Alginate Hydrogel Research Articles

Nanoarchitectonics with self-healing hydrogel for hierarchical porous carbons and its application in cadmium-arsenic complex pollution

A cheap and green method for porous carbons (CAC-1) with high surface area (409.41 mg/g) is constructed benefiting from self-healing properties of calcium alginate hydrogel under atmospheric drying. Layered double hydroxides modified CAC-1 (CAC-LDH-1) is applied in cadmium-arsenic complex pollution. The adsorption capacities of the CAC-LDH-1 on Cd(II) and As(V) are 331.03 mg/g and 33.48 mg/g in single system, and 79.87 mg/g and 150.59 mg/g in binary system. In binary system, the synergistic action of Cd(II) ions greatly improve the adsorption capacity and adsorption rate of As(V) ions. The adsorption process of cadmium-arsenic by CAC-LDH-1 mainly follows the second-order kinetic model and Freundlich model, and the adsorption process is endothermic and spontaneous. XPS, FTIR, XRD, SEM-EDS mapping and pore size distribution are carried out to explore the structure and adsorption mechanism of CAC-LDH-1. After treatment with 1 % CAC-LDH-1 for 30 days, the proportions of E1-Cd, F1-As, and F2-As that can be utilized by plants decrease from 46.32 % to 33.15 %, 10.08–2.15 %, and 43.06–35.23 %. Compared with CK group, Cd/As contents in the above/under-ground part of red cherry radish seedlings decrease by 31.41∼59.09 %. CAC-LDH-1 inhibits little effect on the microbial diversity of soil, but change the dominant bacterial colonies.

Cell Cycle Modulation through Physical Confinement in Micrometer-Thick Hydrogel Sheaths.

Recently, surface engineering of the cell membrane with biomaterials has attracted great attention for various biomedical applications. In this study, we investigated the possibility of modulating cell cycle progression using alginate and gelatin-based hydrogel sheaths with a thickness of ∼1 μm. The hydrogel sheath was formed on cell surfaces through cross-linking catalyzed by horseradish peroxidase immobilized on the cell surface. The hydrogel sheath did not decrease the viability (>95% during 2 days of culture) of the human cervical carcinoma cell line (HeLa) expressing the fluorescent ubiquitination-based cell cycle indicator 2 (HeLa/Fucci2). Coating the HeLa/Fucci2 cells with the hydrogel sheath resulted in a cell cycle arrest in the G2/M phase, which can be caused by the reduced F-actin formation. As a result of this cell cycle arrest, an inhibition of cell growth was observed in the HeLa/Fucci2 cells. Taken together, our results demonstrate that the hydrogel sheath coating on the cell surface is a feasible approach to modulating cell cycle progression.

A novel bioprinted microtumour model for studying acute-leukemia-cell- contaminated in ovarian tissue

Microtumor models, combining cancer and stromal cells within 3D hydrogels, are vital for testing anticancer therapies. Bioprinting hydrogel scaffolds allows tailored in vitro models. We created a 3D microtumor model using a bioprinter, with varying ratios of ovarian stromal cells and leukemia cells (HL-60). PEGylated fibrinogen and alginate hydrogel were used. Cell dynamics and proliferation were assessed via immunofluorescence staining. Microtumors with different HL-60 ratios (1:1, 1:10, 1:100) were cultured for 5 days. Results showed tumor development modulation by cell ratios and culture time. A significant cell density increase occurred in 1:1 ratio microtumors, indicating rapid cancer cell proliferation. No HL-60 cells were found in 1:100 ratio microtumors by day 5. The 1:10 ratio closely mimicked leukemia invasion in ovarian tissue, showing detectable cancer cells by days 3 and 5 without altering total cell density dynamics significantly. This bioprinted leukemia microtumor model offers better physiological relevance than 2D assays, promising applications in cellular analysis and drug screening.

Preparation and characterization of starch carbamate modified natural sodium alginate composite hydrogel blend formulation and its application for slow-release fertilizer

The exploration of environmentally friendly slow-release fertilizer (SRF) based on natural bio-polymers is of great importance in the development of modern agriculture and horticulture. Herein, a novel starch carbamate (SC) modified sodium alginate (SA) hydrogel (SC/SAH) was prepared utilizing as-synthesized SC and natural SA through the cationic ions crosslinking method and ultimately the corresponding slow-release fertilizer (SC/SAH-SRF) was successfully developed by immersing the dried SC/SAH matrix into saturated urea solution. Due to the low gelation temperature and high viscosity of the synthesized SC, the formed SC/SAH exhibits significantly enhanced properties including excellent water absorbency up to 8.02 g/g with considerable repeatability, abundant pore structure and high hydrophilicity compared with the neat SAH and natural starch based hydrogel (NS/SAH). Accordingly, the SC/SAH leads to higher urea loading amount ∼ 1.28 g/g. Importantly, the resultant SC/SAH-SRF also shows superior slow-release performance, yielding a cumulative urea release of only 61.6 % within 10 h and almost completely release >16 h in water, what's more, only 58.5 % of the urea releases within 25 days and exceeding 50 days for complete release in soil column assays. The slow-release of urea from SC/SAH-SRF well complies for the first-order kinetics and accomplishes via a non-Fickian diffusion process. Moreover, the pot experiment demonstrates that the SC/SAH-SRF has higher growth promotion role for the maize seedlings than those of others. Consequently, this work provides a novel strategy for preparing environmentally friendly SRF by blending modified starch and hydrogel.

Surface- modified preparation of CuFe2O4/sodium alginate hydrogel catalysts for the long-lasting degradation of tetracycline

Copper ferrate spinel (CuFe2O4) catalysts are widely used in advanced oxidation processes for environmental wastewater treatment due to their advantages of low price, mild reaction conditions and ease of operation. Therefore, it is crucial to investigate the factors influence the surface properties of catalysts on their catalytic activity. In this research, the effects of process parameters on the surface properties of CuFe2O4 were investigated, and the relationship between the surface properties of CuFe2O4 and its catalytic activity was clarified. The optimised CuFe2O4 exhibited 92.4 % degradation of tetracycline (TC) and 55 % mineralisation of total organic carbon (TOC) within 30 min, the pseudo-first-order reaction rate was 0.0315 min−1, which was 2.2 times higher than that of the unoptimised CuFe2O4. The mechanism of action for enhancing catalyst performance and the degradation mechanism of tetracycline were clarified through a combination of characterization analysis. To further solve the problems of secondary pollution caused by ion leaching and the difficulty of practical application of powder catalysts, novel hydrogel microspheres composed of sodium alginate and CuFe2O4 were prepared by using the property of metal ions and sodium alginate to form a solid gel (SA/Ort-6). SA/Ort-6 was characterized by low ion leaching, excellent performance and excellent stability. The mass ratio of catalyst to treated water could be up to 1:22,000, and the mass ratio of catalyst to treated water can reach up to 1:22000, the removal rate of TOC was stable above 35 %. This study provides valuable insights into the relationship between surface properties and catalytic performance of CuFe2O4, offers a new approach to effectively solve leaching of metal ions, and opens up a new avenue for practical application of powder catalysts.

Stability and Bioaccessibility of Carotenoids from Sea Buckthorn Pomace Encapsulated in Alginate Hydrogel Beads.

Carotenoids, the natural pigments that confer the bright orange color of sea buckthorn berries, are also associated with several health benefits, such as antioxidant activity and skin and eye protection. Due to their lipophilic nature and localization, carotenoids are largely retained in the sea buckthorn pomace (SBP) resulting from juice production. Carotenoids from SBP (70.03 mg/100 g DW), extracted and characterized by HPLC-PDA, contained zeaxanthin (free and esterified) and beta-carotene as major compounds. The SBP carotenoids-enriched sunflower oil was further encapsulated in Ca-alginate hydrogel beads (98.4% encapsulation efficiency) using ionotropic gelation. The hydrogel beads were characterized by confocal laser scanning microscopy and scanning electron microscopy. Fairly good stability (>64%) of the encapsulated carotenoids in the alginate hydrogel beads during storage (30 days, 4 °C and 25 °C) was found, with zeaxanthin esters being the most stable compounds, for all the experimental conditions. The bioaccessibility of the total carotenoids (INFOGEST protocol) was 42.1 ± 4.6% from hydrated, and, respectively, 40.8 ± 4% from dehydrated SBP alginate hydrogel beads. The addition of yogurt to the dehydrated hydrogel beads had a positive effect on the bioaccessibility of free and esterified zeaxanthin, but not on that of the carotenes. In conclusion, SBP is a valuable source of carotenoids which can be protected by encapsulation in alginate hydrogel beads, thus still retaining a good bioaccessibility.

Improved nitrate removal by polyvinyl alcohol/sodium alginate hydrogel beads entrapping salt-tolerant composite bioagent AHM M3

The effective removal of nitrate from mariculture wastewater remains challenging. Here, novel polyvinyl alcohol (PVA)/sodium alginate (SA) hydrogel beads entrapping the salt-tolerant composite bioagent AHM M3 (PVA/SA&AHM-M3) were prepared. The effects of dosage, pH, and temperature on nitrate removal by PVA/SA&AHM-M3 were investigated in batch experiments, and the improved nitrate removal and bacterial community shifts by PVA/SA&AHM-M3 were investigated in moving bed biological reactors (MBBRs). The results showed that the optimal preparation conditions for PVA/SA&AHM-M3 were PVA 10 % (m/v), SA 2 % (m/v), CaCl2 2 % (m/v), and 48 h crosslinking. The nitrate was completely removed within 48 h, with little accumulation of nitrite in the batch experiments at a PVA/SA&AHM-M3 dosage of 2 % (w/v), pH 7.0, and 30 °C. The MBBR system with PVA/SA&AHM-M3 completely removed nitrate and 88.0 % of total nitrogen. Additionally, Zobellella sp. MAD-44 and Halomonas alkaliphila HRL-9 were successfully enriched in the MBBR, confirming the contributions of PVA/SA&AHM-M3.

Nanocellulose and multi-walled carbon nanotubes reinforced polyacrylamide/sodium alginate conductive hydrogel as flexible sensor

Conductive hydrogels have been widely applied in human–computer interaction, tactile sensing, and sustainable green energy harvesting. Herein, a double cross-linked network composite hydrogel (MWCNTs/CNWs/PAM/SA) by constructing dual enhancers acting together with PAM/SA was constructed. By systematically optimizing the compositions, the hydrogel displayed features advantages of good mechanical adaptability, high conductivity sensitivity (GF = 5.65, 53 ms), low hysteresis (<11 %), and shape memory of water molecules and temperature. The nanocellulose crystals (CNWs) were bent and entangled with the backbone of the polyacrylamide/ sodium alginate (PAM/SA) hydrogel network, which effectively transferred the external mechanical forces to the entire physical and chemical cross-linking domains. Multi-walled carbon nanotubes (MWCNTs) were filled into the cross-linking network of the hydrogel to enhance the conductivity of the hydrogel effectively. Notably, hydrogels are designed as flexible tactile sensors that can accurately recognize and monitor electrical signals from different gesture movements and temperature changes. It was also assembled as a friction nanogenerator (TENG) that continuously generates a stable open circuit voltage (28 V) for self-powered small electronic devices. This research provides a new prospect for designing nanocellulose and MWCNTs reinforced conductive hydrogels via a facile method.

Enhanced pH sensing with cholesteric liquid crystal-infused sodium alginate actuators

The present work developed a novel type of soft actuator capable of pH sensing, named CLC-SAA (Cholesteric Liquid Crystal-Infused Sodium Alginate Actuator). This actuator is created by combining sodium alginate hydrogel with cholesteric liquid crystal via an evaporation method. Our study validates the actuation mechanism by observing shifts in the vibrational stretching of carboxylic group bonds through FTIR spectroscopic investigations. Leveraging the weak acidic nature of carboxylic acid in sodium alginate hydrogel, this actuator offers distinct advantages. The CLC-SAA exhibits remarkably rapid bending responses, with fast responses observed of the order of 4 sec to 0.4 sec and bending angles as low as 3° to as high as 18°. This responsiveness is consistent across a wide range of pH values, making it highly adaptable and valuable for applications in medical, chemical, and bio-robotics fields. Such actuation holds significant promise for various applications due to its adaptability and wide-ranging capabilities.

Relief of Biofilm Hypoxia: A Synergistic Approach with Cyanobacteria and Chlorin e6-Loaded Nanoparticles

AbstractPhotodynamic therapy (PDT) involves the use of photosensitizers, oxygen, and light to generate reactive oxygen species (ROS) for the effective destruction of cancer cells or bacteria. However, in biofilm bacterial infections, the presence of hypoxia significantly reduces the efficacy of PDT. To address this issue, we have developed a synergistic approach wherein Synechococcus elongatus (PCC 7942), cyanobacteria are loaded into a sodium alginate hydrogel, and chlorin e6 (Ce6) is conjugated with mesoporous silica nanoparticles (Ce6-MSNs). Cyanobacteria are photosynthetic organisms capable of releasing oxygen when exposed to 660 nm light. This property facilitates the effective production of ROS by Ce6-MSNs, even in hypoxic conditions, potentially enabling more effective PDT against MRSA planktonic bacteria and biofilm. Our results demonstrate that this system can maintain oxygen generation capacity for the test period of 30 days, thereby enhancing ROS production under hypoxic conditions. In summary, this innovative system combines cyanobacteria's photosynthetic oxygen generation with Ce6-MSNs' ROS production capabilities to address the challenge of hypoxia in biofilm infections. The promising results suggest its potential for improving the efficacy of PDT against bacterial infections, including drug-resistant strains such as MRSA. Graphical Abstract

Desalination of dye and protein by Ba2+/Ca2+ co-crosslinked alginate filtration membrane loaded on polypropylene non-woven

Calcium alginate hydrogel filtration membranes show excellent fouling resistance, but the poor mechanical properties and instability limit the use of the membranes. In this paper, sodium alginate was co-crosslinked with Ba2+ and Ca2+ to prepare barium alginate/calcium alginate composite hydrogel membrane loaded on polypropylene non-woven (Ba/CaAlg-PP). The morphology, structure, and swelling rate of the composite filtration membrane were characterized. The fracture strength of the Ba/CaAlg membrane reached a maximum value of 2.47 MPa. The rejection rates of Ba/CaAlg-PP membrane for Methyl blue and NaCl were close to 100 % and <8.0 %, respectively. Meanwhile, the flux of the Ba/CaAlg-PP membrane in dye/NaCl mixture was 43.2 L·m−2·h−1 and the selectivity coefficient of dye/NaCl reached 154.6. Ba/CaAlg-PP membranes exhibited excellent permeability, rejection and long-term stability in protein desalination. The results of simultaneous fluorescence spectroscopy and molecular dynamics simulations showed that the Ba2+ in the Ba/CaAlg-PP membrane did not disrupt the helical structure of BSA. The Ba/CaAlg-PP membrane has a wide range of applications prospect in proteins and dyes desalination.

Crack-healing and rheological properties of high content fly ash/slag/silica fume green and sustainable cement-based materials incorporating crystalline admixture and calcium alginate biomass hydrogel

Cracking is an important factor affecting the durability of concrete. Rheological properties are important performance indicators of the workability of fresh concrete. Ion chelator (CA) is one kind of crystalline admixture, which can enhance crack-healing of concrete by promoting the formation of calcium carbonate in wet environment. Calcium alginate hydrogel (CaAlg) can maintain the humidity of cementitious matrix and promote the crystallization of inorganic minerals. Therefore, in this study, CaAlg bead was prepared to further improve the crack-healing of cementitious materials containing CA. Self-healing performance was evaluated by visual crack closure and water permeability test. Rheological property was measured by rotor rheometer. Healing mechanism of cementitious materials with CA and CaAlg was analyzed. Results showed that with the increase of CaAlg dosage, yield stress and plastic viscosity of paste decreased gradually. Meanwhile, fly ash and slag reduced viscosity of pastes, while silica fume increased the viscosity of pastes. CA could evidently improve the permeability and mechanical properties of mortar, especially for slag mortar. Self-healing performance test and characterization showed that CaAlg could further enhance crack-healing process of mortar with CA, especially for pure cement and slag mortar. Microscopic testing indicates that CaAlg could induce the formation of vaterite and calcite on its surface to further improve crack-healing efficiency.

Rheological study on 3D printability of alginate hydrogel and effect of graphene oxide

In recent years, hydrogels have been used as important biomaterials for 3D printing of three dimensional tissues or organs. The key issue for printing a successful scaffold is the selection of a material with a good printability. Rheological properties of hydrogels are believed to pay an important role in 3D printability. However the relations between rheological properties of hydrogels and 3D printability have not been extensively studied. In this study, alginate-based hydrogels were prepared as a model material for an extrusion-based printer and graphene oxide was added to modify the rheological properties and 3D printability of the hydrogels. Rheological studies were performed for the hydrogel samples with different formulas. The range of shear rates that the hydrogels suffered during the printing process was deduced. This range of shear rates helped us to select a proper shear rate to investigate the thixotropic properties of the hydrogels. Furthermore, we also defined some measureable parameters to describe and discuss the quality of 3D printing. The present study shows a new approach to analysis of 3D printability of a hydrogel and also provides some suggestion for 3D printing of 3D scaffolds.

Bilayer 3D co‐culture platform inducing the differentiation of normal fibroblasts into cancer‐associated fibroblast like cells: New in vitro source to obtain cancer‐associated fibroblasts

AbstractThis study presents a novel in vitro bilayer 3D co‐culture platform designed to obtain cancer‐associated fibroblasts (CAFs)‐like cells. The platform consists of a bilayer hydrogel structure with a collagen/polyethylene glycol (PEG) hydrogel for fibroblasts as the upper layer and an alginate hydrogel for tumor cells as the lower layer. The platform enabled paracrine interactions between fibroblasts and cancer cells, which allowed for selective retrieval of activated fibroblasts through collagenase treatment for further study. Fibroblasts remained viable throughout the culture periods and showed enhanced proliferation when co‐cultured with cancer cells. Morphological changes in the co‐cultured fibroblasts resembling CAFs were observed, especially in the 3D microenvironment. The mRNA expression levels of CAF‐related markers were significantly upregulated in 3D, but not in 2D co‐culture. Proteomic analysis identified upregulated proteins associated with CAFs, further confirming the transformation of normal fibroblasts into CAF within the proposed 3D co‐culture platform. Moreover, co‐culture with CAF induced radio‐ and chemoresistance in pancreatic cancer cells (PANC‐1). Survival rate of cancer cells post‐irradiation and gemcitabine resistance increased significantly in the co‐culture setting, highlighting the role of CAFs in promoting cancer cell survival and therapeutic resistance. These findings would contribute to understanding molecular and phenotypic changes associated with CAF activation and provide insights into potential therapeutic strategies targeting the tumor microenvironment.

Инновационные продукты питания с заменителями насыщенных жиров

Purpose. Development of plant oil-based bigels using sodium alginate hydrogel and beeswax-based oleogel, selection of the optimal ratio between the concentration of hydrogel and oleogel in the composition of bigel, study of its thermal and textural characteristics. Materials and Мethods. Effect of hydrogel-to-oleogel ratio on bigel production was evaluated in terms of thermal and structural-mechanical properties. The following recipe ingredients: drinking water, sodium alginate, beeswax, grape seed oil, were used to produce bigels. Results. It was found that increasing proportion of hydrogel had influenced on thermal properties, strength and adhesiveness of the bigels. In general, an increase hydrogel fraction made it possible to obtain bigels with stronger mechanical properties and higher heat resistance, which is important to consider when creating technologies for innovative food products. Conclusion. For developing various food products with substitution of saturated fats with food bi-gel matrices, it is necessary to regulate competently their physicochemical and textural properties.

Coaxial nozzle-assisted electrohydrodynamic printing for microscale 3D cell-laden constructs.

Cell printing has found wide applications in biomedical fields due to its unique capability in fabricating living tissue constructs with precise control over cell arrangements. However, it is still challenging to print cell-laden 3D structures simultaneously with high resolution and high cell viability. Here a coaxial nozzle-assisted electrohydrodynamic cell printing strategy was developed to fabricate living 3D cell-laden constructs. Critical process parameters such as feeding rate and stage moving speed were evaluated to achieve smaller hydrogel filaments. The effect of CaCl2 feeding rate on the printing of 3D alginate hydrogel constructs was also investigated. The results indicated that the presented strategy can print 3D hydrogel structures with relatively uniform filament dimension (about 80 μm) and cell distribution. The viability of the encapsulated cells was over 90%. We envision that the coaxial nozzle-assisted electrohydrodynamic printing will become a promising cell printing strategy to advance biomedical innovations.

Functionalization of Alginate Hydrogels with a Multifunctional Peptide Supports Mesenchymal Stem Cell Adhesion and Reduces Bacterial Colonization.

Hydrogels with cell adhesive moieties stand out as promising materials to enhance tissue healing and regeneration. Nonetheless, bacterial infections of the implants represent an unmet major concern. In the present work, we developed an alginate hydrogel modified with a multifunctional peptide containing the RGD cell adhesive motif in combination with an antibacterial peptide derived from the 1-11 region of lactoferrin (LF). The RGD-LF branched peptide was successfully anchored to the alginate backbone by carbodiimide chemistry, as demonstrated by 1H NMR and fluorescence measurements. The functionalized hydrogel presented desirable physicochemical properties (porosity, swelling and rheological behavior) to develop biomaterials for tissue engineering. The viability of mesenchymal stem cells (MSCs) on the peptide-functionalized hydrogels was excellent, with values higher than 85 % at day 1, and higher than 95 % after 14 days in culture. Moreover, the biological characterization demonstrated the ability of the hydrogels to significantly enhance ALP activity of MSCs as well as to decrease bacterial colonization of both Gram-positive and Gram-negative models. Such results prove the potential of the functionalized hydrogels as novel biomaterials for tissue engineering, simultaneously displaying cell adhesive activity and the capacity to prevent bacterial contamination, a dual bioactivity commonly not found for these types of hydrogels.

MOF-based prodrug entrapped in carboxymethyl cellulose and alginate hydrogel: A drug delivery platform

MOF-based prodrug entrapped in carboxymethyl cellulose and alginate hydrogel: A drug delivery platform

Chitosan-Alginate Gels for Sorption of Hazardous Materials: The Effect of Chemical Composition and Physical State.

Chitosan, alginate, and chitosan-alginate (50:50) mixed hydrogels were prepared by freeze casting, freeze-drying, and subsequent physical cross-linking. Chitosan was cross-linked with citrate and alginate with calcium ions, while the mixed gels were cross-linked with both cross-linking agents. Both cryogels and xerogels were obtained by lyophilization and drying of the hydrogels. We investigated the effect of the chemical composition and the physical state of gels on the gel structure and sorption of model dyes. Alginate and mixed gels cross-linked with Ca2+ ions sorbed 80-95% of cationic dye from the solutions. The chitosan gels are primarily capable of adsorbing anionic dyes, but at near-neutral pH, their capacity is lower than that of alginate gels, showing 50-60% dye sorption. In the case of alginate gels, the dye sorption capacity of xerogels, cryogels, and hydrogels was the same, but for chitosan gels, the hydrogels adsorbed slightly less dye than the dried gels.

Synthesis and Adsorption of Alginate and Starch-Based Hydrogels for Cationic Dye from Aqueous Solution: Thermodynamic and Isotherm Modeling Non-linear

Synthesis and Adsorption of Alginate and Starch-Based Hydrogels for Cationic Dye from Aqueous Solution: Thermodynamic and Isotherm Modeling Non-linear