Search Results (221)

Cutibacterium acnes is linked to the prevalent inflammatory skin disorder known as Acne Vulgaris (AV). Some topical agents exhibit unfavorable side effects like dryness and skin inflammation, and antimicrobial resistance (AMR) poses an increasing risk to effective AV management. This study develops and characterizes stable topical essential oil (EO)-loaded microemulgels with in vitro validated antimicrobial activities against C. acnes ATCC 6919, providing a solid scientific basis for their effectiveness. These microemulgels, with their potential to serve as an alternative to AMR-prone synthetic agents, could revolutionize the field of acne treatment. The MICs of the EOs (citronella, tea tree, and lemongrass) against C. acnes were determined. EO-loaded microemulgels were developed using a blend of microemulsion and carbopol/hyaluronic acid gel in a ratio of 1:1 and characterized, and their stability was observed over three months. The MICs of citronella, tea tree, and lemongrass EOs were 0.08, 0.16, and 0.62% v/v, respectively. The microemulgels were whitish and smooth, with characteristic EO odors. They demonstrated pH values ranging between 4.81 ± 0.20 and 5.00 ± 0.03, good homogeneity, a spreadability of 9.79 ± 0.6 and 12.76 ± 0.8 cm², a viscosity of 29,500 and 31,130 cP, and retained stability at 4, 25, and 40 °C. EO-loaded microemulgels were developed with the potential of C. acnes management. The formulation shows adequate potential for further pharmaceutical development towards translational adoption in acne management. Full article

Background: Oral wound healing is a complex process influenced by extracellular matrix (ECM) remodeling and cellular migration. Hyaluronic acid (HA) and spermidine (SP) have shown regenerative potential, but their combined effects on oral tissues remain unexplored. This study aimed to characterize the effect of a gel composed of a mixture of HA and SP on the epithelial and connective compartments of oral tissue separately, evaluating (i) collagen turnover and cell migration on primary human gingival fibroblasts (HGFs) and (ii) epithelial integrity and cell proliferation on gingival organotypic cultures (OCs). Methods: HGFs were cultured, treated with HA-SP gel (1:0.5 HA-SP ratio) and evaluated for collagen types I and III (COL-I, COL-III), matrix metalloproteinase (MMP-1) protein and tissue inhibitor of MMP-1 (TIMP-1) levels secreted by the cells upon gel treatment, compared to CT. HGFs were also analyzed through a wound healing assay. Gingival samples were obtained to set OCs and were treated with different HA-SP formulations (HA 0.2%; 1:0.5 HA-SP ratio; 1:5 HA-SP ratio) to evaluate the beneficial addition of SP to HA for epithelial tissue. OC samples were formalin-fixed and paraffin-embedded and were stained with hematoxylin and eosin and immunostained for Ki-67 analysis. Results: In HGFs, the gel induced increased COL-III gene expression relative to that of COL-I after 48 h and stimulated cell migration, in turn favoring connective tissue remodeling and repair. In OCs, the gel preserved epithelial integrity up to 48 h, with the best effects observed with the 1:0.5 HA-SP ratio. After 72 h, epithelial detachment was more evident in HA formulations, suggesting that SP contributes to epithelial integrity. Conclusions: The HA-SP gel may support oral tissue healing by modulating ECM remodeling and maintaining epithelial integrity. The gel containing HA and SP at the 1:0.5 ratio may provide a promising solution for enhancing wound healing. Full article

In this study, we designed an injectable skin-rejuvenating formulation based on polyethylene glycol–polycaprolactone–polyethylene glycol (PEG-PCL-PEG) copolymers to provide a synergistic combination of biocompatibility, antioxidative capacity, and regenerative potential. Through the systematic optimization of the precursor molar ratio and molecular weight, well-defined PEG-PCL-PEG copolymers were synthesized and structurally characterized using gel permeation chromatography (GPC), proton nuclear magnetic resonance (¹H-NMR), and Fourier transform infrared (FT-IR) spectroscopy. An optimized precipitation and drying protocol effectively reduced residual solvents, as confirmed by gas chromatography (GC). Idebenone was incorporated as an antioxidant to prevent skin aging, while hyaluronic acid (HA), L-arginine, and glycerin were included to promote collagen regeneration. In vitro assays demonstrated that idebenone-loaded samples exhibited prolonged intracellular antioxidant activity with low cytotoxicity. The collagen-promoting formulation, containing HA, glycerin, and L-arginine, enhanced the expression of transforming growth factor-β (TGF-β) and type III collagen (COL3) while suppressing inflammatory genes, suggesting a favorable environment for extracellular matrix remodeling. In vivo evaluation corroborated these outcomes, showing angiogenesis, collagen reorganization, and progressive dermal thickness. Histological analysis further confirmed sustained matrix regeneration and tissue integration. These results highlight the potential of PEG-PCL-PEG-based injectables as a multifunctional platform for collagen regeneration, offering a promising strategy for both cosmetic and clinical applications. Full article

The synthesis of novel biodegradable polymers as non-viral vectors remains one of the challenging tasks in the field of gene delivery. In this study, the synthesis of the polysaccharide-g-polypeptide copolymers, namely, hyaluronic acid-g-polylysine (HA-g-PLys), using a copper-free strain-promoted azide-alkyne cycloaddition reaction was proposed. For this purpose, hyaluronic acid was modified with dibenzocyclooctyne moieties, and poly-L-lysine with a terminal azido group was obtained using ring-opening polymerization of N-carboxyanhydride of the corresponding protected amino acid, initiated with the amino group azido-PEG₃-amine. Two HA-g-PLys samples with different degrees of grafting were synthesized, and the structures of all modified and synthesized polymers were confirmed using ¹H NMR and FTIR spectroscopy. The HA-g-PLys samples obtained were able to form nanoparticles in aqueous media due to self-assembly driven by electrostatic interactions. The binding of DNA and model siRNA by copolymers to form polyplexes was analyzed using ethidium bromide, agarose gel electrophoresis, and SybrGreen I assays. The hydrodynamic diameter of polyplexes was ˂300 nm (polydispersity index, PDI ˂ 0.3). The release of a model fluorescently-labeled oligonucleotide in the complex biological medium was significantly higher in the case of HA-g-PLys as compared to that in the case of PLys-based polyplexes. In addition, the cytotoxicity in normal and cancer cells, as well as the ability of HA-g-PLys to facilitate intracellular delivery of anti-GFP siRNA to NIH-3T3/GFP+ cells, were evaluated. Full article

Background: The combination of polynucleotides and hyaluronic acid with bovine bone grafts in maxillary sinus lift procedures appears to be a promising strategy to enhance bone regeneration. This study aimed to analyze implant osseointegration, bone repair and sinus mucosa integrity using Bio-Oss^® and Hyaluronic Acid-Polynucleotide Gel (Regenfast^®) in maxillary sinus augmentation in rabbits. Methods: Sinus floor elevation was performed in 12 rabbits, with one implant placed per sinus simultaneously. In the control group, sinuses were grafted with deproteinized bovine bone mineral (Bio-Oss^®) alone; in the test group, Bio-Oss^® was combined with Regenfast^®. Two histological slides were obtained per sinus after 2 weeks (six animals) and 10 weeks (six animals): one from the grafted area alone (non-implant sites), and one from the implant site. Primary outcome variables included the percentage of newly formed bone, the extent of implant osseointegration, and the number of sinus mucosa perforations caused by contact with graft granules. Results: After 10 weeks of healing, the test group showed a significantly higher percentage of new bone formation (37.2 ± 6.7%) compared to the control group (26.8 ± 10.0%; p = 0.031); osseointegration extended to the implant apex in both groups; fewer sinus mucosa perforations were observed in the test group (n = 5) than in the control group (n = 14). Conclusions: The addition of Regenfast^® to Bio-Oss^® granules promoted enhanced bone regeneration within the elevated sinus area and was associated with a lower incidence of sinus membrane perforations compared to the use of Bio-Oss^® alone. Full article

Spinal cord injuries (SCIs) present a major clinical challenge, often resulting in permanent loss of function and limited treatment options. Traditional approaches, including surgery, drugs, and rehabilitation, have had modest success in restoring neural connectivity due to the complex pathophysiology of SCI. In recent years, bioactive hydrogels have gained attention as a versatile platform for neural repair. Their ability to mimic the extracellular matrix, deliver therapeutic agents, and support cell survival makes them promising tools in regenerative medicine. This narrative review highlights the latest advances in hydrogel-based therapies for SCI, with a focus on innovations such as self-healing, conductive, and anti-inflammatory hydrogels. We also explore hybrid approaches that integrate nanomaterials, stem cells, and bioelectronics to address both primary and secondary injury mechanisms. While various hydrogel systems have been investigated, we place particular emphasis on gelatin-based hydrogels, especially gelatin methacryloyl (GelMA), due to their emerging clinical relevance. GelMA stands out for its bioactivity, tunable mechanics, and compatibility with 3D printing, making it a strong candidate for personalized therapies and scalable production. Unlike previous reviews that broadly summarize hydrogel use, this work specifically contextualizes gelatin-based platforms within the wider landscape of SCI repair, underscoring their translational potential. We also address current challenges, such as immune response, long-term integration, and clinical validation, and suggest future directions for bridging the gap from bench to bedside. Full article

Hyaluronic acid (HA) dermal fillers represent a cornerstone of modern esthetic medicine, providing a minimally invasive solution for facial volume restoration and skin rejuvenation. However, the diversity of available products, each utilizing distinct crosslinking technologies, presents a challenge for objective comparison and clinical decision making. This study introduces a scientific framework to evaluate and categorize the physicochemical properties of HA fillers based on two key parameter groups: dynamic parameters (e.g., rheology and gel content) and consistency parameters (e.g., extrusion force, water uptake, and gel particle size). Using standardized methodologies, 23 commercially available fillers from five major manufacturers were analyzed, enabling cross-technology comparisons. The findings reveal how specific crosslinking approaches influence the rheological behavior, handling characteristics, and potential clinical applications. By offering an integrated and reproducible assessment, this work helps practitioners select the most suitable filler for individualized treatment plans and encourages manufacturers to enhance product transparency through harmonized testing protocols. Full article

This study presents a detailed Raman spectroscopic investigation of hydrogels composed of sodium hyaluronate and two N-terminally blocked dipeptides: N-acetyl-L-alanine-methyl-amide (NAcAlaNHMA) and N-acetyl-L-tyrosine-methyl-amide (NAcTyrNHMA). Vibrational spectra of the dipeptides in both crystalline and aqueous forms were analyzed and supported by density functional theory (DFT) calculations. Spectral features of the hyaluronan component were elucidated by simulating the vibrational modes of its two principal disaccharide building blocks. Gels were prepared with varying dipeptide-to-hyaluronan ratios, and their structural characteristics were examined using Raman spectroscopy and atomic force microscopy. The results showed that while NAcAlaNHMA exhibited no significant interaction with the HA matrix, NAcTyrNHMA demonstrated specific binding behavior, as evidenced by notable shifts in its N–H and C–O–H vibrational bands. These findings indicate that NAcTyrNHMA binds to hyaluronic acid via hydrogen bonding, likely involving carboxyl and hydroxyl functional groups. This study highlights the potential for selective tuning of HA-based hydrogels using dipeptides, with implications for biomedical applications such as drug delivery, antimicrobial gels and biomaterial design. Full article

Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan widely recognised for its biocompatibility, biodegradability, and unique viscoelastic properties. Its structural versatility enables the formation of hydrogels with tuneable physicochemical characteristics, making it a valuable biomaterial in drug delivery and regenerative medicine. This review outlines HA properties, gel-forming approaches, and modern medicine and bioengineering applications. It provides a comprehensive overview of advances in HA production strategies, including microbial fermentation, animal tissue extraction, and production in vitro. Particular attention is given to gel-forming mechanisms, emphasising physical and chemical crosslinking methods like carbodiimide crosslinking, radical polymerisation, and enzymatic crosslinking. Advances in HA-based drug delivery systems and applications of HA-based materials in tissue engineering are also discussed, focusing on HA-based hydrogels with conjugates and combinations with compounds like collagen, alginate, and chitosan. Full article

Glioblastoma (GBM, isocitrate dehydrogenase wild-type) is the most common primary malignant brain tumor in adults and is associated with a severely low survival rate. Treatments offer mere palliation and are ineffective, due, in part, to a lack of understanding of the intricate mechanisms underlying the disease, including the contribution of the tumor microenvironment (TME). Current GBM models continue to face challenges as they lack the critical components and properties required. To address this limitation, we developed innovative and practical three-dimensional (3D) GBM models with structural and mechanical biomimicry and tunability. These models allowed for more accurate emulation of the extracellular matrix (ECM) and vasculature characteristics of the native GBM TME. Additionally, 3D bioprinting was utilized to integrate these complexities, employing a hydrogel composite to mimic the native environment that is known to contribute to tumor cell growth. First, we examined the changes in physical properties that resulted from adjoining hydrogels at diverse concentrations using Fourier-Transform Infrared Spectroscopy (FTIR), compression testing, scanning electron microscopy (SEM), rheological analysis, and degradation analysis. Subsequently, we refined and optimized the embedded bioprinting processes. The resulting 3D GBM models were structurally reliable and reproducible, featuring integrated inner channels and possessing tunable properties to emulate the characteristics of the GBM ECM. Biocompatibility testing was performed via live/dead and AlamarBlue analyses using GBM cells (both commercial cell lines and patient-derived cell lines) encapsulated in the constructs, along with immunohistochemistry staining to understand how ECM properties altered the functions of GBM cells. The observed behavior of GBM cells indicated greater functionality in softer matrices, while the incorporation of hyaluronic acid (HA) into the gelatin methacryloyl (gelMA) matrix enhanced its biomimicry of the native GBM TME. The findings underscore the critical role of TME components, particularly ECM properties, in influencing GBM survival, proliferation, and molecular expression, laying the groundwork for further mechanistic studies. Additionally, the outcomes validate the potential of leveraging 3D bioprinting for GBM modeling, providing a fully controllable environment to explore specific pathways and therapeutic targets that are challenging to study in conventional model systems. Full article

Bullfrog skin, as a by-product of bullfrog processing, is an ideal source of high-quality collagen due to its high protein content and low-fat characteristics. However, its comprehensive utilization is relatively low, and the discarded skins cause resource waste and environmental pollution. In this study, a citric acid extraction process for frog skin collagen was established through single-factor optimization. A multifunctional double-network hydrogel was developed by combining the prepared high-purity type I collagen with oxidized hyaluronic acid (OHA). Due to the network structure design of Schiff base bonds and Zn²⁺ coordination bonds, the mechanical strength of the hydrogel based on collagen and OHA compositing Zn²⁺ (Gel–CO@Zn) enhanced significantly. It was found that the Gel–CO@Zn hydrogel had strong tissue adhesion (16.58 kPa shear strength), rapid self-healing (<6 h), and low hemolysis (<5%). Furthermore, the Gel–CO@Zn hydrogel could reduce the survival rate of Staphylococcus aureus and Escherichia coli to 1.06% and 6.73%, respectively, showing good antibacterial properties. Through the treatment of Gel–CO@Zn, the clotting time was shortened from 433 s to 160 s and greatly reduced the blood loss (>60%) in the liver injury model of male Kunming mice. This research not only presents a novel approach for the high-value utilization of aquaculture by-products but also establishes a new paradigm for developing cost-effective, multifunctional biomedical materials, demonstrating the transformation of waste into high-value resources. Full article

Health benefits associated with hyaluronic acid, along with its properties such as water-binding capacity and antimicrobial activity, suggest that incorporating it into meat systems could provide a basis for formulating functional meat products. This study aimed to evaluate the properties of myofibrillar protein gels and emulsions with varying concentrations of hyaluronic acid. The results indicate that increasing the hyaluronic acid concentration (0.008% to 0.04%) does not significantly affect the cooking loss, while a concentration of 0.08% enhances cooking loss. This, in turn, increased gel hardness, while the water-holding capacity remains unaffected. Cryo-scanning electron microscopy (Cryo-SEM) images revealed a partial disruption of the gel structure, with rising hyaluronic concentrations. In pork myofibrillar protein emulsions, smaller droplets and higher stability were observed after HA incorporation. Samples containing hyaluronic acid were more viscous and exhibited shear-thinning properties. Overall, the hyaluronic acid used in this study improved emulsion properties, whereas the gel structure was compromised. Full article

Background/Objectives: Intra-articularly administered hyaluronic acid (HA) products improve the mechanical properties of the synovial fluid (SF) in an osteoarthritic (OA) joint and thus improve joint motion quality. However, current diagnostic methods, used to assess the clinical effectiveness of HA-based therapy are based on subjective tools, and are unable to deliver solid data about the actual impact of this molecule on joint functioning. Consequently, the aim of this study was to objectively assess the effect of HA IA injection on joint motion quality with vibroarthrography (VAG) and the subsequent evaluation of patient clinical status. Methods: A total of 40 patients with knee OA and 50 healthy individuals as the control group were enrolled in this non-randomized clinical and were subjected to therapy consisting of a single IA administration of highly concentrated HA gel (Biolevox™ HA ONE). The therapy assessment included an evaluation of joint motion quality with the VAG method and a subsequent evaluation of the knee joint function using the WOMAC questionnaire for up to 60 days after the therapy. Results: A single IA injection of HA led to an immediate and sustained improvement of the motion quality of OA-affected synovial joints, as proven by the significant reduction in all measured vibroacoustic emissions (VMS, R4, P1, and P2). Furthermore, this was followed by a significant improvement in all WOMAC sub-scales, observed at 30 and 60 days after the therapy. Conclusions: The results of this study demonstrate that an IA-HA injection can improve the motion quality of OA-affected joints. Importantly, the observed improvement in joint motion quality is directly correlated with early recovery of joint function. These findings provide objective evidence that HA effectively enhances OA-affected joint biomechanics, contributing to a better understanding of the actual impact of this prevalent OA therapy on knee joint motion quality. Full article

Polymeric scaffolds are promising in tissue engineering due to their structural similarity to extracellular matrix components. This study aimed to design freeze-dried hydrogels based on chitosan (CHT) and hyaluronic acid (HA). Chitosan-based gels were crosslinked with oxidized maltodextrin (MDo) before the freeze-drying step, resulting in spongy porous scaffolds. Based on the state-of-the-art, our hypothesis was that crosslinking would increase scaffold stiffness and delay the degradation of the CHT:HA resorbable scaffolds swelled in a hydrated physiological environment. The physicochemical and mechanical properties of crosslinked CHT- and CHT:HA-based scaffolds were analyzed. Hygroscopic and swelling behavior were assessed using dynamic vapor sorption analysis and batch studies. Degradation was evaluated under different conditions, including in phosphate-buffered saline (PBS), PBS with lysozyme, and lactic acid solutions, to investigate scaffold resistance against enzymatic and acidic degradation. The porosity of the spongy materials was characterized using scanning electron microscopy, while dynamic mechanical analysis provided information on the mechanical properties. Crosslinked scaffolds showed reduced swelling, slower degradation rates, and increased stiffness, confirming MDo as an effective crosslinking agent. Scaffolds loaded with ciprofloxacin (CFX) demonstrated their ability to deliver therapeutic agents, as the CFX loading capacity was promoted by CHT–CFX interactions. Microbiologic investigation confirmed the results. Finally, cytotoxicity tests displayed no toxicity. In conclusion, MDo-crosslinked CHT and CHT:HA scaffolds exhibit enhanced stability, functionality, and mechanical performance, making them promising for cartilage tissue engineering. Full article

The lack of personalized wound dressings tailored to individual needs can significantly hinder wound healing. Hydrogels offer a promising solution, as they can be engineered to mimic the extracellular matrix (ECM), providing an optimal environment for wound repair. The integration of digital light processing (DLP), a high-resolution 3D printing process, allows precise customization of hydrogel-based wound dressings. In this study, gelatin methacrylate (GelMA)-based formulations were prepared in combination with three different polymeric precursors: methacrylated hyaluronic acid (HAMA), poly (ethylene glycol) diacrylate (PEGDA) and allyl cellulose (MCCA). These precursors were used to print high-resolution micropatterned patches. The printed constructs revealed a high gel content and a good resistance to hydrolytic degradation. To improve the adhesive and antioxidant properties of the printed patches, gallic acid (GA) was incorporated through surface functionalization. This enabled the scavenging of approximately 80% of free radicals within just 4 h. The adhesive properties of the printed wound dressings were also significantly improved, with further enhancement observed upon the addition of Fe³⁺ ions. In vitro cytocompatibility tests using a fibroblast (NHDF) cell line confirmed the suitability of the materials for biomedical applications. Thus, this study demonstrates the potential of DLP-printed hydrogels as advanced personalized wound dressing materials. Full article