RSC Applied Polymers最新文献

Current antioxidant therapies targeting reactive oxygen species (ROS) are often hindered by limitations in stability, efficacy, dosage tolerance, biocompatibility, or immunogenicity. To address these challenges, we developed a therapeutic platform based on polymer microparticles composed of poly(propanediol-co-(hydroxyphenyl methylene)amino-propanediol sebacate) (PAS), fabricated via a straightforward and scalable co-solvent precipitation method. When chelated with copper(ii) ions, these microparticles (Cu-PASmp) catalytically degrade hydrogen peroxide and protect cells under oxidative stress. Both Cu-PASmp and PASmp demonstrate excellent biocompatibility and elicit no detectable immunogenic response in either M0 or M1 macrophages. Moreover, their presence appears to reduce the need for cells to express superoxide dismutase (SOD1), indicating a decrease in oxidative stress experienced by the cells. Collectively, these results position Cu-PASmp as a promising, catalytic antioxidant platform.

The microenvironment of immune cells is an important regulator of their function and fate. Three-dimensional (3D) culture systems provide opportunities for probing immune cell responses to invading pathogens in microenvironments with biophysical and biochemical properties inspired by human tissues. Yet, the low throughput and manual preparation of many 3D culture models present challenges for translation of assays and their broad and accessible use for studying host-pathogen interactions. To address this, we established a high-throughput macrophage-bacteria co-culture model that mimics lung tissue stiffness across healthy and diseased conditions. Using bioprinting, human THP-1 monocytes were encapsulated and differentiated into macrophages within synthetic extracellular matrices (ECMs) fabricated with well-defined polymer and peptide bioinks in a 96-well plate format. Macrophages retained viability and displayed immunocompetence, including phenotype, phagocytosis, and response to stimuli. Macrophages in fibrosis-inspired 'stiffer' (storage modulus (G') ∼4.8 kPa) microenvironments exhibited higher basal expression of both inflammation and traditional fibrosis associated genes compared to more compliant (G' ∼1.1 kPa) synthetic ECMs inspired by healthy lung microenvironments. We applied our model 3D cultures to study immune response to invasion of a bacterial pathogen implicated in hospital born lung infections and mortality, Pseudomonas aeruginosa. Macrophages exhibited differential responses to P. aeruginosa in stiff microenvironments, with decreased cytokine secretion of IL-6 and IL-1β and elevated IL-10 and TNF-α compared to healthy compliant microenvironments, suggesting that microenvironment properties may shape initial immune responses. This high-throughput, accessible controlled platform provides opportunities for understanding human host-pathogen interactions and a foundation for identifying therapeutic strategies for bacterial infections in well-defined physiologically relevant microenvironments.

Hydrogels are polymer networks that swell in aqueous solvents. These materials have applications in many fields, including drug delivery, tissue engineering, and soft robotics. For example, polyethylene glycol (PEG) diacrylate is often used as a light-curable crosslinker for the synthesis of PEG-based hydrogels, e.g., in bioinks for 3D printing. However, a common limitation of PEG hydrogels is their typically poor mechanical properties, particularly when in a swollen state. The mechanical strength of natural polymeric materials, such as spider silk and collagen, arises from the formation of hierarchical secondary protein structures that unfold under mechanical load. Here, we present a bio-inspired approach to reinforcing PEG-based hydrogels that mimics these hierarchical structures by incorporating poly(β-benzyl-l-aspartate) (PBLA) blocks between cross-linking end groups and PEG chain segments. We used this peptide-containing crosslinker in combination with a small hydrophilic comonomer, 2-hydroxyethyl acrylate, to synthesise PHEA-linked by-(PBLA-b-PEG-b-PBLA) co-networks with tailored compositions, yielding improved and tailorable mechanical properties. This approach affords hydrogels with increased strength and toughness while retaining the networks' swelling ability. This research presents a promising avenue for developing robust photocrosslinkable hydrogels with broad practical applications.

The thermal and viscoelastic performance of polymer blends is decisive for their deployment in advanced engineering and electronic applications. Here, we report a systematic investigation of immiscible poly(trimethylene terephthalate) (PTT)/polypropylene (PP) blends reinforced with multiwalled carbon nanotubes (MWCNTs). While the incorporation of MWCNTs did not markedly alter the thermal degradation profiles, it significantly modified the viscoelastic behavior by inducing a constrained polymer region within the PTT phase. Quantitative analysis of filler dispersion effectiveness, entanglement density, reinforcing efficiency, and constrained volume provides new insights into nanotube–matrix interactions. Rheological results revealed a terminal-to-nonterminal transition with increasing nanotube content, confirming percolated network formation at low filler loadings. These findings establish clear structure–property correlations that extend beyond qualitative descriptions, offering a predictive framework for tailoring immiscible blends through nanofiller engineering. Such insights highlight the potential of PTT/PP/MWCNT systems in functional applications, including lightweight structural components and conductive composites for electronics.

The use of RNA therapeutics provides a potent tool to enhance patient outcomes, but successful RNA delivery requires efficient and safe vectors. Cationic polymers provide one technology platform for this delivery and among these materials, poly(beta-amino esters) (PBAEs) have emerged as efficient and well tolerated vectors. Changing the end group of these materials can have a profound impact on their physical and biological properties, and the development of new pathways for end-group functionalisation can provide access to untapped material libraries for further development. We therefore developed a synthetic pathway that exploits the Passerini 3-component reaction as a means to incorporate aldehyde and isocyanide materials into the end-groups of an acid terminated PBAE. Polyplexes were then prepared and studied for encapsulation efficiencies, formulation properties and gene transfectability in vitro. Select polymers demonstrated high mRNA transfection efficiency in HEK293T cells. Our findings indicate that this synthetic pathway provides a versatile and adaptable pathway for the further modification of PBAEs and that this modification serves to provide new materials with enhanced nucleic acid delivery properties.

The growing demand for flexible and multifunctional sensors has driven the development of functional materials that can simultaneously respond to multiple and diverse stimuli, including mechanical stress and changes in temperature. In this work, we report the development of a multifunctional composite dielectric material combining thermochromic polydiacetylene (PDA) and styrene–ethylene–butylene–styrene (SEBS) for use in flexible capacitive pressure sensors. To further enhance pressure sensitivity, the dielectric layer was patterned with Mesoamerican pyramid (MAP) microstructures, which amplify mechanical deformation and increase effective contact area. It also shows the soft molding fabrication capability of the composite. The composite demonstrates excellent mechanical resilience, maintaining stable capacitance over 10 000 loading cycles at 220 N, and exhibits thermally responsive behavior, with reversible color transitions at 45 °C and irreversible changes at 90 °C. The resulting sensors display reliable performance across a broad dynamic range of pressure and temperature, making them well-suited for applications in wearable electronics, biomedical monitoring, and smart human–machine interfaces. This work highlights the potential of combining structural patterning with functional composites to engineer responsive and robust soft sensing platforms.

The demand for durable and sustainable construction materials has driven significant interest in self-healing techniques for cement-based materials (CBMs). This review focuses on the comprehensive analysis of microcapsule-based self-healing systems, demonstrating their comparative advantages over conventional methods such as groove filling, structural strengthening, grouting and surface coating by enabling autonomous, localized repair of microcracks. Key microcapsule architectures, such as single-core, dual-core and multi-walled types, are examined to explain how their unique structures contribute to enhancing the efficiency and effectiveness of the self-healing process. A critical comparison of existing microcapsule formulations identifies major challenges such as premature leaching, shell instability and poor dispersion, alongside innovative strategies to overcome these issues. The review further explores diverse fabrication techniques and the influence of factors like pH, stirring speed and emulsifier type on microcapsule performance, providing valuable insights for optimized design. It also addresses the evaluation of self-healing efficiency in CBMs through different methods, emphasizing ways to accurately assess healing performance. Current characterization and healing evaluation techniques are evaluated, with recommendations for improving the accuracy and reliability of self-healing assessments. Finally, practical applications, implementation challenges and future prospects are discussed, positioning microcapsule-based self-healing as an emerging avenue to extend the lifespan and resilience of infrastructure while supporting sustainable development goals. This integrative review aims to guide researchers and engineers in advancing next-generation self-healing CBMs for safer and longer-lasting built environments.

The development of highly conductive and stable fluorine-free polymer materials is critical for transitioning from perfluorosulfonic acid-based membranes to non-fluorinated alternatives for proton exchange membrane fuel cells and water electrolyzers. Among these, sulfonated poly(phenylene sulfones) (sPPS) are a promising class of polymers. However, little is known about their stability when used for these applications. To gain deeper insight into the aging mechanisms of sPPS membranes, confocal Raman microscopy was employed as a non-destructive, contact-free technique to determine membrane thickness and local equivalent weight. In this study, two sandwiched sPPS membranes were aged in situ using an accelerated stress test under open-circuit voltage (OCV) conditions in a fuel cell setup. Confocal Raman microscopy revealed that after the OCV-hold test, the combined thickness of sPPS membranes decreased from 27 µm to 15 µm, confirming chemical degradation. 60% of this reduction occurs on the membrane facing the anode side of the cell, indicating localized acceleration of degradation processes near the anode. Notably, despite the observed degradation, the local EW remained unchanged at the end of the test. This hints at a mechanism where chain scission is prevalent over desulfonation. Complementary techniques, nuclear magnetic resonance spectroscopy and gel permeation chromatography, were used on aged polymers to further validate these findings. It was found that despite no clear chemical changes (e.g. the degree of sulfonation or EW), the molecular weight decreased by 50%.

The dynamic thermoregulation of skin is often hindered by traditional clothing, leading to discomfort and skin issues. To address this issue, we developed a humidity-responsive bilayered nanofiber textile, combining hydrophilic polyamide (PA) and superhydrophobic polyvinylidene fluoride/fluorinated polyurethane (PVDF/FPU) via electrospinning, enabling asymmetric hygroscopic bending up to 165.4° at 100% relative humidity (RH). This enhances moisture permeability (12 602 g m⁻² d⁻¹), 2.8 times higher than that of non-windowed textiles. Reversible water adsorption/desorption enables dynamic actuation for improved sweat evaporation and heat dissipation. This smart textile offers promising applications in sportswear and medical dressings, bridging the gap between static fabrics and dynamic physiological needs.

We present a systematic study of thermoplastic polypropylene (PP) composites reinforced with wood fibers (WF) derived from Norway spruce industrial residues (FibraQ) as scalable, sustainable alternatives to conventional polymers. The wood fibers retain a characteristic softwood monosaccharide profile and display robust morphological integrity and uniform dispersion across loadings from 20 to 50 wt%. Mechanical characterization demonstrates a linear increase in tensile modulus and strength with increasing WF content, counterbalanced by reduced ductility and impact toughness due to increasing fiber network density. Thermal analyses confirm enhanced stability and elevated Vicat softening temperatures upon WF addition. Importantly, these composites exhibit outstanding closed-loop mechanical recyclability: after three industrially relevant processing cycles, PPWF retains >90% of initial stiffness and >94% tensile strength, significantly outperforming neat PP and previously reported biocomposite systems. Our study provides the first direct quantitative comparison of recyclability and structural retention for industrially relevant PPWF composites. These advances offer a pathway for integrating renewable residues into high-performance, durable, and circular materials platforms beyond the capabilities of conventional polymers.