Search Results (3,024)

Hydrogels have garnered significant interest in the biomedical field owing to their tissue-like properties and capability to incorporate various fillers. Among these, injectable hydrogels have been highlighted for their unique advantages, especially their minimally invasive administration mode for implantable use. These injectable hydrogels can be utilized in their pristine forms or as composites by integrating them with therapeutic filler materials. Given their primary application in implantable platforms, enzymatically crosslinked injectable hydrogels have been actively explored due to their excellent biocompatibility and easily controllable mechanical properties for the desired use. This review introduces the crosslinking mechanisms of such hydrogels, focusing on those mediated by horseradish peroxidase (HRP), transglutaminase (TG), and tyrosinase. Furthermore, several parameters and their relationships with the intrinsic properties of hydrogels are investigated. Subsequently, the representative biomedical applications of enzymatically crosslinked-injectable hydrogels are presented, including those for wound healing, preventing post-operative adhesion (POA), and hemostasis. Furthermore, hydrogel composites containing filler materials, such as therapeutic cells, proteins, and drugs, are analyzed. In conclusion, we examine the scientific challenges and directions for future developments in the field of enzymatically crosslinked-injectable hydrogels, focusing on material selection, intrinsic properties, and filler integration. Full article

This research systematically investigates the influence of raw material particle size and calcium content on the geopolymerization process to gain insight into the physical and mechanical properties of geopolymer gels, including setting time, fluidity, pore structure, compressive strength, and leaching characteristics of encapsulated Cr³⁺ heavy metal ions. Utilizing a diverse range of particle sizes of metakaolin (MK; 3.75, 7.5, and 12 µm) and fly ash (FA; 18, 45, and 75 µm), along with varied calcium levels, this study assesses the dual impact of these factors on the final properties of both metakaolin- and fly-ash-based geopolymers. Employing sophisticated analytical techniques such as Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Nuclear Magnetic Resonance (NMR), the research meticulously documents alterations in chemical bonding, micro-morphology, and pore structures. Key findings reveal that reducing the size of MK and FA particles to 3.75 and 18 µm, respectively, enhances the compressive strength of their matrices by 128.37 and 297.58%, respectively, compared to their original values (63.59 and 33.87 MPa, respectively) at larger particle sizes. While smaller particle sizes significantly bolster compressive strength, they adversely affect slurry flow and reduce the leaching rates of Cr³⁺ from MK- and FA-based matrices, reaching 0.42 and 0.75 mg/L at 3.75 and 18 µm, respectively. Conversely, increased calcium content markedly enhances setting times and contributes to the formation of dense microstructures through the production of calcium aluminate silicate hydrate (C-A-S-H) gels, thus improving the overall curing performance and durability of the materials. These insights underline the importance of fine-tuning particle size and calcium content to optimize geopolymer formulations, offering substantial benefits for varied engineering applications and promoting more sustainable construction practices. Full article

Incorporating nanoparticles into injectable hydrogels is a well-known technique for improving the mechanical properties of these materials. However, significant differences in the mechanical properties of the polymer matrix and the nanoparticles can result in localized stress concentrations at the polymer–nanoparticle interface. This situation can lead to problems such as particle–matrix debonding, void formation, and material failure. This work introduces boronic acid/boronate ester dynamic covalent bonds (DCBs) as energy dissipation sites to mitigate stress concentrations at the polymer–nanoparticle interface. Once boronic acid groups were immobilized on the surface of SiO₂ nanoparticles (SiO₂-BA) and incorporated into an alginate matrix, the nanocomposite hydrogels exhibited enhanced viscoelastic properties. Compared to unmodified SiO₂ nanoparticles, introducing SiO₂ nanoparticles with boronic acid on their surface improved the structural integrity and stability of the hydrogel. In addition, nanoparticle-reinforced hydrogels showed increased stiffness and deformation resistance compared to controls. These properties were dependent on nanoparticle concentration. Injectability tests showed shear-thinning behavior for the modified hydrogels with injection force within clinically acceptable ranges and superior recovery. Full article

In this study, we developed sodium alginate-chitosan hydrogels using a microwave-assisted synthesis method, aligning with green chemistry principles for enhanced sustainability. This eco-friendly approach minimizes chemical use and waste while boosting efficiency. A curcumin:2-hydroxypropyl-β-cyclodextrin complex was incorporated into the hydrogels, significantly increasing the solubility and bioavailability of curcumin. Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed the structure and successful incorporation of curcumin, in both its pure and complexed forms, into the polymer matrix. Differential scanning calorimetry revealed distinct thermal transitions influenced by the hydrogel composition and physical cross-linking. Hydrogels with higher alginate content had higher swelling ratios (338%), while those with more chitosan showed the lowest swelling ratios (254%). Scanning Electron Microscopy (SEM) micrographs showed a porous structure as well as successful incorporation of curcumin or its complex. Curcumin release studies indicated varying releasing rates between its pure and complexed forms. The chitosan-dominant hydrogel exhibited the slowest release rate of pure curcumin, while the alginate-dominant hydrogel exhibited the fastest. Conversely, for curcumin from the inclusion complex, a higher chitosan proportion led to the fastest release rate, while a higher alginate proportion resulted in the slowest. This study demonstrates that the form of curcumin incorporation and gel matrix composition critically influence the release profile. Our findings offer valuable insights for designing effective curcumin delivery systems, representing a significant advancement in biodegradable and sustainable drug delivery technologies. Full article

Rheumatoid arthritis, a chronic autoimmune disorder affecting millions worldwide each year, poses a significant threat due to its potential for progressive joint damage and debilitating pain if left untreated. Topical anti-inflammatory and analgesic treatments offer localized relief with reduced systemic side effects compared to conventional oral therapies, making them a promising option for managing rheumatoid arthritis. Therefore, the current study endeavored to formulate a microemulsion gel formulation loaded with diclofenac and curcumin for topical administration in the management of rheumatoid arthritis, utilizing Tea tree oil. The ratio of surfactant and cosurfactant was 4:1, assessed by pseudoternary phase diagram on the basis of the maximum emulsification region. The microemulsion underwent optimization using a Central Composite Rotatable Design (CCRD) with constraints of minimum particle size, polydispersity index, and maximum transmittance. The Curcufenac-T microemulsion had a particle size, polydispersity index (PDI), and transmittance of 151.82 ± 15.9 nm, 0.287 ± 0.021, and −5.78 ± 0.26 mV, respectively. DSC analyses confirmed the stability and compatibility of diclofenac and curcumin within the formulation. The microemulsion was changed into gel form by incorporating 1% carbopol-934. Skin permeation analysis revealed that the percentage of diclofenac permeated at 0.5 h from Curcufenac-T microemugel and the conventional gel was 12.1% and 3.9%, respectively, while at 12 h, the rates were 82.6% and 34.2%, respectively. In vitro permeability demonstrated significant potential for the effective delivery of diclofenac and curcumin to targeted sites, compared to conventional gel. Therefore, it was deduced that the Tea tree oil integrated diclofenac and curcumin microemulsion gel could enhance the effectiveness of diclofenac and serve as a promising vehicle for rheumatoid arthritis treatment. Full article

The innovative fusion of essential oils with hydrogel engineering offers an optimistic perspective for the design and development of next-generation materials incorporating natural bioactive compounds. This review provides a comprehensive overview of the latest advances in the use of hydrogels containing essential oils for biomedical, dental, cosmetic, food, food packaging, and restoration of cultural heritage applications. Polymeric sources, methods of obtaining, cross-linking techniques, and functional properties of hydrogels are discussed. The unique characteristics of polymer hydrogels containing bioactive agents are highlighted. These include biocompatibility, nontoxicity, effective antibacterial activity, control of the sustained and prolonged release of active substances, optimal porosity, and outstanding cytocompatibility. Additionally, the specific characteristics and distinctive properties of essential oils are explored, along with their extraction and encapsulation methods. The advantages and disadvantages of these methods are also discussed. We have considered limitations due to volatility, solubility, environmental factors, and stability. The importance of loading essential oils in hydrogels, their stability, and biological activity is analyzed. This review highlights through an in-depth analysis, the recent innovations, challenges, and future prospects of hydrogels encapsulated with essential oils and their potential for multiple applications including biomedicine, dentistry, cosmetics, food, food packaging, and cultural heritage conservation. Full article

Staphylococcus aureus (S. aureus) is a Gram-positive bacterium that causes infections ranging from mild superficial cases to more severe, potentially fatal conditions. Many photosensitisers used in photodynamic therapy are more effective against superficial infections due to limitations in treating deeper tissue infections. Recently, attention to this bacterium has increased due to the emergence of multidrug-resistant strains, which complicate antibiotic treatment. As a result, alternative therapies, such as antimicrobial photodynamic therapy (PDT), have emerged as promising options for treating non-systemic infections. PDT combines a photosensitiser (PS) with light and oxygen to generate free radicals that destroy bacterial structures. This systematic review evaluates the effectiveness of PDT delivered via different types of hydrogels in treating wounds, burns, and contamination by S. aureus. Following PRISMA 2020 guidelines, a bibliographic search was conducted in PubMed, Web of Science, and Scopus databases, including articles published in English between 2013 and 2024. Seven relevant studies were included, demonstrating evidence of PDT use against S. aureus in in vitro and in vivo studies. We concluded that PDT can effectively complement antimicrobial therapy in the healing of wounds and burns. The effectiveness of this technique depends on the PS used, the type of hydrogel, and the lesion location. However, further in vivo studies are needed to confirm the safety and efficacy of PDT delivered via hydrogels. Full article

Lost circulation is one of the important problems that restricts the speed and efficiency of oil and gas drilling and production. In this study, a resin plugging system was successfully developed for lost circulation formation. The resin plugging system showed excellent performance under high temperature and pressure conditions. The experimental results showed that the compressive strength of the resin plugging material can reach 9.23 MPa after curing, which is significantly higher than that of the traditional polymer gel material. The resin material can achieve effective curing in the temperature range of 60 °C to 100 °C, and the curing time decreases with the increase of temperature and only needs 3.46 h at 140 °C. The microstructure results showed that the resin material can form a chain or three-dimensional network structure after curing, which can effectively increase the toughness and strength of the cured plugging layer. Infrared and thermogravimetric analysis further confirmed the thermal stability of the chemical bonds in the material, and the initial decomposition temperature was about 241 °C, indicating that it had good thermal stability at about 300 °C. In addition, the effects of curing temperature, salinity, and drilling fluid pollution on the properties of the resin plugging agent were also investigated. The results showed that curing agent dosage and curing temperature are the key factors affecting curing time, while salinity and drilling fluid pollution affect the curing strength and overall properties of the materials. After adding 20% KCl polysulfonate drilling fluid, the compressive strength of the consolidated body decreased to 4.55 MPa. This study can provide an efficient and reliable plugging solution for malignant loss formation. Full article

This study investigates the synthesis, characterization, and antimicrobial properties of hydrogels synthesized through the UV-pulsed laser photopolymerization of a polymer–photoinitiator–chlorpromazine mixture. Chlorpromazine was used for its known enhanced antimicrobial properties when exposed to UV laser radiation. The hydrogel was formed from a mixture containing 0.05% Irgacure 2959, 10% gelatin methacryloyl, and various concentrations of chlorpromazine (1, 2, and 4 mg/mL). Laser-induced fluorescence spectroscopy was employed to monitor the photoinduced changes of chlorpromazine and Irgacure 2959 during hydrogel formation, providing insight into the photodegradation dynamics. FTIR spectroscopy confirmed the incorporation of irradiated chlorpromazine within the hydrogel matrix, while the release profiles of chlorpromazine showed sustained release only in hydrogels containing 1 mg/mL of CPZ. The hydrogel showed significant antimicrobial activity against MRSA bacteria when compared to that of penicillin. These findings highlight the potential of CPZ loaded during the photopolymerization process into hydrogels as effective antimicrobial agents with sustained release properties, making them suitable for combating resistant bacterial strains. Full article

The development of new biomaterials for musculoskeletal tissue repair is currently an important branch in biomedicine research. The approach presented here is centered around the development of a prototypic synthetic glycerogel scaffold for bone regeneration, which simultaneously features therapeutic activity. The main novelty of this work lies in the combination of an open meso and macroporous nanocrystalline cellulose (NCC)-based glycerogel with a fully biocompatible microporous bioMOF system (CaSyr-1) composed of calcium ions and syringic acid. The bioMOF framework is further impregnated with a third bioactive component, i.e., ibuprofen (ibu), to generate a multifold bioactive system. The integrated CaSyr-1(ibu) serves as a reservoir for bioactive compounds delivery, while the NCC scaffold is the proposed matrix for cell ingrowth, proliferation and differentiation. The measured drug delivery profiles, studied in a phosphate-buffered saline solution at 310 K, indicate that the bioactive components are released concurrently with bioMOF dissolution after ca. 30 min following a pseudo-first-order kinetic model. Furthermore, according to the semi-empirical Korsmeyer-Peppas kinetic model, this release is governed by a case-II mechanism, suggesting that the molecular transport is influenced by the relaxation of the NCC matrix. Preliminary in vitro results denote that the initial high concentration of glycerol in the NCC scaffold can be toxic in direct contact with human osteoblasts (HObs). However, when the excess of glycerol is diluted in the system (after the second day of the experiment), the direct and indirect assays confirm full biocompatibility and suitability for HOb proliferation. Full article

High-quality water availability is substantial for sustaining life, so its contamination presents a serious problem that has been the focus of several studies. The presence of heavy metals, such as cadmium, is frequently studied due to the increase in the contamination levels caused by fast industrial expansion. Cadmium ions were removed from aqueous solutions at pH 7.0 by chitosan–magnetite (ChM) xerogel beads and chitosan–FeO (ChF) xerogel beads in batch systems. Kinetic studies were best modeled by the Elovich model. The adsorption isotherms obtained showed an inflection point suggesting the formation of a second layer, and the BET model adjusted to liquid–solid systems was adequate for the description of the experimental data. Maximum uptake capacities of 36.97 ± 0.77 and 28.60 ± 2.09 mg Cd/g xerogel were obtained for ChM and ChF, respectively. The studied composites are considered promising adsorbent materials for removing cadmium ions from aqueous systems. Full article

Self-assembly of peptide building blocks offers unique opportunities for bottom-up preparation of exquisite nanostructures, nanoarchitectures, and nanostructured bulk materials, namely hydrogels. In this work we describe the synthesis, characterization, gelation, and rheological properties of new dehydrotripeptides, Cbz-L-Lys(Cbz)-L,D-Asp-∆Phe-OH and (2-Naph)-L-Lys(2-Naph)-L,D-Asp-∆Phe-OH, containing a N-terminal lysine residue N_α,ε-bis-capped with carboxybenzyl (Cbz) and 2-Naphthylacetyl (2-Naph) aromatic moieties, an aspartic acid residue (Asp), and a C-terminal dehydrophenylalanine (∆Phe) residue. The dehydrotripeptides were obtained as diastereomeric mixtures (L,L,Z and L,D,Z), presumably via aspartimide chemistry. The dehydrotripeptides afforded hydrogels at exceedingly low concentrations (0.1 and 0.04 wt%). The hydrogels revealed exceptional elasticity (G’ = 5.44 × 10⁴ and 3.43 × 10⁶ Pa) and self-healing properties. STEM studies showed that the diastereomers of the Cbz-capped peptide undergo co-assembly, generating a fibrillar 3D network, while the diastereomers of the 2-Naph-capped dehydropeptide seem to undergo self-sorting, originating a fibril network with embedded spheroidal nanostructures. The 2-Naph-capped hydrogel displayed full fast recovery following breakup by a mechanical stimulus. Spheroidal nanostructures are absent in the recovered hydrogel, as seen by STEM, suggesting that the mechanical stimulus triggers rearrangement of the spheroidal nanostructures into fibers. Overall, this study demonstrates that diastereomeric mixtures of peptides can be efficacious gelators. Importantly, these results suggest that the structure (size, aromaticity) of the capping group can have a directing effect on the self-assembly (co-assembly vs. self-sorting) of diastereomers. The cytotoxicity of the newly synthesized gelators was evaluated using human keratinocytes (HaCaT cell line). The results indicated that the two gelators exhibited some cytotoxicity, having a small impact on cell viability. In sustained release experiments, the influence of the charge on model drug compounds was assessed in relation to their release rate from the hydrogel matrix. The hydrogels demonstrated sustained release for methyl orange (anionic), while methylene blue (cationic) was retained within the network. Full article

A fracture-related infection (FRI) is a severe complication of an orthopedic trauma, often leading to challenging treatments and poor outcomes. The surgical strategies are typically categorized into one-stage or two-stage procedures, with the use of systemic and local antibiotics being crucial for infection management. This study assessed the efficacy of an antibiotic-loaded hydrogel (ALH) applied over the internal fixation devices for treating FRIs, comparing the outcomes between the one-stage (OS) and two-stage (TS) reconstructions. This retrospective study included 17 patients with an FRI treated using the ALH at a single center. The patients were divided into OS and TS reconstruction groups. The data on demographics, surgical procedures, antibiotic regimens, and outcomes were collected. The primary and secondary outcomes included the infection cure rate, bone union, complications, and reoperation rates. Among the 17 patients (mean age 48.5 years, 16 males), infections were predominantly in the tibia, with 12 chronic and 5 acute cases. Seven patients had monomicrobial infections, and nine had multidrug-resistant pathogens. No significant differences were found between the OS and TS groups in terms of the infection cure rate, bone union, or complications. One patient in the OS group experienced an infection recurrence, and bone healing was achieved in all but one case. Additional complications included delayed wound closure in two cases and implant failure in one case, requiring a reoperation. The ALH demonstrated potential as an effective local antibiotic treatment for FRIs, particularly in the one-stage reconstructions, allowing for a safe application of internal fixation devices. However, further research with larger sample sizes and longer follow-ups is needed to validate these findings. Full article

Origanum vulgare ssp. hirtum essential oil (OEO) is a natural oil with high therapeutic potential. For some applications, however, the development of novel formulations is still needed to improve the bioavailability and stability of OEO. In this study, we describe the fabrication of an original nanocomposite hydroxypropyl cellulose (HPC) physical hydrogel, containing OEO-loaded polymeric micelles, for topical delivery. The concentration of the main active compounds of OEO—carvacol and thymol—was determined using gas chromatography (GC) analysis. OEO was first encapsulated into Pluronic F127 micelles, and then embedded into HPC gel. Micellar and gel formulations of pure polymers and OEO-containing systems were characterized by dynamic light scattering (DLS) and rheology measurements, respectively. Selected formulations were evaluated for cytotoxicity and antiproliferative activity. The hydrogel formulation of HPC with micellar OEO (8% HPC, 2% F127, 1% OEO) exhibited sustained release of the oil and selectivity towards SH-4 tumor cells (an in vitro model of melanoma). Full article

Converting solar energy into fuels/chemicals through photochemical approaches holds significant promise for addressing global energy demands. Currently, semiconductor photocatalysis combined with redox techniques has been intensively researched in pollutant degradation and secondary energy generation owing to its dual advantages of oxidizability and reducibility; however, challenges remain, particularly with improving conversion efficiency. Since graphene’s initial introduction in 2004, three-dimensional (3D) graphene-based photocatalysts have garnered considerable attention due to their exceptional properties, such as their large specific surface area, abundant pore structure, diverse surface chemistry, adjustable band gap, and high electrical conductivity. Herein, this review provides an in-depth analysis of the commonly used photocatalysts based on 3D graphene, outlining their construction strategies and recent applications in photocatalytic degradation of organic pollutants, H₂ evolution, and CO₂ reduction. Additionally, the paper explores the multifaceted roles that 3D graphene plays in enhancing photocatalytic performance. By offering a comprehensive overview, we hope to highlight the potential of 3D graphene as an environmentally beneficial material and to inspire the development of more efficient, versatile graphene-based aerogel photocatalysts for future applications. Full article