Simultaneous viscoelasticity and sprayability in antimicrobial acetic acid-alginate fluid gels.

Acetic acid is a promising alternative to antibiotics for topical applications, particularly burn wounds, however its site specificity and retention are impaired by poor material properties. In this study, acetic acid was investigated as both the gelling agent and antimicrobial active in alginate fluid gels. The formed microstructure was found to be directly dependent on acetic acid concentration, leading to highly tuneable material properties. At clinically relevant concentrations of 2.5-5 % acetic acid, the fluid gels were elastically dominated at rest, with viscosities up to 7 orders of magnitude greater than acetic acid alone. These material properties imparted long term surface retention and microparticle barrier function, not seen with either acetic acid or alginate solutions. Most notably, sprayability was enhanced simultaneously with the increased viscosity and elasticity due to the introduction of a discretised microstructure, leading to a remarkable tenfold increase in spray coverage. Formulation was found not to inhibit antimicrobial activity, despite the less acidic pH, with common burn wound pathogens Staphylococcus aureus and Pseudomonas aeruginosa being equally susceptible to the fluid gels as to acetic acid solutions.

Developing Advanced Antibacterial Alginic Acid Biomaterials through Dual Functionalization.

This paper delves into the intersection of biomaterials and antibacterial agents, highlighting the importance of alginic acid-based biomaterials. We investigate enhancing antibacterial properties by functionalizing alginic acid with an ionic liquid and a potent chelating agent, tris(hydroxypyridinone) (THP). Initial functionalization with the ionic liquid markedly improves the material's antibacterial efficacy. Subsequent functionalization with THP further enhances this activity, reducing the minimum inhibitory concentration from 6 to 3 mg/mL. Notably, the newly developed dual-functionalized materials exhibit no cytotoxic effects at the concentrations tested, underscoring their potential for safe and effective antibacterial applications. These findings highlight the promising role of dual-functionalized alginic acid biomaterials in developing advanced antibacterial treatments.

Nature-inspired innovation: Alginic-kojic acid material for sustainable antibacterial and carbon dioxide fixation.

The current environmental consciousness of the world's population encourages researchers to work on new materials that are environmentally benign and able to display the appropriate features for the needed application. To develop high-performing, inexpensive eco-materials, scientists have frequently turned to nature, attempting to mimic its processes' excellent performance at a reasonable price. In this regard, we decided to focus on alginic acid (AA), a polysaccharide widely found in brown algae, and kojic acid (KA), a chelating agent fungi produces. This study proposes rapidly synthesizing a sustainable, biocompatible material (AK) based on AA and KA, employing chlorokojic acid (CKA). The material has a dual function: antibacterial activity on both Gram-positive and Gram-negative bacteria, without any cytotoxic action on human cells in vitro, and catalytic ability to convert CO2 into cyclic carbonates at atmospheric pressure, without solvents, with high yields, and without the use of metals. Furthermore, the material's insolubility in organic solvents allows it to be easily separated from the reaction product and reused for other catalytic cycles. Both applications have a key role in the medical and environmental fields, combating the outbreak of infections and providing an innovative methodology to fix the CO2 on specific substrates.

Protonated amine and pyrene co-functionalized sodium alginate templated on reduced graphene oxide for highly efficient removal of formaldehyde and acid pollutants.

Indoor formaldehyde pollution can cause inestimable harm to human health and even cancers, thus studies on the removal of formaldehyde attract extensive attentions. In this paper, an environmentally friendly and low-cost biomass material, sodium alginate (SA) was utilized to prepare pyrene functionalized amido-amine-alginic acid (AmAA-Py) by acidification and two-step amidation, which is subsequently self-assembled on reduced graphene oxide (rGO) by π-π stacking interaction, and the final composites were acidified to afford a highly porous composite material for chemical removal of formaldehyde. The formaldehyde chemical removal performance of composite is evaluated at different conditions and find that 1.0 g of acidified alginate derivatives and graphene composites (HCl·AmAA-Py-rGO) can adsorb 69.2 mg of HCHO. Simultaneously, amino groups in amido-amine derivative of acidified sodium alginate (AmAA) can react with acidic pollutants such as H2S and HCl via forming ionic bonding without generating any other by-products, which enables efficient and environment-friendly removal of acidic pollutants. The subtle design of the highly porous composite material utilizing low-cost SA and rGO with large specific surface area opens up a new methodology for fabricating highly porous materials for efficient removal of formaldehyde and other indoor hazardous pollutants.

Efficiency of Alginic Acid, Sodium Carboxymethylcellulose, and Potassium Polyaspartate as Calcium Tartrate Stabilizers in Wines.

The instability of calcium tartrate (CaT) in wines occurs when the effective concentration of ions surpasses the solubility product, leading to the formation of CaT crystals. Unlike potassium hydrogen tartrate (KHT), temperature has little effect on the rate of CaT precipitation, making cold stabilization ineffective. Additives like metatartaric acid and carboxymethylcellulose (CMC) have been used to mitigate this problem, but metatartaric acid's effectiveness is limited due to hydrolysis. Additionally, potassium polyaspartate (KPA), commonly used as a KHT stabilizer, has been reported to reduce wine stability regarding CaT instability. Therefore, exploring alternative stabilization methods is crucial. Alginic acid, permitted as a processing aid in winemaking, can be an alternative to CMC and metatartaric acid due to its strong negative charge and ability to bind calcium ions. This study aimed to assess alginic acid's efficacy as a CaT stabilizer compared to CMC and investigate the impact of KPA on CaT instability. The results showed that KPA did not increase CaT instability and even improved its stability in some wines. Alginic acid outperformed both CMC and KPA in mitigating CaT instability, possibly due to its higher zeta potential and calcium ion complexation ability. This study is the first to investigate the use of alginic acid for CaT stability in wine.

Layered complexity, reorganisational ability and self-healing mechanisms of heteropolysaccharide solutions.

Heteropolysaccharides are among the most widely distributed compounds in nature, acting as both tissue building blocks and as a source of nutrients. Their physicochemical and biological properties have been studied thoroughly; however, the microstructural properties of heteropolysaccharides are still poorly understood. This study aims to investigate the micro-structural peculiarities of agarose, gum arabic, hyaluronic and alginic acids by means of confocal laser scanning microscopy (CLSM) and cryogenic scanning electron microscopy (cryo-SEM). Herein, attention is paid to layered complexity of the microstructure differentiating surface, under surface, inner, and substrate interface layers. The scale and pattern of the polysaccharide's microstructure depend on the concentration, changing from lamellae to cell-like porous structures. This work provides the insight into micro- and nanoscale mechanisms of self-healing and substrate-induced reorganisation. Thus, investigation of the self-healing mechanism revealed that this diffusion-based process starts from the fibres, turning into lamellae, following by cell-like structures with smaller dimensions. Investigation of the substrate-induced reorganisation ability showed that nano-to-micro (scale) porous substrate causes reorganisation in the interface layer of the studied heteropolysaccharides. This work contributes to understanding the structural peculiarities of heteropolysaccharides by looking at them through a supramolecular, micro-level prism.

On-Line pH Measurement Cation Exchange Kinetics of Y3+-Exchanged Alginic Acid for Y2O3 Nanoparticles Synthesis.

A new sol-gel method that employs cation exchange from an aqueous metal ion solution with H+ ions of granulated alginic acid was developed for synthesizing high-purity Y2O3 nanoparticles. In this study, the cation exchange kinetics of H+~Y3+ in aqueous solution were analyzed using on-line pH technology and off-line inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis. Pseudo 2nd-order models were utilized to evaluate the parameters of the kinetics, suggesting that the concentration of H+~Y3+ involved in the cation exchange reaction was 1:1.733. Further, a comprehensive understanding of the Y-ALG calcination process was developed using thermo-gravimetric analysis, along with results obtained from differential scanning calorimetry (TGA/DSC). A detailed analysis of the XRD Rietveld refinement plots revealed that the crystallite sizes of Y2O3 nanoparticles were about 4 nm (500 °C) and 15 nm (800 °C), respectively. Differential pulse voltammetry (DPV) was employed to investigate the electrochemical oxidation of catechol. The oxidation peak currents of catechol at Y2O3 (500 °C)/GCE and Y2O3 (800 °C)/GCE showed two stages linear function of concentration (2.0~20.0 × 10-6 mol/L, 20.0~60.0 × 10-6 mol/L). The results indicated that the detection limits were equal to 2.4 × 10-7 mol/L (Y2O3 (500 °C)/GCE) and 7.8 × 10-7 mol/L (Y2O3 (800 °C)/GCE). The study not only provided a method to synthesize metal oxide, but also proposed a promising on-line pH model to study cation exchange kinetics.

Functionalized Gelatin/Polysaccharide Hydrogels for Encapsulation of Hepatocytes.

Liver diseases represent a considerable burden to patients and healthcare systems. Hydrogels play an important role in the engineering of soft tissues and may be useful for embedding hepatocytes for different therapeutic interventions or the development of in vitro models to study the pathogenesis of liver diseases or testing of drugs. Here, we developed two types of hydrogels by crosslinking hydrazide-functionalized gelatin with either oxidized dialdehyde hyaluronan or alginate through the formation of hydrazone bonds. Gel formulations were studied through texture analysis and rheometry, showing mechanical properties comparable to those of liver tissue while also demonstrating long-term stability. The biocompatibility of hydrogels and their ability to host hepatocytes was studied in vitro in comparison to pure gelatin hydrogels crosslinked by transglutaminase using the hepatocellular line HepG2. It was found that HepG2 cells could be successfully embedded in the hydrogels, showing no signs of gel toxicity and proliferating in a 3D environment comparable to pure transglutaminase cross-linked gelatin hydrogels used as control. Altogether, hydrazide gelatin in combination with oxidized polysaccharides makes stable in situ gelling systems for the incorporation of hepatocytes, which may pave the way for use in liver tissue engineering and drug testing.

Ascophyllum nodosum (Linnaeus) Le Jolis from Arctic: Its Biochemical Composition, Antiradical Potential, and Human Health Risk.

Ascophyllum nodosum is a brown seaweed common in Arctic tidal waters. We have collected A. nodosum samples from the Barents Sea (BS), Irminger Sea (IS), and Norwegian Sea (NS) in different reproductive stages and have evaluated their biochemical composition, radical scavenging potential, and health risks. The total content of dominating carbohydrates (fucoidan, mannitol, alginate, and laminaran) ranged from 347 mg/g DW in NS to 528 mg/g DW in BS. The proportion of two main structural monosaccharides of fucoidan (fucose and xylose) differed significantly between the seas and reproductive phase, reaching a maximum at the fertile phase in the BS sample. Polyphenols and flavonoids totals were highest in NS A. nodosum samples and increased on average in the following order: BS < IS < NS. A positive correlation of free radical scavenging activity for seaweed extracts with polyphenols content was observed. The concentration of elements in A. nodosum from the Arctic seas region was in the following order: Ca > Mg > Sr > Fe > Al > Zn > As total > Rb > Mn > Ba > Cu > Co. Seaweeds from BS had the lowest metal pollution index (MPI) of 38.4. A. nodosum from IS had the highest MPI of 83. According to the calculated target hazard quotient (THQ) and hazard index (HI) values, Arctic A. nodosum samples pose no carcinogenic risk to adult and child health and are safe for regular consumption. Our results suggest that the Arctic A. nodosum has a remarkable potential for food and pharmaceutical industries as an underestimated source of polysaccharides, polyphenols, and flavonoids.

In situ formation of alginic acid-gold nanohybrids for application in cancer photothermal therapy.

Gold-based nanoparticles present excellent optical properties that propelled their widespread application in biomedicine, from bioimaging to photothermal applications. Nevertheless, commonly employed manufacturing methods for gold-based nanoparticles require long periods and laborious protocols that reduce cost-effectiveness and scalability. Herein, a novel methodology was used for producing gold-alginic acid nanohybrids (Au-Alg-NH) with photothermal capabilities. This was accomplished by promoting the in situ reduction and nucleation of gold ions throughout a matrix of alginic acid by using ascorbic acid. The results obtained reveal that the Au-Alg-NHs present a uniform size distribution and a spike-like shape. Moreover, the nanomaterials were capable to mediate a temperature increase of ≈11°C in response to the irradiation with a near-infrared region (NIR) laser (808 nm, 1.7 W cm-2 ). The in vitro assays showed that Au-Alg-NHs were able to perform a NIR light-triggered ablation of cancer cells (MCF-7), being observed a reduction in the cell viability to ≈27%. Therefore, the results demonstrate that this novel methodology holds the potential for producing Au-Alg-NH with photothermal capacity and higher translatability to the clinical practice, namely for cancer therapy.

Alginic acid-functionalized silver nanoparticles: A rapid monitoring tool for detecting the technology-critical element tellurium.

The increasing global demand for tellurium, driven by its critical role in alloys, photovoltaic devices, and electronics, has raised concerns about its environmental pollution and neurotoxicity. In response, the potential of alginic acid (AA), a renewable, low-cost, and sustainable biopolymer, was explored for the biosynthesis of ultra-small silver nanoparticles (AgNPs) and their application in the detection of tellurium (Te(IV)). The effect of key synthesis parameters on desired physicochemical properties and yield of AgNPs was established to ensure high specificity and sensitivity towards Te(IV). The purified AgNPs with AA surface ligands were utilized to demonstrate a ratiometric absorbance sensor that exhibits excellent linearity and nanomolar-level affinity. This approach achieved a high correlation coefficient of ∼ 0.982, with a low detection limit of about 22 nM. Further investigations into the effect of pH, ionic strength, and organic molecules were conducted to elucidate detection performance and molecular understanding. The detection mechanism relies on the coordination between Te(IV) ions and the carboxylate groups of AA, which initiates aggregation-induced plasmon coupling in adjacent AgNPs. The capability of this analytical method to monitor Te(IV) in real-world water samples features its rapidity, user-friendliness, and suitability for point-of-care monitoring, making it a promising alternative to more complex techniques.

Blood Coagulation Activities of Cotton-Alginate-Copper Composites.

Alginate-based materials have gained significant attention in the medical industry due to their biochemical properties. In this article, we aimed to synthesize Cotton-Alginate-Copper Composite Materials (COT-Alg(-)Cu(2+)). The main purpose of this study was to assess the biochemical properties of new composites in the area of blood plasma coagulation processes, including activated partial thromboplastin time (aPTT), prothrombin time (PT), and thrombin time (TT). This study also involved in vitro antimicrobial activity evaluation of materials against representative colonies of Gram-positive and Gram-negative bacteria and antifungal susceptibility tests. The materials were prepared by immersing cotton fibers in an aqueous solution of sodium alginate, followed by ionic cross-linking of alginate chains within the fibers with Cu(II) ions to yield antimicrobial activity. The results showed that the obtained cotton-alginate-copper composites were promising materials to be used in biomedical applications, e.g., wound dressing.

Effect of a Composite Alginate/Grape Pomace Extract Packaging Material for Improving Meat Storage.

The development of food packaging materials that reduce the production of plastic, preserving at the same time the quality of food, is a topic of great interest today for the scientific community. Therefore, this article aims to report the effectiveness of an eco-friendly packaging material based on alginic acid and grape pomace extract from Vitis vinifera L. (winemaking by-products) for storing red meat in a domestic refrigerator. Specifically, biogenic amines are considered "sentinels" of the putrefactive processes, and their presence was thus monitored. For this purpose, an experimental analytical protocol based on the use of solid-phase microextraction coupled with gas chromatography-mass spectrometry was developed during this work for the determination of six biogenic amines (butylamine, cadaverine, isobutylamine, isopentylamine, putrescine, and tyramine). Moreover, by combining the analytical results with those of pH and weight loss measurements, differential scanning calorimetry, and microbiological analysis, it was proved that the studied materials could be proposed as an alternative packaging material for storing foods of animal origin, thus lowering the environmental impact according to sustainability principles.

Effects of Alginic Acid on the Porcine Granulosa Cells and Maturation of Porcine Oocytes.

SCOPE: Alginic acid (AA) from brown algae is a marine organic compound. There is extensive use of AA in the food industry and healthcare, suggesting a high probability of AA exposure. The present study investigates the effects of AA on porcine ovarian granulosa cells (GCs) and oocytes to explore its mechanism in female reproduction because of its adverse effects on reproduction. METHODS AND RESULTS: The study adds 20 µM AA to the porcine primary ovarian GCs medium and porcine oocyte in vitro maturation (IVM) medium. Estrogen and progesterone levels are downregulated in GCs. Reactive oxygen species are excessive, and the antioxidant capacity declines. Then mitochondria-mediated apoptosis pathway is involved in GCs apoptosis. In addition, scores of autophagosomes are found in the experimental cells. Furthermore, AA significantly inhibits the proliferation of GCs around cumulus-oocyte complexes (COCs) accompanied by abnormal spindle assembly, chromosome arrangement disorder, and aberrant cortical granules distribution in oocytes, leading to a decreased oocyte maturation rate. CONCLUSION: These findings suggest that 20 µM AA is toxic to sow reproduction by interfering with estrogen production, oxidative stress, mitochondria-mediated apoptosis, autophagy in GCs of sows, and oocyte maturation.

The Protective Effects of Water-Soluble Alginic Acid on the N-Terminal of Thymopentin.

Thymopentin (TP5) has exhibited strong antitumor and immunomodulatory effects in vivo. However, the polypeptide is rapidly degraded by protease and aminopeptidase within a minute at the N-terminal of TP5, resulting in severe limitations for further practical applications. In this study, the protective effects of water-soluble alginic acid (WSAA) on the N-terminal of TP5 were investigated by establishing an H22 tumor-bearing mice model and determining thymus, spleen, and liver indices, immune cells activities, TNF-α, IFN-γ, IL-2, and IL-4 levels, and cell cycle distributions. The results demonstrated that WSAA+TP5 groups exhibited the obvious advantages of the individual treatments and showed superior antitumor effects on H22 tumor-bearing mice by effectively protecting the immune organs, activating CD4+ T cells and CD19+ B cells, and promoting immune-related cytokines secretions, finally resulting in the high apoptotic rates of H22 cells through arresting them in S phase. These data suggest that WSAA could effectively protect the N-terminal of TP5, thereby improving its antitumor and immunoregulatory activities, which indicates that WSAA has the potential to be applied in patients bearing cancer or immune deficiency diseases as a novel immunologic adjuvant.

Cost-effectiveness of alginic acid in combination with proton pump inhibitor for the treatment of gastroesophageal reflux disease in systemic sclerosis patients.

BACKGROUND: Systemic sclerosis (SSc) patients often become refractory to proton pump inhibitors (PPI)-a standard treatment for gastroesophageal reflux disease (GERD)-and intolerant to PPI in combination with domperidone. PPI with alginic acid is an alternative treatment option, but alginic acid is costly. OBJECTIVES: We compared the costs and effectiveness of alginic acid plus PPI versus standard treatments (PPI with/without antacids as needed and lifestyle modifications) for GERD in SSc patients unsuitable for, or intolerant to, domperidone. METHODS: An economic evaluation using the Markov model was conducted among SSc patients aged between 40 and 65 years with GERD, having a partial or non-response to 4 weeks of standard-dose omeprazole (40 mg/day) and being unsuitable for or intolerant to domperidone. Using a societal perspective, we computed the incremental cost-effectiveness ratios (ICERs) in terms of Thai baht (THB) per quality-adjusted life-year (QALY) between a combination of alginic acid plus PPI and standard treatment for GERD. The lifetime time horizon was used. RESULTS: The ICER for alginic acid plus PPI versus standard treatments was 377 101 THB/QALY. According to the one-way sensitivity analysis, the cost of alginic acid was the most impactful parameter. If the market prices of alginic acid plus PPI were reduced by 61%, this treatment option would become cost-effective at the willingness-to-pay threshold of 160 000 THB/QALY (34.68 THB/USD data on 25 May 2023). Furthermore, if alginic acid were included in the public health insurance program, the national budget would be increased by 66 313 THB per patient, resulting in an overall budget increase of 5 106 101 to 8 885 942 THB compared with the standard treatment. CONCLUSIONS: Alginic acid plus PPI does not represent good value for money compared with the standard treatment among such SSc patients in Thailand unless its price is reduced significantly.

Synthesis and Applications of Hybrid Polymer Networks Based on Renewable Natural Macromolecules.

Macromolecules obtained from renewable natural sources are gaining increasing attention as components for a vast variety of sustainable polymer-based materials. Natural raw materials can facilitate continuous-flow production due to their year-round availability and short replenishment period. They also open new opportunities for chemists and biologists to design and create "bioreplacement" and "bioadvantaged" polymers, where complex structures produced by nature are being modified, upgraded, and utilized to create novel materials. Bio-based macromonomers are expected not only to compete with but to replace some petroleum-based analogs, as well. The development of novel sustainable materials is an ongoing and very dynamic process. There are multiple strategies for transforming natural macromolecules into sophisticated value-added products. Some methods include chemical modification of macromolecules, while others include blending several components into one new system. One of the most promising approaches for incorporating renewable macromolecules into new products is the synthesis of hybrid networks based on one or more natural components. Each one has unique characteristics, so its incorporation into a network brings new sustainable materials with properties that can be tuned according to their end-use. This article reviews the current state-of-the-art and future potential of renewable natural macromolecules as sustainable building blocks for the synthesis and use of hybrid polymer networks. The most recent advancements and applications that involve polymers, such as cellulose, chitin, alginic acid, gellan gum, lignin, and their derivatives, are discussed.

Multitargeted molecular modelling of alginic acid modified with 4-aminophenol dopped with silver nanoparticles as a potent cytotoxic agent.

The activity of alginic acid as a cytotoxic agent was improved by structure modification using 4-aminophenol (4-AP) through condensation and polymerization processes. Then, silver nanoparticles were employed through doping to further enhance the cytotoxic activity of the modified polymer. The structure of the prepared materials was characterized by FT-IR, 1HNMR, UV spectroscopy, X-ray diffraction, and electron microscopy, and the thermal behavior of all synthesized materials was intensively studied. The cytotoxicity of the prepared compounds against cell lines of human hepatocellular (HepG-2) and lung (A-549) carcinomas was investigated. Alginic acid modified with 4-AP (Alg-4-AP3) showed the highest activity against HepG-2 and A-549 among all tested materials with IC50 values of 3.0 ± 0.19 µg/mL and 3.63 ± 0.23 µg/mL, respectively. Multitargeted molecular docking was employed to explore the binding modes of our compounds with the receptors EGFR, HER2, and VEGFR 2. The results revealed the inhibitory activity of our tested compounds against the proposed protein receptors, findings coincided with the in vitro results. In conclusion, the modification of alginic acid with 4-AP improved its cytotoxic activity against HepG-2 and A-549 cancer cells. In addition, doping the new materials with silver nanoparticles (AgNPs) further enhanced the cytotoxic activity.

Gradient assembly of alginic acid/quaternary chitosan into biomimetic hidden nanoporous textiles for thermal management.

Hidden pores (including compact shell and porous core pores) occur naturally in polar animals' feathers/fur, and they show exceptional capability for thermal insulation. The facile implementation of such an architecture in macroscopic fibers is challenging. In this work, gradient assembly is developed to prepare biological hidden nanoporous fibers (average aperture, ~80 nm). Namely, a weak polyanion (alginic acid) and a polycation (quaternary chitosan) were dissolved in dimethyl sulphoxide (the anion charge of alginic acid was largely shielded) and then spun to ethanol/water/ammonia solution, whereby ammonia triggered the polymer assembly from the shell to the core. This presents an efficient process in 20 min, which is in stark contrast to tedious freeze-spinning or template methods. The as-prepared green textiles featuring much lower thermally conductivity (0.033 W m-1 K-1) compared with the conventional microporous/compact fibers, as well as robust mechanical strength and enhanced solar/electric-heat-harvesting properties, holding great potential to replace the unsustainable animal products.

Ultrasound-assisted extraction of alginic acid from Sargassum angustifolium harvested from Persian Gulf shores using response surface methodology.

In this study, the extraction and characterization of alginic acid, the most abundant compound among brown algae were investigated. The used algae were Sargassum angustifolium from the family of brown algae native to the coasts of the Persian Gulf. The effect of temperature, time, algae mass to solvent volume ratio, and ultrasonic power on the extraction yield and ratio of monomers (M/G) was investigated using the central composite design method. Moreover, the effect of the mentioned parameters on the poly dispersity index and cytotoxic effects against breast cancer cells were also investigated. The maximum obtained extraction yield was 46 %, which was higher than those reported for algae in tropical climates. This shows the effectiveness of ultrasound in facilitating the extraction process. In addition, the minimum monomer ratio was 0.45, the minimum poly dispersity index was 2.5 and the maximum cytotoxicity for using the extract on breast cancer cell line (MCF-7) was 20.3 % (with alginic acid concentration of 250 micrograms per milliliter).