Search Results (187)

Edible hydrogels are the central material class in 3D food printing because they reconcile two competing needs: (i) low resistance to flow under nozzle shear and (ii) fast recovery of elastic structure after deposition to preserve geometry. This review consolidates the recent years of progress on hydrogel formulations—gelatin, alginate, pectin, carrageenan, agar, starch-based gels, gellan, and cellulose derivatives, xanthan/konjac blends, protein–polysaccharide composites, and emulsion gels alongside a critical analysis of printing technologies relevant to food: extrusion, inkjet, binder jetting, and laser-based approaches. For each material, this review connects gelation triggers and compositional variables to rheology signatures that govern printability and then maps these to process windows and post-processing routes. This review consolidates a decision-oriented workflow for edible-hydrogel printability that links formulation variables, process parameters, and geometric fidelity through standardized test constructs (single line, bridge, thin wall) and rheology-anchored gates (e.g., yield stress and recovery). Building on these elements, a “printability map/window” is formalized to position inks within actionable operating regions, enabling recipe screening and process transfer. Compared with prior reviews, the emphasis is on decisions: what to measure, how to interpret it, and how to adjust inks and post-set enablers to meet target fidelity and texture. Reporting minima and a stability checklist are identified to close the loop from design to shelf. Full article

Hydrogels have emerged as promising biomaterials for oral tissue regeneration thanks to their high-water content, excellent biocompatibility, and ability to mimic native tissue environments. These versatile materials can be tailored to support cell adhesion, proliferation, and differentiation, making them suitable for repairing both soft and hard oral tissues. When engineered from natural polymers and enriched with bioactive agents, hydrogels offer enhanced regenerative potential. Biopolymer-based hydrogels, derived from materials such as chitosan, alginate, collagen, hyaluronic acid, and gelatin, are particularly attractive due to their biodegradability, bioactivity, and structural similarity to the extracellular matrix, creating an optimal microenvironment for cell growth and tissue remodeling. Recent innovations have transformed these systems into multifunctional platforms capable of supporting targeted regeneration of periodontal tissues, alveolar bone, oral mucosa, dental pulp, and dentin. Integration of bioactive molecules, particularly essential oils, bio-derived constituents, cells, or growth factors, has introduced intrinsic antimicrobial, anti-inflammatory, and antioxidant functionalities, addressing the dual challenge of promoting tissue regeneration while at the same time attenuating microbial contamination in the oral environment. This review explores the design strategies, material selection, functional properties, and biomedical applications in periodontal therapy, guided tissue regeneration, and implant integration of natural polymer-based hydrogels enriched with bioactive factors, highlighting their role in promoting oral tissue regeneration. In addition, we discuss current challenges related to mechanical stability, degradation rates, and clinical translation, while highlighting future directions for optimizing these next-generation bioactive hydrogel systems in regenerative dentistry. Full article

Hydrogels with protein–polysaccharide combinations are widely used in the field of tissue engineering, as they can mimic the in vivo environments of native tissues, specifically the extracellular matrix (ECM). However, achieving stability and mechanical properties comparable to those of tissues by employing natural polymers remains a challenge due to their weak structural characteristics. In this work, we optimized the fabrication strategy of a hydrogel composite, comprising gelatin and sodium alginate (Gel-SA), by varying reaction parameters. Magnetite (Fe₃O₄) nanoparticles were incorporated to enhance the mechanical stability and structural integrity of the scaffold. The changes in hydrogel stiffness and viscoelastic properties due to variations in polymer mixing ratio, crosslinking time, and heating cycle, both before and after nanoparticle incorporation, were compared. FTIR spectra of crosslinked hydrogels confirmed physical interactions of Gel-SA, metal coordination bonds of alginate with Ca²⁺, and magnetite nanoparticles. Tensile and rheology tests confirmed that even at low magnetite concentration, the Gel-SA-Fe₃O₄ hydrogel exhibits mechanical properties comparable to soft tissues. This work has demonstrated enhanced resilience of magnetite-incorporated Gel-SA hydrogels during the heating cycle, compared to Gel-SA gel, as thermal stability is a significant concern for hydrogels containing gelatin. The interactions of thermoreversible gelatin, anionic alginate, and nanoparticles result in dynamic hydrogels, facilitating their use as viscoelastic acellular matrices. Full article

Alginate hydrogels are promising tissue engineering biomaterials due to their biocompatibility and structural similarity to the extracellular matrix, but their poor mechanical strength, rapid degradation, and lack of bioactivity limit applications. To address this, a novel oxidized alginate/polyacrylamide/silica nanoparticle–gelatin (OA/PAAm/SiO₂-GT) composite hydrogel was developed using an interpenetrating polymer network (IPN) strategy, reinforced with silica nanoparticles and coated with gelatin. The influence of SiO₂ content on the microstructure, mechanical properties, swelling behavior, biodegradability, biomineralization, and cytocompatibility of the composite hydrogel was systematically investigated. Experimental results revealed that SiO₂ nanoparticles interacted with the polymer matrix within the composite hydrogel. With increasing content of SiO₂, the porosity of the OA/PAAm/SiO₂-GT composite hydrogel gradually decreased, while the mechanical properties exhibited a trend of initial enhancement followed by reduction, with maximum compressive strength at a SiO₂ content of 1.0% (w/v). Moreover, the incorporation of SiO₂ nanoparticles effectively modulated the swelling behavior, biodegradability, and biomineralization capacity of the composite hydrogel under in vitro conditions. Meanwhile, the OA/PAAm/SiO₂-GT composite hydrogel supported favorable cell adhesion and proliferation, optimal at a SiO₂ content of 0.5% (w/v). Furthermore, with increasing concentration of SiO₂ nanoparticles, the intracellular alkaline phosphatase (ALP) activity progressively increased, suggesting a promotive effect of SiO₂ nanoparticles on the osteogenic differentiation of MG63 cells. Therefore, the incorporation of SiO₂ nanoparticles into the OA/PAAm IPN matrices provides an effective means to tailor its biological properties, rendering it great potential for biomedical applications such as tissue engineering. Full article

In this study, the effect of cationic participation on the swelling behavior and pH-responsive release characteristics of polyelectrolyte hydrogel based on gelatin (Gel), sodium alginate (Alg), and carboxymethyl chitosan (CMCS) was explored. The shell–core morphology of the cationic coordination hydrogels was prepared by introducing Na⁺, Ca²⁺, and Fe³⁺ into the crosslinking system, which significantly altered the inherent pH-responsive swelling properties of Gel/Alg-CMCS hydrogel. The modified hydrogel demonstrated a release resistance of carvacrol (CAR) under acidic conditions while facilitating rapid release under neutral conditions. Notably, the CAR release profile was substantially modified by the distinct anti-swelling properties of cationic coordination hydrogels. In particular, Gel/Alg-CMCS-Fe³⁺ hydrogel exhibited high accumulative release of 58.34% at pH 1.0 while maintaining a minimal release degree of merely 7% in weakly acidic and neutral environments. These intriguing findings provide valuable insights into intelligent active delivery for future applications. 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

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

Cultured meat is emerging as a sustainable alternative to conventional animal agriculture, with scaffolds playing a central role in supporting cellular attachment, growth, and tissue maturation. This review focuses on the development of gel-based hybrid biomaterials that meet the dual requirements of biocompatibility and food safety. We explore recent advances in the use of naturally derived gel-forming polymers such as gelatin, chitosan, cellulose, alginate, and plant-based proteins as the structural backbone for edible scaffolds. Particular attention is given to the integration of food-grade functional additives into hydrogel-based scaffolds. These include nanocellulose, dietary fibers, modified starches, polyphenols, and enzymatic crosslinkers such as transglutaminase, which enhance mechanical stability, rheological properties, and cell-guidance capabilities. Rather than focusing on fabrication methods or individual case studies, this review emphasizes the material-centric design strategies for building scalable, printable, and digestible gel scaffolds suitable for cultured meat production. By systemically evaluating the role of each component in structural reinforcement and biological interaction, this work provides a comprehensive frame work for designing next-generation edible scaffold systems. Nonetheless, the field continues to face challenges, including structural optimization, regulatory validation, and scale-up, which are critical for future implementation. Ultimately, hybrid gel-based scaffolds are positioned as a foundational technology for advancing the functionality, manufacturability, and consumer readiness of cultured meat products, distinguishing this work from previous reviews. Unlike previous reviews that have focused primarily on fabrication techniques or tissue engineering applications, this review provides a uniquely food-centric perspective by systematically evaluating the compositional design of hybrid hydrogel-based scaffolds with edibility, scalability, and consumer acceptance in mind. Through a comparative analysis of food-safe additives and naturally derived biopolymers, this review establishes a framework that bridges biomaterials science and food engineering to advance the practical realization of cultured meat products. Full article

Organoids and microphysiological systems (MPSs) have emerged as physiologically relevant platforms that recapitulate key structural and functional features of human organs, tissues, and microenvironments. As one of the essential components that define the success of these systems, hydrogels play the central role of providing a three-dimensional, biomimetic scaffold that supports cell viability, spatial organization, and dynamic signaling. Natural polymer-based hydrogels, derived from materials such as collagen, gelatin, hyaluronic acid, and alginate, offer favorable properties including biocompatibility, degradability, and an extracellular matrix-like architecture. This review presents recent advances in the design and application of such hydrogels, focusing on crosslinking strategies (physical, chemical, and hybrid), the viscoelastic characteristics, and stimuli-responsive behaviors. The influence of these materials on cellular processes, such as stemness maintenance, differentiation, and morphogenesis, is critically examined. Furthermore, the applications of organoid culture and dynamic MPS platforms are discussed, highlighting their roles in morphogen delivery, barrier formation, and vascularization. Current challenges and future perspectives toward achieving standardized, scalable, and translational hydrogel systems are also addressed. Full article

In the rapidly evolving field of biomedical engineering, hydrogels have emerged as highly versatile biomaterials that bridge biology and technology through their high water content, exceptional biocompatibility, and tunable mechanical properties. This review provides an integrated overview of both natural and synthetic hydrogels, examining their structural properties, fabrication methods, and broad biomedical applications, including drug delivery systems, tissue engineering, wound healing, and regenerative medicine. Natural hydrogels derived from sources such as alginate, gelatin, and chitosan are highlighted for their biodegradability and biocompatibility, though often limited by poor mechanical strength and batch variability. Conversely, synthetic hydrogels offer precise control over physical and chemical characteristics via advanced polymer chemistry, enabling customization for specific biomedical functions, yet may present challenges related to bioactivity and degradability. The review also explores intelligent hydrogel systems with stimuli-responsive and bioactive functionalities, emphasizing their role in next-generation healthcare solutions. In modern medicine, temperature-, pH-, enzyme-, light-, electric field-, magnetic field-, and glucose-responsive hydrogels are among the most promising “smart materials”. Their ability to respond to biological signals makes them uniquely suited for next-generation therapeutics, from responsive drug systems to adaptive tissue scaffolds. Key challenges such as scalability, clinical translation, and regulatory approval are discussed, underscoring the need for interdisciplinary collaboration and continued innovation. Overall, this review fosters a comprehensive understanding of hydrogel technologies and their transformative potential in enhancing patient care through advanced, adaptable, and responsive biomaterial systems. Full article

Stimulus-responsive hydrogels have broad applications in the biomedical, sensing, and actuation fields. However, conventional fabrication methods are often limited to 2D structures, hindering the creation of complex, personalized 3D hydrogel architectures. Furthermore, hydrogels responding to only a single stimulus and delays in fabrication techniques restrict their practical utility in biomedicine. In this study, we developed two novel multi-stimuli-responsive hydrogels (based on Gelatin/Sodium Alginate and Tannic Acid/EDTA-FeNa complexes) specifically designed for direct ink writing (DIW) 3D printing. We systematically characterized the printed properties and optimized component ratio, revealing sufficient mechanical strength (e.g., tensile modulus: Gel/SA-TA ≥ 0.22854 ± 0.021 MPa and Gel/SA-TA@Fe³⁺ ≥ 0.35881 ± 0.021 MPa), high water content (e.g., water absorption rate Gel/SA-TA ≥ 70.21% ± 1.5% and Gel/SA-TA@Fe³⁺ ≥ 64.86% ± 1.28%), excellent biocompatibility (e.g., cell viability: Gel/SA-TA and Gel/SA-TA@Fe³⁺ ≥ 90%) and good shape memory performance (e.g., the highest shape recovery rate of Gel/SA-TA reaches 74.85% ± 4.776%). Furthermore, we explored electrical characteristics, showing that the impedance value of Gel/SA-TA@Fe³⁺ hydrogel changes significantly under finger bending and NIR irradiation. This investigation demonstrates the potential of these 3D-printed multi-stimuli hydrogels for applications such as wearable flexible strain sensors. Full article

Spinal cord injuries (SCIs) present a major clinical challenge, often resulting in permanent loss of function and limited treatment options. Traditional approaches, including surgery, drugs, and rehabilitation, have had modest success in restoring neural connectivity due to the complex pathophysiology of SCI. In recent years, bioactive hydrogels have gained attention as a versatile platform for neural repair. Their ability to mimic the extracellular matrix, deliver therapeutic agents, and support cell survival makes them promising tools in regenerative medicine. This narrative review highlights the latest advances in hydrogel-based therapies for SCI, with a focus on innovations such as self-healing, conductive, and anti-inflammatory hydrogels. We also explore hybrid approaches that integrate nanomaterials, stem cells, and bioelectronics to address both primary and secondary injury mechanisms. While various hydrogel systems have been investigated, we place particular emphasis on gelatin-based hydrogels, especially gelatin methacryloyl (GelMA), due to their emerging clinical relevance. GelMA stands out for its bioactivity, tunable mechanics, and compatibility with 3D printing, making it a strong candidate for personalized therapies and scalable production. Unlike previous reviews that broadly summarize hydrogel use, this work specifically contextualizes gelatin-based platforms within the wider landscape of SCI repair, underscoring their translational potential. We also address current challenges, such as immune response, long-term integration, and clinical validation, and suggest future directions for bridging the gap from bench to bedside. Full article

Background: In this study, we aimed to develop and optimize unique eco-friendly gelatin–alginate hydrogels enriched with sustainable grape skin extract for advanced wound healing applications. Methods: Following confirmation of the extract’s antioxidant activity, hydrogels were synthesized by varying gelatin content and CaCl₂ concentration to achieve desirable crosslinking density, mechanical properties, and extract release behavior. Physicochemical characterization of hydrogels included equilibrium swelling analysis, mechanical testing, FTIR analysis, and in vitro release of extract from hydrogel. Moreover, the biocompatibility of hydrogels enriched with extract was assessed via MTT assay, while antimicrobial activity was tested against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 10145, and Candida albicans ATCC 10231. The antioxidant capacity of the hydrogels was evaluated using DPPH, ABTS, and FRAP assays. Results: Our results showed that higher gelatin and CaCl₂ concentrations produced denser crosslinked networks, leading to reduced swelling and increased stiffness. Additionally, the extract exhibited a biphasic release profile from hydrogels, featuring an initial rapid release followed by sustained release over 24 h. Conclusions: The hydrogels maintained high biocompatibility and demonstrated selective antimicrobial activity, particularly against Escherichia coli, and satisfactory antioxidant activity. Obtained multifunctional sustainable hydrogels enriched with grape skin extract represent promising agents for managing skin conditions associated with oxidative stress and bacterial infections. Full article