Katherina Fernández

Wound healing remains a major clinical challenge due to the complex metabolic disturbances present within the wound microenvironment. In this study, we report the development and comprehensive validation of a novel multifunctional hydrogel composed of chitosan (CS), reduced graphene oxide (rGO), and tannins (TA) (CS-rGO-TA), specifically engineered as an advanced wound dressing. The hydrogel was thoroughly characterized using SEM to examine its porous microstructure, FTIR to analyze component interactions, the DPPH assay to assess antioxidant capacity, and total phenols to evaluate the release kinetics of TA. Antibacterial activity was tested in vitro against Escherichia coli and Staphylococcus aureus using standard colony-forming unit assays. Biocompatibility and regenerative potential were assessed through cell viability and migration assays using human dermal fibroblasts. In vivo evaluation included a skin irritability model in guinea pigs and a full-thickness excisional wound model in rats, divided into four treatment groups. Wound closure progression was monitored over time, and histological analysis was performed using hematoxylin and eosin (H&E), Mallory, and Masson's Trichrome staining to assess tissue morphology and collagen deposition. The CS-rGO-TA₃ hydrogel demonstrated controlled and sustained TA release, strong antioxidant and antibacterial properties, and excellent biocompatibility, with no signs of irritation or adverse effects. Its application significantly accelerated wound closure and promoted organized deposition of collagen (types I and III). Molecular analysis revealed early resolution of inflammation, enhanced angiogenesis, and polarization of macrophages toward a reparative M2 phenotype, as evidenced by modulation of markers such as MPO, CD68, ARG1, and interleukins IL-6, IL-10, IL-1β, and IL-1rn. Collectively, these findings highlight the CS-rGO-TA₃ hydrogel as a safe and effective therapeutic platform with strong potential for tissue regeneration and clinical wound management.

Sulfated nanocellulose (SCNF) and reduced graphene oxide (rGO) films were fabricated through environmentally friendly methods to develop an effective platform for electrochemical applications. The hybrid materials were extensively characterized by FTIR, XRD, Raman spectroscopy, TGA, SEM, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Results showed that incorporating rGO into the SCNF matrix significantly improved the electrical conductivity and structural robustness of the films. FTIR confirmed interactions between sulfate groups on cellulose and residual oxygen-containing groups on rGO, while XRD and Raman analyses indicated reduced crystallinity and increased structural disorder, supporting the successful integration of both phases. XPS further demonstrated that SCNF and rGO form chemical bonds rather than simply mixing, with both components remaining active at the surface—evidence of strong interfacial interactions that contribute to enhanced stability and efficient charge transfer. The 1:5 (rGO:SCNF) composition showed the best electrochemical performance, exhibiting minimal charge-transfer resistance and improved hydrazine oxidation, as reflected by a shift of the anodic peak potential toward lower values. Additionally, functionalization with cobalt porphyrin significantly boosted catalytic activity. Overall, the SCNF:rGO films offer a sustainable and scalable platform for electrochemical sensing and energy-conversion applications, demonstrating excellent adaptability and functional performance.

This study developed a novel conductive wound dressing composed of chitosan (CS), reduced graphene oxide (rGO), and Pluronic F‐127 (PF). A 2 ² + star factorial design was used to evaluate the effects of rGO and PF concentrations on conductivity, swelling capacity, mechanical properties, and cell migration. Analysis of variance identified the factors that significantly influenced these properties. The results showed that higher rGO concentrations improved conductivity, while PF had a significant impact on swelling capacity. Additionally, rGO influenced tensile strength, elastomeric modulus, and cell migration. The dressings were characterized using SEM, FTIR, XRD, TGA, wettability tests, antibacterial assessments, and cell viability analysis. Statistical optimization determined that the optimal formulation (CS‐rGO‐PF10) exhibited excellent conductivity (2.30 mS/cm), high fluid absorption (577%), strong mechanical properties (tensile strength of 22.14 MPa and elastic modulus of 170 MPa), and enhanced cell migration (100% closure rate after 48 h). Furthermore, it demonstrated strong antibacterial activity against Escherichia coli and Staphylococcus aureus . In vivo tests on a porcine model confirmed that the dressing accelerated wound healing and improved tissue regeneration, as evidenced by enhanced re‐epithelialization and vascularization. In conclusion, the CS‐rGO‐PF10 conductive hydrogel represents a promising solution for wound treatment.

The global proliferation of Pinus radiata, known for its rapid growth and wood density, has led to an environmental challenge—significant waste production, especially bark, without a clear valorization route. This waste poses ecological concerns, and despite the crucial role of forest resources in structural applications, their limited fire resistance requires the use of coatings. However, traditional coatings lack an eco-friendly footprint. Addressing this challenge, this study aims to develop an intumescent coating with tannins extracted from waste bark, offering a sustainable alternative. This not only repurposes waste on a global scale but also aligns with the imperative for environmentally friendly materials, contributing to sustainable practices in the construction and wood treatment industry. This study achieved an eco-friendly FRR15 (fire resistance ratio 15) fire resistance classification with a 15% equivalence of low-molecular-weight tannins, presenting a sustainable alternative to commercial products. Characterization showed low-molecular-weight tannins comparable to conventional charring agents, with high hydroxyl content and oil absorption, while high-molecular-weight tannins exhibited lower viability. A reference coating achieved FRR30 fire resistance, aligning with commercial strength. The mechanical properties of tannin-based coatings matched commercial standards, with increased abrasion resistance and adhesion and decreased flexibility. Intumescent coatings with higher tannin content significantly reduced wood substrate charring and mass loss in flame response assessments.

In this study, an innovative conductive hybrid biomaterial was synthetized using collagen (COL) and reduced graphene oxide (rGO) in order for it to be used as a wound dressing. The hydrogels were plasticized with glycerol and enzymatically cross-linked with horseradish peroxidase (HRP). A successful interaction among the components was demonstrated by FTIR, XRD, and XPS. It was demonstrated that increasing the rGO concentration led to higher conductivity and negative charge density values. Moreover, rGO also improved the stability of hydrogels, which was expressed by a reduction in the biodegradation rate. Furthermore, the hydrogel’s stability against the enzymatic action of collagenase type I was also strengthened by both the enzymatic cross-linking and the polymerization of dopamine. However, their absorption capacity, reaching values of 215 g/g, indicates the high potential of the hydrogels to absorb fluids. The rise of these properties positively influenced the wound closure process, achieving an 84.5% in vitro closure rate after 48 h. These findings clearly demonstrate that these original composite biomaterials can be a viable choice for wound healing purposes.