Search Results (731)

This study evaluates the effect of chemical treatments on the short-beam shear strength, vibrational, and acoustic performance of banana-fibre-reinforced carbon–Kevlar hybrid composites. Banana fibres were treated with 5% NaOH and 0.5% KMnO₄ to improve fibre surface characteristics and interfacial bonding within a sandwich laminate of carbon–Kevlar intraply skins and banana fibre core fabricated by hand lay-up and compression moulding. Short-beam shear strength (SBSS) increased from 14.27 MPa in untreated composites to 17.65 MPa and 19.52 MPa with KMnO₄ and NaOH treatments, respectively, due to enhanced fibrematrix adhesion and removal of surface impurities. Vibrational analysis showed untreated composites had low stiffness (7780.23 N/m) and damping ratio (0.00716), whereas NaOH treatment increased stiffness (9480.51 N/m) and natural frequency (28.68 Hz), improving rigidity and moderate damping. KMnO₄ treatment yielded the highest damping ratio (0.0557) with reduced stiffness, favouring vibration energy dissipation. Acoustic tests revealed KMnO₄-treated composites have superior sound transmission loss across low to middle frequencies, peaking at 15.6 dB at 63 Hz, indicating effective acoustic insulation linked to better mechanical damping. Scanning electron microscopy confirmed enhanced fibre impregnation and fewer defects after treatments. These findings highlight the significant role of chemical surface modification in optimising structural integrity, vibration control, and acoustic insulation in sustainable banana fibre/carbon–Kevlar hybrids. The improved multifunctional properties suggest promising applications in aerospace, automotive, and structural fields requiring lightweight, durable, and sound-mitigating materials. Full article

Microneedle (MN) patches comprise a promising platform for transdermal delivery of macromolecular therapeutics. However, achieving sufficient mechanical strength for skin penetration while maintaining high biocompatibility and efficient antibody loading remains a major challenge. In this study, we designed and developed a core–shell-structured hydrogel MN patch composed of a silk fibroin core and a protein-based shell layer for antibody loading and potential transdermal release. The latter was constructed using a fusion protein consisting of the B and C domains of Staphylococcus aureus protein A (BC) and a tyrosine-rich mussel adhesive protein (MAP), thereby enabling antibody binding via the BC domains. By harnessing biomimetic design strategies, the BC-MAP shell facilitates antibody immobilization via specific affinity interactions, while the silk fibroin core provides substantial mechanical strength: the MN patch demonstrated a penetration force approximately 4.2 times greater than that required to pierce porcine skin. Collectively, our core–shell-structured hydrogel MN patch is a promising platform for transdermal antibody delivery. Full article

Background: Hyaluronan, or hyaluronic acid (HA), is a glycosaminoglycan with structural and signaling functions playing key roles in human skin homeostasis. It ensures hydration and biomechanical properties of this tissue as well as regulates cell adhesion, migration, proliferation, and inflammation. Its biocompatibility, viscoelastic properties, biological functions, and large-scale sustainable bioproduction made this polysaccharide a hero molecule of the cosmetic industry. Methods: A literature search was conducted to discuss the skin and hair benefits of the external use of HA and its derivatives. Four main questions were addressed: What are the different forms of HA in cosmetic formulations? What about their safety? Does HA penetrate human skin and hair? What are the benefits and mode of actions of HA, and its derivatives, in the fields of cosmetic and dermatology? Results: The analysis revealed HA below 100 kDa to penetrate skin, and lower molecular weight being able to reach the dermis. The safety of HA-containing formulations has been evaluated in several clinical trials and is supported by independent reports of commercial ingredients. We described HA molecules having beneficial effects on skin and hair, as well as their mode of action. Conclusions: This review provides comprehensive information on the nature and efficacy of topical HA, and its derivatives, in cosmetic applications, with an emphasis on hair care. New areas of research were highlighted as the vectorization of high-molecular-weight HA. Full article

With growing concerns over the safety of synthetic substances, the development of plant-derived alternatives with minimal adverse effects has gained significant attention. Carica papaya L. peel contains a rich profile of bioactive compounds, including papain, flavonoids, and vitamin C, which exhibit potent antioxidant and anti-inflammatory properties. This study aimed to evaluate the effects of an ethanol extract of C. papaya peel (EECP) on inflammation and skin barrier dysfunction in a mouse model of contact dermatitis (CD) induced by 1-fluoro-2,4-dinitrofluorobenzene (DNFB). Mice were treated by applying EECP at three different levels (60, 80, and 600 μg) to dorsal skin for six days. Skin lesion severity, skin color, skin barrier function (SBF, as indicated by water content and water-holding capacity (WHC)), histopathological abnormalities, cytokine levels, filaggrin and Intercellular Adhesion Molecule-1 (ICAM-1) expression, and phosphorylation of MAPK (Mitogen-Activated Protein Kinase) signaling molecules were assessed. EECP treatment significantly alleviated the CD-associated dermal symptoms induced by DNFB, including skin fissures, scabbing, roughness, changes in color, water content, and WHC, as well as petechiae. EECP also prevented histopathological abnormalities such as epidermal hyperplasia, spongiotic changes, and immune cell infiltration. In addition, EECP suppressed the production of pro-inflammatory cytokines, viz. TNF-α, IFN-γ, IL-6, and MCP-1. In addition, EECP restored filaggrin expression and inhibited ERK (Extracellular signal-regulated kinases) phosphorylation and ICAM-1 expression in HaCaT cells. In summary, C. papaya peel demonstrated therapeutic potential by effectively suppressing inflammation and restoring SBF. These findings support the potential use of EECP as a safe and effective botanical candidate for the treatment of CD and the promotion of overall skin health Full article

Current trends in intelligent hydrogels design for tissue engineering demand multifunctional biomaterials that respond to external stimuli, while maintaining adhesion, controlled degradation, and cytocompatibility. The present work describes the synthesis and characterization of a novel, intelligent and synergistic hydrogel for promoting osteoblastic growth and regeneration. The hydrogel comprises a complex matrix blend of natural biodegradable polymers, vitamins (A, K2, D3, and E), and bioactive components such as zinc phosphate nanoparticles and manganese-doped hydroxyapatite to improve osteoblastic functionality. The hydrogel proved to have physicochemical properties for recovery and self-healing, highlighting its potential application as an auxiliary in bone rehabilitation. Key parameters such as rheological behavior, moisture content, water absorption, solubility, swelling, biodegradability, and responsiveness to temperature and pH variations were thoroughly evaluated. Furthermore, its adhesion to different surfaces and biocompatibility were confirmed. Skin contact test revealed no inflammatory, allergic, or secondary effects, indicating its safety for medical applications. Importantly, the hydrogel showed high biocompatibility with no cytotoxicity signs, favoring cell migration and highlighting its potential for applications in regenerative medicine. Full article

Platelet-rich plasma (PRP) is an autologous blood-derived concentrate increasingly utilized in regenerative medicine for its ability to accelerate healing and tissue repair. PRP is broadly classified by leukocyte content, fibrin architecture, and platelet concentration, with classification systems developed to standardize characterization. Preparation methods, including single- or double-spin centrifugation and buffy coat techniques, influence the final composition of PRP, determining the relative proportions of platelets, leukocytes, plasma proteins, and extracellular vesicles. These components act synergistically, with platelets releasing growth factors (e.g., VEGF, PDGF, TGF-β) that stimulate angiogenesis and matrix synthesis, leukocytes providing immunomodulation, plasma proteins facilitating scaffolding, and exosomes regulating intercellular signaling. Mechanistically, PRP enhances tissue repair through four key pathways: platelet adhesion molecules promote hemostasis and cell recruitment; immunomodulation reduces pro-inflammatory cytokines and favors M2 macrophage polarization; angiogenesis supports vascular remodeling and nutrient delivery; and serotonin-mediated pathways contribute to analgesia. These processes establish a regenerative microenvironment that supports both structural repair and functional recovery. Clinically, PRP has been applied across multiple specialties. In orthopedics, it promotes tendon, cartilage, and bone healing in conditions such as tendinopathy and osteoarthritis. In dermatology, PRP enhances skin rejuvenation, scar remodeling, and hair restoration. Gynecology has adopted PRP for ovarian rejuvenation, endometrial repair, and vulvovaginal atrophy. In dentistry and oral surgery, PRP accelerates wound closure and osseointegration, while chronic wound care benefits from its angiogenic and anti-inflammatory effects. PRP has also favored gingival recession coverage, regeneration of intrabony periodontal defects, and sinus grafting. Although preparation heterogeneity remains a challenge, PRP offers a versatile, biologically active therapy with expanding clinical utility. Full article

Scale adhesion strength is a key trait in aquaculture, directly influencing disease resistance, survival, and commercial value. The Dongting crucian carp (Carassius auratus indigentiaus, hereafter CaDT) is valued for its rapid growth and superior flesh quality but is characterized by loosely attached scales. In this study, we investigated the morphological and molecular basis underlying scale adhesion by comparing CaDT with the tight-scaled allogynogenetic gibel carp, Zhongke No. 3 (Carassius auratus gibelio, hereafter CaGB). Morphological analysis revealed a significantly lower scale-embedding ratio in CaDT compared to CaGB. To unravel the molecular mechanisms underpinning these phenotypic differences, a comparative transcriptomic analysis was conducted on scale sac, skin, and muscle tissues in CaDT and CaGB. In CaGB, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of differentially expressed genes (DEGs) in the critical scale sac tissue showed a significant upregulation of genes involved in ribosomal pathways. Specifically, key epithelial differentiation markers, including keratin 13 (krt13), keratin 15 (krt15), and metabolic genes, enolase 3-like (eno3l), and phosphoglycerate mutase 2 (pgam2) were significantly down-regulated in CaDT, which suggests a compromised epithelial cell differentiation capacity and reduced energetic and biosynthetic activity. Quantitative PCR (qPCR) validation across three tissues showed high concordance with the RNA-seq results, thereby confirming the reliability of the transcriptomic data. The results offer insight into the molecular basis for understanding scale adhesion traits, and provide valuable insights for selective breeding strategies to improve scale retention in aquaculture species. Full article

Chronic lower-extremity wounds in patients undergoing exoskeleton-assisted rehabilitation require materials that can both protect tissue and enable real-time physiological monitoring. Conventional dressings lack dynamic sensing capability, while current conductive hydrogels often compromise either adhesion or electronic performance. Here, we present a biointegrated hydrogel (CPSD) composed of carboxymethyl chitosan (CMCS) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) forming the conductive backbone, integrated with dopamine-functionalized sodium alginate (SD); the network is assembled via electrostatic complexation and carbodiimide (EDC/NHS)-mediated covalent crosslinking. The resulting hydrogel exhibits a dense, tissue-conformal porous network with tunable swelling, stable mechanical integrity, and high photothermal conversion efficiency. In vitro assays confirmed potent antioxidant activity, strong antibacterial performance (>90% under near-infrared), and excellent cytocompatibility and hemocompatibility. CPSD shows bulk conductivity ~1.6 S·m⁻¹, compressive modulus ~15 kPa, lap-shear adhesion on porcine skin ~9.5 kPa, and WVTR ~75 g·m⁻²·h⁻¹, supporting stable biointerfaces for motion/sEMG sensing. Integrated into a lower-limb exoskeleton, CPSD hydrogels adhered securely during motion and reliably captured electromyographic and strain signals, enabling movement-intent detection. These results highlight CPSD hydrogel as a multifunctional interface material for next-generation closed-loop rehabilitation systems and mobile health monitoring. Full article

This study examines the biocompatibility of 11 modern wound dressings (WDs)―Syspur-derm^®, Parapran^®, Lomatuell^®H, Voskopran^®, Metalline^®, Granuflex^®, Chitopran^®, HydroTac^®transparent, Branolind^®N, Aquacel^TM adhesive foam, Aquacel^TMAg⁺―developed for the treatment of acute and chronic wounds, and their potential use as secondary WD for the hydrogel-based bioengineered skin equivalent (BSE) “Equivalent Dermal, ED”. The study was conducted to better understand the properties of these WDs that influence the healing process. The biocompatibility of WDs was evaluated in vitro based on their effects on the viability of human dermal fibroblasts (DFs). The MTT assay, lifetime analysis of DFs’ morphological state, and analysis of their actin cytoskeletal organization using a WDs’ extracts showed that effects of WD on DFs varied among WDs. It has been revealed that WDs Parapran^®, Lomatuell^®H, Voskopran^®, Metalline^® and Chitopran^® have high biocompatibility and can be effectively used for wound treatment, whereas Granuflex^®, Syspyr-derm^®, HydroTac^® transparent, Branolind^®N, Aquacel^TM adhesive foam and Aquacel^TMAg⁺ have lower biocompatibility, so they could be used for wound therapy with caution. Only Parapran^® with chlorhexidine showed high biocompatibility with the BSE “The Dermal Equivalent, ED” and can be safely used in combination with it as a secondary WD. Full article

Wound healing is a complex, multi-phase process involving hemostasis, inflammation, proliferation, and tissue remodeling. Syndecans (SDCs), a family of transmembrane heparan sulfate proteoglycans, serve as co-receptors for growth factors, cytokines, and ECM components, playing critical roles in cell adhesion, migration, proliferation, and angiogenesis. Among them, SDC-1 and SDC-4 are key regulators of skin wound healing. Due to their distinct spatial and temporal expression across various cell types—such as epithelial cells, fibroblasts, and immune cells—SDCs are well-positioned to coordinate regenerative responses. This review focuses on the spatial regulation of SDCs during skin wound healing, highlighting their roles in epidermal and dermal repair, modulation of intracellular signaling, and remodeling of the wound microenvironment. Overall, SDCs are emerging as central modulators of skin wound healing, with promising implications for regenerative medicine in the skin and beyond. Full article

Background/Objectives: A comparative study of silver (Ag), titanium nitride (TiN), zirconium nitride (ZrN), and copper (Cu) coatings on titanium (Ti) disks, considering the specifications of a microporous skin- and bone-integrated titanium pylon (SBIP), was performed to assess their biocompatibility, osseointegration, and mechanical properties. Methods: To assess cytotoxicity and biocompatibility, Ti disks with various metal coatings were co-cultured with FetMSCs and MG-63 cells for 1, 3, 7, and 14 days and subsequently evaluated using a cell viability assay, as supported by SEM and confocal microscopy studies. The antimicrobial activity of the selected four materials coating the implants was tested against S. aureus by mounting Ti disks onto the surface of LB agar dishes spread with a bacterial suspension and measuring the diameter of the growth inhibition zones. Quantitative Real-Time Polymerase Chain Reaction (RT-PCR) analysis of the relative gene expression of biomarkers that are associated with extracellular matrix components (fibronectin, vitronectin, type I collagen) and cell adhesion (α2, α5, αV integrins), as well as of osteogenic markers (osteopontin, osteonectin, TGF-β1, SMAD), was performed during the 14-day follow-up period. Additionally, the activity of matrix metalloproteinases (MMP-1, -2, -8, -9) was assessed. Results: All samples with metal coatings, except the copper coating, demonstrated a good cytotoxicity profile, as evidenced by the presence of a cellular monolayer on the sample surface on the 14th day of the follow-up period (as shown by SEM and inverted confocal microscopy). All metal coatings enhanced MMP activity, as well as cellular adhesion and osteogenic marker expression; however, TiN showed the highest values of these parameters. Significant inhibition of bacterial growth was observed only in the Ag-coated Ti disks, and it persisted for over 35 days. Conclusions: The silver-based coating, due to its high antibacterial activity, low cytotoxicity, and biointegrative capacity, can be recommended as the coating of choice for microporous titanium implants for further preclinical studies. Full article

Background: Diabetic wound healing has always been a clinical challenge with minimal response or efficacy to standard treatment. This study aims to assess the therapeutic potential of hypoxia-induced extracellular vesicles (hy-EVs) produced by human umbilical cord mesenchymal stem cells (HUCMSCs) to treat diabetic wounds. Methods: HUCMSCs were isolated from umbilical cord tissue, cultured under hypoxic conditions to induce the release of extracellular vesicles (EVs) and compared with normoxia-induced extracellular vesicles (n-EVs). We assessed the functions of hy-EVs on human skin fibroblasts (HSFs) and human umbilical vein endothelial cells (HUVECs) in vitro. Simultaneously, we analyzed the pro-angiogenic effects of hy-EVs, their effects on macrophage polarization, and their ability to scavenge endogenous reactive oxygen species (ROS). In addition, a diabetic wound model was established to assess the curative effect of hy-EVs in diabetic wound healing. Results: We found by in vitro study that hy-EVs markedly improved the functional activities of HSFs, thus significantly promoting wound repair. Remarkably, it was determined that hy-EVs greatly enhanced the proliferation and migration ability as well as the angiogenic ability of HUVECs, while promoting the expression of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial-generation-associated factor A (VEGFA), and platelet endothelial adhesion molecule (CD31), which suggested that hy-EVs can effectively activate the HIF-1α pathway to promote angiogenesis. Above all, we found that hy-EVs promoted the expression of CD206 while decreasing the expression of CD86, suggesting that hy-EVs could induce macrophages to shift from M1-type (pro-inflammatory) to M2-type (anti-inflammatory), thereby modulating the inflammatory response. Additionally, hy-EVs inhibited ROS production in both HSFs and HUVECs to reduce oxidative stress. In vivo results showed that hy-EVs enhanced collagen deposition and angiogenesis, modulated macrophage polarization, and inhibited immune response at the wound spot, which significantly enhanced diabetic wound healing. Conclusions: Our study shows that hy-EVs significantly promote angiogenesis through activation of the HIF-1α pathway, modulate macrophage polarization and attenuate cellular oxidative stress, possibly through delivery of specific miRNAs and proteins. Our discoveries offer a key theoretical basis and potential application to develop novel therapeutic strategies against diabetes-related tissue injury. Full article

Cyanoacrylate-based adhesives are commonly used for wound closure due to their short synthesis time, aesthetic outcomes, and minimal discomfort. However, reported adverse effects include the release of cytotoxic metabolites, inflammation, and foreign body reactions. This study evaluated and compared the effectiveness of three cyanoacrylate-based adhesives for skin incision closure in Rattus norvegicus. The subjects were divided into three groups based on the type of monomer: G1 (n-2-ethyl-cyanoacrylate), G2 (n-2-butyl-cyanoacrylate), and G3 (n-2-octyl-cyanoacrylate). Each animal received two 2 cm paramedian incisions, which were closed using either a topical over dermal (OD) or a topical transdermal (TD) application, resulting in two subgroups per group. Wounds were evaluated on postoperative days 3, 7, 14, and 21 to compare the different monomers and application techniques. Assessment of the inflammatory infiltrate revealed differences in polynuclear cells between the TD and OD on days 3 and 7, while TD demonstrated improved results in mononuclear cells at all time points. Sustained inflammatory processes and foreign body reactions were observed. Quantification of tumor necrosis factor (TNF-α) and thiobarbituric acid reactive substances (TBARS) indicated that TD maintained stability throughout the assessment periods, though it exhibited higher values than OD from days 7 to 21. These higher values were associated with a foreign body reaction and increased oxidative stress. Regarding tissue formation, OD produced more aligned wound edges, supporting the production of types I and III collagen and improving scar resolution compared to TD. Our findings indicate that the patch application technique has a greater impact on healing than the size of the cyanoacrylate monomer. Full article

Electroencephalography (EEG) electrodes require low impedance, high biocompatibility, and long-term performance. Conventional Ag/AgCl wet electrodes achieve low impedance but suffer from dehydration and skin irritation, whereas dry electrodes often induce discomfort or exhibit high impedance. To address these limitations, this study engineered a hydrogel-based electrode by incorporating PEDOT:PSS and the nonionic surfactant Triton X-100 into an acrylic acid hydrogel matrix. The flexible acrylic acid backbone, conductive PEDOT:PSS domains, and the nanofibrillar network promoted by Triton X-100 simultaneously enhanced mechanical compliance and electrical stability. In addition, the structural rearrangement of PEDOT:PSS was verified through morphological analyses. The fabricated electrode exhibited a modulus comparable to human soft tissue, demonstrated strong interfacial adhesion in shear tests, and significantly reduced skin–electrode contact impedance. Furthermore, EEG measurements showed that the hydrogel electrode achieved alpha- and beta-band signal power comparable to commercial Ag/AgCl electrodes. These findings establish the PEDOT:PSS–Triton X-100 hydrogel electrode as a promising candidate to replace conventional wet and dry electrodes for reliable EEG applications. Full article

Background: Cannabinoids, such as tetrahydrocannabinol (∆-9-THC) and cannabidiol (CBD) have been proposed for topical medicinal use as a treatment for tissue inflammation. In this context, keratinocytes are the first cells that encounter cannabinoids. The present study evaluated the dose–response relationship between different concentrations of THC and CBD and their effects on human skin and gingival keratinocyte growth and migration, to identify suitable non-toxic concentrations of cannabinoids. Methods: Human gingival and skin keratinocytes were exposed to CBD or THC at different concentrations for 24 h, and then cell adhesion, morphology, and growth/viability were assessed. The effects of cannabinoids on keratinocyte migration were evaluated at 6, 12, and 24 h. Cytotoxicity of CBD and THC against keratinocyte cells was assessed using an LHD cytotoxicity test. Cell metabolic profiles were evaluated using Mito and Glyco Stress Assays. The anti-inflammatory effects of cannabis derivatives were assessed against LPS-stimulated keratinocytes. Data analysis was performed by one-way ANOVA. Results: Only high concentrations (10 and 20 μg/mL) of CBD and THC were cytotoxic to gingival and skin keratinocytes, reduced cell adhesion and growth, and were associated with a delay in cell migration after wounding. Cells exposed to high concentrations (20 μg/mL) of cannabinoids displayed high levels of lactate dehydrogenase (LDH) activity and changes in mitochondrial activities. CBD induced a metabolic shift in skin keratinocyte cells toward glycolysis, while reducing mitochondrial oxidative phosphorylation. In contrast, THC did not alter the metabolic profile of skin keratinocytes. Interestingly, both CBD and THC significantly reduced the LPS-induced inflammatory response by decreasing secretion of IL-6 and IL-8 by gingival and skin keratinocytes. Conclusions: Gingival and skin keratinocytes interact differently with cannabinoids. Only high concentrations of cannabinoids were cytotoxic, suggesting that the use of low concentrations of CBD and THC for topical medicinal applications may help control tissue inflammation. Full article