Search Results (80)

Three-dimensional (3D) bioprinting has emerged as a versatile biofabrication strategy that enables the precise, spatiotemporally controlled co-deposition of living cells, biomaterials, and bioactive agents, including growth factors, cytokines, and extracellular matrix (ECM) components, into geometrically defined 3D constructs. By translating digital design models derived from computed tomography (CT), magnetic resonance imaging (MRI), or computational modeling directly into physical tissue architectures, 3D bioprinting facilitates the assembly of hierarchically organized constructs that closely recapitulate the structural, mechanical, and functional characteristics of native tissues. The principal 3D bioprinting strategies are broadly classified into scaffold-based and scaffold-free approaches. Engineered bioinks, whether formulated as cell-laden natural, synthetic, or composite polymer hydrogels, tissue-derived decellularized ECM (dECM) components, or pure cellular spheroids and organoids, constitute the cornerstone of these biofabrication platforms. Scaffold-based 3D bioprinting comprises extrusion-based, droplet-based (inkjet and drop-on-demand), light-based vat photopolymerization (stereolithography and digital light processing), and laser-assisted bioprinting based on laser-induced forward transfer (LIFT). Each of these modalities imposes distinct constraints on bioink rheology, crosslinking mechanisms, spatial resolution, throughput, and post-printing cell viability; consequently, a specific 3D bioprinting strategy is selected according to the specific requirements of the target tissue application. Scaffold-free 3D bioprinting and bioassembly techniques, including the Kenzan method, aspiration-assisted bioprinting, magnetic bioprinting, and other field-directed tissue assembly approaches, enable the fabrication of spheroid- and organoid-based constructs without the necessity for exogenous biomaterial scaffolds. Because native tissues exhibit diversity in cellular composition, ECM architecture, mechanical properties, and physiological function, no individual bioprinting platform or bioink formulation serves as a universal 3D bioprinting solution. The engineering of biomimetic tissue constructs, therefore, requires the selection of application-tailored fabrication approaches. Under this biofabrication paradigm, 3D bioprinting has been applied across a wide range of tissue engineering targets, including skin, bone, cartilage, osteochondral interfaces, cardiac and vascular tissue, neural structures, ocular, dental, and adipose tissue. This review discusses recent advances in scaffold-based and scaffold-free 3D bioprinting applications for tissue engineering and regenerative medicine across diverse tissue systems. Full article

High-salinity waters, including seawater, brines, and saline radioactive effluents, contain recoverable uranium or require uranium removal, but their complex chemistry complicates both capture and regeneration. Under seawater-relevant conditions, U(VI) occurs mainly as uranyl carbonate complexes and ternary uranyl carbonate complexes containing Ca²⁺ or Mg²⁺ rather than as free UO₂²⁺. Selective separation therefore depends on coupled transport, hydration-shell reorganization, carbonate displacement, and interfacial coordination. Conventional sorbents largely optimize binding strength and adsorption capacity, often at the expense of harsh stripping and secondary waste. This review frames thermoresponsive uranium separation as a coupled aqueous-speciation, interfacial-state, and process-design problem. It examines how LCST and UCST transitions, polymer-brush reorganization, hydration-layer reconstruction, pore gating, and localized photothermal heating regulate access to binding sites and release pathways. Polymer brushes, hydrogels and microgels, membranes and nanochannels, ion-imprinted magnetic composites, and MXene-based hybrids are critically compared using cycle-level criteria, including U/V selectivity, switching time, regeneration demand, energy input, fouling resistance, material loss, synthesis reproducibility, and environmental performance. Particular emphasis is placed on distinguishing genuine structural gating from the generic effects of temperature on diffusion, ligand exchange, and adsorption equilibria. Current evidence supports the feasibility of programmable capture–release interfaces but remains limited by matrix-dependent transition windows, incomplete mechanistic attribution, scarce quantitative energy and temperature-gradient data, short cycling tests, and limited device-scale validation. Progress will require standardized testing in realistic saline matrices and complete capture–release mass and energy balances rather than evaluation by maximum adsorption capacity alone. Full article

The emergence of organic–inorganic hybrid composites integrating magnetic nanoparticles (MNPs) with polymers has been an important advancement in modern biological research. Among these systems, magnetic sodium alginate (SA)-based hydrogels (MSABHs), produced by embedding MNPs within an SA framework, exhibit remarkable potential for biomedical applications owing to their high biocompatibility, rapid magnetic response, controllable spatiotemporal behavior, and remote, non-invasive operation. Under the influence of an alternating magnetic field (AMF), MSABHs can exhibit various responses, including deformation, motion, and thermal generation, which are highly valuable for diagnostic and therapeutic medical applications. This review first outlines the key studies on SA and MNPs, along with the various synthesis routes used to fabricate MSABHs. Subsequently, the discussion primarily focuses on their versatile biomedical applications, including tissue engineering, targeted drug delivery, thermotherapy, imaging, and micro-robotics, followed by an evaluation of current challenges and prospects for future improvement. Through this comprehensive examination and synthesis, the review aims to further reveal the full potential of MSABHs and broaden their applications in the biological domain. Full article

Here, the degradation of a β-blocker drug (Nadolol (NAD)) and real pharmaceutical wastewater was achieved using magnetized cow bone waste-derived char (MCBWC)–alginate hydrogel beads via a periodate (PI) activation system in a continuous-flow fluidized-bed photoreactor. The removal of NAD by PI-based degradation systems has not been previously reported, and the degradation of real industrial wastewater in continuous-flow photoreactors remains underexplored. The fabricated beads exhibited a high surface area of 78.58 m² g⁻¹, a total pore volume of 0.19 cm³ g⁻¹, and an effective integration of all composite components. The MCBWC–alginate hydrogel beads/PI/light degradation system degraded 71.47% of NAD, which was higher than that of the sole photocatalysis and PI activation systems. Further, the optimal operating condition could achieve a NAD degradation efficiency of 97.1% and a total organic carbon (TOC) removal efficiency of 82.78%. Furthermore, the degradation system demonstrated the non-formation of toxic iodinated byproducts. The hydrogel beads demonstrated high stability, where the NAD degradation efficiency slightly decreased by only 2.85% across five successive experiments. Singlet oxygen and iodine-based radicals contributed to NAD degradation more than other reactive species. Bicarbonate showed the highest suppressive effect on the degradation performance, while adding 10 mg L⁻¹ of humic acid decreased the degradation efficiency to 85.58%. The degradation system could further degrade other pharmaceuticals (e.g., ibuprofen, paracetamol, carbamazepine, tetracycline) and real pharmaceutical wastewater, attaining 78.37% degradation efficiency of NAD and 44.25% TOC mineralization. This study presents a stable, effective, and continuous degradation system that can be employed in real-world industrial wastewater treatment applications. Full article

The development of adsorbents with high adsorption capacity, easy separation, and good reusability is critical for the treatment of dye-contaminated wastewater. Herein, a novel magnetic composite hydrogel, P(AA-AM)/SA-BC-Fe₃O₄, was synthesized via free radical polymerization, integrating acrylic acid (AA), acrylamide (AM), sodium alginate (SA), biochar (BC), and magnetic Fe₃O₄ nanoparticles. The material was systematically characterized by FTIR, XRD, SEM, BET, and VSM, which confirmed the successful formation of a three-dimensional porous network with well-dispersed Fe₃O₄ nanoparticles and BC, endowing the hydrogel with superparamagnetic properties. The adsorption performance of the hydrogel towards methylene blue (MB) was evaluated under various conditions. The results demonstrated that the adsorption process followed the pseudo-second-order kinetic model and the Langmuir isotherm, indicating that chemisorption is an important mechanism in the monolayer adsorption process. The hydrogel exhibited excellent swelling properties and remarkable pH-dependent adsorption behavior, with optimal performance in weakly alkaline environments. Notably, the incorporation of BC enhanced the adsorption capacity, while Fe₃O₄ enabled rapid magnetic separation, with the adsorbent retaining approximately 77% of its initial capacity after five regeneration cycles. This work presents a promising strategy for constructing magnetic hydrogel adsorbents that synergistically combine high adsorption efficiency, facile separability, and good reusability for practical wastewater treatment applications. Full article

Micro- and nanoplastic pollution poses an emerging challenge for aquatic environments, driving the need for efficient and scalable removal strategies. Functional polymeric materials (FPMs) have emerged as a versatile platform to address this issue, owing to their tunable chemical composition, structural diversity, and ability to promote multiple removal mechanisms, including adsorption, filtration, and coagulation/flocculation. This review provides an overview of recent advances in polymer-based strategies for the removal of micro- and nanoplastics, with emphasis on material design, interaction mechanisms, and process performance. A broad range of materials, including natural hydrogels, polysaccharide aerogels, synthetic polymer composites, magnetic hybrids, and metal–organic frameworks (MOFs)–polymer systems, have demonstrated high removal efficiencies through electrostatic interactions, hydrogen bonding, hydrophobic effects, π–π stacking, and physical entrapment. Removal performance is strongly influenced by surface functionalization, porosity, surface area, and polymer network architecture, enabling targeted design for specific particle types and water matrices. Hybrid and multifunctional materials further enhance capacity and reusability, while natural polymers offer sustainable alternatives. Despite these advances, challenges remain in standardization, scalability, long-term stability, fouling resistance, and economic feasibility under realistic environmental conditions. Future research should focus on sustainable, multi-target, and scalable FPMs, integrating hybrid architectures, stimuli-responsive functionalities, and bioinspired design strategies. Particular attention should be given to mechanistic studies under environmentally relevant conditions and the establishment of structure–property design criteria to enable efficient removal of heterogeneous MPs/NPs mixtures. Overall, functional polymeric materials represent a flexible and high-performance platform for mitigating micro- and nanoplastic contamination, although their successful implementation will depend on bridging the gap between laboratory-scale performance and real-world water treatment applications. Full article

Four-dimensional (4D) printing integrates additive manufacturing with stimuli-responsive materials to fabricate biomedical implants and functional healthcare devices that undergo programmed, time-dependent changes in shape or function. Unlike static 3D-printed constructs, 4D-printed systems can respond to clinically relevant stimuli such as temperature, hydration, pH, light (including near-infrared), magnetic fields, or electrical inputs. These triggers drive defined actuation mechanisms, most commonly thermomechanical shape-memory recovery, swelling-induced morphing, and magnetothermal activation. This review synthesizes the principal material platforms used for biomedical 4D printing, including shape-memory polymers and alloys, hydrogels, liquid-crystal elastomers, and responsive composites, and links material choice to device behavior and translational feasibility. Applications are discussed across self-expanding stents, cardiac occluders, tissue-engineered constructs, implantable drug delivery systems, and adaptive wearables. Key translational challenges include sterilization compatibility, manufacturing reproducibility and quality control, safe stimulus delivery, predictable biodegradation and long-term biocompatibility, and regulatory pathway definition. Full article

Repairing maxillofacial bone defects remains a major clinical challenge due to inadequate vascularisation and poor integration with host tissue. While bioactive scaffolds have shown promise in supporting osteogenesis and angiogenesis, achieving robust and synchronised dual regenerative outcomes is still elusive. This study presents a multifunctional, cell-free magnetic hydrogel platform designed to biomimetically coordinate osteogenic and angiogenic processes for effective maxillofacial bone regeneration. The composite poly(vinyl alcohol)-vaterite (PVA-Vat) hydrogel scaffold incorporates tuneable magnetic nanoparticles (MNPs) composed of single-domain superparamagnetic iron oxide (Fe₃O₄). By harnessing magneto-mechanical cues to orchestrate bilateral communication between human bone mesenchymal stem cells and endothelial cells, this platform provides a deeper mechanistic understanding of coupled tissue regeneration and delivers superior dual-regenerative performance for maxillofacial bone repair. Under magnetic stimulation, a coculture system demonstrated strong osteogenesis-angiogenesis coupling mediated by reciprocal VEGFA-BMP2 signalling. This reciprocal crosstalk was evidenced by a synergistic amplification of VEGFA and BMP2 expression in coculture compared to monocultures, where MNP-stimulated osteoprogenitors secreted VEGFA to drive endothelial capillary-like network formation, while endothelial cells reciprocally enhanced endogenous BMP2 levels to accelerate osteoblastic mineralisation. These findings establish MNP-integrated hydrogels as a cell-free, multifunctional platform capable of synchronising dual regenerative pathways, offering a biomimetic strategy to overcome vascularisation and integration barriers in maxillofacial bone repair. Full article

Polysaccharide–protein composite hydrogels have demonstrated remarkable potential in targeted gastrointestinal delivery owing to their excellent biocompatibility, adjustable physicochemical characteristics, and intelligent responsiveness. This review provides a comprehensive overview of the underlying mechanisms and diverse applications of these composite hydrogels in gastrointestinal targeted delivery, with a particular emphasis on their stimuli-responsive release behaviors triggered by internal and external factors such as pH, enzymes, magnetic fields. Special attention is also given to their advantages in protecting sensitive bioactive ingredients, including curcumin, EGCG, probiotics. Furthermore, this review highlights their capabilities in achieving high encapsulation efficiency, smart controlled release and targeted delivery, while also presenting current challenges associated with material stability, targeting precision, large-scale production, and clinical translation. Finally, future perspectives are discussed, focusing on the development of multi-response system design, innovative biomaterials, advanced manufacturing technology applications, and AI-assisted optimization. These directions aim to provide theoretical foundations and technical strategies for advanced research and practical applications of polysaccharide–protein composite hydrogels in a targeted gastrointestinal delivery system. Overall, this review underscores the significant promise of polysaccharide–protein composite hydrogels as intelligent gastrointestinal delivery platforms and provides a systematic reference for their rational design and future translational development. Full article

Stimuli-responsive hydrogels are an emerging class of smart materials with immense potential across biomedical engineering, soft robotics, environmental systems, and advanced manufacturing. In this review, we present an in-depth exploration of their material design, classification, fabrication strategies, and real-world applications. We examine how a wide range of external stimuli—such as temperature, pH, moisture, ions, electricity, magnetism, redox conditions, and light—interact with polymer composition and crosslinking chemistry to shape the responsive behavior of hydrogels. Special attention is given to the growing field of 4D printing, where time-dependent shape and property changes enable dynamic, programmable systems. Unlike existing reviews that often treat materials, stimuli, or applications in isolation, this work introduces a multidimensional comparative framework that connects stimulus-response behavior with fabrication techniques and end-use domains. We also highlight key challenges that limit practical deployment—including mechanical fragility, slow actuation, and scale-up difficulties—and outline engineering solutions such as hybrid material design, anisotropic structuring, and multi-stimuli integration. Our aim is to offer a forward-looking perspective that bridges material innovation with functional design, serving as a resource for researchers and engineers working to develop next-generation adaptive systems. Full article

Multi-component polymer hydrogels present complex physiochemical interactions that make accurate compositional analysis challenging. This study evaluates three analytical techniques: Nuclear Magnetic Resonance (NMR), Advanced Polymer Chromatography (APC), and Thermogravimetric Analysis (TGA) to quantify polyvinyl alcohol (PVA) and polyethylene glycol (PEG) content in hybrid freeze-thaw derived PVA/PEG/PVP hydrogels. Hydrogels were synthesized using an adapted freeze–thaw method across a wide range of PVA:PEG ratios, with PVP included at 1 wt% to assess potential intermolecular effects. NMR and APC reliably quantified polymer content with low average errors of 2.77% and 2.01%, respectively, and were unaffected by phase separation or hydrogen bonding within the composite matrix. TGA enabled accurate quantification at PVA contents ≤ 62.5%, where PEG and PVA maintained distinct thermal decomposition behaviors. At higher PVA concentrations, increased hydrogen bonding and crystalline restructuring, confirmed by FTIR through shifts near 1140 cm⁻¹ and significant changes in the -OH region, altered thermal profiles and reduced TGA accuracy. Together, these findings establish APC as a high-throughput alternative to NMR for multi-component polymer analysis and outline critical thermal and structural thresholds that influence TGA-based quantification. This work provides a framework for characterizing complex polymer networks in biomedical hydrogel systems. Full article

Gallic acid (GA) exhibits a broad range of biological activities; however, its clinical application is significantly limited by poor stability, rapid degradation, and low bioavailability. Consequently, developing responsive delivery platforms to enhance GA stability and targeted release has become an important research focus. Herein, GA was encapsulated within novel composite hydrogel beads (CMC-SA-Fe₃O₄@GA) prepared via crosslinking carboxymethyl chitosan (CMC) and sodium alginate (SA) with Fe₃O₄ nanoparticles (NPs) to facilitate efficient drug delivery. The formulation was characterized and evaluated in terms of drug-loading capacity, controlled-release properties, antioxidant activity, antibacterial performance, and biocompatibility. The results indicated that the GA loading efficiency reached 31.07 ± 1.23%. Application of an external magnetic field accelerated GA release, with the observed release kinetics fitting the Ritger–Peppas model. Furthermore, antioxidant capacity, evaluated by DPPH assays, demonstrated excellent antioxidant activity of the CMC-SA-Fe₃O₄@GA composite beads. Antibacterial tests confirmed sustained inhibitory effects against Escherichia coli and Staphylococcus aureus. In vitro, cellular assays indicated favorable biocompatibility with normal hepatic cells (HL-7702) and effective inhibition of hepatocellular carcinoma cells (HepG2). Overall, the novel pH- and magnetic field-responsive CMC-SA-Fe₃O₄@GA hydrogel system developed in this work offers considerable potential for controlled delivery of phenolic compounds, demonstrating promising applicability in biomedical and food-related fields. Full article

Rare earth elements (REEs) are critical for advanced technologies, with neodymium and praseodymium being essential to high-performance permanent magnets. The separation of these adjacent lanthanides represents a significant challenge due to their nearly identical chemical properties, with traditional chitosan surfaces exhibiting limited discrimination between chemically similar elements. Current separation methods require multiple processing steps and cannot maintain predetermined compositional ratios. Engineered polymer interfaces with controlled binding site distribution represents a critical advancement for selective separation, but achieving ratio-controlled extraction of adjacent elements remains challenging. Here, we demonstrate a novel interface engineering approach using alkali/urea dissolution to restructure chitosan networks, creating dual-template alkali/urea chitosan hydrogels (NdPr-AUCH) for simultaneous selective co-extraction of Nd(III) and Pr(III). We show that the dissolution–reformation process enables templated Nd:Pr selectivity ratios (1:1, 2:1, and 4:1) that directly correspond to synthesis compositions. NdPr-AUCH-11 achieved maximum uptake capacities of 19.85 mg/g for Nd(III) and 16.89 mg/g for Pr(III), while NdPr-AUCH-41 maintained 3.07:1 Nd:Pr selectivity in competitive environments. Thermodynamic analyses reveal consistently lower energy requirements for Nd(III) binding compared to Pr(III), demonstrating how interface engineering amplifies coordination differences between adjacent lanthanides. This work represents the first demonstration of ratio-controlled extraction of adjacent lanthanides within a single polymer matrix, advancing interface-engineered materials for selective rare earth recovery. Full article

A swellable magnetic polymer with high removal capacity was produced. The copolymer consisting of acrylamide and 2,4,6-triallyloxy-1,3,5-triazine was synthesized via the radical polymerization method. Previously prepared magnetic Fe₃O₄ particles with the co-precipitation method were added during the synthesis, and then the obtained composite was hydrolyzed. The composite became a swellable hydrogel after hydrolysis. The synthesized magnetic composite hydrogel polymer was used for Malachite Green (MG) and Acid Violet 19 (AV19) binary textile dye mixture removal. A derivative method was developed to calculate the individual concentration of dyes in mixture solutions. The accuracy and precision of the developed method were examined by calculating the recovery percentage (R%) and relative standard deviation (RSD%). The highest removal percentages (~99% for MG and ~100% for AV19) were achieved at the dye mixture’s natural pH (pH 4). Antibacterial tests were examined against Gram-negative and Gram-positive bacteria, and the synthesized composite hydrogel polymer showed higher activity. The FTIR, XRD, SEM, and EDS analyses were also performed to characterize the synthesized materials. Full article

To address the growing demand for environmentally friendly flexible sensors, here, a composite hydrogel of nanocellulose (NC) and polyvinyl alcohol (PVA) was designed and fabricated using Camellia oleifera shells as a sustainable alternative to petroleum-based raw materials. Firstly, NC was extracted from Camellia oleifera shells and modified with 2-chloropropyl chloride to obtain a nanocellulose-based initiator (Init-NC) for atomic transfer radical polymerization (ATRP). Subsequently, sulfonyl betaine methacrylate (SBMA) was polymerized by Init-NC initiating to yield zwitterion-functionalized nanocellulose (NC-PSBMA). Finally, the NC-PSBMA/PVA hydrogel was fabricated by blending NC-PSBMA with PVA. A Fourier transform infrared spectrometer (FT-IR), proton nuclear magnetic resonance spectrometer (¹H-NMR), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), universal mechanical testing machine, and digital source-meter were used to characterize the chemical structure, surface microstructure, and sensing performance. The results indicated that: (1) FT-IR and ¹H NMR confirmed the successful synthesis of NC-PSBMA; (2) SEM, TEM, and alternating current (AC) impedance spectroscopy verified that the NC-PSBMA/PVA hydrogel exhibits a uniform porous structure (pore diameter was 1.1737 μm), resulting in significantly better porosity (15.75%) and ionic conductivity (2.652 S·m⁻¹) compared to the pure PVA hydrogel; and (3) mechanical testing combined with source meter testing showed that the tensile strength of the composite hydrogel increased by 6.4 times compared to the pure PVA hydrogel; meanwhile, it showed a high sensitivity (GF = 1.40, strain range 0–5%; GF = 1.67, strain range 5–20%) and rapid response time (<0.05 s). This study presents a novel approach to developing bio-based, flexible sensing materials. Full article