Search Results (366)

The increasing demand for sustainable materials is driving research into the valorization of agro-industrial waste as lignocellulosic alternatives in engineered wood product manufacturing. This study investigates the use of bitter orange (Citrus aurantium L.) peel as a bio-based filler in particleboards bonded with a bio-based tannin/hexamine adhesive. Panels were fabricated by partially substituting wood chips with orange peel powder at five levels (0, 2.5, 5, 10, and 15 wt%), hot-pressed at 180 °C for 8 min at a constant biomass-to-adhesive ratio of 9:1 (w/w). Firstly, the effect of temperature on orange peels and then the microscopic structure of the composite was observed through optical stereomicroscopy and SEM. Then, mechanical performance, water resistance, and thermal conductivity were also analyzed. Substitution of up to 10 wt% of wood chips with orange peel allowed for the maintenance of internal bond strength, modulus of rupture, and modulus of elasticity, while the 2.5 wt% formulation yielded a statistically significant improvement in axial thermal insulation. Conversely, when the amount of orange waste rises over 10 wt%, significant decreases in internal bond and modulus of rupture were recorded. These findings demonstrate that C. aurantium peels can be used as a viable filler for formaldehyde-free particleboards, offering a promising strategy for orange waste valorization in the wood panel industry. Full article

Background/Objectives: Despite available treatment options, glaucoma continues to be a leading cause of irreversible blindness. Current medications have multiple limitations, including rapid drainage, ocular irritation, requirement for multiple daily dosings, and systemic side effects. The current study was designed to engineer and characterize a pregabalin-containing enhanced delivery formulation (PRG-EDF) to directly address these inadequacies. Methods: PRG-EDF eye drops were prepared using ingredients that are either U.S. Food and Drug Administration (FDA)-approved for ophthalmic use or have established safety profiles. The formulation was characterized using multiple evaluations, including pH, zetasizer analyses, viscosity, in vitro drug release, transcorneal permeability, determination of dose concentration and volume, systemic exposure, and potential for tachyphylaxis. Efficacy was evaluated using both Dutch belted rabbits and baboons. Results: PRG-EDF provides extended release for up to 24 h. Ex vivo data reveal that PRG-EDF does not alter the inherent high PRG corneal permeability. An intraocular pressure (IOP) study using DB rabbits demonstrates that 40 µL of PRG-EDF, 0.6%, is the optimum dose of our formulation. Comparison of the efficacy of PRG-EDF with commercial products demonstrated its superiority in overall IOP-lowering efficacy. An extended in vivo assessment demonstrated that the potency of PRG-EDF reached maximum IOP-lowering amplitude after 4 weeks of daily dosing. Moreover, an in vivo bioadhesion assay demonstrated that EDF remained on the ocular surface for up to 24 h. Impressively, PRG-EDF is as effective in baboons as in rabbits. Conclusions: We have successfully engineered a highly promising once-daily glaucoma medication with superior efficacy, as illustrated by higher IOP-lowering ability and prolonged duration of action. Full article

Chitosan and chitin-derived biomaterials, including native chitosan and chemically modified derivatives, have been widely investigated across orthopedic tissue engineering, implant functionalization, infection control, local delivery, and interface repair, but the evidence is dispersed across heterogeneous formats and indications. This single-author structured narrative review synthesizes 258 unique publications and interprets chitosan through a polymer design, quantitative performance, and clinical translation framework. Literature was identified (January–May 2026) using PubMed/MEDLINE as the primary database, with targeted verification in Web of Science, Scopus, and Google Scholar; no formal risk-of-bias or certainty grading was performed. Chitosan was studied as scaffolds, hydrogels, coatings, nanoparticles, microspheres, fibers, bioadhesives, bone-cement additives, cartilage adjuncts, tendon-to-bone systems, and intervertebral disk biomaterials. The highest human clinical evidence supported BST-CarGel/chitosan–blood implant augmentation of knee marrow stimulation, where randomized, 5-year, and biopsy data favored structural repair over microfracture alone; most other applications—bone regeneration, coatings, osteomyelitis hydrogels, bone cements, tendon/rotator cuff systems, and disk biomaterials—remain preclinical or translational-preclinical. Chitosan should be interpreted as a tunable polymer platform, not a single material; translation requires chemistry-defined formulation, indication-specific mechanical qualification, clinically relevant comparators, and standardized reporting. Full article

Recurrent aphthous ulcers (RAU) are highly prevalent oral mucosal lesions, while current therapies are limited by short residence time and poor efficacy in the dynamic oral environment. Probiotics such as Lactobacillus reuteri (L. reuteri) exhibit antimicrobial, immunomodulatory, and tissue-repair functions; however, their direct application is restricted by low stability and retention in the oral cavity. In this study, L. reuteri-loaded sodium alginate/chitosan composite hydrogels were developed via ionic crosslinking as a bioadhesive platform for local delivery. The hydrogels exhibited well-defined porous structures, favorable viscoelastic properties, and tunable swelling and degradation behaviors under simulated physiological conditions. Importantly, the system enabled sustained probiotic release and maintained high viability during 30 days of storage. In vitro antibacterial assays demonstrated that the hydrogels effectively inhibited the growth of Staphylococcus aureus and Candida albicans. Among the formulations, the hydrogel with 10 mg·mL⁻¹ chitosan achieved an optimal balance between structural stability and mass transfer, resulting in enhanced release performance and antibacterial efficacy. Overall, this study presents a microecology-oriented hydrogel system for efficient probiotic delivery in oral environments, offering a promising bioadhesive probiotic delivery platform with potential applications in RAU management and advancing the development of bioactive, mucosa-adaptive therapeutic platforms. Full article

Polysaccharide-based hydrogels represent promising platforms for the development of bioactive wound dressings due to their biocompatibility, bioadhesive properties, and ability to maintain a moist environment at the wound interface. In this study, polymeric films were developed from natural polysaccharides incorporating olive mill wastewater (OMW) as a natural antibacterial agent. Chitosan (medium molecular weight), sodium alginate, sodium hyaluronate, and xanthan gum were selected to prepare hydrogel formulations either as single polymers or binary mixtures. Hydrogels were prepared by aqueous dispersion under magnetic stirring and subsequently converted into films using a solvent casting method. The resulting films were characterized in terms of rheological behavior, pH, morphology, thickness and water content. The obtained hydrogel films showed good casting ability, producing smooth and homogeneous matrices with adequate deformability and skin adhesion. Furthermore, they demonstrated a suitable capacity to absorb and retain water, mimicking the management of wound exudate. OMW was incorporated into the hydrogel formulations as a source of phenolic compounds with well-known antioxidant and antimicrobial properties. The presence of these bioactive compounds provides the films with potential antibacterial and antibiofilm activity against clinically relevant multidrug-resistant staphylococcal strains. These findings suggest that OMW-loaded polysaccharide hydrogels represent a promising and sustainable strategy for the development of antibacterial films for wound healing applications. Full article

Background: Thymoquinone (TQ), a bioactive compound derived from Nigella sativa L., exhibits promising antioxidant, anti-inflammatory, and wound-healing properties; however, its clinical application is limited by poor solubility and instability. Methods: In this study, three electrospun nanofiber systems based on different polymeric matrices, PVP (N1), PVP/HPβCD (N2), and PVP/PCL (N3), were developed as potential wound dressing materials for controlled TQ delivery. Results: All formulations produced uniform nanofibrous structures with TQ molecularly dispersed within the polymer matrix, as confirmed by SEM, XRPD, and FTIR analyses. The composition of the nanofibers significantly influenced their physicochemical and functional properties. The N2 system, containing hydroxypropyl-β-cyclodextrin (HPβCD), exhibited the smallest fiber diameter (~208 nm), the fastest drug release, and enhanced antioxidant and anti-inflammatory activity due to improved TQ solubility. In contrast, the N3 system, incorporating polycaprolactone (PCL), formed thicker fibers (~1089 nm) and demonstrated sustained release behavior, the highest mucoadhesion, and the most pronounced wound-healing effect (90% closure after 24 h). Stability studies revealed that HPβCD significantly improved TQ resistance to thermal, humidity, and photolytic degradation, whereas the PVP-based system without stabilizers showed the lowest stability. Principal component analysis (PCA) confirmed that nanofiber performance is governed by two key factors: drug availability and sustained release combined with bioadhesion. Importantly, wound-healing efficiency correlated more strongly with the latter. Conclusions: The results demonstrate that rational design of polymer composition enables modulation of TQ delivery and biological response. Among the tested systems, PVP/PCL nanofibers appear to be the most promising candidates for wound-dressing applications due to their ability to provide sustained drug release and enhance tissue regeneration. Full article

Bronchopleural fistula is a rare but severe complication of lung resection, associated with significant morbidity and mortality, especially when an open-window thoracostomy is required. The clinical and surgical management is complex and becomes even more challenging in the presence of underlying conditions such as recurrent infections or malignancy. Postoperative management is equally demanding, as local compression may help prevent fistula recurrence but can compromise flap perfusion. A 65-year-old male with a history of right upper lobectomy and subsequent sublobar resection for lung adenocarcinoma presented with an 8 × 4 cm open-window thoracostomy complicated by chronic bronchopleural fistula and empyema. Extensive fibrosis of the surrounding tissues, including the ipsilateral latissimus dorsi muscle, limited the available reconstructive locoregional options. Reconstruction was performed using primary fistula closure reinforced with a contralateral free latissimus dorsi musculocutaneous flap and a fascia patch graft secured with cyanoacrylate-based bioadhesive. Postoperatively, continuous near-infrared spectroscopy monitoring enabled safe application of compressive bandage while minimizing the risk of flap perfusion compromise. Complete fistula closure was achieved. Apart from a surgical site abscess requiring debridement on postoperative day 7, no further complications occurred. At the 2-year follow-up, the patient remains free of fistula recurrence, wound dehiscence, or oncological relapse. We describe a novel approach for open-window thoracostomy closure combining a free musculocutaneous flap with a fascia patch graft reinforced by bioadhesive, together with postoperative perfusion monitoring using near-infrared spectroscopy. This strategy may help address both the reconstructive and postoperative challenges associated with complex bronchopleural fistulas. Full article

Hydrogels constructed from peptide components often rely on β-sheet architectures for their assembly, yet the process of developing such materials in aqueous environments presents notable hurdles in the context of biological systems. To address this, a novel functional dodecapeptide has been developed, capable of self-assembling into supra-molecular hydrogels via zinc chelation interactions. Morphological observations revealed a compact meshwork structure in the hydrogel formed with 9 mM Zn²⁺, differing from the relatively sparse or excessively tangled fiber architectures seen at other zinc concentrations. Alkaline phosphatase activity, an early marker of osteoblast differentiation, was notably enhanced when MC3T3-E1 cells were cultivated for 72 h in the hydrogel extract containing 300 μg/mL of the peptide, 9 μg/mL ZnCl₂, and 18.93 μg/mL H₃BO₃. Furthermore, increased protein levels of p-p38/p38, p-ERK/ERK, and p-JNK1/2/3/JNK1/2/3 were observed in P-300-ZnB and P-300 B hydrogel-treated groups, suggesting an association with MAPK pathway activation. P-Zn-9 hydrogel also promoted MC3T3-E1 cell proliferation and demonstrated favorable biocompatibility in short-term in vitro and in vivo assays. Long-term toxicity and causal relationships via inhibitor studies remain to be investigated. These results offer a viable approach to endow zinc-chelating properties in the fabrication of assembled hydrogels, presenting an innovative and potential method for constructing injectable drug delivery systems and in situ bone repair through biomaterials in subsequent applications. Full article

Wound healing remains a persistent health problem with no definitive solution. It is crucial to characterize the complex wound healing process and the various growth factors, cytokines, and polypeptides involved. Transforming growth factor beta1 (rhTGF-β1) stimulates different cell types, providing multifunctionality in the wound healing process. Since proteins are sensitive to proteases, drug delivery systems are needed. Developed polymeric carrier systems are as important as the active substance. The carrier systems used in our study aim to contribute to wound healing in addition to the rhTGF-β1. We hypothesized that PLGA nanoparticles embedded in PVA/Chitosan (PVA/Chi) hydrogels could enhance the therapeutic effect of rhTGF-β1. PVA/Chitosan hydrogels were prepared by the freezing/thawing method. Several characterization studies (Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), texture analysis, and cell culture) were performed to investigate the potential of the prepared formulations to enhance the therapeutic effect of rhTGF-β1. Hydrogel formulations reduced the inhibitory effect of rhTGF-β1 on keratinocytes. The H5 hydrogel exhibited a proliferative effect on fibroblast cells, which play a crucial role in wound healing, resulting in a 78.8% increase compared to the control. As the PVA content in the hydrogel formulations increased, bioadhesion and viscosity also increased. Although TGF-β1 inhibited keratinocytes, it induced migration of both NIH-3T3 and HACAT cell lines. The formulations developed exhibit the potential to improve the therapeutic efficacy of rhTGF-β1 in wound healing. A small amount of the protein can have the same therapeutic efficacy and fewer side effects because the developed polymeric carrier systems contribute to the therapeutic efficacy. Full article

A propolis-based nano-formulated bioadhesive oral gel (NBF gel) containing vitamins C and E has been proposed as a supportive topical therapy for oral mucosal lesions. The aim of this study was to evaluate clinical outcomes associated with the use of the gel during a 15-year institutional clinical experience and to assess its adjunctive effect on periodontal status in patients with intellectual disabilities. The study consisted of two components: a retrospective observational case series and a non-randomized controlled clinical study. In the retrospective component, 295 patients (219 females and 76 males) received topical NBF gel treatment for various oral mucosal conditions, including xerostomia-associated mucositis, inflammatory lesions, aphthous ulcers, herpes infections, glossodynia, leukoplakia, erythroplakia, and post-surgical conditions. Treatment response was assessed descriptively using patient-reported symptom improvement combined with clinical evaluation. Overall, treatment was considered successful in 265/295 patients (89.8%), while 14/295 patients (4.7%) were classified as ineffective and 16/295 patients (5.4%) as inconclusive. More favorable responses were observed in inflammatory and post-treatment lesions than in potentially premalignant or neuropathic conditions. In the controlled periodontal component, 40 patients with mild to moderate intellectual disabilities were allocated into a control group performing toothbrushing alone and a test group additionally receiving topical NBF gel application. Periodontal status was assessed using the Basic Periodontal Examination (BPE) index at baseline and after 1 and 2 weeks. Adjunctive gel application was associated with greater improvement in periodontal status compared with toothbrushing alone. No clinically relevant adverse effects were documented during the observation period; however, because adverse events were not assessed using a predefined safety-monitoring protocol, these findings should be interpreted cautiously. The present findings suggest that the investigated nano-formulated bioadhesive oral gel may represent a potentially useful adjunctive topical therapy in selected oral mucosal and periodontal conditions. Further randomized controlled studies with standardized objective outcome measures are required to confirm these preliminary findings. Full article

Chronic and infected wounds remain difficult to treat due to persistent microbial burden, biofilm formation, and dysregulated inflammation. As a multifunctional polyphenol, curcumin exhibits broad-spectrum antimicrobial, anti-inflammatory, and antioxidant activities. Nevertheless, the clinical application of curcumin is constrained by its limited solubility in water, inherent instability, and insufficient bioavailability. Chitosan, a cationic polysaccharide, provides complementary advantages including intrinsic antimicrobial activity, mucoadhesion, and the capacity to form versatile delivery platforms such as nanoparticles, hydrogels, and films. This review reframes chitosan–curcumin systems as dual-function bioactive platforms in which both the carrier and payload actively contribute to therapeutic outcomes. Mechanistically, chitosan disrupts microbial membranes, enhances bioadhesion, and supports tissue regeneration, while curcumin modulates intracellular targets including reactive oxygen species, quorum sensing, and inflammatory signaling pathways. Their integration enables multimodal antimicrobial activity, improved biofilm disruption, and coordinated regulation of the wound-healing cascade. This review critically examines the structure–function relationships governing release kinetics, stability, and cytocompatibility, with particular emphasis on chitosan molecular weight, degree of deacetylation, crosslinking strategies, and curcumin loading. Solubility-enhancement strategies for curcumin, including surfactants, nanoparticles, solid dispersions, and chemical derivatives, are evaluated in the context of antimicrobial efficacy and cytotoxicity. Finally, the review highlights translational challenges and future directions, such as antibiotic synergy, antifungal applications, formulation complexity, and the emerging role of artificial intelligence in predictive material design. Collectively, these insights establish design principles for next-generation multifunctional biomaterials that integrate antimicrobial activity with immune modulation and tissue repair. Full article

Hyaluronic acid (HA) hydrogels have attracted increasing interest for biomedical applications due to their tunable properties and biocompatibility. Methods: In this study, hyaluronic acid HA-based hydrogels were developed using two distinct crosslinking strategies: physical crosslinking through poly(vinyl alcohol) (PVA) incorporation and covalent crosslinking via DCC/NHS-mediated reactions. Piroxicam (Px) was included as a model drug to evaluate the drug delivery potential of the resulting systems. The hydrogels were characterized in terms of morphology, swelling behaviour, adhesion, enzymatic degradation, drug release, and in vitro cytocompatibility. Results: The results indicate that formulation parameters significantly influence the overall performance of the systems. PVA-containing hydrogels exhibited higher swelling capacity and improved adhesive properties, while covalently crosslinked networks showed reduced swelling and enhanced structural stability and resistance to enzymatic degradation. Drug release profiles were dependent on network structure, with more compact systems displaying slower release behaviour. In vitro assays suggested that the developed hydrogels are cytocompatible and that drug incorporation influences both release kinetics and cellular response. However, it should be noted that the biological evaluation was performed under simplified in vitro conditions, which primarily reflect specific aspects such as cell viability and migration. Conclusions: This study provides a comparative analysis of physical and covalent crosslinking strategies within a HA platform and highlights how formulation variables influence key physicochemical and biological properties. These findings contribute to the rational design of HA-based hydrogels, although further studies are required to establish their performance in more complex biological environments. Full article

Articular cartilage defects affect millions of patients annually and pose one of the most persistent challenges in orthopedic surgery, owing to the tissue’s inherent avascular and alymphatic nature. Current surgical approaches, microfracture, autologous chondrocyte implantation (ACI/MACI), and osteochondral grafting, share a common failure mode: inadequate adhesion between repair constructs and surrounding native cartilage, contributing to deterioration rates of 15–75% at five-year follow-up across all techniques. This review repositions adhesion not as a supplementary material property but as the central determinant of clinical success in cartilage repair. We systematically evaluate the biomechanical demands imposed by the joint environment and define clinically relevant adhesion thresholds. Adhesive hydrogel strategies are categorized by surgical context: microfracture augmentation, ACI/MACI enhancement, osteochondral graft integration, and standalone repair platforms. Material platforms are analyzed across catechol/dopamine systems, NHS ester chemistry, photocrosslinkable hydrogels, supramolecular approaches, and multi-mechanism hybrids. Injectable formulations for arthroscopic delivery are critically examined alongside key translational barriers, including fatigue durability, biocompatibility–adhesion trade-offs, sterilization compatibility, batch variability, and regulatory classification ambiguity. Future directions encompass 4D bioprinting, AI-guided formulation optimization, and stimuli-responsive reversible adhesion systems. Adhesive hydrogels represent the missing link that current cartilage repair paradigms require. Full article

This study aimed to develop antibacterial polyphenol–chitosan hydrogel dressings and, more importantly, to compare how three structurally distinct low-cost natural polyphenols—protocatechuic acid (PCA), gallic acid (GA), and tannic acid (TA)—regulate hydrogel performance within the same chitosan platform. PCA, GA, and TA were incorporated into chitosan to obtain the corresponding hydrogels, denoted CS-PCA, CS-GA, and CS-TA. Scanning electron microscopy confirmed that all formulations possessed a three-dimensional porous network. Rheological characterization revealed favorable viscoelastic behavior for all polyphenol-containing hydrogels, with CS-TA showing the highest mechanical strength in the present system. The hydrogels also exhibited pH-responsive swelling, good tissue adhesion, self-healing ability, and injectability. In vitro antibacterial assays demonstrated activity against both Gram-positive and Gram-negative microorganisms, with CS-TA showing the most favorable overall antibacterial performance under the tested conditions. In a rat full-thickness wound model, hydrogel treatment accelerated wound closure, while H&E staining indicated enhanced granulation tissue formation, collagen deposition, and reduced inflammatory cell infiltration. Collectively, these findings support the use of polyphenol–chitosan composite hydrogels as promising wound-dressing candidates and highlight the value of a side-by-side comparison of PCA, GA, and TA for understanding structure–property–function relationships in this class of materials. Full article

Catechol (benzene-1,2-diol) is a highly versatile chemical motif that plays a central role in both terrestrial and marine systems, where its reactivity is governed by a combination of enzymatic oxidation and non-enzymatic interactions. This review examines the diverse enzymatic pathways responsible for catechol oxidation, including polyphenol oxidases, laccases, peroxidases, and microbial dioxygenases, and highlights how these conserved systems are adapted to distinct ecological functions such as plant defense, carbon cycling, bioadhesion, and material formation. A key focus is placed on the non-enzymatic formation of boron–catechol complexes, which can significantly modulate catechol reactivity. These complexes, formed through reversible interactions between boron species and the 1,2-diol group, can act as inhibitors of catechol oxidation by limiting substrate availability and altering redox behavior. Importantly, the extent of this inhibition is strongly dependent on pH, which governs both the speciation of boron (e.g., boric acid vs. borate) and the stability of borate esters, as well as the activity of oxidative enzymes. In terrestrial systems, variable pH conditions and soil chemistry influence the balance between oxidation, complexation, and degradation, whereas in marine environments, relatively stable and slightly alkaline conditions favor distinct modes of regulation. By integrating enzymatic and non-enzymatic perspectives, this review underscores the importance of boron–catechol interactions as a previously underappreciated control on catechol oxidation across ecosystems, with implications for biogeochemical cycling and the design of bioinspired materials. Full article