe:130.01 mg/g) and chromate(qe:144.12 mg/g) at the equilibration time: 90 min and dosage: 0.10 g/150 mL. The nano mixed oxide as well as beads are characterized by FTIR, XRD, FESEM and EDX techniques. Spontaneous and endothermic nature of sorption is revealed by thermodynamic investigations. The adsorbents are robust and effective up to six regeneration cycles. The experimental data are best fitted with the Langmuir isotherm and pseudo-second-order kinetic models with R2 values > 0.99 for both the adsorbates. The methodology developed is applied to water remediation for phosphate and chromate. The importance of the present investigation is that the adsorbents based on nanomaterials synthesised by new green methods are identified to have high adsorption capacities for the simultaneous extraction of chromate and phosphate from polluted water. [ABSTRACT FROM AUTHOR]