Journal of Polymers and the Environment最新文献

Chronic wound infections, especially those involving antibiotic-resistant bacteria, pose a serious clinical challenge and demand the development of advanced wound dressings that not only offer strong antimicrobial properties but also promote effective wound healing. In this study, we present the development of innovative carboxymethyl chitosan hydrogels crosslinked with methacrylated bio-ionic liquids using a photo-induced crosslinking method. The hydrogels were designed by methacrylating O-carboxymethyl chitosan, followed by crosslinking with a series of biocompatible, anion-exchanged choline-based ionic liquids. FTIR and NMR analyses confirmed the successful functionalization and effective crosslinking of the hydrogel structure. All modified polymers were further analysed using X-ray diffraction (XRD) to assess their crystallinity, thermogravimetric analysis (TGA) to evaluate thermal stability, and scanning electron microscopy (SEM) to examine surface morphology. Antibacterial assays revealed superior activity, with choline benzoate derivatives outperforming gentamicin against E. coli. Cytocompatibility assessments demonstrated that O-carboxymethyl chitosan coupled with choline acetate (CMCh-Ac) and O-carboxymethyl chitosan coupled with choline propionate (CMCh-Prop) maintained approximately 90% cell viability in normal cells. In contrast, O-carboxymethyl chitosan (O-CMCh) and O-carboxymethyl chitosan coupled with choline succinate (CMCh-Su) displayed potent anticancer activity by markedly decreasing the viability of HEPG-2 cancer cells. In vivo, wound contraction reached 100% by day 8 for treated groups vs. 47.1% in controls, highlighting excellent healing potential. These findings underscore the dual functionality of the synthesized hydrogels as potent antibacterial agents and enhancers of tissue regeneration, offering a promising platform for advanced wound care against complex, drug-resistant infections.

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With the global agricultural sector facing major challenges including; drought, water runoff, and fertiliser loss, the growing demand for sustainable practices has intensified. As a result, superabsorbent polymers (SAPs) have garnered attention due to their ability to improve soil water retention and the controlled, slow-release of nutrient molecules. This study explores the synthesis and characterisation of semi-synthetic chitin-based SAPs derived from shellfish waste, offering an eco-friendly alternative to conventional synthetic SAPs. Two SAP variants were synthesised: one without urea (SCNU) and the other incorporating urea (SCU) to enhance solubility and performance. The chemical structure, absorption kinetics, and urea slow-release behaviour were analysed using Fourier-transform infrared (FTIR) spectroscopy, zeta potential measurements, and UV/Vis spectrophotometry. Results revealed that the urea-based SAP (SCU) exhibited superior water absorption and swelling capacity, reaching a maximum absorption capacity of 355 g/g compared to 155 g/g for SCNU SAP. Both SAPs exhibited good biodegradability within just 7 days, highlighting their environmental benefit. We also investigated the SAPs’ surface charge behaviour across a range of pH values by measuring zeta potential, which provided insight into their water absorption capacity in varying environmental conditions. Absorption experiments supported the trends observed in the zeta potential analysis. As pH increases, the surface charge becomes more negative, which enhances electrostatic repulsion between polymer chains and results in greater water absorption. Desorption studies showed sustained water release over 14 days, indicating potential to reduce irrigation frequency. Post-synthetic urea loading confirmed the SAPs’ slow-release fertiliser capability. Incorporation of indole butyric acid (IBA) further enhanced plant growth, demonstrating the SAPs’ dual function in moisture retention and nutrient delivery.

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The delivery of chemotherapeutic agents to bone tumors is a hindered by limited bone bioavailability and a dense extracellular matrix. Recent research has focused on targeted anticancer drug delivery to bone-tumor sites using various polymeric nanomicelles. In this study, hyaluronic acid-based polymeric nanomicelles, functionalized with the bone-targeting ligand sodium alendronate, were developed for the targeted treatment of metastatic bone cancers. The successful synthesis of polymer was confirmed using ¹HNMR and FTIR spectroscopy. The synthesized polymer exhibited a low critical micelle concentration (CMC) of 19.3 µg/ml, indicating its robust ability to form and maintain stable nanomicelles in biological media. Dynamic light scattering (DLS) analysis revealed an average nanomicelle size of 129 nm, and field-emission scanning electron microscopy (FESEM) confirmed their spherical morphology. Curcumin (CUR) was selected as the anticancer therapeutic compound and encapsulated within the hydrophobic core of the nanomicelles, achieving a high drug loading capacity of 9.8%. A sustained in vitro release profile of CUR was observed over 100 h. The in vitro affinity of the nanomicelles for hydroxyapatite was determined to be 77.5%. Cytotoxicity and hemolysis assays demonstrated that the nanomicelles exhibited no significant toxicity towards fibroblast cells or red blood cells. The IC50 values, determined by MTT assay on MDA-MB-231 cell Lines after 24 h of incubation, were 72.1 µg/mL for the drug-loaded nanomicelles and 110.3 µg/mL for free CUR. These findings suggest that these bone-targeted polymeric nanomicelles hold promise as a potential therapeutic strategy for bone cancer metastasis.

Poly(ε-caprolactone) (PCL) scaffolds face dual challenges of insufficient mechanical strength and poor bioactivity. To address these limitations, multi-walled carbon nanotubes (MWCNTs) modified with sodium dodecylbenzene sulfonate (SDBS) were introduced into the PCL matrix as reinforcing phases. Triply periodic minimal surface (TPMS) structured PCL/SDBS-modified MWCNTs (S-MWCNTs) composite scaffolds were fabricated using selective laser sintering (SLS) technology. The experimental results show that SDBS can effectively improve the agglomeration of MWCNTs through electrostatic repulsion. The ultimate tensile strength of the composite scaffold containing 0.75 wt% S-modified MWCNTs reached 11.08 MPa, representing a 269.33% increase compared to that of the PCL scaffold (3 MPa), primarily due to the bridging and pull-out effects of MWCNTs. Additionally, compared to the unmodified 0.75 wt% MWCNTs composite scaffold, the tensile strength was further improved by 52.33%, which is attributed to the more uniform dispersion of MWCNTs after SDBS modification. In addition, the composite scaffold exhibited enhanced hydrophilicity and demonstrated favorable apatite-forming ability in simulated body fluid (SBF). Cytocompatibility experiments (live/dead staining) further confirmed their favorable bioactivity and cell compatibility. These results demonstrate that the S-MWCNTs reinforced PCL composite scaffold exhibits enhanced mechanical properties and bioactivity, indicating its potential as a candidate material for bone tissue engineering applications.

Chronic wounds and their associated infections pose a considerable challenge in clinical practice, often resulting in prolonged healing and increased healthcare costs. Berberine (BBR), a bioactive plant-derived alkaloid, exhibits a broad spectrum of pharmacological activities, including antimicrobial and anti-inflammatory effects. This study aimed to develop a bacterial nanocellulose (BNC) scaffold incorporated with BBR to systematically evaluate its antimicrobial efficacy and wound healing potential. The BNC-BBR composite scaffold was fabricated via a conventional freeze-drying method and thoroughly characterized using fourier infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). Antimicrobial activity was quantitatively assessed through colony count assays against key pathogens. An in vivo wound healing model involving a standardized 1 × 1 cm full-thickness cutaneous wound on the dorsum of rats was employed, with scaffold application sustained over a 21-day period. Antimicrobial activity was assessed through colony count assays. The 1 × 1 cm cutaneous wound model was created on the back of rats and the scaffolds were applied over the wounds, for 21 days. SEM analysis confirmed a homogeneous and porous scaffold architecture. The BNC-BBR scaffold demonstrated potent antimicrobial activity, achieving inhibition rates of 99.97% against Escherichia coli and 100% against Candida albicans. Histological analysis revealed that the BNC-BBR scaffold significantly promoted angiogenesis and fibroblast proliferation compared to the injured untreated animals (negative control) on day 7 post-wounding. Besides, the BNC-BBR scaffold significantly reduced inflammation on day 7 compared to the injured untreated animals. These findings indicate that the BNC scaffold loaded with Berberine accelerates cutaneous wound healing and exhibits strong antibacterial properties under in vitro conditions. This multifunctional scaffold thus represents a promising candidate for the development of advanced wound dressings with enhanced therapeutic efficacy.

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The present work is devoted to the search for new bacterial species capable for hydrolysis of industrial polymeric materials containing aromatic monomers such as: polyethylene terephthalate (PET), polystyrene (PS), and polyurethane (PUR). Methods for obtaining agar media with PET-, PS-, and PUR-nanoparticles were developed for bacterial screening. As a result, new species of Streptomyces hydrolyzing all three types of plastic were found. The selected bacteria were capable for production of various hydrolases with different substrate selectivity towards polymeric compounds such as: olive oil, Tween 20, Tween 80, polycaprolactone (PCL), PET, PS, and PUR. At the same time, enzymes that hydrolyzed industrial plastics differed in induction time and substrate selectivity from the other hydrolases produced by the same bacteria. It was shown that only Tween 80 from all tested polymers of natural and artificial origin increased the hydrolase activity of bacteria towards PET-, PS-, and PUR-nanoparticles during solid-state cultivation. Universal primers have been developed based on all known genes encoding enzymes with PETase-like activity. The primers have been used to demonstrate the presence of PETase-like genes in the genomes of the selected streptomycetes. Phylogenetic analysis of the obtained nucleotide sequences confirms that they belong to the genes encoding enzymes with PETase activity. The presence of PETase-like hydrolase genes in the genomes of the new streptomycetes, along with the wide distribution of streptomycetes in soil, water resources, on plants and animals makes them a promising source of new hydrolases degrading industrial plastic.

In response to the growing demand for biodegradable and functional materials, this study introduces a novel luminescent additive based on benzoxazine for enhancing the performance of poly(lactic acid) nonwoven fabrics. A hydroxyl-functionalized benzoxazine monomer, 3,4-dihydro-6-ethyl-3-(6’-hydroxylhexyl)-2 H-benzoxazine (HEn), was synthesized via a Mannich reaction and used as an initiator for the ring opening polymerization of ε-caprolactone to yield benzoxazine-terminated poly(caprolactone) (HPCL). The resulting HPCL exhibited a molecular weight of ~ 4000 g/mol and luminescent properties. HPCL was compounded with PLA to prepare a masterbatch (MHPCL), which was further processed via the melt-blown technique to fabricate PLA/MHPCL nonwoven fabrics at various loadings (5–20 phr). Comprehensive morphological analysis revealed that MHPCL incorporation significantly reduced fiber diameter (up to 60%) and increased density and entangled fiber network, thereby enhancing mechanical strength. The breaking force of the nonwoven fabric increased nearly threefold at 20 phr of MHPCL. Optical characterization confirmed preserved luminescent functionality in the fabrics, although the emission was non-uniform. Thermal analysis indicated reduced crystallinity and thermal stability, while accelerated weathering tests showed enhanced degradability attributed to the presence of HPCL. This study demonstrates the feasibility of using functionalized benzoxazine-terminated PCL to improve both the mechanical and luminescent properties of PLA nonwoven fabrics, thereby supporting the development of eco-friendly functional materials with strong potential for applications in biodegradable smart textiles, filtration, and packaging industries.

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Polyglycolic acid (PGA) is recognized as a highly promising biodegradable polyester, with its production scale gradually expanding. However, its inherent brittleness and low toughness significantly limit its potential applications. The present study aims to explore the reactive blending of PGA and poly(butylene adipate-co-terephthalate) (PBAT) with a multi-epoxy resin (styrene-methyl methacrylate-glycidoxy methyl methacrylate terpolymer, ADR) as compatibilizer, in order to address these limitations while maintaining degradability. The terminal hydroxyl and carboxyl groups of PBAT and PGA reacted in situ with ADR’s epoxy groups, thereby facilitating the formation of PGA-g-ADR-g-PBAT copolymers. The particle size of PBAT in PGA/PBAT/ADR blend has been reduced from 1.59 μm to 0.41 μm, indicating an improved compatibility between PGA and PBAT. The PGA/PBAT/ADR blend demonstrated high elongation at break of 185% and a notched impact strength of 15.0 kJ/m², with respective increments of 2500% and 780%. The research has presented a viable pathway for the modification of PGA, highlighting its potential applications in the domains of medical devices and food packaging.

The development of multifunctional biocomposite scaffolds based on polycaprolactone (PCL) and polyglycerol azelaic acid (PGAZ) matrices has been and continues to be essential for enhancing bone regeneration. The porous scaffolds in this study are fabricated through salt-leaching and are functionalized by polyethylene glycol (PEG1000) and/or barium titanate (BaTiO₃) nanoparticles to improve hydrophilicity and bioactivity. The copolymer interactions and structural modifications are confirmed through Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses, while scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) analyses reveal optimal porosity and surface area in scaffold S4 composed of PCL/PGAZ (70/30 wt%) with 40 wt% PEG and 3 wt% BaTiO₃ (PCL/PGAZ-PEG1000/ BaTiO₃) (mean pore size: 156.9 µm, surface area: 24.38 m²/g, total pore volume: 0.2558 cm³/g). The in vitro assessments demonstrate that S4 loaded with dexamethasone (S4-D) reaches the highest cell proliferation in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay (p < 0.001), enhances infiltration by hematoxylin and eosin (H&E) staining, with calcium deposition in Alizarin Red Staining (ARS) at day 21. The results of reverse transcription polymerase chain reaction (Real-time RT-PCR) indicate a significant upregulation of osteocalcin (OC) (1.509 ± 6.102; p < 0.001) in the S4-D group, while no substantial changes are observed in runt-related transcription factor 2 (h-RUNX2) (2.567 ± 1.346; p = 0.338), type I collagen (COL1A1) (1.569 ± 0.992; p = 0.338), and osteonectin (ON) (2.828 ± 1.620; p = 0.338). Although this article mainly focuses on biological performance, the mechanical properties are evaluated to assure sufficient scaffold strength for bone tissue applications. These findings suggest that the synergistic incorporation of PEG and BaTiO₃ into PGAZ/PCL scaffolds significantly promotes osteogenic differentiation, offering a promising strategy for bone tissue engineering.

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