3D polyurethane scaffolds for exploring osteogenic differentiation and mechanical stimulation of mesenchymal stromal cells.

• Magnetically guided sharkskin MRE yields a robust superhydrophobic surface. • Retains WCA > 150° after 500 cm abrasion via self-regenerating superhydrophobicity. • Stable to water-jet shear and 90-day open-air exposure. • Compressive strength increased 59% due to magnetically aligned microchains. • SHIP incorporation and magnetic curing enhanced shear storage modulus and loss factor of SHS. Superhydrophobic surfaces (SHS) promise multifunctional performance, but practical use is often limited by poor mechanical resilience. Many SHS rely on soft polymer matrices that are structurally vulnerable; water repellency and related functions degrade under stress. This study introduces a novel method to fabricate multifunctional SHS by combining anisotropic magnetorheological elastomers (MREs) with bio-inspired sharkskin microstructures and hydrophobic iron oxide nanoparticle (SHIP) coating. The SHS fabrication involved a two-step process: soft lithography to imprint a sharkskin pattern on a polyurethane (PU) matrix containing SHIP, followed by SHIP deposition during partial curing under a vertical magnetic field. This process promoted the formation of rebar-like chain microstructures and micro–nano hierarchical roughness, enabling durable superhydrophobicity. The resulting coating exhibited a water contact angle of 163° and contact angle hysteresis of 1°, and retained superhydrophobicity after 500 cm of 240-grit sandpaper abrasion (3.3 kPa), water-jet impact, and 90 days of open-air exposure. The new material showed enhanced compressive strength (59.4% improvement from the control), attributed to vertically aligned iron particle chains, and higher loss modulus and loss factor. Collectively, these results demonstrate a robust, multifunctional coating for applications demanding water repellency, toughness, and vibration damping—for example, marine protective surfaces.

Evaluation of a stable non-aqueous coupling medium for transcranial ultrasonic stimulation and sonogenetics.

Packing media regulate nitric oxide removal performance by driving community assembly and biofilm evolution in biotrickling filters.

The objective of the study was to compare the accuracy and fit of direct-printed and thermoformed aligners. The in vitro study included a pre-treatment scan as a reference model. Thirteen successive treatment stages were digitally planned and exported as Standard Tessellation Language (STL) files. Based on the treatment plan, 39 aligners were manufactured for three groups: Group 1, direct-printed aligners with TA-28 resin; Group 2, thermoformed polyurethane (PU) aligners; and Group 3, thermoformed polyethylene terephthalate glycol-modified (PET-G) aligners. All aligners were subsequently scanned, and the resulting STL files were superimposed on the baseline models. The dimensional accuracy and fit of the aligners were evaluated. The groups were compared using the Kruskal-Wallis test, followed by Dunn-Bonferroni post-hoc comparisons, with significance set at p≤0.05. Intra-rater and inter-rater reliability were evaluated via intraclass correlation coefficients. Group 1 exhibited greater dimensional accuracy, as evidenced by the lowest mean deviation compared with Groups 2 and 3 (p<0.001). Pairwise comparisons indicated significant differences between Group 1 and Group 2 and between Group 1 and Group 3 (p<0.001); however, no significant difference was found between Groups 2 and 3 (p=0.489). Landmark-based deviation analysis indicated that Group 1 demonstrated the least deviation across all nine evaluated anatomical landmarks (p<0.001). Group 3 showed slightly greater deviations than Group 2 for most landmarks. Direct-printed aligners fabricated using TA-28 resin exhibited significantly higher dimensional accuracy and a better fit than thermoformed aligners manufactured from PU and PET-G.

The fabrication of superhydrophobic sponges with multifunctionality is of great importance in various practical fields. Herein, a fluorine-free, durable, and photothermal superhydrophobic polyurethane (PU) sponge is obtained using a dual-layer design, consisting of acetylene black (AB) via the adhesion of epoxy resin and lignin microparticles (LMPs) via the adhesion of polydimethylsiloxane (PDMS). The introduction of AB and LMPs not only creates hierarchical surface roughness on the skeletons of the PU sponge but also acts as photothermal absorbers. The as-prepared superhydrophobic PU sponge possesses excellent chemical resistance, hydrothermal and photothermal stabilities, and mechanical durability. Due to surface superhydrophobicity and superoleophilicity, it exhibits high adsorption capacities up to 56.3 g/g for various oils and organic solvents, and shows high separation efficiencies up to 99.9%. Benefiting from an enhanced photothermal property caused by introducing AB and LMPs, the superhydrophobic PU sponge displays a maximum surface temperature of 75.8 °C under 1 sun irradiation. Consequently, it can rapidly adsorb a droplet of viscous crude oil (1 mL) within 70 s (1 sun), and achieve an ice-free property at -18.5 °C (0.5 sun). Furthermore, the superhydrophobic PU sponge can effectively separate water-in-oil (or oil-in-water) emulsions and adsorb five types of microplastics (PE, PP, PET, PS, and PVC) due to the rich functional surface groups. This work provides a dual-layer design for fabricating fluorine-free, durable, and photothermal superhydrophobic PU sponge, and opens a new avenue for preparing superhydrophobic sponges with multifunctionality for diverse practical applications.

We report a robust and scalable approach for covalently grafting cationic polythiophene (CPT) nanowires onto polyurethane (PU)-functionalized gold surfaces using a surface-assisted (SurfAst) polymerization strategy. The methodology involves sequential incubations of hexamethylene diisocyanate (HDI) and 1,4-butanediol (1,4-BDO) on an 11-mercaptoundecanoic acid (MUA)-functionalized gold substrate, forming an OH-terminated PU interface. Subsequent functionalization with 2-isocyanatoethyl methacrylate yields a methacrylate-terminated PU interface, enabling the grafting of CPT nanowires through an UV-induced reaction between the methacrylate group on the PU interface and the allyl moieties of CPT. Atomic force microscopy (AFM) reveals the formation of highly elongated and well-defined CPT nanowires with stability. Electrostatic force microscopy (EFM) further confirms distinct phase shifts in the CPT-grafted regions. These findings demonstrate not only the successful immobilization of CPT on the PU-functionalized gold surface but also the preservation of accessible cationic functionalities, which ensure surface activity. A key aspect of this platform is the use of ethylene glycol (EG) as the solvent for CPT during the grafting process, which facilitates well-dissolved CPT chains and may provide the polymer in a dispersed state in solution, allowing effective interaction with the functionalized surface. These results establish a chemically robust and electrostatically tunable CPT-PU interphase, offering new opportunities for integration into next-generation electronic and sensing technologies.

Articular cartilage (AC) defects can lead to joint destruction and osteoarthritis, necessitating immediate intervention to prevent progressive cartilage degeneration. To support cartilage repair, hydrogels have been explored due to their structural similarity to the extracellular matrix (ECM), offering a hydrated microenvironment for chondrocytes that promotes cell adhesion and proliferation. Polyurethane (PU) is a promising candidate with adjustable mechanical properties, high biocompatibility, and degradability. Given the advantages of both hydrogels and PU for biomedical applications, functional degradable PU hydrogels present a potential solution for cartilage regeneration. This review summarizes the structure-property relationship and degradation mechanisms of PU hydrogels. Their advanced functionalities in cartilage repair are highlighted, including anti-inflammatory and antibacterial properties, controlled drug delivery, injectability, self-healing, and stimulus responsiveness. By reviewing recent advances and emerging technologies, this review provides valuable insights and a future outlook for the development of next-generation cartilage repair materials.

Enzymatic depolymerization of polyurethanes: discovery, mechanisms, and engineering of hydrolases.

High-performance polyurethane (PU) elastomers fundamentally suffer from a trade-off between structural resilience and recyclability. Herein, we propose a strategy to reconcile this dichotomy by developing Diels-Alder (DA) dynamic covalently cross-linked PU elastomers (DAPU-EEs) with precisely tailored polyether-to-polyester soft segment ratios. Systematically modulating this composition elucidates the structure-property relationship, enabling the programmable optimization of mechanical robustness, thermal stability, and dynamic responsiveness. Empowered by the thermoreversible DA network, the optimized elastomer (DAPU-EE2) exhibits efficient recyclability, retaining pristine mechanical properties after multiple hot-pressing cycles. Crucially, DAPU-EE2 demonstrates a remarkably low compression set of 15%, representing a 40% improvement over typical commercial TPU sealing materials. Furthermore, it exhibits superior solvent resistance and highly efficient processability with significantly reduced complex viscosities. Ultimately, this work provides a practical material design strategy that balances demanding mechanical performance with sustainable reprocessing, demonstrating promising potential for advanced sealing applications.

This study presents the design of a sustainable, triazine-containing, polyurethane-based magnetic catalyst (Fe3O4@PUN-Pd) that exhibits better catalytic activity and desirable reusability for the efficient reduction of nitroarenes. Uniform polyurethane (PUN) microspheres were prepared by surfactant-free precipitation polymerization of toluene diisocyanate (TDI), the triazine-based polyol 3-THA and subsequently decorated with magnetic nanoparticles (MNPs) and palladium (Pd) to form magnetically separable Fe3O4@PUN-Pd catalysts. Comprehensive characterisation using FT-IR, XRD, HRSEM, HRTEM, EDX, TGA, DLS, UV-vis, ICP-OES and XPS confirmed the molecular interactions, structural integrity, thermal stability, and uniform dispersion of Pd NPs. HRSEM confirmed PUN's spherical shape, while XPS determined the surface-bound Pd's oxidation state. The resulting catalyst offers a sustainable platform with substantial recovery and reuse potential. The synthesized catalysts were evaluated for their hydrogenation activity towards 4-nitrophenol (4-NP) in an aqueous medium. The catalytic efficiency varied depending on the method used to prepare the MNPs and the Pd NP loading. Among the prepared catalysts with different synthesis methods, Fe3O4@PUN-Pd(2) demonstrated the best performance in the aqueous-phase hydrogenation of 4-nitrophenol (4-NP), delivering a high rate constant of 0.430 min-1 and maintaining ∼95% conversion over 10 consecutive cycles, possessing high stability and magnetic recoverability. The catalyst showed good activity and stability in water compared to organic solvents viz., methanol, ethanol, and acetonitrile, underscoring its green applicability. Additionally, the reduction of various hazardous nitroarenes, such as 4-nitroaniline (4-NA), 2-nitroaniline (2-NA), nitrobenzene (NB) and 2-nitrotoluene (2-NT), was also investigated in aqueous medium. The catalyst showed potent stability and good catalytic performance in water, a green solvent, compared to methanol, ethanol, and acetonitrile.

Medical catheters face certain challenges in clinical treatment, such as bacterial biofilm adhesion and thrombus formation. Antifouling and antibacterial coatings have been proven to be an effective solution to diminish these undesirable events. Herein, we developed a facile and environmentally friendly strategy for constructing a dual-functional coating by grafting an antibacterial-zwitterionic copolymer onto polyurethane (PU) surfaces. The copolymer was designed and synthesized via a one-pot polymerization in an aqueous system by integrating 2-methacryloyloxyethyl phosphorylcholine (MPC), dimethyl diallyl ammonium chloride (DADMAC), and glycidyl methacrylate (GMA) as a functional monomer to enable surface immobilization. The resulting copolymer (PMDG) was robustly grafted onto a PU substrate pretreated with polydopamine/polyethylenimine (PDA/PEI) through a ring-opening reaction. The P/P-PMDG coating significantly improved the hydrophilicity of the surface, with the water contact angle (WCA) decreasing from 85.95° to 18.25°. Meanwhile, the coating demonstrated effective resistance to protein adsorption and bactericidal activity up to 99%, and such effects were well maintained after 4 weeks of immersion of the membrane in PBS solution, as well as after 3 cycles of reuse. Notably, the modified membranes exhibited excellent biocompatibility and hemocompatibility. This work provided a promising strategy for surface modification to improve biofouling and antibacterial efficiency of medical polymeric devices.

The development of high-performance polyurethanes (PUs) is intrinsically connected to the molecular structure of polyol precursors. However, single-structure polyols, such as polyester polyols and polyether polyols, exhibit limited potential for broadly regulating PU properties. Herein, we engineered random poly(ether-ester-carbonate) polyols with tailored compositions via telomerization of anhydride/epoxide/CO2 enabled by a robust supported aluminum porphyrin catalyst. Ultralow molecular weight polyols (0.8 kg/mol) with narrow dispersity (Đ = 1.08) were easily obtained due to the catalyst's extraordinary proton tolerance. Additionally, our supported catalyst produced near-white products while maintaining recyclability for at least three cycles. Our work provides a versatile platform for designing next-generation PU precursors.

Wound exudate contains rich biochemical markers, among which dynamic pH fluctuations serve as a key predictor of infection progression and healing prognosis. However, real-time pH monitoring remains limited by the lack of platforms enabling exudate extraction and stable sensing. Here, we present an asymmetric theranostic Janus wound dressing that integrates unidirectional exudate transport, wide-gamut colorimetric pH sensing, and antibacterial therapy into a single closed-loop platform. The bilayer rapidly drains exudate from the curcumin/Ag-loaded hydrophobic polyurethane (PU) layer into a hydrophilic hydrogel for biochemical analysis. To overcome the inherent instability and leaching issues of conventional pH indicators, phenol red is confined within zeolitic imidazolate framework-8 nanoparticles, forming a leaching-resistant optical sensor with enhanced sensitivity and a broadened dynamic color range. This strategy enables accurate, lighting-independent pH quantification via a deep-learning-assisted smartphone application, enabling objective in situ assessment of infection risk and healing status. Both in vitro and in vivo evaluations confirm that this platform not only suppresses infection and accelerates wound closure but also provides prognostic biochemical feedback with clinical relevance. This work presents a comprehensive AI-assisted theranostic strategy that integrates wound microenvironment engineering with digital health tools to precision wound management.

The dynamic interaction between breast implants and tissues influences long-term aesthetic outcomes after augmentation mammaplasty. Implant characteristics such as shape, gel cohesivity, and surface texture may affect postoperative results. The aim of this study was to assess the stability of 5 implant types over a 12-month period with 3-dimensional (3D) image analysis. A prospective single-surgeon study was conducted on 106 patients (212 breasts) undergoing primary breast augmentation. Five implant types were evaluated: smooth Progressive Gel ULTIMA (PgU) round; smooth high-strength cohesivity gel (HSC+) round; microtextured round; microtextured anatomical; and polyurethane (PU)-coated anatomical. Three-dimensional morphometric analysis (with Arbrea software) measured nipple-to-inframammary fold distance (N-IMF) and lower pole ratio (LPR) at 6 and 12 months. Statistical associations between implant type, volume, and elongation were analyzed. Complication and satisfaction rates were compared across groups. Smooth PgU round implants demonstrated the greatest elongation (Δ N-IMF: .98 ± 0.26 cm; Δ LPR: 6.84 ± 3.02 p.p.) (P < .001), whereas PU anatomical implants showed negligible change (Δ N-IMF: 0.04 ± 0.35 cm; Δ LPR: 0.46 ± 2.75 percentage points [p.p.]). Implant type and volume were significantly associated with elongation (P < .0001 and P < .05, respectively) in all categories except PU-coated implants (P > .05). The overall complication-per-implant rate was 2.4%, predominantly among smooth PgU implants (P = .011). Patient satisfaction was high and comparable across groups. Implant gel cohesivity, surface texture, and volume affect implant stability. PU-coated anatomical implants showed the least change, whereas smooth groups presented the highest elongation and complication rate. For image description, please refer to the figure legend and surrounding text.

Distribution characteristics and potential microbial degradation mechanisms of microplastics in oyster aquaculture areas of southern China.

Numerous studies have reported the polymerization and stabilization of castor oil (CO) with isocyanates for the synthesis of polyurethanes (PUs) intended for adhesive applications. In this work, we propose a novel strategy for stabilizing PU emulsions, employing modified styrene-co-maleic anhydride (SMA) copolymers as surfactants, in combination with carbon nanotubes (CNTs). We synthesized emulsified PU nanocomposites using isophorone diisocyanate and 4,4′-dicyclohexylmethane diisocyanate (H12MDI), which were reacted with CO as the polyol source. Stabilization of the PU adhesives was achieved by emulsifying the resulting PUs in the presence of a modified SMA copolymer, functionalized via imidization reaction with tallow amine with two different styrene and maleic anhydride ratios, along with water and functionalized CNTs. The resulting material is a stable, flowable PU emulsion capable of effectively bonding wood substrates. Lap shear tests were performed to evaluate the adhesive bonding strength showing values of 1.2 MPa. The presence of the SMA-based plays a crucial role in emulsion stability, as it reduces the oil–water interfacial tension by approximately 40%. The combination of CNTs and SMA copolymers resulted in emulsions that remained stable for over ten months after preparation exhibiting droplet sizes smaller than 2 µm in diameter, maintaining their performance as adhesive materials.

Source identification of microplastics (MPs) is important for controlling pollution, however, an effective method is still lacking. In the present paper, a low-dosage froth flotation separation protocol was developed to separate MPs efficiently, and coupled with Raman fingerprints to identify the source. By analyzing the alterations in surface properties of MPs, the inhibitory mechanism of activated sludge on froth flotation efficiency of MPs was elucidated, attributed to the reduced hydrophobicity, adsorption of humic acid (HA), and the concentration of HA in flotation solution. Sieving pretreatment was applied to mitigate the inhibition caused by HA, while the flotation efficiency (exceeding 70%) was enhanced by the addition of 16 mg/L cetyltrimethylammonium bromide (CTAB). The concentration of MPs in actual samples was quantified by FT-IR spectroscopy at 38-46 particles/L, with identified polymers, including polyamide (PA), polyethylene terephthalate (PET), polystyrene (PS), and polyurethane (PU). MPs in different treatment units were identified using 20 mM KBr-modified SERS via detection of surface-adsorbed substances on MPs (detection limit: 10 μg/L). Raman fingerprints were obtained by froth flotation coupled with SERS, enabling the successful detection of surface substances and source identification in actual samples. This integrated approach offers high anti-interference capability for analyzing surface-adsorbed substances on MPs, thereby improving the accuracy of environmental fate tracing in treatment systems, and promising to be an efficient and accurate traceability method for MPs.

Developing multifunctional textiles integrating energy-efficient thermal management and robust electromagnetic interference (EMI) shielding remains a significant challenge. Herein, a stretchable phase-change fiber membrane with a programmable wrinkled conductive network is fabricated by in situ depositing silver nanoparticles (AgNPs) on a pre-stretched coaxial electrospun substrate. Its hierarchical structure, comprising paraffin wax (PW) encapsulated in the polyurethane (PU) shell and a surface-wrinkled AgNP layer, delivers a high latent heat of 73.8 J g-1, along with deformable photothermal and Joule heating. Numerical simulations corroborate that the synergy of dual-mode heating and PW-based energy storage allows effective personal thermal management at low temperatures. Moreover, the membrane exhibits an initial EMI shielding effectiveness (SE) of 66.4 dB, retaining 33.71 dB even at 100% strain due to its elastic wrinkled topology. Endowed with hydrophobicity, breathability, and mechanical stretchability, the composite presents a promising platform for next-generation wearable devices requiring integrated thermal regulation and adaptive EMI protection.

Corrosion and fire-induced strength degradation are primary drivers of severe economic losses and catastrophic failures in metallic structures. Polymer coatings serve as critical safeguards against corrosion; however, their flammability presents a fire risk, undermining the overall safety of the protected structure. Polyvinyl chloride (PVC) exhibits excellent inherent barrier properties and flame retardancy, but its poor film-forming ability has limited its practical application in high-performance coatings. To address this limitation, a core-shell nanostructure hybrid latex was successfully synthesized via seed emulsion polymerization, combining PVC with polyurethane (PU) and polybutyl acrylate (PBA). The resulting coating exhibits exceptional anti-corrosion performance, demonstrated by a low-frequency impedance modulus (|Z|0.01Hz) exceeding 4 × 1011 Ω cm2 after 30 days of immersion in a 3.5 wt% NaCl solution, confirming its robust and durable protective capability. Furthermore, the cone calorimeter test (CCT) revealed a 7.3% reduction in the peak heat release rate (PHRR) and an increased fire performance index (FPI) of 0.079 m2 s kW-1 for the PVC-PU-PBA film. This work presents a feasible and scalable strategy for fabricating multifunctional waterborne coatings with integrated corrosion resistance and flame retardancy, offering a promising solution for advanced steel protection.