Search Results (280)

Additive manufacturing enables rapid fabrication of polymer components, but the direct production of well-defined microchannels remains challenging. Laser processing offers an attractive approach for introducing microscale features and modifying polymer surface properties. This study investigates visible diode laser processing of four additively manufactured polymers: acrylonitrile butadiene styrene (ABS), polyethylene terephthalate glycol (PETG), Anycubic Standard resin, and Industrial Rigid resin. Laser-processing conditions were screened and selected for each material, and surface modifications were evaluated using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, contact angle measurements, and surface free energy calculations. ABS and PETG enabled successful microchannel formation, whereas continuous microchannels could not be obtained in the photopolymer resins under the investigated conditions. ATR-FTIR analysis revealed material-dependent surface modifications while largely preserving the characteristic polymer fingerprints. Laser treatment increased the water contact angle of ABS from 88.9° to 122.3° and PETG from 73.5° to 92.2°. In contrast, it decreased from 85.4° to 59.0° for Anycubic Standard resin and from 103.7° to 81.6° for Industrial Rigid resin. These contrasting responses demonstrate that diode laser processing can induce microstructuring, surface modification, or both, depending on the polymer substrate. Full article

Polymeric antistatic additives offer improved resistance to migration compared with low-molecular-weight agents, but high loadings are generally required to establish effective charge-dissipation pathways in nonpolar polypropylene (PP). Herein, a series of quaternary ammonium salt-functionalized polyamide 6/polyethylene glycol elastomers (QASPA6PEG) was synthesized by melt copolymerization and used as multifunctional antistatic additives for PP. Increasing the nominal QAS content decreased the surface resistivity of the elastomers from 3.24 $\times$ 10⁹ Ω to 9.71 × 10⁸ Ω. The elastomers were subsequently melt-blended with PP at loadings of 10–20 wt% using maleic-anhydride-grafted polypropylene as a compatibilizer. The surface resistivity of the blends decreased with increasing QAS content and elastomer loading, consistent with the formation of increasingly interconnected ion-conducting domains. The blend containing 20 wt% 0.4QASPA6PEG exhibited surface resistivities of 3.64 $\times$ 10¹¹ Ω and 4.69 $\times$ 10¹⁰ Ω on days 0 and 60, respectively. Its saturated water absorption reached 4.38%, compared with 0.27% for neat PP, supporting a moisture-assisted ionic conduction mechanism. The measured bromine content remained nearly unchanged after 60 days of storage, indicating limited loss of the QAS-containing component. In addition to improving charge dissipation, QASPA6PEG enhanced the ductility and impact resistance of PP. At a loading of 20 wt%, 0.4QASPA6PEG increased the elongation at break from 358 ± 23% to 690 ± 81% and the notched impact strength from 3.16 ± 0.37 to 4.93 ± 0.45 kJm⁻². These results demonstrate that covalently introducing ionic structures into PA6/PEG elastomers is an effective strategy for coupling antistatic modification with toughening in PP. Full article

Background: Osteoarthritis (OA), affecting approximately 240 million people worldwide, currently lacks targeted, long-acting therapeutic options. This study investigates how physicochemical properties (i.e., size, surface charge, polydispersity) influence poly(lactic-co-glycolic acid) (PLGA) microsphere (MS) diffusion into articular cartilage for enhanced corticosteroid delivery. Methods: PLGA MSs were synthesized via oil/water emulsions to create a variety of sizes and surface charges. MSs were loaded with corticosteroid (H-17-B) and release kinetics were studied in vitro and analyzed via HPLC. Diffusion of the MSs was investigated via a bovine explant model. Results: Unmodified PLGA MSs (approximately 0.58–0.98 µm) were synthesized via single-stage oil/water emulsion with varying poly(vinyl alcohol) concentrations and sonication intensities. All formulations exhibited near-neutral surface charges (−0.27 to 4.28 mV). Smaller particles achieved greater cartilage penetration, with bi-exponential diffusion models (R² = 0.706–0.999) outperforming classical Fickian approaches. However, multi-timepoint validation demonstrated fundamentally non-diffusive transport, likely governed by steric exclusion from the dense collagen network (0.05–0.06 µm pore size). Surface functionalization with avidin/palmitic acid or polyethylene glycol (PEG)/biotin yielded microspheres with controlled properties (0.36–0.97 µm; PDI: 0.10–0.32). In vitro release studies with hydrocortisone-17-butyrate (H-17-B; encapsulation efficiency of 79.8% ± 4.8%) demonstrated biphasic kinetics best fit by bi-exponential models (R² > 0.95). Unmodified microspheres exhibited 7.1% cumulative release by Day 14. High-performance liquid chromatography revealed that H-17-B undergoes ester hydrolysis to hydrocortisone during release, with surface modifications significantly affecting drug stability. Specifically, PEGylated microspheres maintained 96% of the drug in H-17-B form at Day 14 compared to only 37% for unmodified particles. Release was governed by PLGA degradation with concentration-independent kinetics, enabling predictable dose scalability. Conclusions: This work establishes that the behavior of PLGA microspheres in cartilage is controlled by size, charge, and surface functionalization. Surface modifications overcome physical barriers while stabilizing the encapsulated corticosteroid against premature hydrolysis, providing a framework for designing intra-articular drug delivery systems for osteoarthritis treatment. Full article

Aiming at severe soil secondary salinization, poor water retention and insufficient salt tolerance of conventional acrylic-based modifiers in arid and semi-arid regions of China, a poly(ethylene glycol) maleate citrate (PEGMC) crosslinking monomer was synthesized through esterification, and a dual covalent–hydrogen crosslinked P(PEGMC/AA) hydrogel was fabricated via free radical copolymerization with acrylic acid (AA). The hydrogel was characterized by NMR, FTIR, SEM, TGA and elemental mapping, while its binding mechanism with saline–alkali ions was elucidated through DFT calculations and molecular dynamics simulations. Its amelioration performance was evaluated through swelling, soil water retention, desalination and pot germination experiments. The hydrogel exhibited outstanding water absorbency, salt resistance and dry–wet cycling stability, with swelling ratios of 712 g/g in deionized water and 285 g/g in 0.9% NaCl solution, and remained 200 g/g after four dry–wet cycles. It enhanced soil water retention remarkably (over 93% after 72 h). At 0.30% dosage, soil salt content declined from 7.1 g/kg to 1.3 g/kg with desalination efficiency exceeding 80%, owing to porous physical adsorption and chemical chelation toward Na⁺, Ca²⁺ and Mg²⁺, with a binding energy of −136.936 kJ/mol. Pot tests revealed that crop germination rate rose from 19% (blank) to 75% under severe saline–alkali stress. Meanwhile, the hydrogel inhibited nutrient leaching and favored soil-water conservation. This work first incorporated PEGMC monomer into agricultural hydrogels to construct a stable dual crosslinked network, clarifying its synergistic mechanisms for salt fixation and water retention macroscopically and microscopically. It provides a promising functional material and theoretical basis for green, efficient in situ amelioration of dryland saline–alkali soil. Full article

Surface functionalization of metallic implants is widely explored to enhance their performance and functionality. In this study, multifunctional hydrogel coatings based on poly(vinylpyrrolidone) and polyethylene glycol were developed and functionalized with a taxifolin (TAX) inclusion complex and collagen to introduce bioactive features. TAX, a naturally occurring flavonoid with antioxidant and anti-inflammatory properties, was incorporated using β-cyclodextrin to improve its stability and enable controlled release. The coatings were applied to titanium-hydroxyapatite composites and titanium sheet substrates to evaluate their applicability across surfaces with varying morphologies, ranging from porous to relatively smooth. The ceramic phase was modified with magnesium ions to enhance its bioactivity and better mimic the composition of natural bone tissue. FTIR and SEM analyses confirmed hydrogel formation and effective surface coverage. Degradation and incubation studies in simulated physiological environments demonstrated the material’s stability, while UV–Vis analysis indicated TAX release, highlighting the system’s potential as a carrier for flavonoid-based compounds. Indirect cytotoxicity studies using MC3T3-E1 preosteoblasts indicated low cytotoxicity and a favorable biological response of collagen- and taxifolin-modified systems. The developed coatings represent a versatile platform for surface modification of titanium-based biomaterials and demonstrate potential for application across substrates with diverse surface characteristics. Further studies are required to assess their biological potential. Full article

To address the application bottlenecks of organic phase change materials characterized by low thermal conductivity and susceptibility to liquid leakage, this study utilized natural poplar wood as a raw material to construct a three-dimensional carbon/silver heterogeneous porous skeleton via delignification, gradient carbonization, and in situ electroless silver plating. Polyethylene glycol (PEG) was then vacuum-encapsulated within this structure to prepare form-stable composite phase change materials (CPCMs). The regulatory effects of carbonization temperature and metal interface modification on the microscopic morphology and thermophysical properties of the materials were systematically investigated. The results indicate that the skeleton carbonized at 800 °C achieves an optimal balance between pore distribution and skeleton rigidity, ensuring the uniform conformal growth of silver nanoparticles and endowing the material with excellent anti-leakage performance. The thermal conductivity of the optimal sample reaches as high as 0.683 W/(m·K), with the melting latent heat maintained at 133.9 J/g, while also demonstrating an agile and stable photothermal conversion response. Non-equilibrium molecular dynamics (NEMD) simulations further confirm that the silver nanoparticle modification layer smooths the phonon vibration frequency mismatch between the carbon substrate and organic segments, significantly reducing the interfacial thermal resistance. This research provides an important reference for the structural design and microscopic heat transfer mechanism analysis of high-performance phase change energy storage materials. Full article

Local pulmonary delivery offers a non-invasive application route for mRNA therapeutics with the potential for high bioavailability at the target-site of applications such as mucosal vaccination or the treatment of lung diseases. However, efficient delivery remains challenging due to major lung-specific barriers, particularly mucus. Herein, pH-responsive, amphiphilic xenopeptides comprising lipoamino fatty acids and oligoamino acids (OAAs) connected in distinct branched U-shape or bundle topologies were evaluated as mRNA polyplexes for delivery to A549 and Calu-3 lung cells under standard submerged or air–liquid interface (ALI) transfection conditions, and upon intratracheal application in BALB/c mice. Optionally, polyplexes were coated with negatively charged hyaluronic acid (HA) or colloidally stabilized with poly(ethylene glycol) (PEG). For U-shapes, hydrophobic modification of the OAA domain boosted their efficiency. Interestingly, best-performing formulations varied across transfection conditions. While the bundle topology showed the highest potential in submerged cell culture, U-shaped carriers were more efficient under ALI conditions. Polyplex surface modification with HA or PEG did not strongly alter in vitro transfections, whereas hydrophobized U-shape core polyplexes combined with surface modification enhanced their efficiency in vivo. Thus, the cationizable core and surface properties of mRNA nanoparticles require specific balancing in various lung cell models and lung. Full article

Localized surface plasmon resonance (LSPR) is an optical phenomenon that occurs when light interacts with free electrons on the surface of metallic thin films, producing intensified electromagnetic fields at specific sites, often called “hot spots”. LSPR-based sensing technologies respond to chemical and associated optical interfacial changes. Inherent advantages include enhanced sensitivity, compact size, low production cost, and strong potential for integration into portable, point-of-care diagnostic systems. This study focuses on a detailed investigation into the surface functionalization of localized surface plasmon resonance (LSPR)-based nanohole array (NHA) sensors for biomedical applications. Gold-coated NHA surfaces were functionalized using polyethylene glycol (PEG) self-assembled monolayers (SAMs), enabling specific attachment of biomolecular species. As a proof-of-concept, bovine serum albumin (BSA) and SARS-CoV-2 nanobody proteins were successfully immobilized on the PEGylated surfaces. Individual steps of surface modification including PEGylation, protein immobilization and nanobody immobilization were validated through a dual-method approach which combined measurement of LSPR optical spectral shifts and x-ray photoelectron spectroscopy (XPS) chemical analyses. Reproducibility was assessed across multiple sensors and repeated trials, confirming the repeatability of each functionalization and binding process. The sensor system, consisting of NHA-based plasmonic platform, microfluidics, and a portable optical spectrometer, exhibits the capability for reliable and sensitive, label-free detection of biomolecular targets, including viral antigens, in liquid-phase environments. Full article

Hierarchical functionalisation of the UiO-66(Zr)-NH₂ metal–organic framework with cysteine, poly(ethylene glycol) (PEG), and the SARS-CoV-2 spike receptor-binding domain (RBD) was developed to enable receptor-specific interaction with the angiotensin-converting enzyme 2 receptor (ACE2) in model cells. Post-synthetic modification using cysteine and heterobifunctional PEG linkers allowed controlled bioconjugation of SpyTag-labelled RBD via SpyTag/SpyCatcher chemistry, while preserving the crystallinity, microporosity, and intrinsic optical properties of the UiO-66(Zr)-NH₂ framework. Comprehensive physicochemical characterisation confirmed successful surface functionalisation, tunable aggregation behaviour, and retention of multimodal optical characteristics. Cellular studies in HEK293T and HeLa cells overexpressing EGFP-tagged ACE2 demonstrated enhanced and selective association and uptake of RBD-functionalised nanoparticles compared with non-targeted analogues. Multimodal fluorescence imaging, fluorescence lifetime imaging microscopy, flow-cytometry, and electron microscopy indicated ACE2-dependent endocytic internalisation, with predominant localisation in endosomal and autophagosomal compartments, while both amine- and cysteine-modified formulations exhibited good biocompatibility. Overall, this study establishes a virus-mimetic, ACE2-targeted UiO-66(Zr)-based nanosystem as a proof-of-concept biointerface platform for receptor-specific cellular delivery and imaging, providing a foundation for future MOF-based nanocarriers exploiting ligand–receptor interactions. Full article

Dispersion stabilization of nanoparticles for catalytic reactions is an important issue. However, dispersing agents should be carefully selected not to hinder catalytic performance. In the present study, physisorption of cyclic poly(ethylene glycol) (c-PEG) onto platinum nanoparticles (PtNPs) was investigated in comparison with unmodified PtNPs (PtNPs/No PEG), PtNPs mixed with linear PEG (PtNPs/HO-PEG-OH), and PtNPs chemisorbed with HS-PEG-OMe (PtNPs/HS-PEG-OMe). DLS showed a significant increase in the particle size for PtNPs/c-PEG and PtNPs/HS-PEG-OMe compared to PtNPs/No PEG and PtNPs/HO-PEG-OH. ζ-potential measurements revealed values around −30 mV for PtNPs/No PEG and PtNPs/HO-PEG-OH, whereas PtNPs/c-PEG and PtNPs/HS-PEG-OMe approached 0 mV, which indicated that c-PEG and HS-PEG-OMe adsorb onto PtNPs to form a shielding layer. Moreover, PtNPs/c-PEG and PtNPs/HS-PEG-OMe were stable in a phosphate-buffered saline (PBS) solution, but PtNPs/No PEG and PtNPs/HO-PEG-OH immediately aggregated. This suggests that high dispersion stability by c-PEG is comparable to ordinary surface modification using HS-PEG-OMe. Furthermore, the catalytic ability of PtNPs/c-PEG and PtNPs/HS-PEG-OMe was compared in various reactions. As a result, physisorbed PtNPs/c-PEG showed suitable catalytic activities, whereas chemisorbed PtNPs/HS-PEG-OMe was significantly hampered by the blocking of the catalytic sites with thiol in some reactions. Thus, physisorption of c-PEG endows PtNPs with dispersion stability and maintains the catalytic ability, leading to an alternative way of modifying metal nanoparticles. Full article

In this current study, beech wood (Fagus sylvatica) was modified by cross-linking via esterification with combinations of polyethylene glycol (PEG) 400 and various carboxylic acids. Promising combinations (1,2,3,4-butanetetracarboxylic acid (BTCA)/PEG400; citric acid (CA)/PEG400; malic acid (MA)/PEG400) were examined in previous studies. The goal of this study was the optimisation of the treatment. The use of a catalyst, the concentration of the chemicals and the curing conditions were varied. The weight percentage gain (WPG), bulking and anti-swelling efficiency (ASE) after leaching in water were used to evaluate the success of modification. Optimal results were achieved with a curing temperature of 160 °C. Without the addition of PEG, the WPG and bulking values were lower. The use of sodium hypophosphite monohydrate (SHP) as a catalyst had a positive effect only on the combination of BTCA/PEG400. Variations of concentrations usually had a higher impact on WPG and bulking than on ASE. The combination of MA/PEG 400 generally showed lower values. Full article

Materials derived from renewable and recycled resources offer a promising route toward more sustainable thermoset composites. In this study, waste poly(ethylene terephthalate) (PET) was depolymerized by glycolysis with propylene glycol to obtain a glycolysate, and subsequently polycondensed with biobased propylene glycol, maleic anhydride, and trimethylolpropane diallyl ether to synthesize biobased UV-curable unsaturated polyester resin (UV-bUPR). The composites were prepared with acryloyl-modified Kraft lignin (K_rL-A) as a reactive bio-filler using a dual-curing approach, in which rapid UV curing was followed by thermal/redox post-curing to improve conversion and network homogeneity. The structure of the synthesized resin and composites was confirmed by FTIR and NMR spectroscopy. Mechanical properties were evaluated by tensile testing and hardness measurements, while morphology and fracture behavior were analyzed by scanning electron microscopy. The unmodified lignin decreased tensile performance due to limited compatibility with the polyester matrix and the formation of interfacial defects and agglomerates. In contrast, K_rL-A exhibited improved dispersion and stronger filler–matrix interactions, resulting in superior mechanical performance. The most pronounced effect of lignin modification was observed at 15 wt.% filler loading, where the tensile strength reached 27.83 MPa, compared with 13.91 MPa for the corresponding unmodified system. The developed composites also showed improved sustainability, assessed through the E-factor, due to the combined use of recycled PET and renewable lignin. Full article

Background/Objectives: Bone-targeted drug delivery systems hold great promise for treating skeletal diseases, yet the optimal strategy for functionalizing lipid nanoparticles (LNPs) with bone-homing ligands remains insufficiently explored. Herein, we compared two alendronate sodium (Alen) modification approaches (pre-conjugation and post-conjugation) for constructing bone-targeted LNPs capable of delivering mRNA to skeletal tissues. Methods: LNPs were fabricated via microfluidic mixing, and the 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol-alendronate conjugate (DSPE-PEG-Alen) required for the pre-conjugation method was synthesized. The bone-targeting ability of LNPs prepared by the two Alen modification strategies was evaluated using an in vitro hydroxyapatite (HAP) binding assay. Furthermore, the physicochemical properties, bone-targeting performance, mRNA delivery efficiency, and biosafety of the LNPs prepared by the post-conjugation method were assessed through cellular uptake, in vivo imaging, and other methods. Results: Hydroxyapatite binding assays revealed that the post-conjugation strategy afforded significantly superior bone affinity compared to the pre-conjugation approach. In addition, ex vivo bone fragment binding experiments further confirmed that the bone-targeting LNPs prepared by the post-conjugation method exhibited stronger bone-binding capability compared to unmodified LNPs. The optimized Alen-LNPs demonstrated efficient cellular uptake and functional mRNA translation in bone marrow mesenchymal stem cells with negligible cytotoxicity. In vivo studies in mice confirmed the preferential accumulation of Alen-LNPs in bone tissues, with successful green fluorescent protein (GFP) mRNA translation detected in bone tissue sections. Histopathological analysis confirmed the biosafety of the formulation. Conclusions: This study establishes the post-conjugation strategy as the superior approach for Alen functionalization of LNPs, providing a robust and reproducible platform for bone-targeted mRNA therapeutics. Full article

Calcium peroxide nanoparticles (CaO₂ NPs) have recently attracted increasing attention as oxygen-generating nanomaterials with potential biomedical applications. Their ability to release molecular oxygen and reactive oxygen species (ROS) in aqueous environments enables modulation of hypoxic and oxidative microenvironments, which play critical roles in infection control, tumor progression, and tissue regeneration. Despite growing interest in oxygen-releasing biomaterials, the literature specifically addressing CaO₂ nanomaterials remains comparatively limited and fragmented, particularly when compared with the extensive body of work on calcium oxide-based systems. This review provides a comprehensive overview of CaO₂ nanoparticles, focusing on synthesis strategies, physicochemical properties, and emerging biomedical applications. Conventional bottom-up synthesis routes based on calcium salts, calcium hydroxide, and calcium oxide are critically compared, highlighting the influence of reaction parameters and stabilizing agents on particle size, morphology, crystallinity, and colloidal stability. Surface modification strategies, including polyethylene glycol, polyvinylpyrrolidone, and hyaluronic acid, are also discussed for their role in improving nanoparticle stability, regulating decomposition kinetics, and enhancing biocompatibility. The mechanisms governing oxygen and ROS generation are analysed in relation to antibacterial activity, hypoxia alleviation in tumor microenvironments, and oxygen-supplying biomaterials for tissue engineering and wound healing. In addition, key challenges associated with oxidative stress responses are discussed. Finally, the review outlines current limitations and perspectives regarding the clinical translation of CaO₂-based nanotherapeutic systems. Overall, this work aims to consolidate the currently dispersed knowledge on CaO₂ nanoparticles and provide a critical framework to guide future research in oxygen-releasing nanomedicine. Full article

Zeolitic imidazolate framework-8 (ZIF-8) is one of the most extensively studied metal–organic frameworks due to its high surface area, tunable porosity, chemical stability, and intrinsic antimicrobial activity. Recent research has focused on engineering ZIF-8 through metal doping and surface functionalization to enhance its physicochemical performance and expand its applications in food safety and environmental systems. Metal-doped ZIF-8 incorporating Cu²⁺, Fe²⁺/Fe³⁺, Ag⁺, or Mn²⁺ improves reactive oxygen species generation, enables controlled metal-ion release, and promotes synergistic bactericidal mechanisms against both Gram-positive and Gram-negative pathogens. In parallel, surface modification using biopolymers such as hyaluronic acid, chitosan, alginate, and polyethylene glycol enhances colloidal stability, reduces cytotoxicity, modulates surface charge, and improves adhesion to food-contact surfaces, thereby enhancing coating stability and sustained antimicrobial activity. These combined strategies support the development of multifunctional nanoplatforms with improved dispersibility, controlled release behavior, and compatibility with food packaging, sanitization, and water treatment applications. From a sustainability perspective, ZIF-8-based systems offer the potential to reduce reliance on conventional chemical disinfectants, minimize chemical residues, and enable the integration of biodegradable polymer matrices for safer and more environmentally responsible antimicrobial solutions. This review summarizes recent advances in synthesis strategies, structure–property relationships, antimicrobial and antibiofilm mechanisms, and environmental safety considerations. Key challenges, including scalability, regulatory acceptance, stability, and long-term ecotoxicological impact, are discussed, along with perspectives on stimuli-responsive systems, essential oil encapsulation, and smart antimicrobial coatings. Full article