Synthesis of Antibacterial Gelatin/Sodium Alginate Sponges and Their Antibacterial Activity

Development of a ROS-responsive, glutathione-functionalized injectable hydrogel system for controlled drug release

Oxidative stress arises from an imbalance between excessive production of reactive oxygen species (ROS) and the body's antioxidant defenses. In neurodegenerative diseases, this imbalance leads to ROS accumulation, causing neuronal dysfunction and cell death. Traditional drug therapies often fail to address the dynamic nature of neuroinflammation, limiting their therapeutic efficacy. To overcome this challenge, we have developed an innovative ROS-responsive injectable hydrogel. This hydrogel is designed to detect oxidative stress sensitively and release glutathione in a controlled manner, thereby modulating inflammation and restoring the damaged immune microenvironment to facilitate tissue repair. The hydrogel was synthesized by crosslinking polyvinyl alcohol (PVA) with sodium alginate modified with 3-aminophenylboronic acid (Alg-PBA). We investigated the hydrogel's formation mechanism and analyzed how component variations affect its morphological and rheological properties. Our findings demonstrate that an optimal Alg-PBA to PVA weight ratio of 2:1 yields a hydrogel with superior mechanical strength. Glutathione (GSH) release studies confirmed the hydrogel's pronounced ROS-responsive drug release behavior. Furthermore, biocompatibility assessments revealed that the hydrogel loaded with 100 μg/mL GSH exhibited excellent compatibility and significantly inhibited neuronal apoptosis under oxygen-glucose deprivation (OGD) conditions. This work presents a promising strategy for treating inflammation-related diseases and provides valuable insights for designing next-generation hydrogels that adapt to injury-responsive microenvironments.

Fabrication, characterization, and application of gelatin/alginate-based hydrogels incorporating selenium-doped deferoxamine-derived carbon quantum dots: In vitro and in vivo studies

This study developed a gelatin/alginate-based nanocomposite hydrogel (NC gel), incorporating selenium-doped deferoxamine-derived carbon quantum dots (Se.DFO-CQDs). Initially, Se.DFO-CQDs were synthesized and characterized through several tests, and subsequently, NC gels were created using an dual crosslinking method and analyzed through characterization tests such as SEM, EDX, FT-IR, XRD, tensile strength, water uptake, water vapor transmission rate, weight loss, porosity, blood compatibility, microbial penetration, and DPPH. In vivo studies revealed that NC gels containing Se.DFO-CQDs at 50 % and 0 % exhibited higher wound closure percentages than the control group. The highest wound closure percentage was observed in NC gels with Se.DFO-CQDs at 50 %, reaching 85.7 ± 3.98 % on the 7th day and 98.1 ± 3.95 % on the 14th day. Histological examinations demonstrated that NC gels with Se.DFO-CQDs at 50 % promoted more significant neovascularization, re-epithelialization, and collagen synthesis. Additionally, RT-qPCR results indicated that NC gels with Se.DFO-CQDs at 50 % significantly upregulated the mRNA expression of VEGF-A, bFGF, PDGF-b, and lncRNA GAS5 on the 7th day and COL1A1 on the 14th day. In conclusion, our findings suggest that the NC gels with Se.DFO-CQDs at 50 % show promise for enhancing wound healing and skin regeneration, potentially offering clinical applications.

The gelatin sponge loaded with curcumin coating exhibits a synergistic effect of hemostasis, anti-inflammatory, and anti-scarring

Postoperative wound healing has been extensively studied and well-documented. Gelatin sponges are commonly used in surgeries for blood absorption. If these sponges can also release drugs with anti-scarring and anti-inflammatory effects, they would significantly enhance wound healing. In this study, we investigated for the first time the application of curcumin films on the surface of gelatin sponges with high hemostatic efficiency using the Electron Beam Deposition (EBD) method. The structure of curcumin was analyzed using 1H NMR, FT-IR and XPS techniques. We examined the influence of the film on the sponge's absorption capacity and the impact of the sponge on drug release kinetics. Results showed that the presence of the curcumin film did not compromise the sponge's hemostatic ability. Additionally, compared to a flat substrate, the curcumin film on this highly porous substrate facilitated better curcumin release. Further experiments, including cytotoxicity tests, live/dead double staining, western blotting, and a scar model in mice, demonstrated that gelatin sponges with curcumin films exhibit a synergistic effect, combining anti-scarring, anti-inflammatory, and hemostatic properties.

Development of a hydrogel-based three-dimensional (3D) glioblastoma cell lines culture as a model system for CD73 inhibitor response study

BACKGROUND

Despite the development of various therapeutic approaches over the past decades, the treatment of glioblastoma multiforme (GBM) remains a major challenge. The extracellular adenosine-generating enzyme, CD73, is involved in the pathogenesis and progression of GBM, and targeting CD73 may represent a novel approach to treat this cancer. In this study, three-dimensional culture systems based on three hydrogel compositions were characterized and an optimal type was selected to simulate the GBM microenvironment. In addition, the effect of a CD73 inhibitor on GBM cell aggregates and spheroids was investigated as a potential therapeutic approach for this disease.

METHODS

Rheology measurements, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and cell proliferation assays were performed to analyze the synthesized hydrogel and select an optimal formulation. The viability of tumor cells in the optimal hydrogel was examined histologically and by confocal microscopy. In addition, the sensitivity of the tumor cells to the CD73 inhibitor was investigated using a cell proliferation assay and real-time PCR.

RESULTS

The data showed that the hydrogel containing 5 wt% gelatin and 5 wt% sodium alginate had better rheological properties and higher cell viability. Therefore, it could provide a more suitable environment for GBM cells and better mimic the natural microenvironment. GBM cells treated with CD73 inhibitors significantly decreased the proliferation rate and expression of VEGF and HIF1-α in the optimal hydrogel.

CONCLUSION

Our current research demonstrates the great potential of CD73 inhibitor for clinical translation of cancer studies by analyzing the behavior and function of 3D tumor cells, and thus for more effective treatment protocols for GBM.

Preparation of N-Halamine Gelatin Sponge and Its Application in the Treatment of Skin Infection

Nowadays, there has been an increasing research interest into N-halamine compounds due to their wide antimicrobial properties and no drug resistance. Most of the research mainly focuses on small molecular N-halamines, while few studies are on macromolecule N-halamines. In this work, antibacterial N-halamine polymer materials based on proteins (GS-Cl) were synthesized with an antibacterial component of oxidative chlorine, a support component of a gelatin sponge. After carrying out systematic characterization, the GS-Cls exhibited well-defined porous morphology and had a high efficiency in the killing of Gram-positive bacteria (E. coli) and Gram-negative bacteria (S. aureus). The loading of oxidative chlorine (Cl+%) could be controlled by changing the NaClO concentrations and chlorination times. The biocompatibility was confirmed as well. In vivo experiments suggested that the GS-Cl sample could effectively promote the healing of skin wounds in mice E. coli and S. aureus infection models. These studies show that proteins can be chlorinated and endowed with antimicrobial properties, which has great application potential in the treatment of bacteria-infected wounds.

Blood Coagulation Activities and Influence on DNA Condition of Alginate-Calcium Composites Prepared by Freeze-Drying Technique

The aim of this research was to synthesize and characterize alginate-calcium composites using a freeze-drying method, with a focus on their potential applications in biomedicine. This study specifically explored the biochemical properties of these composites, emphasizing their role in blood coagulation and their capacity to interact with DNA. Additionally, the research aimed to assess how the cross-linking process influences the structural and chemical characteristics of the composites. Detailed analyses, including microscopic examination, surface area assessment, and atomic absorption spectrometry, yielded significant results. The objective of this study was to examine the impact of calcium chloride concentration on the calcium content in alginate composites. Specifically, the study assessed how varying concentrations of the cross-linking solution (ranging from 0.5% to 2%) influence the calcium ion saturation within the composites. This investigation is essential for understanding the physicochemical properties of the materials, including calcium content, porosity, and specific surface area. The results are intended to identify the optimal cross-linking conditions that maximize calcium enrichment efficiency while preserving the material's structural integrity. The study found that higher calcium chloride concentrations in alginate cross-linking improve the formation of a porous structure, enhanced by two-stage freeze-drying. Increased calcium levels led to a larger surface area and pore volume, and significantly higher calcium content. Furthermore, assays of activated partial thromboplastin time (aPTT) showed a reduction in clotting time for alginate composites containing calcium ions, indicating their potential as hemostatic agents. The aPTT test showed shorter clotting times with higher calcium ion concentrations, without enhanced activation of the extrinsic clotting pathway. The developed alginate material with calcium effectively supports hemostasis and reduces the risk of infection. The study also explored the capacity of these composites to interact with and modify the structure of plasmid DNA, underscoring their potential for future biomedical applications.

Characterization of a Delivery System Based on a Hyaluronic Acid 3D Scaffold and Gelatin Microparticles

The objective of this study was to develop and characterize a novel hyaluronic acid (HA) 3D scaffold integrated with gelatin microparticles for sustained-delivery applications. To achieve this goal, the delivery microparticles were synthesized and thoroughly characterized, focusing on their crosslinking mechanisms (vanillin and genipin), degradation profiles, and release kinetics. Additionally, the cytotoxicity of the system was assessed, and its impact on the cell adhesion and distribution using mouse fibroblasts was examined. The combination of both biomaterials offers a novel platform for the gradual release of various factors encapsulated within the microparticles while simultaneously providing cell protection, support, and controlled factor dispersion due to the HA 3D scaffold matrix. Hence, this system offers a platform for addressing injure repair by continuously releasing specific encapsulated factors for optimal tissue regeneration. Additionally, by leveraging the properties of HA conjugates with small drug molecules, we can enhance the solubility, targeting capabilities, and cellular absorption, as well as prolong the system stability and half-life. As a result, this integrated approach presents a versatile strategy for therapeutic interventions aimed at promoting tissue repair and regeneration.

Development of 3D-Printable Albumin-Alginate Foam for Wound Dressing Applications

In this article, a method to develop 3D printable hybrid sodium alginate and albumin foam, crosslinked with calcium chloride mist is introduced. Using this method, highly porous structures are produced without the need of further postprocessing (such as freeze drying). The proposed method is particularly beneficial in the development of wound dressing as the printed foams show excellent lift-off and water absorption properties. Compared with methods that use liquid crosslinker, the use of mist prevents the leaching of biocompounds into the liquid crosslinker. 3D printing technique was chosen to provide more versatility over the wound dressing geometry. Calcium chloride and rhodamine B were used as the crosslinking material and the model drug, respectively. Various biomaterial inks were prepared by different concentrations of sodium alginate and albumin, and the fabricated scaffolds were crosslinked in mist, liquid, or kept without crosslinking. The effects of biomaterial composition and the crosslinking density on the wound dressing properties were assessed through printability studies. The mist-crosslinked biomaterial ink composed of 1% (w/v) sodium alginate and 12% (w/v) albumin showed the superior printability. The fabricated scaffolds were also characterized through porosity, mechanical, degradation, and drug release tests. The mist-crosslinked scaffolds showed superior mechanical properties and provided relatively prolonged drug release.

Cationized gelatin-sodium alginate polyelectrolyte nanoparticles encapsulating moxifloxacin as an eye drop to treat bacterial keratitis

A mucoadhesive polyelectrolyte complex (PEC) nanoparticles were developed for ocular moxifloxacin (Mox) delivery in Bacterial Keratitis (BK). Moxifloxacin-loaded G/CG-Alg NPs were prepared by an amalgamation of cationic polymers (gelatin (G)/cationized gelatin (CG)), and anionic polymer (sodium alginate (Alg)) along with Mox respectively. Mox@CG-Alg NPs were characterized for physicochemical parameters such as particle size (DLS technique), morphology (SEM analysis), DSC, XRD, encapsulation efficiency, drug loading, mucoadhesive study (by texture analyzer), mucin turbidity, and viscosity assessment. The NPs uptake and toxicity of the formulation were analyzed in the Human Corneal Epithelial (HCE) cell line and an ocular irritation study was performed on the HET-CAM. The results indicated that the CG-Alg NPs, with optimal size (217.2 ± 4 nm) and polydispersity (0.22 ± 0.05), have shown high cellular uptake in monolayer and spheroids of HCE. The drug-loaded formulation displayed mucoadhesiveness, trans-corneal permeation, and sustained the release of the Mox. The anti-bacterial efficacy studied on planktonic bacteria/biofilms of P. aeruginosa and S. aureus (in vitro) indicated that the Mox@CG-Alg NPs displayed low MIC, higher zone of bacterial growth inhibition, and cell death compared to free Mox. A significant reduction of bacterial load was observed in the BK-induced mouse model.

Accelerating Full-Thickness Wound Healing with Bacterial Cellulose-Based Multilayer Composites

Materials that speed up wound healing can be of great benefit to patients and healthcare providers. One-layer dressings, however, have unsatisfactory healing efficacy since it is impossible to use materials with different properties simultaneously, and drug delivery is limited by the depth of penetration. The present study utilized a multilayer wound dressing composed of bacterial cellulose (BC) hydrogel, gelatin/alginate (Gel/Alg) hydrogel, and polycaprolactone (PCL) nanofibers loaded with ciprofloxacin (CIP) to promote the healing process in vivo. The designed dressings showed significant water absorption and sufficient water vapor transmission rate (WVTR) after one week, confirming their ability to absorb wound exudate. Within the first four hours, significant amounts of CIP were released from the drug-containing dressing. Then, between hours 4 and 24, the rate decreased and plateaued on day 9. Both positive and negative bacterial strains were inhibited by the gradual release of CIP, while fibroblasts retained their normal morphology and metabolic activity. Lastly, in vivo tests demonstrated that CIP-loaded multilayer dressings could significantly speed up full-thickness wound healing during 14 days, by reducing inflammation, stimulating re-epithelialization, and enhancing skin regeneration. Our findings indicate that multilayering BC hydrogels with drug-loaded nanofibers provide a promising way to promote wound healing by utilizing all the distinctive properties of these layers.

Carboxymethyl cellulose/poloxamer gels enriched with essential oil and Ag nanoparticles: promising wound dressings

Aim: Essential oils are promising antibacterial and wound-healing agents that should be explored for the design of wound dressings. Materials & methods: Topical gels prepared from a combination of carboxymethyl cellulose and poloxamer were incorporated with tea tree and lavender oil together with Ag nanoparticles. In vitro release, cytotoxicity, antibacterial, and wound healing studies were performed. Results: The gels displayed good spreadability with viscosity in the range of 210-1200 cP. The gels displayed promising antibacterial activity against selected Gram-positive and Gram-negative bacteria used in the study. The % cell viability of the gels was more than 90.83%. Conclusion: The topical gels displayed excellent wound closure in vitro revealing that they are potential wound dressings for bacteria-infected wounds.

Highly hygroscopicity and antioxidant nanofibrous dressing base on alginate for accelerating wound healing

The removal of bacterium and free radicals is important for wound healing. Therefore, it is necessary to prepare biological dressings with antibacterial and antioxidant properties. In this study, high-performance calcium alginate/carbon polymer dots/forsythin composite nanofibrous membrane (CA/CPDs/FT) was explored under the influence of carbon polymer dots and forsythin. The addition of carbon polymer dots improved the nanofiber morphology and therefore enhanced the mechanical strength of the composite membrane. Moreover, CA/CPDs/FT membranes displayed satisfactory antibacterial and antioxidant properties because of the natural properties of forsythin. Meanwhile, outstanding hygroscopicity over 700% was also obtained for the composite membrane. In vitro and in vivo experiments showed that the CA/CPDs/FT nanofibrous membrane could prevent the invasion of bacteria, scavenge free radicals, and promote wound healing. Moreover, its good hygroscopicity and antioxidation characteristics were friendly for the clinical application of high-exudate wounds.

Are Natural Compounds a Promising Alternative to Synthetic Cross-Linking Agents in the Preparation of Hydrogels?

The main aim of this review is to assess the potential use of natural cross-linking agents, such as genipin, citric acid, tannic acid, epigallocatechin gallate, and vanillin in preparing chemically cross-linked hydrogels for the biomedical, pharmaceutical, and cosmetic industries. Chemical cross-linking is one of the most important methods that is commonly used to form mechanically strong hydrogels based on biopolymers, such as alginates, chitosan, hyaluronic acid, collagen, gelatin, and fibroin. Moreover, the properties of natural cross-linking agents and their advantages and disadvantages are compared relative to their commonly known synthetic cross-linking counterparts. Nowadays, advanced technologies can facilitate the acquisition of high-purity biomaterials from unreacted components with no additional purification steps. However, while planning and designing a chemical process, energy and water consumption should be limited in order to reduce the risks associated with global warming. However, many synthetic cross-linking agents, such as N,N'-methylenebisacrylamide, ethylene glycol dimethacrylate, poly (ethylene glycol) diacrylates, epichlorohydrin, and glutaraldehyde, are harmful to both humans and the environment. One solution to this problem could be the use of bio-cross-linking agents obtained from natural resources, which would eliminate their toxic effects and ensure the safety for humans and the environment.

Fabrication of ZnO@Plant Polyphenols/Cellulose as Active Food Packaging and Its Enhanced Antibacterial Activity

To investigate the efficient use of bioresources and bioproducts, plant polyphenol (PPL) was extracted from larch bark and further applied to prepare ZnO@PPL/Cel with cellulose to examine its potential as an active package material. The structure and morphology were fully characterized by XRD, SEM, FTIR, XPS and Raman spectra. It was found that PPL is able to cover ZnO and form a coating layer. In addition, PPL cross-links with cellulose and makes ZnO distribute evenly on the cellulose fibers. Coating with PPL creates a pinecone-like morphology in ZnO, which is constructed by subunits of 50 nm ZnO slices. The interactions among ZnO, PPL and cellulose have been attributed to hydrogen bonding, which plays an important role in guiding the formation of composites. The antibacterial properties against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) were tested by the inhibition zone method. Our composite ZnO@PPL/Cel has superior antibacterial activity compared to ZnO/Cel. The antibacterial mechanism has also been elaborated on. The low cost, simple preparation method and good performance of ZnO@PPL/Cel suggest the potential for it to be applied as active food packaging.

Synthesis of hybrid biosorbent based on 1,2-cyclohexylenedinitrilotetraacetic acid modified crosslinked chitosan and organo-functionalized calcium alginate for adsorptive removal of Cu(II)

The present study is based on the synthesis of a novel hybrid biosorbent using 1,2-cyclohexylenedinitrilotetraacetic acid modified crosslinked chitosan and amino-thiocarbamate moiety functionalized sodium alginate (CDTA-CS/TSC-CA). The fabricated sorbent was employed to investigate the efficient recovery of Cu(II) from aqueous media. CDTA-CS/TSC-CA was characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Analysis confirmed the successful modification of both biopolymers and subsequent loading of Cu(II) ions. CDTA-CS/TSC-CA was casted in the form of hydrogel beads having different CDTA-CS to TSC-CA mass ratios i.e., 10.0-40.0% by mass. The hydrogel beads 4CDTA-CS/TSC-CA with CDTA-CS/TSC-CA mass ratio of 40.0% was found most effective for copper sorption. Equilibrium sorption results showed that initial concentration of copper, medium pH, contact time, sorbent dosage and temperature influenced the sorption capacity (q_e). Rate of sorption data was interpreted using different kinetic models and found best fitted with pseudo second order rate expression (R² ≈ 0.99), illustrating that the rate determining step includes the electron density transfer from sorbent coordination sites to central copper ions. Crank's RIDE equation and Elovich chemisorption model (ECM) revealed the presence of two sorption phases, initially rapid sorption followed by comparatively a slow uptake. Equilibrium sorption data was well depicted by Langmuir model and maximum monolayer adsorption capacity (q_m) was computed as 276.53 mg·g^-1 at 298 K. Standard Gibbs free energy change, ∆G° (-19.99, -20.18 and -20.36 kJ/ mol), standard enthalpy change, ∆H° (-8.95 kJmol) and standard entropy change, ∆S° (0.04 kJ/mol K^-1) values suggested that the adsorption process is spontaneous and exothermic. Hence, 4CDTA-CS/TSC-CA was found efficient biosorbent for copper removal from its dilute effluents.

Modified alginate-chitosan-TiO2 composites for adsorptive removal of Ni(II) ions from aqueous medium

In this study, organo-funtionalization of sodium-alginate has been carried out using phenylsemicarbazide as modifier to graft N, O-donor atoms containing functional groups (amino-carbamate moieties) to offer novel support for TiO₂ immobilization. Hybrid composite made of aminocarbamated alginate, carboxymethyl chitosan (CMC) and titanium oxide TiO₂ (MCA-TiO₂) was prepared for the promising adsorptive remediation of Ni(II). FT-IR, SEM-EDX were employed to characterize MCA-TiO₂. The optimization of TiO₂ to modified alginate mass ratio was carried out and hydrogel beads with TiO₂/MCA mass ratio of 10.0% (2MCA-TiO₂) revealed highest sorption efficiency. The produced sorbents were adapted in the form of hydrogel beads for operation. Organic functionalization based on aminocarbamate (OCONHNH₂) moieties on linear chains of alginate embedded additional chelating functional sites which enhanced sorption and selectivity. Batch mode experiments were conducted for optimization of pH and sorbent dose. Equilibrium sorption, kinetic and thermodynamic studies were performed to pattern the nature of sorption. Kinetic data was found in close agreement with pseudo-second order rate expression (PSORE). Isothermal equilibrium sorption data was well fitted with Langmuir adsorption model. Maximum sorption capacity was evaluated as 229 mg/g at 298 K and pH = 6.0.

Gelatin-Based Hybrid Scaffolds: Promising Wound Dressings

Wound care is a major biomedical field that is challenging due to the delayed wound healing process. Some factors are responsible for delayed wound healing such as malnutrition, poor oxygen flow, smoking, diseases (such as diabetes and cancer), microbial infections, etc. The currently used wound dressings suffer from various limitations, including poor antimicrobial activity, etc. Wound dressings that are formulated from biopolymers (e.g., cellulose, chitin, gelatin, chitosan, etc.) demonstrate interesting properties, such as good biocompatibility, non-toxicity, biodegradability, and attractive antimicrobial activity. Although biopolymer-based wound dressings display the aforementioned excellent features, they possess poor mechanical properties. Gelatin, a biopolymer has excellent biocompatibility, hemostatic property, reduced cytotoxicity, low antigenicity, and promotes cellular attachment and growth. However, it suffers from poor mechanical properties and antimicrobial activity. It is crosslinked with other polymers to enhance its mechanical properties. Furthermore, the incorporation of antimicrobial agents into gelatin-based wound dressings enhance their antimicrobial activity in vitro and in vivo. This review is focused on the development of hybrid wound dressings from a combination of gelatin and other polymers with good biological, mechanical, and physicochemical features which are appropriate for ideal wound dressings. Gelatin-based wound dressings are promising scaffolds for the treatment of infected, exuding, and bleeding wounds. This review article reports gelatin-based wound dressings which were developed between 2016 and 2021.