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Owing to their native extracellular matrix-like features, magnetic hydrogels have been proven to be promising biomaterials as tissue engineering templates In the present work, magnetic hydrogels scaffold based on chitosan, gelatin, hyaluronic acid, containing Fe3O4 as magnetic nanoparticles (IONPs) were prepared. The prepared hydrogels were loaded with ciprofloxacin hydrochloride as a model drug. The magnetic hydrogel was prepared using different volumes of chitosan, 1%, gelatin, 10%, and hyaluronic acid, 1% in glutaraldehyde as the crosslinking agent and Fe3O4 as magnetic nanoparticles. The hydrogel scaffold and magnetic scaffold hydrogel samples were characterized by scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), and Fourier-transform infrared spectroscopy (FTIR). The porosity, mechanical properties, swelling degree, and antibacterial activity of the hydrogel scaffold were also determined as well as the drug release profiles of the hydrogels. SEM imaging revealed that the magnetic hydrogel scaffold showed a relatively rough morphology with an irregular surface. The data obtained indicated that the hydrogel surface has three-dimensional porous microstructures and the porosity varied depending on the hydrogel formulation. The breaking load of the hydrogel scaffold increased from 1.361 Kgf to 4.98 Kgf by increasing the glutaraldehyde concentration from 0.2 mL to 0.8 mL. Swelling degree values in water were from 250 to 2000% after 24 h. The antibacterial activity of the hydrogel scaffold ranged from 54% to about 97% for Gram-positive bacteria (S. aureus) and from about 26–92% for Gram-negative bacteria (E. coli). The ciprofloxacin hydrochloride loaded hydrogel has a sustained release of ciprofloxacin hydrochloride over 10 h. The presence of IONPs gave a faster release of ciprofloxacin hydrochloride. [ABSTRACT FROM AUTHOR]

4D printing technology offers the potential to create smart structures that respond to external stimuli. This study focuses on a novel magnetic hydrogel with promising applications in 4D printing, particularly for medical devices such as guidewire robots, drug delivery systems, and vascular stents. Magnetic‐responsive hydrogels suitable for 4D printing are scarce, and their complex rheological properties pose challenges for printing. The study investigates these properties and optimizes them through adjustments in ink composition and the application of an external magnetic field, improving printability. Using the direct writing (DLP) method, which allows magnetic programming of individual strands, the study achieves greater flexibility compared to the traditional SLA method. Optimized printing parameters and material ratios produced high‐quality single strands, grids, and sheet‐like structures, demonstrating responsiveness to varying magnetic fields. Results confirm that DLP can be effectively applied to hydrogel 4D printing, achieving flexible structures with tunable mechanical properties. Additionally, magnetic‐responsive, self‐folding hydrogel structures were created, with a response speed of 180 ms under a magnetic field. This research establishes a foundation for magnetic hydrogel 4D printing and offers insights for the development of future smart medical devices. [ABSTRACT FROM AUTHOR]

Dual-stimuli sensitive hybrid Polyvinyl alcohol (PVA)/Starch/Manganese iron oxide (MnFe2O4), i.e. PS/pp-MI hydrogel membranes were successfully developed in a non-toxic way. Different hydrogels (PS, PS/pp-MI1, PS/pp-MI2 and PS/pp-MI3) were synthesized by varying the amount of MnFe2O4 nanoparticles (pp-MI NPs) in polymer matrix. From TG-DTA, peak decomposition temperatures were found at 211, 210, 216 and 273 ℃ for PS, PS/pp-MI1, PS/pp-MI2 and PS/pp-MI3 hydrogels, respectively, and pp-MI NPs were found to improve the thermal stability of hydrogel. Electron microscopy images display the increase in pore size from 3.3 to 8.6 μm with increase in pp-MI loading in hydrogels. PS/pp-MI1 revealed magnetic behaviour due to incorporation of ferromagnetic pp-MI NPs with the magnetization value of 0.614 emu/g. Also, the water absorption and retention capability of the hydrogels were assessed. Swelling studies revealed high responsiveness of the synthesized hydrogels to pH changes. The 5-Fluorouracil (5-FU) loading of hydrogels with highest encapsulation efficiency of 90% was observed for PS/pp-MI3. In vitro release studies revealed the suitability of hydrogels for sustained 5-FU release with the absence of initial burst release. Korsmeyer-Peppa kinetic model was used to study the drug release mechanisms. Through MTT assay, pp-MI NPs were found to possess significant antitumour activity with the 50% inhibition concentration (IC50) values of 51.26 µg/ml for 24 h and 35.03 µg/ml for 48 h treatments. Whereas, hybrid hydrogels have no tumour-toxicity due to successful entrapment of pp-MI NPs in the hydrogels. All these studies suggest that the novel PS/pp-MI hydrogel is an effective choice for cancer therapeutics. [ABSTRACT FROM AUTHOR]

BACKGROUND: Endoscopic submucosal dissection (ESD) is a well-established treatment for gastrointestinal tumors and enables en bloc resection. Adequate counter traction with good visualization is important for safe and effective dissection. OBJECTIVE: Based on magnetic anchor-guided endoscopic submucosal dissection (MAG-ESD), we would like to explore the feasibility of magnetic hydrogel as an internal magnetic anchor that can be injected into the submucosa through an endoscopic needle to assist colonic endoscopic submucosal dissection. METHODS: This prospective trial was conducted on 20 porcine colons ex vivo. We injected magnetic hydrogel into submucosa of the porcine colons ex vivo for MAG-ESD to evaluate the traction effect and operation satisfaction. RESULTS: Magnetic hydrogel assisted ESD was successfully performed on 20 porcine colons ex vivo. Adequate counter traction with good visualization was successfully obtained during the procedure of dissection. CONCLUSION: Magnetic hydrogel assisted MAG-ESD is feasible and effective. [ABSTRACT FROM AUTHOR]

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A novel approach was devised to address the challenges in delivering cisplatin (CIS) for lung cancer treatment. This involved the development of a non-invasive hydrogel delivery system, aiming to minimize side effects associated with its administration. Using carbopol 971 (CP) and chitosan (CH) at varying ratios, the hydrogels were prepared and loaded with eco-friendly iron oxide nanoparticles (IONPs) conjugated to CIS. The physical properties, yield, drug loading, and cytotoxicity against lung cancer cell lines (A549) were assessed, along with hydrogel rheological properties and in vitro drug diffusion. Hydrogel A1 that composed of 1:1 of CP:CH hydrogel loaded with 100 mg IONPs and 250 µg CIS demonstrated distinctive properties that indicate its suitability for potential delivery. The loaded greenly synthesized IONPs@CIS exhibited a particle size of 23.0 nm, polydispersity index of 0.47, yield of 71.6%, with 88.28% drug loading. They displayed significant cytotoxicity (61.7%) against lung cancer cell lines (A549), surpassing free CIS cytotoxicity (28.1%). Moreover, they demonstrated shear-thinning behaviour, viscoelastic properties, and Fickian drug release profile over 24 h (flux 2.34 µg/cm2/h, and permeability 0.31 cm/h). [ABSTRACT FROM AUTHOR]

Articular cartilage defects afflict millions of individuals worldwide, presenting a significant challenge due to the tissue's limited self‐repair capability and anisotropic nature. Hydrogel‐based biomaterials have emerged as promising candidates for scaffold production in artificial cartilage construction, owing to their water‐rich composition, biocompatibility, and tunable properties. Nevertheless, conventional hydrogels typically lack the anisotropic structure inherent to natural cartilage, impeding their clinical and preclinical applications. Recent advancements in tissue engineering (TE) have introduced magnetically responsive hydrogels, a type of intelligent hydrogel that can be remotely controlled using an external magnetic field. These innovative materials offer a means to create the desired anisotropic architecture required for successful cartilage TE. In this review, we first explore conventional techniques employed for cartilage repair and subsequently delve into recent breakthroughs in the application and utilization of magnetic hydrogels across various aspects of articular cartilage TE. [ABSTRACT FROM AUTHOR]

Gamma-aminobutyric acid (GABA) is an vital neurotransmitter, and the reaction to obtain GABA through biocatalysis requires coenzymes, which are therefore limited in the production of GABA. In this study, polyacrylamide hydrogels doped with chitosan and waste toner were synthesized for glutamate decarboxylase (GAD) and coenzyme co-immobilization to realize the production of GABA and the recovery of coenzymes. Enzymatic properties of immobilized GAD were discussed. The immobilized enzymes have significantly improved pH and temperature tolerance compared to free enzymes. In terms of reusability, after 10 repeated reuses of the immobilized GAD, the residual enzyme activity of immobilized GAD still retains 100% of the initial enzyme activity, and the immobilized coenzyme can also be kept at about 32%, with better stability and reusability. And under the control of no exogenous pH, immobilized GAD showed good performance in producing GABA. Therefore, in many ways, the new composite hydrogel provides another way for the utilization of waste toner and promises the possibility of industrial production of GABA. [ABSTRACT FROM AUTHOR]

Magnetic composite hydrogels exhibit promising prospects for diverse applications, but their mechanical properties impose limitations on their further advancement. In this study, a novel approach is proposed to directly prepare magnetic composite hydrogels utilizing nanoferroferric oxide, aiming to replace the existing preparation method. Meanwhile, graphene oxide (GO) is introduced into magnetic composite hydrogels to enhance their mechanical characteristics. By employing ammonium citrate (AC) as a dispersant, the dispersion of ferroferric oxide magnetic nanoparticles at a concentration of 40 mg/mL is achieved, enabling their coexistence with GO for the preparation of magnetic composite hydrogels. Notably, the incorporation of 3 mg/mL GO and 40 mg/mL magnetic nanoparticles in polyacrylamide (PAM) hydrogel yields remarkable improvements in maximum stress and strain, reaching 148 kPa and 496%, respectively. In contrast, magnetic composite hydrogels without GO exhibit lower values of 46.5 kPa and 351%. The presence of magnetic nanoparticles imparts magnetism to the hydrogel, with higher concentrations of magnetic nanoparticles leading to increased magnetism. Moreover, the presence of AC and GO renders the hydrogels electronegative, thereby endowing them with selective adsorption capabilities. In summary, the magnetic composite hydrogels prepared by one‐pot method have good mechanical properties and selective adsorption capacity, and have good application potential. [ABSTRACT FROM AUTHOR]

Bone marrow-derived mesenchymal stem cell (MSC) is one of the most actively studied cell types due to its regenerative potential and immunomodulatory properties. Conventional cell expansion methods using 2D tissue culture plates and 2.5D microcarriers in bioreactors can generate large cell numbers, but they compromise stem cell potency and lack mechanical preconditioning to prepare MSC for physiological loading expected in vivo. To overcome these challenges, in this work, we describe a 3D dynamic hydrogel using magneto-stimulation for direct MSC manufacturing to therapy. With our technology, we found that dynamic mechanical stimulation (DMS) enhanced matrix-integrin β1 interactions which induced MSCs spreading and proliferation. In addition, DMS could modulate MSC biofunctions including directing MSC differentiation into specific lineages and boosting paracrine activities (e.g., growth factor secretion) through YAP nuclear localization and FAK-ERK pathway. With our magnetic hydrogel, complex procedures from MSC manufacturing to final clinical use, can be integrated into one single platform, and we believe this ‘all-in-one’ technology could offer a paradigm shift to existing standards in MSC therapy.

In this research, a novel magnetic hydrogel (MHG) adsorbent based on Fe3O4/poly(2-hydroxyethylmethacrylate-co-2-acrylamido-2-methylpropanesulfonic acid) Fe3O4/poly(HEMA-co-AMPS) was synthesized by in situ co-precipitation of Fe3O4 magnetic particles inside poly(HEMA-co-AMPS) hydrogels. This adsorbent was used to adsorb the organic cationic dye methylene blue (MB) from aqueous solutions. The properties of the adsorbent were characterized by FT-IR, TGA, XRD, VSM, and EDX-SEM techniques. The degree of swelling was recorded in water, acidic medium (HCl 0.01 M), and basic medium (NaOH 0.01 M). The results confirmed that Fe3O4 particles were successfully synthesized within the poly(HEMA-co-AMPS) hydrogel structure. Magnetic hydrogels have higher swelling and reach equilibrium faster than hydrogels. The magnetic hydrogel prepared with 3 % crosslinker and 10 % AMPS (MHG3(10)) showed better potential to remove MB dye, adsorption capacity Qmax = 445.35 mg/g, this was obtained under the best conditions at pH 6.5, dose of 1 g/L, and contact time of 10 min. Over the test pHpzc, the surface of the MHG3(10) is predominantly negative at pH values higher than 2.47. The adsorption process of MHG3(10) for MB removal follows the Langmuir model and obeys pseudo-second-order kinetics. In addition, thermodynamic studies performed show that the adsorption process is endothermic (ΔH0 = 75.946 kJ/mol) and spontaneous with a positive value of entropy (ΔS0 = 263.562 J/mol·K). Regeneration experiments showed that MHG3(10) can be reused several times as its removal efficiency is still 94 % after 10 adsorption–desorption cycles. Therefore, the magnetic hydrogel MHG3(10) proved to be a promising adsorbent for the removal of the pollutant MB dye from aqueous media.

Magnetic hybrid hydrogels have exhibited remarkable efficacy in various areas, particularly in the biomedical sciences, where these inventive substances exhibit intriguing prospects for controlled drug delivery, tissue engineering, magnetic separation, MRI contrast agents, hyperthermia, and thermal ablation. Additionally, droplet-based microfluidic technology enables the fabrication of microgels possessing monodisperse characteristics and controlled morphological shapes. Here, alginate microgels containing citrated magnetic nanoparticles (MNPs) were produced by a microfluidic flow-focusing system. Superparamagnetic magnetite nanoparticles with an average size of 29.1 ± 2.5 nm and saturation magnetization of 66.92 emu/g were synthesized via the co-precipitation method. The hydrodynamic size of MNPs was changed from 142 nm to 826.7 nm after the citrate group's attachment led to an increase in dispersion and the stability of the aqueous phase. A microfluidic flow-focusing chip was designed, and the mold was 3D printed by stereo lithographic technology. Depending on inlet fluid rates, monodisperse and polydisperse microgels in the range of 20–120 μm were produced. Different conditions of droplet generation in the microfluidic device (break-up) were discussed considering the model of rate-of-flow-controlled-breakup (squeezing). Practically, this study indicates guidelines for generating droplets with a predetermined size and polydispersity from liquids with well-defined macroscopic properties, utilizing a microfluidic flow-focusing device (MFFD). Fourier transform infrared spectrometer (FT-IR) results indicated a chemical attachment of citrate groups on MNPs and the existence of MNPs in the hydrogels. Magnetic hydrogel proliferation assay after 72 h showed a better rate of cell growth in comparison to the control group (p = 0.042). [ABSTRACT FROM AUTHOR]

Caffeine (CAF) is a psychostimulant present in many beverages and with rapid bioabsorption. For this reason, matrices that effectuate the sustained release of a low amount of CAF would help reduce the intake frequency and side effects caused by high doses of this stimulant. Thus, in this study, CAF was loaded into magnetic gelatin/alginate (Gel/Alg/MNP) hydrogels at 18.5 mg/ghydrogel. The in vitro release of CAF was evaluated in the absence and presence of an external magnetic field (EMF) and Ca2+. In all cases, the presence of Ca2+ (0.002 M) retarded the release of CAF due to favorable interactions between them. Remarkably, the release of CAF from Gel/Alg/MNP in PBS/CaCl2 (0.002 M) at 37 °C under an EMF was more sustained due to synergic effects. In PBS/CaCl2 (0.002 M) and at 37 °C, the amounts of CAF released after 45 min from Gel/Alg and Gel/Alg/MNP/EMF were 8.3 ± 0.2 mg/ghydrogel and 6.1 ± 0.8 mg/ghydrogel, respectively. The concentration of CAF released from Gel/Alg and Gel/Alg/MNP hydrogels amounted to ~0.35 mM, thereby promoting an increase in cell viability for 48 h. Gel/Alg and Gel/Alg/MNP hydrogels can be applied as reservoirs to release CAF at suitable concentrations, thus forestalling possible side effects and improving the viability of SH-SY5Y cells. [ABSTRACT FROM AUTHOR]

Conversion of the renewable biopolymers to magnetic adsorbents is a sustainable approach for environmental concerns. Herein, the microwave-assisted micro-carboxymethylated cellulose (MCMC) with DS = 0.76, the in situ polymerized acrylamide, and nano g-Fe2O3–SO3H were fabricated in a three-dimensional hydrogel network by one-pot radical polymerization with an aromatic bis-amide cross-linker. This SO3H/phenyl implanted various methods characterized nano-composite hydrogel as a granular porous network with excellent swelling performance for the adsorption of heavy metal ions (HMIs). The results of the influences of pH, organic solvent, and salt onto the hydrogel swelling capacity (SC) showed an increase by raising the pH, a decrease in organic solvents, and a decrease in chloride salt solutions by order of Na+ < Ca2+ < Fe3+. The mechanism and kinetics of hydrogel swelling with a capacity of 60.7 g/g were consistent with the non-Fickian diffusion and Schott's second-order kinetic models. As an adsorbent, the hydrogel removed Pb2+ and Hg2+ with an adsorption capacity 91.12 mg/g and 79.64 mg/g at neutral pH 7. The adsorption isotherms of hydrogel for Pb2+ and Hg2+ were adequately fitted with the Langmuir model (R2 = 0.99). The chelation of carboxylate groups to HMIs, electrostatic interactions between the charged surface groups and HMIs, and hydrogen bonding are significant parameters of the adsorption mechanism. The successive adsorption/desorption cycles for HMIs removal offer high potential of this hydrogel for the treatment of industrial wastewaters. [ABSTRACT FROM AUTHOR]

Recent advancement in biomaterials have led to the development of magnetic hydrogel as promising tool for anticancer therapy. Magnetic hydrogels improve injectability over bare nanoparticles by controlling particle dispersion and reducing aggregation, ensuring uniform delivery and minimizing clogging, thereby enhancing anticancer therapy effectiveness and safety. This review explores the fundamental crosslinking methodologies and chemical strategies for the formation of hydrogels, transitioning into detailed discussions on the synthesis of magnetic hydrogels, emphasizing their unique properties essential for biomedical applications. Key properties such as injectability, shear thinning, biocompatibility, porosity, mechanical properties, and biodegradability underpinning the efficacy of magnetic hydrogels in biomedical applications are discussed. Furthermore, the review highlights the diverse applications of magnetic hydrogels in the biomedical field, including hyperthermia, MRI-guided therapy, targeted drug delivery, and tissue engineering. These properties and applications demonstrate the potential of magnetic hydrogels to revolutionize cancer treatment and other medical therapies, offering a multifunctional platform that can address various biomedical challenges with enhanced precision and effectiveness. Finally, future research trends and applications of magnetic hydrogels are also recommended and examined. [Display omitted] • Fundamental methods & chemical strategies for creating hydrogel. • Key properties of magnetic hydrogel drives their biomedical applications. [ABSTRACT FROM AUTHOR]

We present the fabrication and application of a magnetically actuated, macro-porous, drug–delivery hydrogel exhibiting significant reversible volume change (down to 55% of its original size) in response to a small magnetic field (23 Gauss) from a permanent magnet. When integrating the hydrogel in a microchannel, the system demonstrates a magnetically regulated flow dynamics, showing a wide range of controllable flow rate from 10 to 100 µL/s. It is fabricated via a straightforward and economical process in which macro-pores are incorporated into the hydrogel by generating micro-bubbles during its crosslinking process. The resulting hydrogel enables simultaneous control over liquid flow and drug release rate. [ABSTRACT FROM AUTHOR]

Three-dimensional printing enables building objects shaped with a large degree of freedom. Additional functionalities can be included by modifying the printing material, e.g., by embedding nanoparticles in the molten polymer feedstock, the resin, or the solution used for printing, respectively. Such composite materials may be stronger or more flexible, conductive, magnetic, etc. Here, we give an overview of magnetic composites, 3D-printed by different techniques, and their potential applications. The production of the feedstock is described as well as the influence of printing parameters on the magnetic and mechanical properties of such polymer/magnetic composites. [ABSTRACT FROM AUTHOR]

Magnetic hybrid hydrogels have exhibited remarkable efficacy in various areas, particularly in the biomedical sciences, where these inventive substances exhibit intriguing prospects for controlled drug delivery, tissue engineering, magnetic separation, MRI contrast agents, hyperthermia, and thermal ablation. Additionally, droplet-based microfluidic technology enables the fabrication of microgels possessing monodisperse characteristics and controlled morphological shapes. Here, alginate microgels containing citrated magnetic nanoparticles (MNPs) were produced by a microfluidic flow-focusing system. Superparamagnetic magnetite nanoparticles with an average size of 29.1 ± 2.5 nm and saturation magnetization of 66.92 emu/g were synthesized via the co-precipitation method. The hydrodynamic size of MNPs was changed from 142 nm to 826.7 nm after the citrate group’s attachment led to an increase in dispersion and the stability of the aqueous phase. A microfluidic flow-focusing chip was designed, and the mold was 3D printed by stereo lithographic technology. Depending on inlet fluid rates, monodisperse and polydisperse microgels in the range of 20–120 μm were produced. Different conditions of droplet generation in the microfluidic device (break-up) were discussed considering the model of rate-of-flow-controlled-breakup (squeezing). Practically, this study indicates guidelines for generating droplets with a predetermined size and polydispersity from liquids with well-defined macroscopic properties, utilizing a microfluidic flow-focusing device (MFFD). Fourier transform infrared spectrometer (FT-IR) results indicated a chemical attachment of citrate groups on MNPs and the existence of MNPs in the hydrogels. Magnetic hydrogel proliferation assay after 72 h showed a better rate of cell growth in comparison to the control group (p = 0.042).

• This paper developed a magnetic hydrogel that can be 4D printed. Our work provides a solution for the integration of structural and functional properties in soft robots and fills the gap in the field of 4D printing of magnetic hydrogels. • Unlike conventional hydrogels used for 3D printing, we added bentonite to the printing ink to thicken it, making it easier to print with a stable yield stress, and preventing the aggregation and settling of internal magnetic particles. • Instead of the conventional magnetic domain programming method, we incorporated a large capacitor into the circuit to magnetize the printing ink through the charging and instantaneous discharging of the capacitor. This integrated the material pre-treatment process with the programming process, rather than magnetizing the material first and then programming the printing in the printer. • In this paper, we created various soft actuators with different structures to achieve different functions, exploring practical applications. In recent years, with the development of materials science, various new materials that can sense external stimuli and respond have emerged. This ability to respond to external stimuli enables these materials to empower other materials or structures, greatly promoting the development of soft robots. In recent years, many 4D printed magnetic silicon gels have appeared, while 4D printing of magnetic hydrogels is still a blank slate. Here, we have developed a light-curable magnetic hydrogel that can be 4D printed. Unlike traditional methods of thickening hydrogels for 3D printing, we added bentonite to thicken the printing ink and controlled its rheological properties to make it suitable for printing. During the printing process, we used capacitive momentary discharge to generate a strong magnetic field to program the printing ink, eliminating the need for pre-treatment of the printing ink. We also studied the influence of the content of ferromagnetic particles and the size of the external magnetic field on its responsiveness. Finally, we printed and programmed the hydrogel on a silicone sheet to empower the silicone sheet. Based on this, we have created a variety of different types of soft actuators to achieve different movements and functions. [ABSTRACT FROM AUTHOR]

GRAPHICAL ABSTRACTPreparation and magnetic stimulation of SFH-DOX/MNPs for in vitro drug release study.

Aim: Magnetic hydrogels (MHGs) have been proposed to avoid the redistribution and loss of magnetic nanoparticles (MNPs) when administrated by intratumoral injection. However, the requirement of complex cooling systems and temperature monitoring systems still hinder the clinical application of MHGs. This study investigates the feasibility of developing an MHG to realize the self-regulation of hyperthermia temperature. Methods: The MHG was developed by dispersing the MNPs with self-regulating temperature property into the temperature-sensitive hydrogel through physical crosslinking. The MHG's gelation temperature was tested by measuring the storage modulus and loss modulus on a rotational rheometer. The biocompatibility of the MHG and MNPs was characterized by CCK-8 assay against HaCaT cells. The in vivo magnetic heating property was examined through monitoring the temperature in the MHG on mice back upon the application of the alternating magnetic field (400 ± 5 Oe, 100 ± 5 kHz) every week for successive six weeks. Results: The gelation temperature of the MHG falls in 28.4°C-37.4°C. At in vivo applied concentration of 80 mg/mL, the MHG exhibits over 80% cell viability after 72 h, significantly higher than 50% cell viability of the MNPs (p

An efficient and facile strategy for the fabrication of a bioinspired drug delivery system (DDS) was designed and developed successfully based on tragacanth gum (TG) owing to its wide range of biological and pharmacological activities (e.g., anti-tumor). For this objective, the reduced TG (TG-OH) was tosylated (TG-OTs), and then 2-ethyl-2-oxazoline (EtOx) monomer was grafted onto purified TG through a cationic ring-opening polymerization (CROP) technique. The polymerization was terminated and simultaneously crosslinked by the addition of amine-modified Fe3O4 nanoparticles and cystamine (Cys) moiety to afford a TG-g-PEtOx/Fe3O4 as a pH- and reduction-sensitive magnetic hydrogel (MH). The fabricated MH exhibited excellent doxorubicin hydrochloride (Dox) encapsulation efficiency (83.1 ± 3.1) owing to its porous micro-structure and robust physical interactions between the drug molecule and polymeric network. In vitro drug release studies results confirmed the pH- and reduction-responsiveness of the developed MH/Dox system. The anticancer performance study by MTT-assay revealed that the developed MH/Dox has excellent potential for "smart" chemo/hyperthermia therapy of cancerous cells. [ABSTRACT FROM AUTHOR]

Smart hydrogels which can respond to external stimuli have been widely focused with increasing interest. Thereinto, magnetic-responsive hydrogels that are prepared by embedding magnetic nanomaterials into hydrogel networks are more advantageous in biomedical applications due to their rapid magnetic response, precisely temporal and spatial control and non-invasively remote actuation. Upon the application of an external magnetic field, magnetic hydrogels can be actuated to perform multiple response modes such as locomotion, deformation and thermogenesis for therapeutic purposes without the limit of tissue penetration depth. This review summarizes the latest advances of magnetic-responsive hydrogels with focus on biomedical applications. The synthetic methods of magnetic hydrogels are firstly introduced. Then, the roles of different response modes of magnetic hydrogels played in different biomedical applications are emphatically discussed in detail. In the end, the current limitations and future perspectives for magnetic hydrogels are given. [Display omitted] • The recent advances of magnetic hydrogels in biomedical applications are summarized. • The design and synthetic strategies of magnetic hydrogels are summarized. • Magnetic hydrogels can perform multiple response modes under external magnetic fields. • Magnetic hydrogels hold the promise as remotely controlled micro-/nanorobots in theranostics. [ABSTRACT FROM AUTHOR]

Thermal-responsive magnetic hydrogels (Hydrogel 1 and Hydrogel 2) were synthesized through the copolymerization of maleic anhydride-functionalized Tragacanth gum macromonomer (MATGM), N-isopropylacrylamide (NIPAAm) monomer, and 3-(trimethoxysilyl) propylmethacrylate-modifed magnetic nanoparticles (MPS-MNPs) in the presence of N,N´-methylene-bis(acrylamide) (MBAm) and N,N,N´,N´-tetramethylethylenediamine (TEMED) as crosslinker and accelerator, respectively, using a free radical polymerization approach. The scanning electron microscopy (SEM) images were revealed that the fabricated hydrogels had porous microstructure without microphase separation. The synthesized magnetic hydrogels were loaded with methotrexate (MTX) as an anticancer drug, and their drug loading and encapsulation efficiencies as well as thermal-triggered drug release behaviors were investigated. The biocompatibilities of the fabricated hydrogels were confirmed using MMT assay. The MTX loaded hydrogels were exhibited better anticancer performance than those of the free MTX. Since the biological as well as physicochemical results, the fabricated magnetic hydrogels have high potential for cancer chemotherapy. [ABSTRACT FROM AUTHOR]

Tissue engineering is a promising strategy for the repair and regeneration of damaged tissues or organs. Biomaterials are one of the most important components in tissue engineering. Recently, magnetic hydrogels, which are fabricated using iron oxide-based particles and different types of hydrogel matrices, are becoming more and more attractive in biomedical applications by taking advantage of their biocompatibility, controlled architectures, and smart response to magnetic field remotely. In this literature review, the aim is to summarize the current development of magnetically sensitive smart hydrogels in tissue engineering, which is of great importance but has not yet been comprehensively viewed.

For coloration of products, dyes are used in various industries such as pulp, paper, leather, pharmaceuticals, and textiles. Disposal of colored textile wastewater into the environment, without efficient treatment, imposes serious damages to aquatic life by reducing sunlight penetration to water. Different treatment techniques including chemical coagulation, electrochemical coagulation, advanced oxidation processes, membrane technology, and adsorption have been applied to remove dyes from industrial wastewater. Among these, adsorption is an easy-operating, effective, and cost-effective option. Activated carbon has been employed for removal of various pollutants from wastewater, but it has high cost of regeneration. Hence low-cost adsorbents alternative to activated carbon are gaining attention in recent years. In the present study methylene blue was selected as the model dye molecule. Methylene blue adsorption kinetics and equilibrium of poly(viny) alcohol hydrogel films containing different amounts of magnetic particles were investigated. The hydrogels were synthesised by freezing-thawing method. The amounts of dye adsorbed by the hydrogels at equilibrium were in the range of 2.5–3.4 mg/g almost independent of the hydrogel magnetic particle content. The MB adsorption kinetics of the magnetic hydrogels can be represented by the pseudo-second order kinetic model and the model parameters were determined. It was not possible to desorb all the adsorbed dye by contacting the saturated hydrogels with water at 25C.

Every year more than 100,000 kinds of commercially available dyestuff are produced. Most of industrial dyes have synthetic origin, which are applied in many industries such as textiles, rubber, paper, plastics, leather, petrochemicals etc. The textile industry is one of the major consumers of dyestuff and the effluent from textile industries carries a large number of dyes and other additives which are added as auxiliary chemicals. During the dyeing process some of dyestuff does not bind and approximately 10-15 % of them remains in the wastewater effluents. The release of synthetic dyes to the environment cause serious environmental problems and detrimental effects to human health. Therefore development of an effective treatment method for removing dyes from wastewater is of great significance. In this study poly(vinyl) alcohol hydrogels containing different amounts of magnetic particles were prepared and characterized for dye adsorption from wastewater. The magnetic particles synthesized by co-precipitation methos were dispersed in aqueous poly(vinyl) alcohol solutions. The solutions were then physically crosslinked by the freezing-thawing method. The hydrogels prepared were characterized for their drying, swelling and gelation properties. It was found that the hydrogels has high water absorption capacity (equilibrium degree of swelling: 200–214% and equilibrium water content: 66–68%) and high crosslinking degree (95%) almost independent from their magnetic particle content. They gained magnetic property after addition of the magnetic particles in the polymer matrix.

The drug delivery performances of pH‐responsive magnetic hydrogels (MHs) composed of tragacanth gum (TG), poly(acrylic acid) (PAA), and Fe3O4 nanoparticles (NPs) were investigated in terms of physicochemical as well as biological features. The fabricated drug delivery systems (DDSs) were analyzed using Fourier transform infrared spectroscopy, X‐ray diffraction, vibrating sample magnetometer, scanning electron microscopy, and transmission electron microscopy. The synthesized MHs were loaded with doxorubicin hydrochloride (Dox) as a universal model anti‐cancer drug. The MHs showed excellent Dox loading and encapsulation efficiencies, mainly due to strong hydrogen bonding and electrostatic interaction between the drug and polymeric matrix, as well as porous micro‐structures of the fabricated MHs. The drug‐loaded MHs showed negligible drug release values in physiological condition. In contrast, in cancerous condition (pH 5.0), both MHs exhibited highest drug release values that qualified them as "smart" DDSs. The cytocompatibilities of the MHs as well as the cytotoxicity of the Dox‐loaded MHs were investigated against human epidermoid‐like carcinoma (Hela) cells through MTT assay. In addition, hyperthermia therapy induced by Fe3O4 NPs was applied to locally raise temperature inside the Hela cells at 45 ± 3°C to promote cell death. As a result, the Dox‐loaded MHs can be considered as potential DDSs for chemo/hyperthermia therapy of solid tumors. [ABSTRACT FROM AUTHOR]

Aim: Magnetic hydrogels (MHGs) have been proposed to avoid the redistribution and loss of magnetic nanoparticles (MNPs) when administrated by intratumoral injection. However, the requirement of complex cooling systems and temperature monitoring systems still hinder the clinical application of MHGs. This study investigates the feasibility of developing an MHG to realize the self-regulation of hyperthermia temperature. Methods: The MHG was developed by dispersing the MNPs with self-regulating temperature property into the temperature-sensitive hydrogel through physical crosslinking. The MHG's gelation temperature was tested by measuring the storage modulus and loss modulus on a rotational rheometer. The biocompatibility of the MHG and MNPs was characterized by CCK-8 assay against HaCaT cells. The in vivo magnetic heating property was examined through monitoring the temperature in the MHG on mice back upon the application of the alternating magnetic field (400 ± 5 Oe, 100 ± 5 kHz) every week for successive six weeks. Results: The gelation temperature of the MHG falls in 28.4°C-37.4°C. At in vivo applied concentration of 80 mg/mL, the MHG exhibits over 80% cell viability after 72 h, significantly higher than 50% cell viability of the MNPs (p<0.001). The MHG's stable magnetic hyperthermia temperatures in vivo are in the range of 43.4°C–43.8°C. Conclusions: The developed MHG can be injected using a syringe and will solidify upon body temperature. The biocompatibility is improved after the MNPs being made into MHG. The MHG can self-regulate the temperature for six weeks, exhibiting application potential for self-regulating temperature hyperthermia. [ABSTRACT FROM AUTHOR]

We propose an innovative magnetic separation technique to separate a very important toxic inorganic pollutant (nitrate) from wastewater, using a recyclable magnetic adsorbent system. Our recyclable adsorbent system is a novel magnetic hydrogel composite, based on cross‐linked polyacrylic acid (MNP‐pAAc). The as‐synthesized magnetic hydrogel composite has very well controlled properties related to the thicknesses (each particle is individually covered with a thin layer of cross linked poly acrylic acid shell) which offer a relatively high surface area and a high level of saturation magnetization. The maximum separation efficiency was relatively high, between 80 and 90% while the magnetization value, around 60 emu/g, was considered high for polymeric composite material. This characteristic makes the as‐synthesized material a potential material for future water purification device but which is more important is that the material can be recycled, washed and reused which is not reported in the literature for similar kinds of materials. The recyclability was demonstrated in five subsequent adsorption–desorption cycles and maintenance of adsorption capacity over altogether 5 adsorption/desorption cycles to so high levels represents an important advantage and a novel idea over single‐use materials. Using this kind of recycling material for effective depollution of nitrate by water we offer a new solution to avoid secondary pollution. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: Magnetic hydrogels have found extensive applications in fields such as soft robotics, drug delivery and shape morphing. Here a facile method was fabricated to prepare polysaccharide‐based magnetic hydrogels. The chitosan‐Fe3O4 ferrofluid was obtained by dispersing carboxyl groups modified Fe3O4 nanoparticles uniformly in chitosan matrix. Subsequently, the magnetic polysaccharide hydrogel was obtained by simply mixing cellulose acetoacetate solution with chitosan‐Fe3O4 ferrofluid. The structures and properties of the magnetic hydrogel were analyzed using Fourier‐transform infrared spectroscopy, rheological recovery, responsiveness, and stability measurements. The results indicated that magnetic polysaccharide hydrogel showed pH responsiveness and excellent self‐healing properties, and the hydrogel manifested outstanding stability under physiological conditions (37 °C) for 72 h. In addition, the injectable polysaccharide‐based hydrogel exhibited sensitive magnetic responsive and shape‐shifting ability under an external magnetic field. Therefore, the strategy for the facile preparation of the magnetic polysaccharide‐based hydrogel in this work could provide a benign and versatile method for achieving self‐healing, responsive, injectable properties for the application in biomedical fields. [ABSTRACT FROM AUTHOR]

Ferrogels based on polyvinylpyrrolidone/polyvinyl alcohol (PVP/PVA) matrices with Mn0.6Fe2.4O4–polyethylene glycol (Mn0.6Fe2.4O4–PEG) were synthesized using the freezing–thawing method. The phase structure and morphology of ferrogels with Mn0.6Fe2.4O4–PEG filler were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The Mn0.6Fe2.4O4–PEG/PVP/PVA ferrogel was characterized using small-angle X-ray scattering to determine the distribution of Mn0.6Fe2.4O4–PEG nanoparticles through two-lognormal data analysis; the semicrystallite distribution of the PVP/PVA was investigated using the Beaucage and Teubner–Strey models. The optical and electrical properties of the Mn0.6Fe2.4O4–PEG nanoparticles were characterized using a UV–Vis spectrophotometer. The XRD analysis showed that the Mn0.6Fe2.4O4–PEG exhibits an inverse-spinel cubic structure with an average particle size of 10.2 nm. This result was corroborated by TEM analysis, which revealed an average size of 10.9 nm through the Image-J software analysis. The two-lognormal method was used to analyze the distribution of Mn0.6Fe2.4O4–PEG nanoparticles in the ferrogel, revealing a secondary particle size of approximately 9.8 nm. These secondary particles are, on average, evenly arranged with respect to the primary particles with a diameter of 3.3 nm. UV–Vis data analysis showed that the refractive index and energy gap of the Mn0.6Fe2.4O4–PEG nanoparticles were approximately 2.79 and 2.24 eV, respectively. The optical conductivity and electrical conductivity calculated from the refractive-index and energy-gap data were 1.27 × 108 and 70 Ω−1 cm−1, respectively. These results indicate that the Mn0.6Fe2.4O4–PEG nanoparticles exhibit strong potential for use as a base material in optoelectronics applications. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: Magnetic hydrogels have found extensive applications in fields such as soft robotics, drug delivery and shape morphing. Here a facile method was fabricated to prepare polysaccharide‐based magnetic hydrogels. The chitosan‐Fe3O4 ferrofluid was obtained by dispersing carboxyl groups modified Fe3O4 nanoparticles uniformly in chitosan matrix. Subsequently, the magnetic polysaccharide hydrogel was obtained by simply mixing cellulose acetoacetate solution with chitosan‐Fe3O4 ferrofluid. The structures and properties of the magnetic hydrogel were analyzed using Fourier‐transform infrared spectroscopy, rheological recovery, responsiveness, and stability measurements. The results indicated that magnetic polysaccharide hydrogel showed pH responsiveness and excellent self‐healing properties, and the hydrogel manifested outstanding stability under physiological conditions (37 °C) for 72 h. In addition, the injectable polysaccharide‐based hydrogel exhibited sensitive magnetic responsive and shape‐shifting ability under an external magnetic field. Therefore, the strategy for the facile preparation of the magnetic polysaccharide‐based hydrogel in this work could provide a benign and versatile method for achieving self‐healing, responsive, injectable properties for the application in biomedical fields. [ABSTRACT FROM AUTHOR]

Novel magnetic hydrogels based on acrylamide/2-acrylamido-2-methyl-1-propanesulfonic acid/poly(ethylene glycol) were prepared by free radical solution polymerization using ammonium persulfate/N,N,N′,N′-tetramethylethylenediamine as redox initiating pair in the presence of poly(ethylene glycol) dimethacrylate as a cross-linker. In this study, the water uptake and dye sorption performances of a series of novel magnetic hydrogel sorbents were investigated. For the preparation of magnetic polymeric hydrogels and semi-IPNs, they were loaded with iron (Fe2+, Fe3+) ions. Dynamic swelling tests were applied at 25 °C gravimetrically. According to obtained data, swelling kinetics parameters and diffusion mechanisms were calculated. The magnetic hydrogels synthesized in this study showed high water absorbency. Some water uptake and diffusion parameters were calculated, and they were discussed for the hydrogels prepared under various formulations. Structural characterization of polymers was completed with Fourier transform infrared spectroscopy analysis. Scanning electron microscopy images were taken for the determination of surface porosity of hydrogels and semi-IPNs. For adsorption studies, Janus Green B was chosen as model molecule. It was determined that semi-IPNs and hydrogels adsorbed Janus Green B from aqueous solutions at high levels. Consequently, the hydrogels developed in this study could serve for potential applications in wastewater treatment for water and dye uptake. [ABSTRACT FROM AUTHOR]

[Display omitted] • The photothermal properties effectively improve the uranium selectivity of Gel-Fe 3 O 4 /PAO. • Gel-Fe 3 O 4 /PAO shows excellent magnetic recovery performance. • Double network structure endows Gel-Fe 3 O 4 /PAO with stronger mechanical elasticity. • Gel-Fe 3 O 4 /PAO shows fast adsorption rate and outstanding adsorption capacity. The development of adsorbents for highly efficient extraction of uranium from seawater is a crucial for generating nuclear energy. However, their practical application is limited because of low U/V selectivity and recovery difficulties. Herein, we developed a new magnetic photothermal composite hydrogel (Gel-Fe 3 O 4 /PAO) adsorbent to facilitate efficient recovery and selective extraction of uranium from seawater. The hydrogel exhibits excellent tensile strength and self-recovery ability owing to the double-network structure formed via the physical crosslinking of gelatin and polymerization of acrylamide (AM). Furthermore, the photothermal conversion performance of Fe 3 O 4 nanoparticles improves the uranium selectivity of PAO and enables magnetic recovery of the hydrogel. Adsorption results show that when the Fe 3 O 4 and gelatin contents are 1.5 wt.% and 16 wt.%, respectively, the hydrogel can be rapidly heated under light, meeting the requirements of high adsorption capacity (515.5 mg·g-1) and selectivity (K d (U) /K d (V) = 2.77) for uranium ions. After seven sorption-desorption cycles, the uranium adsorption capacity of the Gel-Fe 3 O 4 /PAO hydrogel remains at nearly 89 %. In simulated seawater experiments, the Gel-Fe 3 O 4 /PAO hydrogel exhibits excellent impact resistance and a high selective uranium removal rate, demonstrating its considerable potential for practical application in uranium extraction from seawater. [ABSTRACT FROM AUTHOR]

Water pollution by toxic substances, such as dye molecules, remains a major environmental problem that needs to be solved. In the present work, the magnetic composite hydrogel based on the poly(2-(methacryloyloxy)-N-(2-hydroxyethyl)-N,N-dimethylethan-1-aminium bromide-co-N-isopropylacrylamide) copolymer with incorporated Fe3O4 particles ((poly(DMAEAB-co-NIPAm)@Fe3O4)) was prepared by an in situ synthesis technique for the efficient removal of dye molecules from water. The successfully synthesized magnetic hydrogel was characterized by FTIR, XRD, TGA, and TEM. The removal efficiency of the anionic dye bromophenol blue (BPB) and the cationic dye rhodamine B (RDM) by the prepared hydrogel adsorbents was evaluated. Various adsorption parameters, including the concentration of adsorbents and adsorption time, were also investigated. The results showed that the synthesized magnetic hydrogel had excellent BPB removal performance compared to the removal of RDM. The optimum adsorbent concentration for 0.5 mM BPB solution was approximately 0.5 g/L, and the removal efficiency was more than 99%. The kinetics data of BPB removal fitted well into the pseudo-2nd-order model, indicating that BPB dye adsorption involves chemical adsorption and physical adsorption. In addition, recycling studies were conducted to examine the reusability of the magnetic hydrogel for BPB removal for up to five cycles and the hydrogel could be reused without losing its high removal efficiency. The magnetic hydrogel poly(DMAEAB-co-NIPAm)@Fe3O4 with high removal efficiency, good selectivity, and reusability shows great potential for the removal of anionic dyes in wastewater treatment.

Encoded hydrogel microparticles mounting DNA probes are powerful tools for high-performance microRNA (miRNA) detection in terms of sensitivity, specificity, and multiplex detection capability. However, several particle rinsing steps in the assay procedure present challenges for rapid and efficient detection. To overcome this limitation, we encapsulated dense magnetic nanoparticles to reduce the rinsing steps and duration via magnetic separation. A large number of magnetic nanoparticles were encapsulated into hydrogel microparticles based on a discontinuous dewetting technique combined with degassed micromolding lithography. In addition, we attached DNA probes targeting three types of miRNAs related to preeclampsia to magnetically encoded hydrogel microparticles by post-synthesis conjugation and achieved sensitivity comparable to that of conventional nonmagnetic encoded hydrogel microparticles. To demonstrate the multiplex capability of magnetically encoded hydrogel microparticles while maintaining the advantages of the simplified rinsing process when addressing multiple samples, we conducted a triplex detection of preeclampsia-related miRNAs. In conclusion, the introduction of magnetically encoded hydrogel microparticles not only allowed efficient miRNA detection but also provided comparable sensitivity and multiplexed detectability to conventional nonmagnetic encoded hydrogel microparticles.

The present study aimed to synthesize poly(acrylic acid) hydrogel embedded with magnetic cobalt (Co) nanoparticles and to investigate their potential in adsorption and catalysis. The hydrogel was prepared by facile free radical polymerization reaction and Co nanoparticles were fabricated within hydrogel by reducing Co (II) ions using NaBH4 as reducing agent. Co nanoparticles within hydrogel system imparted magnetic properties to the resulting composite gel and also increased the adsorption capacity. The swelling study of hydrogel was carried out by gravimetric analysis. Different functional groups were identified by Fourier Transform Infrared Spectroscopy and Transmission Electron Microscopy analysis was done to investigate dispersion of Co nanoparticles in hydrogel. The bare hydrogel along with Co nanoparticles loaded gel were tested as adsorbent systems for the removal of a cationic dye (methylene blue) from aqueous solution. 95% removal of methylene blue was achieved with a highest adsorption capacity of 836.5 mg/g of adsorbent. The famous adsorption isotherms were used to evaluate adsorption data. Results showed that Freundlich isotherm model was followed with R2 value of 0.95. The hydrogel was also used for catalytic reduction in a toxic pollutant, i.e., 4-nitrophenol. Experimental data for 4-nitrophenol reduction followed pseudo first order kinetics model. Activation energy and apparent rate constant were calculated as 9.24 kJ/mol and 0.24 min−1, respectively. Recycling of the magnetic poly(acrylic acid) hydrogel fabricated with Cobalt nanoparticles was carried out for four consecutive cycles and no significant loss in catalytic activity was observed. [ABSTRACT FROM AUTHOR]

In this work, the polyacrylic acid/carboxymethyl starch/Fe 3 S 4 (PAA/CMS/Fe 3 S 4) magnetic hydrogel was prepared. Pb and Cu in aqueous solution were as targeted pollutants for PAA/CMS/Fe 3 S 4. Fe 3 S 4 as the magnetic factor was added to the hydrogel. The hydrogel that composed by PAA and CMS can prevent Fe 3 S 4 from oxidization. And, Fe 3 S 4 not only had magnetic properties but also promoted the adsorption capacity of PAA/CMS/Fe 3 S 4. In addition, the Fe(II) that in Fe 3 S 4 served as the activator of potassium persulfate to produce SO 4 -· and triggered polymerization without the traditional method that need extra energy including heating and UV lighting, which can simplify the material preparation process. PAA/CMS/Fe 3 S 4 exhibited adsorption stability in the pH from 3.0 to 6.0. The adsorption process fitted to pseudo-second-order and Langmuir-Freundlich models. The functional groups of C O/Metal-O-C and O-C O in PAA/CMS/Fe 3 S 4 were identified by FTIR and XPS, which will adsorb Pb and Cu through complexation. The XRD results showed that the Pb and Cu can also be adsorbed by the formation of PbS and CuS, which due to the present of Fe 3 S 4. The Density-functional theory analysis showed that the orbital hybridization between Pb and Fe 3 S 4 was stronger than that of Cu and Fe 3 S 4 , which result in Fe 3 S 4 had a stronger interaction with Pb than Cu. PAA/CMS/Fe 3 S 4 magnetic hydrogel is a novel magnetic hydrogel and have a good adsorption performance for Pb and Cu from water. This work provides a new method for Fe 3 S 4 application in magnetic adsorbent. [Display omitted] • The hydrogel that composed by PAA and CMS can prevent Fe 3 S 4 from oxidization. • PAA/CMS/Fe 3 S 4 can be self-polymerized by activating KPS with Fe (II) in Fe 3 S 4. • PAA/CMS/Fe 3 S 4 have a good adsorption performance for Pb and Cu. • Orbital hybridization between Pb and Fe 3 S 4 was stronger than that of Cu and Fe 3 S 4. [ABSTRACT FROM AUTHOR]

Direct discharge of electroplating wastewater containing hazardous metal ions such as Cu2+ and Ag + results in environmental pollution. In this study, we rationally prepare a magnetic composite hydrogel consisted of Fe 3 O 4 , UiO-66-NH 2 , chitosan (CTS) and polyethyleneimine (PEI), namely Fe 3 O 4 @UiO-66-NH 2 /CTS-PEI. Thanks to the strong attraction between the amino group and metal cations, the Fe 3 O 4 @UiO-66-NH 2 /CTS-PEI hydrogel shows the maximum adsorption capacities of 321.67 mg g−1 for Cu2+ ions and 226.88 mg g−1 for Ag + ions within 120 min. As real scenario, the Fe 3 O 4 @UiO-66-NH 2 /CTS-PEI hydrogel exhibits excellent removal efficiencies for metallic ions even in the complicated media of actual electroplating wastewater. In addition, we explore the competitive adsorption order of metal cations by using experimental characterization and theoretical calculations. The optimal configuration of CTS-PEI is also discovered with the density functional theory, and the water retention within hydrogel is simulated through molecular dynamics modeling. We find that the Fe 3 O 4 @UiO-66-NH 2 /CTS-PEI hydrogel could be reused and after 5 cycles of adsorption-desorption, removal efficiency could maintain 80%. Finally, the Ag+ accumulated by hydrogel are reduced to generate a photocatalyst for efficient degradation of Rhodamine B. The novel magnetic hydrogel paves a promising path for efficient removal of heavy metal ions in wastewater and further resource utilization as photocatalysts. [Display omitted] • A novel Fe 3 O 4 @UiO-66-NH 2 doped CTS-PEI hydrogel is developed. • The hydrogel has highly efficient adsorption of Cu2+ and Ag+ from wastewater. • The Ag+ ions adsorbed on hydrogel is photo-reduced to form the Ag catalysts. • Ag catalysts show excellent photocatalytic activity for degradation of RhB. [ABSTRACT FROM AUTHOR]

Magnetic polymer gels are a new promising class of nanocomposite gels. In this work, magnetic PEO/iron oxide nanocomposite hydrogels were synthesized using the one-step γ-irradiation method starting from poly(ethylene oxide) (PEO) and iron(III) precursor alkaline aqueous suspensions followed by simultaneous crosslinking of PEO chains and reduction of Fe(III) precursor. γ-irradiation dose and concentrations of Fe3+, 2-propanol and PEO in the initial suspensions were varied and optimized. With 2-propanol and at high doses magnetic gels with embedded magnetite nanoparticles were obtained, as confirmed by XRD, SEM and Mössbauer spectrometry. The quantitative determination of γ-irradiation generated Fe2+ was performed using the 1,10-phenanthroline method. The maximal Fe2+ molar fraction of 0.55 was achieved at 300 kGy, pH = 12 and initial 5% of Fe3+. The DSC and rheological measurements confirmed the formation of a well-structured network. The thermal and rheological properties of gels depended on the dose, PEO concentration and initial Fe3+ content (amount of nanoparticles synthesized inside gels). More amorphous and stronger gels were formed at higher dose and higher nanoparticle content. The properties of synthesized gels were determined by the presence of magnetic iron oxide nanoparticles, which acted as reinforcing agents and additional crosslinkers of PEO chains thus facilitating the one-step gel formation.

Relapse and unresectability have become the main obstacle for further improving hepatocellular carcinoma (HCC) treatment effect. Currently, single therapy for HCC in clinical practice is limited by postoperative recurrence, intraoperative blood loss and poor patient outcomes. Multidisciplinary therapy has been recognized as the key to improving the long-term survival rate for HCC. However, the clinical application of HCC synthetic therapy is restricted by single functional biomaterials. In this study, a magnetic nanocomposite hydrogel (CG-IM) with iron oxide nanoparticle-loaded mica nanosheets (Iron oxide nanoparticles@Mica, IM) is reported. This biocompatible magnetic hydrogel integrated high injectability, magnetocaloric property, mechanical robustness, wet adhesion, and hemostasis, leading to efficient HCC multidisciplinary therapies including postoperative tumor margin treatment and percutaneous locoregional ablation. After minimally invasive hepatectomy of HCC, the CG-IM hydrogel can facilely seal the bleeding hepatic margin, followed by magnetic hyperthermia ablation to effectively prevent recurrence. In addition, CG-IM hydrogel can inhibit unresectable HCC by magnetic hyperthermia through the percutaneous intervention under ultrasound guidance., (© 2023 Wiley-VCH GmbH.)