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•Ionic gelling ability is a key parameter for alginate’s injectable biomaterials.•Alginate properties can be tuned by chemical modification and/or covalent bonding.•The biofabrication ...field for bone engineering is mainly based on alginate.•Organic-inorganic hybrid alginate materials are a promising alternative to study.
This review focuses on recently developed alginate injectable hydrogels and alginate composites for applications in bone tissue regeneration, and it evaluates the alternatives to overcome the problems that avoid their utilization in the field. Section 2 covers the properties of alginates that have made them useful for medical applications, in particular their ionic gelling ability for preparing injectable compositions used as delivery drugs systems. The advantages and shortcomings of these preparations are revised together with the chemical modifications assayed. Section 3 describes how it has been taken advantage of alginates into the new field of biofabrication and the developments in bone engineering. The state of the art of this field is reviewed. Finally in Section 4, new developments and approaches that in opinion of the authors can lead to a breakthrough in bone tissue engineering using alginates are introduced.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Herein, a pH-independent interpenetrating polymeric networks (Fe-SA-C) were fabricated from graphitic biochar (BC) and iron-alginate hydrogel (Fe-SA) for removal of Cr(VI) and Pb(II) in aqueous ...solution. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and scanning electron microscope (SEM) results demonstrated that graphitic BC interpenetration increased surface porosity and distorted surfaces of Fe-SA, which boosted availability of hydroxyl (-OH) group. Fe3+ as a cross-linking agent of the alginate endowed Fe-SA-C with positive surfaces (positive zeta potential) and excellent pH buffering capacity, while excessive Fe3+ was soldered on Fe-SA-C matrix as FeO(OH) and Fe2O3. Cr(VI) removal at pH of 3 by Fe-SA-C (20.3 mg g−1) were 30.3% and 410.6% greater than that by Fe-SA and BC, respectively. Fe-SA-C exhibited minor pH dependence over pH range of 2–7 towards Cr(VI) retention. Greater zeta potential of Fe-SA-C over Fe-SA conferred a better electrostatic attraction with Cr(VI). FTIR and XPS of spent sorbents confirmed the reduction accounted for 98.5% for Cr(VI) removal mainly due to participation of –OH. Cr(VI) reduction was further favored by conductive carbon matrix in Fe-SA-C, as evidenced by more negative Tafel corrosion potential. Reductively formed Cr(III) was subsequently complexed with carboxylic groups originating from oxidation of –OH. Thus, Cr(VI) removal invoked electrostatic attraction, reduction, and surface complexation mechanisms. Pb(II) removal with excellent pH independence was mainly ascribed to surface complexation and possible precipitation. Thus, the functionalized, conductive, and positively-charged Fe-SA-C extended its applicability for Cr(VI) and Pb(II) removal from aqueous solutions in a wide pH range. This research could expand the application of hydrogel materials for removal of both cationic and anionic heavy metals in solutions over an extended pH range.
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•Biochar reformed the conventional structure and conductivity of alginate hydrogel.•Fe3+ crosslinking increased positive charge and contributed to pH-independence.•Composite structure promoted Cr(VI) reduction and retained Pb(II) sorption ability.•Proposed strategy expanded the use of hydrogel removal of anionic heavy metals.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•The addition of ethanol to sodium alginate precursor solution induces temperature-sensitive gelation of sodium alginate hydrogel.•Ethanol-induced gelation is caused by the disruption ...of hydrogen bonding interaction among alginate chains and water.•Ethanol enhances the printability of sodium alginate precursor solution and enables direct 3D printing of hydrogel structures.•Removing ethanol from the printed structures leads to isotropic shrinkage and improves the printing resolution by > 10 %.
Hydrogels have found wide applications in various fields, but further advances in hydrogel-based applications hinge upon overcoming the challenge of generating complex structures. Although three-dimensional (3D) printing enables customized designs, it remains challenging to print hydrogel structures directly without using supporting materials or incorporating polymeric or solid thickeners due to the low printability of hydrogel precursor solutions. Here, we demonstrate that direct 3D printing of sodium alginate (SA) hydrogel structures can be achieved by introducing ethanol into the SA solution. On the one hand, ethanol enables a sol-to-gel transition to occur by lowering the temperature. Our molecular dynamics (MD) simulations reveal that the gelation occurs due to disrupted hydrogen bonding interaction among SA chains and water. On the other hand, the presence of ethanol notably increases the viscosity, yield stress, and shear-thinning feature of SA solution, making it an ideal 3D printing ink. An isotropic shrinkage of the printed structures is observed after further gelation with Ca2+ ions and the removal of ethanol. Our study provides an effective approach for direct printing of SA hydrogels with enhanced printing resolution (>10 %), paving the way for more advanced hydrogel-based applications in various fields.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The salient gelling feature of alginate via forming the egg-box structure with calcium ions has received extensive interests for different applications. Owing to the interfacial incompatibility of ...rigid inorganic solids with soft polymers, the requirement of overall stereocomplexation with calcium released from uniformly distributed solids in alginate remains a challenge. In this study, a novel alginate-incorporated calcium source was proposed to tackle the intractable dispersion for the preparation of injectable alginate hydrogels. Calcium phosphate synthesis in alginate solution yielded CaP-alginate hybrids as a calcium source. The physicochemical characterization confirmed the CaP-alginate hybrid was a nano-scale alginate-hydroxyapatite complex. The colloidally stable CaP-alginate hybrids were uniformly dispersed in alginate solutions even under centrifugation. The calcium-induced gelling of the CaP-alginate hybrids-loaded alginate solutions formed soft yet tough hydrogels including transparent sheets and knittable threads, confirming the homogeneous gelation of the hydrogel. The gelation time, injectability and mechanical properties of the hydrogels could be adjusted by changing preparation parameters. The prepared hydrogels showed uniform porous structure, excellent swelling, wetting properties and cytocompatibility, showing a great potential for applications in different fields. The present strategy with organic/inorganic hybridization could be exemplarily followed in the future development of functional hydrogels especially associated with the interface integration.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Similar fracture behaviour through rubbers method and nonlinear fracture mechanics.•A tearing modulus parameter dependent on the strain energy density is proposed.•Crack blunting holds constant ...during crack propagation.•Steady regime during crack propagation.•Strain field at crack front maintains constant during crack propagation.•Alginate content increase fracture resistance and crack stability.
Polyacrylamide-alginate hydrogels are biphasic materials with double-polymeric structure and considerable percentage of water inside. They exhibit complex mechanical behaviour in which finite deformations, non-linearity and time dependence are mixed. Fracture behaviour is less known, and this work analyses the fracture resistance obtained via methodologies of non-linear elastic materials such as that developed by Rivlin and Thomas and that attained with Non-Linear Fracture Mechanics procedures based on the use of J-integral. Special attention is paid to the fracture parameters on both crack growth initiation and crack propagation stages. The validity of the methodologies was evaluated, and conclusions were drawn about the effect of the alginate content on the fracture resistance of polyacrylamide.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, we established a long-term three-dimensional (3D) culture system by using integrin ligand modified alginate hydrogels to encapsulate and differentiate neural progenitor cells (NPCs) ...toward oligodendrocyte (OL) lineage cells. The porosity of the hydrogel was optimized by varying the alginate concentrations and then characterized by scanning electronic microscopy (SEM). The surface plasmon resonance (SPR) test was used to confirm the ligand-integrin interactions indicating adherence between the NPC surfaces and the hydrogels. Following encapsulation in the hydrogels, both mouse and human NPC sphere cultures could be maintained up to 90 days. Mouse NPC spheres were differentiated into viable neurons, astrocytes and mature OLs by day 60 in all groups whereas human NPC spheres were differentiated into neurons and later into GFAP positive astrocytes and O4 positive pre-OL within 90 days. The species difference in the timeline of OL development between mouse and human was reflected in this system. The ligand LXY30 interacting with the α3β1 integrin receptor was more effective in promoting the differentiation of hNPCs to OL lineage cells compared with the ligand LXW64 interacting with the αvβ3 integrin receptor, hyaluronic acid interacting with CD44 receptor or without any ligand. This study is the first to differentiate O4+ pre-OLs from hNPCs in a LXY30-α3β1 (integrin-ligand) modified alginate 3D hydrogel culture. This 3D platform could serve as a valuable tool in disease modeling, drug discovery, and NPC transplantation.
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IJS, KILJ, NUK, PNG, UL, UM
Emerging organic contaminants in water matrices have challenged ecosystems and human health safety. Persulfate‐based advanced oxidation processes (PS‐AOPs) have attracted much attention as they ...address potential water purification challenges. However, overcoming the mass transfer constraint and the catalyst's inherent site agglomeration in the heterogeneous system remains urgent. Herein, the abundant metal‐anchored loading (≈6–8 g m−2) of alginate hydrogel membranes coupled with cross‐flow mode as an efficient strategy for water purification applications is proposed. The organic flux of the confined hydrogel interfaces sharply enlarges with the reduction of the thickness of the boundary layer via the pressure field. The normalized property of the system displays a remarkable organic (sulfonamides) elimination rate of 4.87 × 104 mg min−1 mol−1. Furthermore, due to the fast reaction time (<1 min), cross‐flow mode only reaches a meager energy cost (≈2.21 Wh m−3) under the pressure drive field. It is anticipated that this finding provides insight into the novel design with ultrafast organic removal performance and low techno‐economic cost (i.e., energy operation cost, material, and reagent cost) for the field of water purification under various PS‐AOPs challenging scenarios.
This work demonstrates the design insight into the peroxymonosulfate activation system by boosting the mass transfer performance within hydrogel interfaces for ultrafast water purification.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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•A 3D activated CaCO3/PAN-PPy-modified GO/alginate hydrogel sorbent was fabricated.•Synergism among components help to gel network formation and pollutants removal.•CaCO3 as ...pore-former, pH buffer and activated additive was help to Cu(II) removal.•High sorption capacity and fast kinetics for the alginate-based hydrogel sorbent.•The gel can be easily separated and show good environment adaptability and stability.
Herein, alginate-based porous nanocomposite hydrogel (CPGA) was produced using alginate as entrapment agent, polyaniline-polypyrrole-modified graphene oxide (GPP) as functional filler, and CaCO3 as pore-former for enhanced Cu(II) removal from water. Synergism among tri-components help to 3D network formation and Cu(II) removal. The parameters of components, solution pH, contact time, adsorbate concentration, temperature, coexisting substances and dosage were investigated in batch sorption mode. Spontaneous and endothermal adsorption process of Cu(II) by CPGA followed pseudo-second-order model and Freundlich model with experimental maximum adsorption capacity of ∼ 291.2 mg/g, which was better than most of reported alginate-based sorbents. CPGA showed good anti-interference ability in the presence of NaCl and humic acid as well as in actual Cu(II)-polluted lake water. In the multi-ions system, little sorption loss was observed for Pb(II), Cu(II) and Cd(II) capture, and even strengthened Cr(VI) removal relative to those in the single system. Furtherly, minor discrepancy (<10%) was noted after eight successive adsorption-desorption cycles. FTIR and XPS revealed that reactive N-/O-containing groups was mainly responsible for Cu(II) removal; the residual CaCO3 acted the role of pH-buffer and provided refresh binding sites for the gel. This work could expand the potential applicability of alginate-based sorbents for heavy metal removal from water.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Improving plant resistance against systemic diseases remains a challenging research topic. In this study, we developed a dual-action pesticide-loaded hydrogel with the capacity to significantly ...induce plant resistance against tobacco mosaic virus (TMV) infection and promote plant growth. We produced an alginate–lentinan–amino-oligosaccharide hydrogel (ALA-hydrogel) by coating the surface of an alginate–lentinan drug-loaded hydrogel (AL-hydrogel) with amino-oligosaccharide using electrostatic action. We determined the formation of the amino-oligosaccharide film using various approaches, including Fourier transform infrared spectrometry, the ζ potential test, scanning electron microscopy, and elemental analysis. It was found that the ALA-hydrogel exhibited stable sustained-release activity, and the release time was significantly longer than that of the AL-hydrogel. In addition, we demonstrated that the ALA-hydrogel was able to continuously and strongly induce plant resistance against TMV and increase the release of calcium ions to promote Nicotiana benthamiana growth. Meanwhile, the ALA-hydrogel maintained an extremely high safety to organisms. Our findings provide an alternative to the traditional approach of applying pesticide for controlling plant viral diseases. In the future, this hydrogel with the simple synthesis method, green synthetic materials, and its efficiency in the induction of plant resistance will attract increasing attention and have good potential to be employed in plant protection and agricultural production.
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IJS, KILJ, NUK, PNG, UL, UM, UPUK
Magnetic nanocellulose alginate hydrogel beads are produced from the assembly of alginate and magnetic nanocellulose (m-CNCs) as a potential drug delivery system. The m-CNCs were synthesized from ...cellulose nanocrystals (CNCs) that were isolated from rice husks (RH) by co-precipitation method and were incorporated into alginate-based hydrogel beads with the aim of enhancing mechanical strength and regulating drug release behavior. Ibuprofen was chosen as a model drug. The prepared CNCs, m-CNCs and the alginate hydrogel beads were characterized by various physicochemical techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and vibrating sample magnetometer studies (VSM). Besides the magnetic property, the presence of m-CNCs increased the integrity of the alginate hydrogel beads and the swelling percentage. The drug release study exhibited a controlled release profiles and based on the drug release data, the drug release mechanism was analyzed and discussed based on mathematical models such as Korsmeyer-Peppas and Peppas-Sahlin.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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