Search Results (1,060)

This study evaluated the surface functionalization of a non-equiatomic TiZrNbTaMo high-entropy alloy (HEA) by micro-arc oxidation (MAO) in Cu-rich electrolytes to tailor its performance for biomedical implants. The Cu content was varied, and the resulting coatings were investigated for their morphology, phase constitution, chemical structure, wettability, and cytocompatibility. X-ray diffraction (XRD) measurements of the substrate indicated a body-centered cubic (BCC) matrix with minor HCP features, while the MAO-treated samples depicted amorphous halo with sparse reflections assignable to CaCO₃, CaO, and CaPO₄. Chemical spectroscopic analyses identified the presence of stable oxides (TiO₂, ZrO₂, Nb₂O₅, Ta₂O₅, MoO₃) and the successful incorporation of bioactive elements (Ca, P, Mg) together with traces of Cu, mainly as Cu₂O. MAO treatment increased surface roughness and rendered a hydrophilic behavior, which are features typically favorable to osseointegration process. In vitro cytotoxic assays with MC3T3-E1 cells (24 h) showed that Cu addition did not induce harmful effects, maintaining or improving cell viability and adhesion compared to the controls. Collectively, MAO in Cu-rich electrolyte yielded porous, bioactive, and Cu-incorporated oxide coatings on TiZrNbTaMo HEA, preserving cytocompatibility and supporting their potential for biomedical applications like orthopedic implants and bone-fixation devices. Full article

The study investigates the performance of polyethersulfone (PES) ultrafiltration (UF) membranes modified with a coating of polymerizable bicontinuous microemulsion (PBM) for membrane bioreactor (MBR) applications. Two types of PBM-modified PES membranes—casting-coated and spray-coated—were compared with a commercial PES membrane. A laboratory side-stream MBR (ssMBR) was employed to treat model wastewater (MW) with activated sludge under aerobic conditions. The fouling propensity of the membranes in ssMBR was evaluated through the implementation of two protocols: (i) flux-step test to treat low-strength domestic model wastewater (DMW) and (ii) constant flux test to treat high-strength olive mill model wastewater (OMW). The findings indicated that both the commercial PES and PBM spray-coated PES membranes started to critically foul at 36 L m⁻² h⁻¹. The PBM spray-coated membranes showed enhanced fouling resistance in comparison to the PBM casting-coated membranes. The deposition of the biofouling layer was the thinnest on PBM spray-coated membranes, which can be attributed to the low surface charge and high hydrophilicity of the modified membrane surface. In contrast, deposition of a thicker fouling layer was found on the commercial PES membrane, which can be attributed to the relatively higher surface charge promoting organic adsorption. A comparison of the fouling trends exhibited by commercial PES and PBM spray-coated membranes in OMW treatment revealed that they have similar fouling tendencies. However, a notable distinction emerged when the PBM spray-coated membrane was observed to demonstrate a lower fouling propensity accompanied by comparatively thinner fouling layers. The results demonstrate that the PBM spray-coated membranes have enhanced fouling resistance and filtration efficacy in MBRs treating wastewater with diverse strengths, thereby affirming their potential for application in wastewater treatment systems. Full article

The development of sustainable, water-based conductive coatings is essential for advancing environmentally responsible wearable and printed electronics. Achieving high electrical conductivity and wash durability remains a key challenge. This is largely dependent on the compatibility between the polymer matrix, the conductive filler and the substrate surface. In this study, a facile formulation strategy is proposed by directly integrating few-layer graphene (FLG, 2.5 wt%) into commercial bio-based thermoplastic polyurethanes (TPUs), combined with polyvinylpyrrolidone (PVP) as a dispersing agent. The investigation focuses on how the segmental architecture of four TPUs with different structure and hard–soft segments composition influences filler dispersion, mechanical integrity, and electrical behavior. Coatings were deposited onto flexible substrates, including textiles and paper, using a bar-coating process and were characterized in terms of morphology, thermal properties, electrical conductivity, and wash resistance. The results demonstrate that TPUs containing a higher presence of hard segments interact more effectively with hydrophobic surfaces, while TPUs with a higher contribution of soft segments improve adhesion to hydrophilic substrates and facilitate the formation of the percolation network, underling the role of TPU microstructure in controlling interfacial interactions and overall coating performance. The proposed comparative approach provides a sustainable pathway toward durable, high-performance, and washable electronic textiles and paper-based devices. Full article

Background: Biomedical device-associated infections pose major challenges in surgical care, particularly in hernia repair where polypropylene (PP) meshes and sutures are prone to bacterial colonization and biofilm formation. The limitations of antibiotic resistance and toxicity warrants the need of developing innovative antibacterial strategies. Methods: We developed a composite coating of hydroxypropyl methylcellulose (HPMC) and zinc oxide nanorods (ZnO NP) synthesized via thermal decomposition. This coating was applied to PP meshes and sutures to enhance anti-adhesive properties. The study evaluated surface hydrophilicity through water contact angles, estimation of Zn²⁺ ions using inductively coupled plasma–mass spectrometry (ICP-MS), and long-term efficacy over six months. Safety was assessed via systemic toxicity studies in murine models. Results: The ZnO NPs exhibited potent antibacterial efficacy, achieving up to 99.999% killing against Klebsiella pneumoniae. When applied as an HPMC-ZnO coating, PP meshes and sutures demonstrated enhanced hydrophilicity, reducing water contact angles by ~41° and facilitating prevention of bacterial adhesion. The coated meshes inhibited bacterial attachment by 83% (Escherichia coli), 60% (Pseudomonas aeruginosa), 99.6% (K. pneumoniae), and 99% (Staphylococcus aureus). Similarly, coated sutures reduced adhesion by 67–96% across these strains. Long-term storage studies showed retained antibiofilm efficacy for up to six months. In vivo assessments indicated negligible systemic toxicity of ZnO NPs in murine models. Conclusions: Collectively, these findings highlight HPMC-ZnO NPs coatings as a safe, durable, and effective strategy to functionalize PP-based meshes and sutures, reducing the risk of surgical site infections and demonstrating the potential for broader biomedical applications. Full article

The coagulation cascade triggered by the contact between blood and the surface of implantable/interventional devices can lead to thrombosis, severely compromising the long-term safety and efficacy of medical devices. As an alternative to systemic anticoagulants, surface anticoagulant modification technology can achieve safer hemocompatibility on the device surface, holding significant potential for clinical application. This article systematically elaborates on the latest research progress in the surface anticoagulant modification of blood-contacting materials. It analyzes and discusses the main strategies and their evolution, spanning from physically inert carbon-based coatings and heparin-based drug-functionalized surfaces to hydrophilic/hydrophobic dynamic physical barriers, biologically signaling regulatory coatings, and bio-integrative/regenerative endothelium-mimicking surfaces. The advantages and limitations of the respective methods are outlined, and the potential for synergistic application of multiple strategies is explored. A special emphasis is placed on current research hotspots regarding novel anticoagulant surface technologies, such as hydrogel coatings, liquid-infused surfaces, and 3D-printed endothelialization, aiming to provide insights and references for developing long-term, safe, and hemocompatible cardiovascular implantable devices. Full article

Polydimethylsiloxane (PDMS) is widely used in microfluidics and medical devices; however, its inherent hydrophobicity limits its applications. This can be resolved by the formation of polyethylene glycol (PEG)-based hydrophilic coatings. Here, we aimed to prove that PDMS surfaces modified with low molecular weight PEG (400) provided a more stable hydrophilic surface. The lowest contact angle achieved via using PEG400 and the “grafting from” approach was 8.6 ± 3.5°. Under perfusion conditions, imitating arterial and capillary flows, such coatings were considerably stable, and the contact angle was kept at 45.5° after 3 days. Moreover, the applied surface modifications preserved surface roughness, elastic modulus, and optical transparency. Thus, these findings confirmed that the “grafting from” approach with low molecular weight PEG could be the most effective strategy to form hydrophilic PDMS coatings with optimal performance in biomedical applications. Full article

The application of bioinspired nanocomposites in orthopedic implants marks a significant innovation in biomedical engineering, aimed at overcoming long-standing limitations of conventional implant materials. Traditional implants frequently suffer from poor osseointegration, mechanical mismatch with bone, and vulnerability to infection. Bioinspired nanocomposites, modeled after the hierarchical structures found in natural tissues such as bone and nacre, offer the potential to enhance mechanical performance, biological compatibility, and implant functionality. This study reviews and synthesizes current advancements in the design, fabrication, and functionalization of bioinspired nanocomposite materials for orthopedic use. Emphasis is placed on the integration of nanocrystalline hydroxyapatite (nHA), carbon nanotubes (CNTs), titanium dioxide (TiO₂) nanotubes, and other nanostructured coatings that mimic the extracellular matrix. Methods include comparative evaluations of mechanical properties, surface modifications for biocompatibility, and analyses of antibacterial efficacy through nano-topographical features. Bioinspired nanocomposites have been shown to improve osteoblast adhesion, proliferation, and differentiation, thereby enhancing osseointegration. Nanostructured coatings such as TiO₂ nanotubes increase surface hydrophilicity and corrosion resistance, supporting long-term implant stability. Mechanically, these composites offer high stiffness, superior wear resistance, and improved strength-to-weight ratios. Biomimetic combinations of hydroxyapatite, zirconia, and biopolymers have demonstrated effective load transfer and reduced stress shielding. Additionally, antibacterial functionality has been achieved via nanostructured surfaces that deter bacterial adhesion while remaining cytocompatible with host tissues. The integration of bioinspired nanocomposites into orthopedic implants provides a multifunctional platform for enhancing clinical outcomes. These materials not only replicate the mechanical and biological properties of native bone but also introduce new capabilities such as infection resistance and stimuli-responsive behavior. Despite these advancements, challenges including manufacturing scalability, long-term durability, and regulatory compliance remain. Continued interdisciplinary research is essential for translating these innovations from laboratory to clinical practice. Full article

The present study investigates the influence of alternating current (AC) frequency on the formation and properties of calcium-, phosphorus-, and selenium-containing micro-arc oxidation (MAO) coatings on high-purity magnesium. Coatings were produced at 50–400 Hz in a phytic-acid-based electrolyte containing Ca, P, and Se precursors, and their structure, chemistry, and functional performance were systematically evaluated. Surface morphology, analyzed by SEM and optical profilometry, revealed frequency-dependent features: lower frequencies (50 Hz) promoted thicker, rougher coatings with extensive cracking, whereas intermediate frequencies (100–200 Hz) yielded more uniform, porous surfaces. The CaPSe_100 specimen exhibited the most homogeneous topography (lowest S10z and SD) combined with the highest porosity (28.4%), strong hydrophilicity, and the greatest selenium incorporation (1.30 wt.%). Hydrogen evolution testing in Hanks’ solution demonstrated a drastic improvement in corrosion resistance following MAO treatment: the degradation rate of bare Mg (5.50 mm/year) was reduced to 0.012 mm/year for the CaPSe_100 coating—well below the clinical tolerance threshold for biodegradable implants. This outstanding performance is attributed to the synergistic effect of a uniform oxide barrier, optimized porosity, and homogeneous surface morphology. The results highlight the potential of frequency-controlled AC-MAO processing as a route to tailor magnesium surfaces for multifunctional, corrosion-resistant biomedical applications. Full article

Conventional polyurethane (PU) synthesis is associated with environmental and health concerns due to the use of toxic isocyanates. In recent years, the development of non-isocyanate polyurethanes (NIPUs) has emerged as a sustainable alternative to conventional polyurethanes. However, these materials still exhibit inconsistencies in their physicomechanical and biological properties. This systematic review was conducted following the PRISMA methodology. A total of sixteen studies published between 2015 and 2025 were analyzed, focusing on functionalization techniques developed for non-isocyanate polyurethanes to evaluate their influence on physicomechanical and biological performance. The results reveal that functionalization can be achieved through the incorporation of inorganic additives, polar or ionic groups, and polymeric modifiers. Among the analyzed systems, those functionalized with azetidinium and Polyethylene glycol diacrylate (PEGDA) exhibited the most balanced performance, combining high mechanical strength, low cytotoxicity, and effective antibacterial activity. Overall, these functionalizations have demonstrated significant improvements in tensile strength, thermal stability, hydrophilicity, and antimicrobial activity, facilitating broader industrial and biomedical applications. Consequently, this review concludes that functionalization plays a pivotal role in improving the overall performance of non-isocyanate polyurethanes. It represents an effective and sustainable strategy to enhance the physicomechanical and biological behavior of these materials, supporting their development for advanced applications such as bioactive coatings, membranes, and wound dressings. Full article

Microfluidic oxygenators promise to advance extracorporeal membrane oxygenation (ECMO) devices with enhanced hemodynamics and low prime volume. We are developing a silicon-based membrane oxygenator that will offer improved gas transfer and fluid flow control. Polyethylene glycol (PEG) has been used to improve hemocompatibility by providing excellent resistance to protein adsorption. Here, we characterized a polyethylene glycol surface modification of composite silicon–PDMS membranes to evaluate their effects on microfluidic oxygenator properties. X-ray photoelectron spectroscopy (XPS) and water contact angle goniometry confirmed successful PEG attachment, evidenced by the presence of characteristic C-O bonds and increased hydrophilicity, which was stable for 2 weeks. Oxygen flux tests demonstrated gas transfer rates as high as 89.6 ± 17.9 mL/min/m² and 50.8 ± 11.7 mL/min/m² for unmodified and PEG-coated membranes, respectively. Protein adsorption studies with human serum albumin (HSA) demonstrated a significant reduction in nonspecific protein binding on PEG-coated membranes with values as low as 14 ± 6 μg/cm². These studies expand on the characterization of our engineered oxygenator membranes and provide insight for the development of future surface optimization strategies to enhance hemocompatibility. Full article

TiO_xN_y coatings are known for their good biocompatibility and corrosion resistance and have been previously explored for biomedical applications, including cardiovascular stents. In this work, emphasis is placed on a systematic investigation of the effect of substrate bias voltage on the structural, morphological, and mechanical properties of TiO_xN_y films deposited by reactive magnetron sputtering. TiO_xN_y coatings were deposited on 316L stainless steel substrates using a pure titanium target (99.99%) in an Ar–N₂–O₂ gas mixture at various substrate bias voltages (0 to −150 V). The influence of substrate bias on the deposition rate, structure, and mechanical properties of the films was investigated. X-ray diffraction (XRD) analysis revealed the sequential phase evolution from cubic TiN to oxynitride TiON and further to TiO₂ (anatase/rutile) with increasing negative substrate bias, indicating that ion bombardment energy plays a decisive role in determining the crystallinity and phase composition of the coatings. The coating deposited at −50 V exhibited the highest hardness (~430 HV) and good adhesion strength (critical load 20–25 N). Contact angle measurements confirmed the hydrophilic behavior of the coatings, which is favorable for biomedical applications. Full article

Softwood-based composites are increasingly used in structural and nonstructural applications owing to their renewability, cost-effectiveness, and favorable strength-to-weight performance. This study applies a systematic literature review and comparative analysis, drawing on approximately 140 sources, to synthesize current knowledge on the physicochemical, mechanical, thermal, and environmental characteristics of engineered wood products derived from softwood species. The intrinsic lignocellulosic composition of softwood, comprising roughly 40%–45% cellulose, 25%–30% hemicelluloses (with mannose as the predominant sugar), and 27%–30% lignin, strongly influences hydrophilicity, stiffness, and thermal behavior. Mechanical properties vary across engineered wood product classes; for example, plywood exhibits a modulus of rupture of 33.72–42.61 MPa and a modulus of elasticity of 6.96–8.55 GPa. Microstructural and spectroscopic analyses highlight the importance of fiber–matrix interactions, chemical bonding, and surface modifications in determining composite performance. Emerging advanced materials, such as scrimber, with densities of 800–1390 kg/m³, and fluorescent transparent wood, achieving optical transmittance above 70%–85%, demonstrate the expanding functional potential of softwood-based composites. Sustainability assessments indicate that coatings, flame-retardants, and adhesives may contribute to volatile organic compound emissions, emphasizing the need for lower-emission, bio-based alternatives. Overall, the findings of this systematic review show that softwood-based composites deliver robust, quantifiable performance advantages and hold strong potential to meet the rising demand for sustainable, low-carbon engineered materials. Full article

Paper plays an important role in the packaging industry due to its low cost, light weight, recyclability and biodegradability. However, the use of paper as a packaging material is severely limited due to its hydrophilicity caused by the hydroxyl groups of cellulose. This study reports a simple preparation of highly hydrophobic kraft paper by a one-step dip coating method using [3-(2,2,3,3-tetrafluoropropoxy)propyl]silsesquioxane, {3-[(2,2,3,3,4,4,5,5-octafluoropentyl)oxy]propyl}silsesquioxane or {3-[(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl)oxy]propyl}silsesquioxane as hydrophobic agents. As a result of modification of kraft paper, a stable covalently bonded coating is formed on its surface. The coated kraft paper has demonstrated (1) high water resistance (the water contact angle (WCA) values were 124–141°, and the water absorption and the water vapor permeability (WVP) rates were significantly decreased), (2) excellent resistance to aggressive environments and temperature, (3) enhanced mechanical properties (tensile strength increased from 46.8 to 70.8 MPa), and (4) high wear resistance, as confirmed by sandpaper abrasion, bending, and finger-wipe tests. It was shown that the maximum contact angle values were achieved for kraft paper modified with a 5% polymer solution. The results of this study have great potential, given the simplicity of the modification method, for use in the production of paper-based packaging materials with water-repellent, enhanced mechanical and moisture-protective properties. Full article

Polycaprolactone (PCL) is a synthetic biodegradable polymer widely used in biomedical research due to its flexibility, safety for use in the body, and FDA approval for medical use. Nevertheless, its inherent hydrophobicity and restricted bioactivity limit its direct utilization in the field of biomaterials. Efforts to overcome these limitations include, but are not limited to, surface modifications, coating, and the use of copolymers of PCL with hydrophilic polymers. Polydopamine (PDA), the oxidative polymerization product of dopamine, a naturally occurring biomolecule in living organisms, is a flexible, bioinspired coating that makes surfaces more hydrophilic and facilitates cell attachment by incorporating numerous catechol and amine functional groups, making it suitable for biomaterial applications. PCL nanofibers were coated with PDA in three concentrations of dopamine solutions (0.2, 2, and 20 mg·mL⁻¹). Then, gold nanoparticles (AuNPs) were deposited in situ using sodium borohydride reduction. Morphological, physicochemical, and electrical properties of both PDA-coated and AuNP-loaded PCL fibers were comparatively investigated. The PDA coating made the surface significantly more hydrophilic compared to PCL-only surfaces, and AuNP-loaded fibers exhibited an extremely hydrophilic character. The primary concern of this article, electrical conductivity, was found to increase by up to a hundredfold with PDA coating and by a thousandfold with loading of AuNPs. PDA coating or loading AuNPs onto PDA-coated electrospun PCL fibers can provide a wide range of applications in the field of biomaterials. Full article

Graphene oxide (GO) is characterized by hydrophilic edges and a more hydrophobic planar/basic skeleton, which makes it has potential applications in the field of corrosion. But its hydrophobicity hinders its co-deposition behavior in the electrolyte. To improve the corrosion resistance of copper-based substrate, this article designs and successfully prepares a nickel/chromium graphene oxide (NiCr-GO) composite coating. The paper studied the influence and mechanism of GO addition on the microstructure and corrosion resistance of the coating. The results indicate that a crack network and nodular structure have formed on the surface of the coating. The coatings with different GO contents are composed of nickel, chromium single-phase, and Cr₂Ni₃ inter-metallic compounds, and the grain size does not significantly change. With the increase in GO, the corrosion resistance of the composite coating is enhanced, and the optimal GO addition amount is 0.750 g/L. GO chips may form physical barriers in the crystal structure defects of the coating, or passive films on the material surface. This dual mechanism is the fundamental reason for improving the corrosion resistance of NiCr-GO. Full article