Search Results (3,842)

Incorporating cyclodextrins (CDs) into ionically crosslinked polysaccharide matrices offers a promising strategy for developing well-defined, safe-by-design and biocompatible carrier systems with tunable rheological properties. In this study, β-cyclodextrin (β-CD) was functionalized with citric acid (CDC) and maleic anhydride (CDM) using solvent-free synthesis to improve compatibility with alginate hydrogels. The modified CDs were characterized by FTIR, ¹H NMR, DLS, zeta potential, and MS, confirming successful esterification (4.0 and 3.4 –OH substitution for CDC and CDM, respectively) and stable aqueous dispersion. Rheological measurements showed that native CD accelerated gelation (within approximately 30 s), while CDC and CDM delayed crosslinking (by 2 to 13 min) and reduced gel strength, narrowing the linear viscoelastic range to 0.015–0.089% strain due to competition between polycarboxylated CDs and alginate chains for Ca²⁺ ions. Vibrational prilling produced alginate microbeads with diameters of 800–1000 µm and a simultaneous increase in size and CD concentration. Hydrogels demonstrated high CD retention (>80% after 28 h) and slightly greater release of CDC and CDM than native CD. Overall, solvent-free modification of CDs with citric and maleic acids provides a sustainable approach to tailoring the gelation kinetics, viscoelasticity, and release behavior of alginate-based hydrogels, offering a versatile, food- and health-compliant platform for controlled delivery of bioactive compounds. Full article

This study explores the development of bigels (BGs) combining a hydrophilic hydrogel (HG) and a lipophilic oleogel (OG) for co-delivery of two carob fruit extracts (CFEs): I-CFE (inositols) and P-CFE (phenolics). The BGs were formulated in HG:OG ratios of 70:30 and 30:70, using a sodium alginate-based HG and an OG composed of olive pomace oil (OPO) and microcrystalline wax (MW). CFEs were loaded in three modes: I-CFE in HG, P-CFE in OG, and both in their respective phases. Rheological, thermal, physicochemical, and microstructural properties were assessed. All the BGs exhibited solid-like viscoelastic behavior, with greater rigidity in 30:70 formulations. The OG phase enhanced the structural BG network, especially when loaded with P-CFE. At 70:30, I-CFE conferred pseudoplasticity and conformational flexibility, particularly in the absence of P-CFE. At 30:70, both extracts acted synergistically, increasing mechanical strength and network organization. Thermal analysis confirmed MW’s role in structuration, with the BGs showing melting peaks between 40–50 °C. The effects studied affected color and stability. Polarized light microscopy confirmed organized microstructures. This is the first work demonstrating the structuring potential and interactive effects of dual carob extracts (I-CFE and P-CFE) within BGs. All the BGs showed suitable fat-replacer properties, remaining self-standing for 21 days, except the 70:30 I-CFE-free formulation. The findings highlight the potential of CFE-loaded BGs as multifunctional fat replacers in healthier meat products. Full article

Seaweed fiber is a new type of functional fiber made from natural seaweed as raw material. Seaweed fiber has excellent moisture absorption, bio compatibilization, controlled degradation profile, and flame retardancy, and can be used to develop high-performance and high value-added textiles. However, seaweed fibers are prone to swelling in salt ion solutions, making dyeing with traditional chemical dyes very difficult. In recent years, the research and application of controllable structural colors have been an important direction and hot spot in the textile field. SiO₂ nanospheres of different sizes were synthesized and combined with polydopamine as an additive to produce structural colors with high visibility. The resulting photonic crystals exhibited vibrant rainbow hues and were successfully applied to stain seaweed fibers. The color of polydopamine-coated silica photonic crystals (PDA/SiO₂) depended on the diameter of the SiO₂ microspheres, while their spectral purity could be tuned by adjusting the ratio of SiO₂ microspheres to dopamine hydrochloride. Full article

Phlorotannin–alginate extracts from brown seaweeds offer promising natural solutions for food preservation. This study investigated the extraction, characterization, and application of phlorotannins and alginate from two brown seaweed species, Sargassum cristaefolium and Nizimuddinia zanardinii, for inhibiting melanosis and preserving quality in Pacific white shrimp during ice storage. Preliminary screening identified N. zanardinii methanol extract as superior, yielding the highest phlorotannin content (19.14 ± 0.65 mg Phloroglucinol/g) with potent antioxidant (98.95 ± 0.74% DPPH inhibition) and copper-chelating (73.44 ± 1.64%) activities. Consequently, N. zanardinii was selected for subsequent extraction and application studies. Alginate extraction efficiency was 4.73 ± 0.38 g/100 g seaweed, demonstrating moderate antioxidant properties. The extracts effectively inhibited shrimp polyphenol oxidase, with 2% phlorotannins + 1% alginate showing 84.51% inhibition. When applied to shrimp, this combination significantly delayed melanosis development, suppressed microbial growth, and maintained lower pH, total volatile basic nitrogen (TVB-N), and lipid oxidation values during 16 days of ice storage compared to untreated controls. Sensory evaluation confirmed better retention of quality attributes in treated shrimp. These findings demonstrate the potential of N. zanardinii phlorotannin–alginate extracts as effective natural preservatives for maintaining shrimp quality during cold storage, offering a sustainable alternative to synthetic additives in seafood processing. Full article

Microplastics (MPs) are increasingly recognized as persistent pollutants in marine and freshwater systems. Their small size, widespread distribution, and ability to adsorb chemical contaminants raise concerns about ecological impacts and human exposure through aquatic food webs. In parallel, marine polysaccharides such as alginate, chitosan, and carrageenan have drawn interest as natural biopolymers with the capacity to interact with MPs. These interactions occur via electrostatic forces, hydrophobic effects, hydrogen bonding, and physical entrapment, influencing the fate and mobility of MPs in aquatic environments. This review critically examines the current state of knowledge on the binding mechanisms between MPs and marine-derived polysaccharides, emphasizing their role in modulating the transport, aggregation, and bioavailability of plastic particles. Recent efforts to modify these biopolymers for improved performance in sorption and stabilization applications are also discussed. Furthermore, analytical strategies for investigating MP–polysaccharide systems are outlined, and the practical limitations associated with scaling up these approaches are considered. The potential use of such materials in environmentally sustainable remediation technologies is explored, along with future research needs related to safety evaluation, lifecycle impact, and feasibility in real-world conditions. Full article

Multidrug resistance has also been accompanied by the prolonged use of antibiotics that makes complications in treatment. Biofilm in pathogenic bacteria is the most serious challenge linked with chronic illnesses and also contributes to virulence and drug resistance. Several bacterial pathogens employ the Quorum-sensing (QS) mechanism to coordinate their collective behaviors like bioluminescence, virulence, and biofilm formation. Therefore, agents that inhibit or interfere with bacterial QS and biofilm formation are emerging as a new class of next-generation antibacterial. Recently, nanoparticles have been employed to improve the efficacy of existing antibacterial agents. In the present study, gold nanocrystals were synthesized by using Koelreuteria paniculata (KP) leaf extract. Synthesized nanocrystals were characterized by a face-centered cubic structure of ~20 nm by XRD, FTIR, Zeta sizer, and TEM. Biogenic Gold nanocrystals (BGNCs) exhibited extended QS inhibition in bio-indicator strains Chromobacterium violaceum and Pseudomonas aeruginosa biosensor strains. BGNCs strongly suppressed QS-controlled violacein production in C. violaceum CV026, and elastase, protease, pyocyanin, alginate, and biofilm formation in P. aeruginosa (PA01). In addition, BGNCs notably suppressed the relative expression of PA01 quorum sensing, biofilm-forming, and virulence-regulating genes, as quantified by qRT-PCR. As a result of the broad-spectrum suppression of QS and biofilm by BGNCs, it is anticipated that these nontoxic bioactive nanocrystals can be employed as surface sterilization agents in nosocomial infections. Full article

Bio-based photo-crosslinkable hydrogels are used in tissue engineering as three-dimensional printable scaffolds due to their functional and biological similarities with the extracellular matrix (ECM). In this work, emerging bioink candidates such as chitosan, alginate and gelatin-based photo-crosslinkable hydrogel were developed using extrusion-based 3D printing to establish a better understanding of their applicability. The polymers were methacrylated by the same methacrylation reaction pathway, which enabled successful light-induced 3D printing. Morphology, swelling (6–40%), mechanical (Young’s modulus, 0.1–0.5 KPa) and rheological properties (300–1000 Pa), degradation kinetics (10->60 days) and printability of the gels were also characterized in identical conditions for the first time. 3D-printability results indicated that methacrylated gelatin enhanced printability, shape fidelity and integrity of printed structures compared to methacrylated alginate, which presents structural instability and poorer printing control due to its low crosslink density. Moreover, cell attachment and Live/Dead assays using bone marrow-derived mesenchymal stem cells (BM-MSCs) showed that all formulations have good biocompatibility for use as scaffolds. Specifically, gelatin-based hydrogels showed a higher level of BM-MSCs attachment and spreading than the other types of hydrogels. Overall, our results suggest that the hydrogels based on these three biopolymers present good potential as a biomaterial for light-induced extrusion-based 3D printing. Full article

Lung cancer remains one of the deadliest cancers worldwide, which highlights the urgent need for new diagnostic tools to detect reliable biomarkers. To enable scalable and cost-effective production, we developed reusable PDMS stamps patterned with electrodes to print flexible electrodes on PET substrates using a microcontact printing (µCP) approach. PET was chosen not only for its flexibility but also as a more sustainable alternative to conventional rigid materials. On these electrodes, three sensing platforms were tested for neuron-specific enolase (NSE) detection: APTES-based monolayers, electrospun PVA/alginate nanofibers, and electropolymerized polypyrrole (PPy) films. Voltammetric and fluorescence/AFM analyses confirmed that all three platforms could recognize the target analyte, with the PPy-CdTe configuration showing the strongest signal variation. Impedance spectroscopy further supported this finding, revealing a clear linear correlation between charge transfer resistance (RCT) and NSE concentration. The PPy-CdTe sensor demonstrated high sensitivity and consistent performance for NSE detection, achieving a detection limit (LOD) of 8.05 pg·µL⁻¹ and a quantification limit (LOQ) of 26.84 pg·µL⁻¹. Full article

The rapid development of industry has led to the discharge of large quantities of organic pollutants into water bodies, posing a significant threat to aquatic safety. It is imperative to develop efficient and environmentally friendly methods for the elimination of organic pollutants. The integration of hydrogel membranes with advanced oxidation processes (AOPs) for water purification has attracted considerable interest due to their high efficiency. However, conventional wet membrane materials stored in aqueous environments are more prone to swelling and leakage of loaded metal species. This limits its application in the degradation of organic pollutants. This study employs a vacuum drying strategy for wet hydrogels, incorporating molybdenum disulfide as a cocatalyst and Co²⁺ cross-linking within the alginate matrix, resulting in a dried MoS₂–cobalt alginate hydrogel membrane (D-MoS₂-CoAlg). The drying process of the D-MoS₂-CoAlg membrane not only significantly enhanced its mechanical strength and anti-swelling capacity but also effectively mitigated the leaching of Co²⁺. Throughout five consecutive cycles, the concentration of leached Co²⁺ remained below 0.032 mg/L. This enables the membrane to achieve a balance between reusability and environmental compatibility. Under the conditions of a drying time of 60 min, a peroxymonosulfate (PMS) dosage of 0.2 mmol/L, and an initial methylisothiazolinone (MIT) concentration of 20 mg/L, the D-MoS₂-CoAlg membrane exhibited exceptional catalytic performance, achieving a degradation rate of MIT as high as 92.14% within 5 min. The D-MoS₂-CoAlg membrane demonstrates high catalytic activity and good stability, showing promising potential for application in the field of organic wastewater treatment. Full article

Phosphatidylserine (PS) holds considerable importance in both the food and medical sectors; however, its biosynthesis is critically dependent on phospholipase D (PLD). The practical application of PLD is constrained by pronounced side reactions in its free form and by reduced selectivity when immobilized. To address these challenges, this study employed a sequential strategy involving bioimprinting to hyperactivate PLD, followed by microencapsulation via ionotropic gelation within an alginate–chitosan matrix. This approach induced conformational rigidification, enabling PLD to maintain its hyperactivated state in aqueous environments. Under optimal conditions, the encapsulation efficiency reached 78.56%, and the enzyme activity recovery achieved 105.27%. The immobilized bioimprinted PLD demonstrated exceptional catalytic performance, achieving a 94.68% PS yield within 20 min, which significantly surpassed that of free PLD (85.82% in 150 min) and non-imprinted immobilized PLD (90.34% in 60 min). This represents 7.27-fold and 2.14-fold efficiency improvements, respectively. Furthermore, the biocatalyst exhibited outstanding storage stability, thermal stability, and reusability (77.53% yield after 8 cycles). To our knowledge, this is the first report combining bioimprinting with alginate-chitosan microencapsulation via ionotropic gelation, which yielded remarkably enhanced PLD activity. These findings highlight the strong potential of this method for efficient PS production. Full article

Bioreduction is an effective method to reduce Cr(VI) for bioremediation. In this study, a hexavalent chromium-reducing bacterium with salt tolerant abilities, Acinetobacter ZQ-1, was isolated, which could efficiently reduce Cr(VI) under a wide range of pH (6.0–9.0), temperatures (28–42 °C) and coexisting heavy metals (Mn²⁺, Pb²⁺ and Fe³⁺). It is worth mentioning that the strain ZQ-1 could reduce Cr(VI) containing 15% (w/v) NaCl, showing strong salt tolerance. Under optimal culture conditions, strain ZQ-1 was able to completely reduce 50 mg/L of Cr(VI) in 24 h. The metabolic data of ZQ-1 showed that salt stress significantly altered the composition of metabolites, in which the accumulation of compatible solutes such as Arginine, Leucine, Lysine and Proline contributed to the alleviation of high salt stress for strain ZQ-1. Meanwhile, the increased content of alginate and betaine also helped to maintain the normal function of strain ZQ-1 in a high-salt environment. This is of great significance for the development, utilization and mechanism of action of salt-tolerant hexavalent chromium-reducing bacteria in the future. Full article

Constructing a zinc delivery system is crucial for scientific zinc supplementation. In this study, gelatin-based zinc-loaded hydrogels were constructed with the assistance of sodium alginate and a ZnSO₄ solution soaking method. The zinc loading capacity, texture properties, rheological properties, microstructure, and pH sensitivity of hydrogels under different ratios of gelatin to sodium alginate were investigated. Results showed that the loading of zinc by hydrogel was successfully achieved through a ZnSO₄ solution soaking method, and increasing the ZnSO₄ concentration was conducive to zinc loading and hydrogel structure strengthening. Adding sodium alginate further enhanced the zinc loading capacity of hydrogel. When the concentration of ZnSO₄ was 25 wt%, the zinc loading of hydrogel containing only gelatin and hydrogel with a 7:3 ratio of gelatin to sodium alginate was 29 mg/g and 52 mg/g, respectively. In addition, sodium alginate also endowed the hydrogel with a certain pH sensitivity. When the ratio of gelatin to sodium alginate was 7:3, the hydrogel showed obvious pH response behavior. Spectroscopy results revealed that zinc sulfate strengthened the hydrogel structure by inducing hydrophobic interactions and the formation of hydrogen bonds, while Zn²⁺ was bound to oxygen atoms through coordination bonds in hydrogel. These results could provide new ideas for the construction of zinc-loaded hydrogels. Full article

Marine macroalgae (seaweed) are a rich source of bioactive polysaccharides such as agar, carrageenan, and alginate. These three compounds are classified as food additive ingredients, widely used as gelling, thickening, stabilizing, and emulsifying agents in the food, nutraceutical, pharmaceutical, and cosmetic industries. However, the growing concern for a safer world has sparked renewed interest in their safety evaluation. Unlike synthetic compounds with specified structures, seaweed polysaccharides exhibit substantial structural heterogeneity due to variations in species, habitat, and processing, affecting bioactivity, digestibility, and interactions within the gastrointestinal tract. Although the safety of these compounds is generally accepted, there are still significant gaps in our understanding of their physicochemical behaviour. This highlights the need to develop a standardized digestion model to ensure their safety and evaluate their potential long-term health effects. Most of these compounds are only partially absorbed in the upper gastrointestinal tract, where they are fermented into metabolites with varying health effects. The safety of carrageenan, in particular, remains a subject of debate due to ambiguous results reported by various researchers’ groups. This review highlights the importance of adopting standardized digestion assays, integrated analytical tools, and multidisciplinary approaches. These are crucial for thoroughly evaluating the molecular integrity, metabolism, and biological impact of seaweed polysaccharides, which will ultimately support evidence-based regulatory frameworks and ensure their safe use in human nutrition. This critical analysis focuses on food safety and security, with a methodology that can be applied to other foods or compounds. Full article

Background/Objectives: Although significant advances in duodenoscope reprocessing have been introduced since mid-2010s—including enhanced cleaning protocols, disposable distal endcaps, and the introduction of fully single-use duodenoscopes—residual contamination and infection risks remain unresolved. Moreover, repeated reprocessing may cause cumulative damage to the polymer surfaces, elevator mechanisms, and internal channels of the duodenoscopes, making them more susceptible to residual contamination. To minimize the duodenoscope polymer degradation caused by intensive use and reprocessing, new alternatives are urgently needed. In this context, calcium peroxide nanoparticles coated with sodium alginate (CaO₂–Alg NPs), synthesized by our group, were tested for the first time as a disinfectant capable of combating nosocomial pathogens while reducing device deterioration associated with repeated investigations and reprocessing. Methods: The disinfectant properties of the CaO₂–Alg NPs were evaluated under biomimetic conditions using reference bacterial strains commonly associated with nosocomial infections. In addition, the compatibility of the nanoparticles with the polymeric duodenoscope coatings was assessed after simulated intensive use. The external polymer coating was structurally and morphologically characterized by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM). Results: The nanoparticles exhibited important antimicrobial activity against the reference bacterial strains Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, and Klebsiella pneumoniae after only 20 min of incubation. Intensive exposure to the CaO₂–Alg NPs did not cause additional structural or morphological damage to the duodenoscope’s external polymers and did not alter their anti-adhesive properties. Conclusions: The CaO₂–Alg NPs appear to be a safe and effective disinfectant for the duodenoscope reprocessing, offering both antimicrobial efficacy and material compatibility. Full article