Search Results (1,053)

Sodium alginate (SA) has the advantages of good biocompatibility, water absorption, oxygen permeability, non-toxicity, and film-forming properties. SA is compounded with other materials to formulate a spinning solution. Subsequently, electrospinning is employed to fabricate nanofiber membranes. These membranes undergo cross-linking modification or hydrogel composite functionalization, yielding nanofiber composites exhibiting essential properties, including biodegradability, biocompatibility, low immunogenicity, and antimicrobial activity. Consequently, these functionalized composites are widely utilized in tissue engineering, regenerative engineering, biological scaffolds, and drug delivery systems, among other biomedical applications. This work reviews the sources, characteristics, and electrospinning preparation methods of SA, with a focus on the application and research status of SA composite nanofibers in tissue engineering scaffolds, wound dressings, drug delivery, and other fields. It can be concluded that SA electrospun nanofibers have great development potential and application prospects in biomedicine, which could better meet the increasingly complex and diverse needs of tissue or wound healing. At the same time, the future development trend of SA composite nanofibers was prospected in order to provide some theoretical reference for the development of biomedical textiles and to promote its development in the direction of being green, safe, and efficient. Full article

With the rapid development of flexible electronic skin materials, the demand for ion-conductive hydrogels is constantly growing. Specifically, these ion-conductive hydrogels are required to simultaneously exhibit excellent mechanical properties, high conductivity, and multifunctionality. Moreover, this performance requirement needs to be met in complex environments. However, the rapid production of hydrogels that combine high conductivity and photochromic properties remains a major challenge. In this study, a simple one-pot method was employed to successfully prepare multifunctional photochromic hydrogels by incorporating ammonium molybdate (Mo₇) and lithium chloride (LiCl) into a dual-network hydrogel composed of polyacrylamide (PAAm) and sodium alginate (SA). PAAm/SA/Mo₇/LiCl (PSML) hydrogels exhibit excellent comprehensive performance, including superior conductivity (average value of 164 S/cm), rapid UV response time (<20 s), good color-changing reversibility, outstanding high stretchability (peak value of 2800%), and high transparency (>70%). The design ingeniously combines two types of synergistic effects: the synergistic effect of the dual-network structure and that of the multifunctional component functional additives (Mo₇, LiCl). Specifically, the PSML hydrogel integrates photochromic properties, excellent mechanical properties, good anti-freezing properties, and 3D printability through this design. Due to these outstanding properties, the PSML hydrogel shows broad application prospects in fields such as flexible strain sensors, information storage, and encryption devices. Full article

Biological hydrogels are widely available in terms of raw material sources and can be processed and molded using relatively simple techniques. Hydrogels can offer abundant three-dimensional, water-containing channels that facilitate the reaction between gases and dye, making them the preferred choice for the solid support layer in colorimetric indicators. However, biomass hydrogels exhibit inferior mechanical properties, making them unsuitable for large-scale manufacturing processes. In this study, four dual-network composite hydrogels Agar/Gelatin, Sodium Alginate/Agar, Sodium Alginate/Poly (vinyl alcohol), Sodium Alginate/Gelatin (AG/Gel, SA/AG, SA/PVA and SA/Gel) prepared through hybrid strategies. Furthermore, the influence of the dual-network structure on the mechanical properties and ammonia response was systematically investigated, using microscopy and Fourier transform infrared spectroscopy (FTIR) characterization method. The experimental results demonstrate that the incorporation of SA into original hydrogel matrices can significantly enhance both the mechanical and ammonia response performance due to the secondary topological network structure. The interpenetrating double network structure was effectively regulated through the calcium ion cross-linking process. The color difference threshold of SA/PVA’s response to ammonia gas is 10, it holds promise for rapid detection applications. The SA/Gel composite hydrogel exhibits excellent mechanical robustness and toughness. The tensile strength of the SA/Gel sample is 11 times that of a single gel, and the toughness is 80 times greater, suggesting its suitability for large-scale manufacturing of colorimetric indicator. Full article

Sim, a potent HMG-CoA reductase inhibitor, exhibits notable anabolic effects on bone and can upregulate osteogenic genes such as BMP-2, thereby promoting bone formation. An ideal drug delivery system for Sim involves its controlled and sustained release at the defect site to minimize adverse side effects. In this study, Sim was first modified via HP-γ-CD to form a hydrophilic Sim/HP-γ-CD inclusion complex, thereby improving drug solubility and dispersion in aqueous systems. A gelatin–sodium alginate (Gel/SA) hydrogel was then employed as the drug delivery matrix to construct a Gel-SA-Sim/HP-γ-CD hydrogel sustained release system. This hydrogel system exhibited a high water content (82%), along with enhanced mechanical properties, including a compressive strength of 0.284 MPa and a compressive modulus of 0.277 MPa, suggesting strong load-bearing capacity and favorable stiffness. Importantly, Sim was released in a controlled and sustained manner over 7 days, without exhibiting burst release behavior. In vitro osteogenic differentiation assays demonstrated that optimal concentrations of Sim effectively enhanced cellular bioactivity and osteoinductive performance, offering a promising approach to enhance the bioactivity, osteogenesis, and osseointegration of orthopedic implants. Full article

Hydrogel-based biosensors are commonly used in diagnostic applications. However, their performance remains constrained by slow analyte diffusion within polymer matrices, particularly when larger biomolecules are involved. Concave hydrogel geometries present a promising solution to enhance diffusion rates through increased surface area. However, the interfacial dynamics governing their formation must be studied. In this research, we investigated the interfacial dynamics that influence the formation of concave hydrogel discs fabricated by a simple pipetting method. We characterized the fluid interactions occurring during droplet deposition of alginate and CaCl₂ solutions. A three-phase flow model incorporating confocal microscopy validation was employed to simulate time-dependent interfacial behaviors. Concave hydrogel discs fabricated with alginate-first deposition exhibited 83% larger surface area compared to hemispherical counterparts at a CaCl₂: alginate volume ratio of one. Increasing the volume ratio further enhanced both surface area and diameter, though this highlighted limitations for microscopy-based detection. According to our results, reaction speed in alginate concave hydrogel discs can be controlled by varying the volume of CaCl₂ solution while keeping the volume of alginate solution constant, which changes the surface area while maintaining constant hydrogel volume. Full article

This study presents an innovative iontophoretic delivery system for glycolic acid (GA) based on polysaccharide microbeads embedded within an electrolyte hydrogel. The mi-crobeads, fabricated using a peristaltic pump, exhibited a uniform morphology with an average diameter of 1078 ± 140.38 μm and were successfully integrated into a hydrogel matrix (thickness: 4542.55 ± 337.24 μm). Comprehensive physicochemical characterization (FT-IR, XRD, SEM) confirmed effective component integration. The hydrogel demonstrated optimal mechanical properties with a tensile strength of 0.02 ± 0.003 MPa and reliable adhesion to various substrates, while maintaining excellent self-healing capabili-ties—post-repair conductivity remained sufficient to power an LED indicator. The material demonstrated favorable conductivity under various storage conditions while maintaining non-cytotoxic properties. Notably, microbead incorporation preserved electrochemical performance, as demonstrated by stable behavior in cyclic voltammetry using an Ag/AgCl reference system. Iontophoretic testing revealed significantly enhanced glycolic acid delivery at −1.0 V com-pared to passive diffusion. The system, combining PVA, PAA, alginate, [Bmim]BF₄, and E. prolifera polysaccharides with gellan gum, shows strong potential for advanced cosmetic dermatology applications requiring precise active ingredient delivery. Full article

Pomegranate (Punica granatum L.), is renowned for its bioactive compounds, offering significant potential in cosmetic applications due to its antioxidant, anti-inflammatory, and antimicrobial properties. This study presents a sustainably sourced cosmetic ingredient developed by enriching pomegranate seed oil with peel powder using optimized ultrasonication, followed by encapsulation in alginate nanobeads and integration into a minimalist hydrogel formulation. A Box–Behnken experimental design was employed to optimize ultrasonication parameters (15 min, 90% power, 202 mg/mL powder-to-oil ratio), yielding an enriched PSO with significantly enhanced total phenolic content (TPC: 69.23 ± 1.66 mg GAE/g), total flavonoid content (TFC: 61.09 ± 1.66 mg QE/g), and robust DPPH antioxidant activity (78.63 ± 3.81%). The enriched oil exhibited enhanced oxidative stability (peroxide value: 5.75 ± 0.30 meq O₂/kg vs. 50.95 ± 0.07 meq O₂/kg for neutral oil), improved fatty acid profile, and significant anti-inflammatory (IC₅₀ = 897.25 µg/mL for NO inhibition) and antibacterial activities. Alginate nanobeads (432.46 ± 12.59 nm, zeta potential: −30.74 ± 3.20 mV) ensured bioactivity preservation, while the hydrogel maintained physicochemical and microbial stability over 60 days under accelerated conditions (40 ± 2 °C, 75 ± 5% RH). This multifunctional formulation, integrating sustainable extraction, advanced encapsulation, and a minimalist delivery system, represents a highly promising natural ingredient for anti-aging and antioxidant cosmetic applications. Full article

The growing depletion of global phosphorus reserves underscores the urgent need for sustainable and circular nutrient recovery solutions. Rich in phosphorus, piggery wastewater represents not just a waste stream but a valuable resource. In this study, we explore an innovative approach by recovering alginate-like exopolymers (ALE) from activated sludge (AS) and utilizing them to produce biosorbent hydrogel beads capable of removing phosphorus directly from real piggery wastewater. The ALE extraction process yielded approximately 175 $\mathrm{m}\mathrm{g} {\mathrm{V}\mathrm{S}}_{\mathrm{A}\mathrm{L}\mathrm{E}}/\mathrm{g}{\mathrm{V}\mathrm{S}}_{\mathrm{s}\mathrm{l}\mathrm{u}\mathrm{d}\mathrm{g}\mathrm{e}}$, highlighting the potential of wastewater biomass as a source of functional biopolymers. Adsorption experiments revealed phosphorus removal efficiencies approaching 80%, with capacities ranging from 0.68 to 1.18 mgP/gVS_ALE. Structural and chemical characterizations confirmed both the successful adsorption of phosphorus and the stability of the biosorbent post-treatment. This work demonstrates a dual benefit: the recovery of critical nutrients and the transformation of wastewater-derived materials into value-added biosolids. By integrating phosphorus capture and biosorbent production, the approach offers a cost-effective and environmentally responsible pathway toward nutrient recycling and wastewater valorization. Full article

In this study, hydrogel dressings based on alginate and carboxymethylcellulose were developed, supplemented with extracts from Tagetes nelsonii, Agave americana, and Aloe vera gel, for the treatment and healing of wounds. For this purpose, the physical and mechanical characterization of the films was carried out using different concentrations of the crosslinker, calcium chloride. Additionally, T. nelsonii was the extract that exhibited the highest antioxidant capacity as well as in vivo wound-healing activity. Subsequently, plant extracts were added, the dressings were characterized, and antibacterial activity was determined by the Kirby–Bauer method against Staphylococcus aureus and Pseudomonas aeruginosa. The results indicated that the prepared dressings have potential for use in wound treatment and healing, with the dressing containing T. nelsonii extract being the only one with antibacterial activity. Therefore, all of them can be used for acute wounds on body parts such as the palms of the hands, knees, elbows, and soles of the feet. Full article

The transition from three-dimensional (3D) to four-dimensional (4D)-bioprinting marks a significant advancement in tissue engineering and drug delivery. 4D-bioprinting offers the potential to more accurately mimic the adaptive qualities of living tissues due to its dynamic flexibility. Structures created with 4D-bioprinting can change shape in response to internal and external stimuli. This article reviews the background, key concepts, techniques, and applications of 4D-bioprinting, focusing on its role in tissue scaffolding and drug delivery. We discuss the limitations of traditional 3D-bioprinting in providing customized and sustained medication release. Shape memory polymers and hydrogels are examples of new responsive materials enabled by 4D-bioprinting that can enhance drug administration. Additionally, we provide a thorough analysis of various biopolymers used in drug delivery systems, including cellulose, collagen, alginate, and chitosan. The use of biopolymers in 4D-printing significantly increases material responsiveness, allowing them to react to stimuli such as temperature, light, and humidity. This capability enables complex designs with programmable shape and function changes. The expansion and contraction of hydrogels in response to temperature changes offer a practical method for controlled drug release. 4D-bioprinting has the potential to address significant challenges in tissue regeneration and medication administration, spurring ongoing research in this technology. By providing precise control over cell positioning and biomaterial integration, traditional 3D-bioprinting has evolved into 4D-bioprinting, enhancing the development of tissue constructs. 4D-bioprinting represents a paradigm shift in tissue engineering and biomaterials, offering enhanced possibilities for creating responsive, adaptive structures that address clinical needs. Researchers can leverage the unique properties of biopolymers within the 4D-printing framework to develop innovative approaches for tissue regeneration and drug delivery, leading to advanced treatments in regenerative medicine. One potential future application is in vivo tissue regeneration using bioprinted structures that can enhance the body’s natural healing capabilities. Full article

Bone defects remain a significant clinical challenge, creating a severe need for advanced biomaterials for tissue regeneration. This study addresses this issue by developing 3D-printed composite hydrogels containing alginate, gelatine, and resorbable calcium phosphates (monetite and brushite) for bone tissue engineering. The scaffolds were fabricated using extrusion-based 3D printing and evaluated for their morphology, porosity, mechanical strength, swelling, degradation, and in vitro mineralization, while their cytocompatibility was assessed using LIVE/DEAD cell viability assays. The key findings demonstrate that calcium phosphate incorporation enhanced the mechanical stability by 15–25% compared to the controls, and mineral deposition increased significantly in the composite scaffolds. The developed hydrogels are bioactive and represent promising, customizable scaffolds for bone regeneration. These results support their further investigation as viable alternatives to traditional bone grafts for clinical bone tissue engineering applications. Full article

Composite scaffolds based on a hydrogel matrix modified with hydroxyapatite, magnesium, or zinc compounds are promising for filling and regenerating osteochondral defects due to the specific biological properties of these modifiers. The aim of this work was to evaluate the influence of hydroxyapatite, nano-hydroxyapatite, magnesium chloride, and zinc oxide on mechanical properties, swelling ability, behavior in a simulated biological environment (ion release, stability, bioactivity), and antibacterial effects. Furthermore, the influence of the hydrogel matrix (alginate, gelatin, alginate/gelatin) on the selected properties was also assessed. The results showed that the addition of ZnO improved the mechanical properties of all types of matrices most effectively. Additionally, zinc ions were gradually released into the environment and partially incorporated into the formed apatite. The released zinc ions increased the inhibition zones of Staphylococcus aureus growth; however, this effect was observed only in scaffolds with an alginate matrix. This indicates that hydrogel plays a key role in antibacterial effects, beyond the contribution of antibacterial additives. No effect of magnesium on bacterial growth inhibition was observed despite its rapid release. Magnesium ions promoted efficient secretion of apatite during incubation, although it was not stable. The addition of nano-HAP significantly increased the stability of the apatite precipitates. Full article

Conductive hydrogels hold great promise for biomedical and electronic applications. However, their practical use is often limited by poor self-healing capability, which can affect long-term stability and durability. To address this, we developed alginate/polyacrylamide-based conductive hydrogels incorporating FeCl₃ and AlCl₃, named CH-Fe and CH-Al, respectively. We systematically studied the influence of metal cations on the hydrogels’ mechanical and electrical properties. CH-Al showed the most optimized performance, with a 329% increase in tensile strength and a 323% improvement in conductivity compared to the blank hydrogel. Additionally, CH-Al demonstrated excellent self-healing ability, with nearly 100% recovery after damage. The introduction of Al³⁺ improved conductivity by forming dynamic electron-conductive pathways through interactions with the polymer network. The self-healing behavior arises from reversible metal–ligand coordination bonds, which enable rapid recovery of the hydrogel’s structure after mechanical disruption. This study successfully developed a conductive hydrogel that combines high electrical conductivity, robust mechanical strength, and an intrinsic self-healing ability, offering significant potential for applications in bioelectronic devices, flexible sensors, and implantable medical technologies. Full article

This study aimed to develop and characterise novel hydrogels based on natural bioactive compounds for topical antimicrobial applications. Four gel systems were formulated using different polymers, namely polyacrylic acid (Carbopol 940, CBP-G), chitosan with high and medium molecular weights (CTH-G and CTM-G), and sodium alginate (ALG-G), incorporating tinctures of Verbena officinalis and Aloysia triphylla, Laurus nobilis essential oil, and a β-cyclodextrin–clove essential oil complex. All gels displayed a homogeneous macroscopic appearance and maintained stability for over 90 days. Rheological studies demonstrated gel-like behaviour for CBP-G and ALG-G, with well-defined linear viscoelastic regions and distinct yield points, while CTM-G exhibited viscoelastic liquid-like properties. SEM imaging confirmed uniform and continuous matrices, supporting controlled active compound distribution. Thermogravimetric analysis (TG-DTA) revealed a two-step degradation profile for all gels, characterised by high thermal stability up to 230 °C and near-total decomposition by 500 °C. FTIR spectra confirmed the incorporation of bioactive compounds and products and highlighted varying interaction strengths with polymer matrices, which were stronger in CBP-G and CTH-G. Antimicrobial evaluation demonstrated that chitosan-based gels exhibited the most potent inhibitory and antibiofilm effects (MIC = 2.34 mg/mL) and a cytocompatibility assessment on HaCaT keratinocytes showed enhanced cell viability for chitosan gels and dose-dependent cytotoxicity for alginate formulations at high concentrations. Overall, chitosan-based gels displayed the most favourable combination of stability, antimicrobial activity, and biocompatibility, suggesting their potential for topical pharmaceutical use. Full article

This work analyzes the radiation shielding effectiveness of biocompatible hydrogel pads containing carbohydrate-based polymer matrices (Alginate, Chitosan, and Cellulose) integrated with the high atomic number (Z) fillers Bismuth Oxide (Bi₂O₃) and Zinc Oxide (ZnO). The Monte Carlo-based toolkit, Geant4, was used to simulate the deposition of the dose throughout a multilayer phantom that mimics the skin (Epidermis, Dermis, Subcutaneous, and Muscle) with a pad on top irradiated with photon and electron beams from 50 keV to 1000 keV. The results indicated that Bi₂O₃ succeeded in causing greater absorption of photons at doses, particularly in deep-layer tissues, from the increase in the filler content as well as the pad thickness. The Cellulose–Bi₂O₃ composites (10 mm thick) not only showed the best deep-shielding property among all investigated combinations but also the Alginate-based pads generally performed better with regard to the surface dose attenuation. The results demonstrate the promising potential of high-Z-doped hydrogels in serving as flexible, light, and biocompatible shielding materials for superficial radiotherapy. Full article