Journal of Polymers and the Environment最新文献

Supramolecular crystalline structures were developed in films prepared from blends of a bio-based waterborne polyurethane (WBPU) based on castor oil/tartaric acid (CO-TA) with two different WBPUs synthesized from polycaprolactone diol (PCL) and dimethylol-propionic acid (PCL-DMPA) or TA (PCL-TA). Partial crystallization of the PCL segments generated topologies that strongly affected the final properties of the films. Depending on the internal emulsifier used in the synthesis of the PCL-based WBPUs and its proportion in the blend, the crystalline structures differed, resulting in lamellar, dendritic, or fiber-like networks. Several techniques were employed in the study: differential scanning calorimetry (DSC) to investigate the crystallization kinetics of the blends; optical and confocal microscopies to identify the topologies; positron annihilation lifetime spectroscopy (PALS) to correlate crystallinity with the mean nanohole volume, and dynamic mechanical analysis (DMA) to characterize the mechanical properties of the films. The crosslinked network from the CO-TA based WBPU and the microphase separation in the blends led to constrained crystal growth, resulting in distinct topologies. The work presents a novel approach to generate supramolecular structures, which had a positive effect on the films properties. The relationship between crystallinity and free volume, as measured by PALS, is also analyzed in terms of chain mobility.

Graphical Abstract

Polyesters and thermoplastic polyurethanes (TPUs) based on polyesters, as biodegradable and eco-friendly synthetic polymers, were the focus of research in recent years with promising for results for tissue engineering (TE) applications. Among the commercially available polyesters, the potential of the semi-crystalline poly (butylene succinate) (PBS) as polyols was not explored in depth. In this regard, we synthesized a PBS-diol oligomer through esterification between butylene glycol and succinic acid; the oligomer was characterized using NMR analysis. It was subsequently used as polyol for the catalyst- free synthesis of TPUs using hexamethylene diisocyanate (HDI). The FTIR results revealed successful completion of prepolymerization reaction after 2 h in the absence of toxic tin- based catalyst. The TPUs possessed high elastic modulus ((:E)) due to high PBS crystallinity. Incorporating CeO₂ nanoparticles, as an antioxidant, into the TPU with HDI: PBS-diol molar ratio of 4:1 resulted in an unprecedented rise in (:E) from 49.0 to 186.5 MPa once 0.25 wt% CeO₂ was used due to its ideal dispersion and its possible role as a nucleating agent. CeO₂ increased PBS crystallites’ thermal stability through disrupting hard domains and acting as a nucleating agent for soft segment. MTT results of the nanocomposites also revealed promising results.

Hepatic cancer remains one of the most difficult conditions to cure, particularly when it comes to detecting and eliminating malignant metastases. To overcome hepatic cancer, various strategies have been implemented in respect to targetability and safety concern. In this study, the anticancer agent quercetin (QU) was effectively encapsulated with biocompatible polymer chitosan (CS)-hyaluronic acid (HA) to improve its poor water solubility as well as dual targetability. The resulting QU-loaded nanoparticles (QU-NPs) were formulated using CS, and HA were employed as a capping and targeting agent, and lactoferrin was added to improve drug bioavailability and targetability as well. The synthesized NPs were characterized using zeta potential analysis, particle size analysis, HR-TEM spectroscopy. The in vitro safety of QCHL-NPs was confirmed through toxicity assays on HepG2 cells. In vitro cytotoxicity data showed that QCHL-NPs required significantly lower concentrations than free QU to achieve significant inhibition 50% (IC₅₀ − 10µM in 24 h and 1 µM in 48 h) of proliferation of HepG2 Cells (p < 0.01). In vivo animal study treatment with QCHL-NPs also significantly reduced antioxidant levels like TBARs (p < 0.01) and PC (p < 0.01) levels, while treatment with QCHL-NPs by increase caspase-3 (p < 0.001) analysis revealed apoptosis at the molecular level. Notably, this study successfully was synthesized QU-loaded CS nanoparticles with enhanced QU loading. The final formulation, Lf-coated, HA-capped CS NPs loaded with QU (QCHL-NPs), showed the dual targetability and antitumor efficacy compared to free QU.

This study posed the fabrication and evaluation of a novel antibacterial material composed of HKUST-1(a copper-based metal–organic framework, MOF) incorporated into a chitosan (CS) dried hydrogel disc. The CS/HKUST-1 dried hydrogel disc was synthesized using varying copper ion (Cu²⁺): trimesic acid (TMA) and CS: HKUST-1 weight ratios to optimize antimicrobial efficacy against a broad spectrum of pathogenic microorganisms. The prepared dried hydrogel disc was characterized and compared with a pure CS dried hydrogel disc. Results demonstrated homogeneous dispersion of HKUST-1 crystals within the CS dried hydrogel matrix, with the BET surface area increasing from 9.5 m²/g (pure CS dried hydrogel) to 69.8 m²/g for CS/HKUST-1. The Fourier-transform infrared spectroscopy (FT-IR) confirmed the incorporation of HKUST-1 crystal within the CS dried hydrogel matrix, and the X-ray diffraction (XRD) analysis shows an increase in crystallinity upon increasing the HKUST-1 ratio in comparison with the pure CS dried hydrogel disc. The synthesized CS/HKUST-1 dried hydrogel disc showed antibacterial activity against both Gram-positive (Staphylococcus aureus, Enterococcus faecalis), Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), and the fungal strain Candida albicans. As expected the CS/HKUST-1 dried hydrogel disc with a Cu²⁺:TMA ratio of 2:1 and a CS: HKUST-1 ratio of 10:10 exhibited the most potent antimicrobial activity. The CS/HKUST-1 dried hydrogel disc exhibited the slow release of copper ions. Notably, this dried hydrogel disc demonstrated strong antimicrobial performance, represented by the low values for both the minimum inhibition concentration (MIC) and the minimum bactericidal concentration (MBC). The enhanced antimicrobial performance is attributed to the synergistic interaction between the biopolymeric matrix and the porous MOF structure, which facilitates sustained Cu²⁺ release and effective disruption of microbial membrane. Overall, these findings highlight the potential of CS/HKUST-1 dried hydrogel discs as promising candidates for advanced antimicrobial materials in biomedical applications.

In this study, we incorporated Astragalus polysaccharide (APS) and MXene (Ti₃C₂T_x) into regenerated silk fibroin (RSF) to fabricate three-dimensional porous scaffolds via freeze-drying. By systematically varying the APS content while keeping the MXene content constant, we achieved enhanced mechanical properties and multifunctionality. The swelling ratio, hydrophilicity, and protein adsorption of the composite scaffolds increased with APS content, while porosity decreased. APS incorporation promoted β-sheet formation, and MXene imparted photothermal properties, enabling a temperature rise to 47 °C under 640–660 nm irradiation for 12 min. The composite scaffolds also showed high antioxidant activity (93% DPPH scavenging) and excellent hemocompatibility (< 2% hemolysis). Compared to the RSF scaffold, the composite scaffolds exhibited a 3.36-fold increase in compressive modulus (6.93 MPa) and a 1.96-fold increase in compressive strength (4.04 MPa) at an APS/RSF mass ratio of 0.2:1. In vitro studies revealed that optimal APS concentrations significantly enhanced biocompatibility by promoting the proliferation and migration of MC3T3-E1 and endothelial cells. For MC3T3-E1 cells, the optimal APS/RSF mass ratio was 0.16:1, while for endothelial cells, it was 0.2:1. Overall, this study demonstrates the potential of APS and MXene incorporation into RSF scaffolds for enhanced tissue engineering applications.

Polylactic acid (PLA) is widely used in additive manufacturing but suffers from low toughness, poor hydrolytic stability, and limited corrosion resistance, restricting its long-term use in marine or humid environments. This study aims to overcome these limitations by investigating the combined effects of printing orientation and PU/CNT nanocomposite coating on the mechanical durability and shape memory performance of 3D-printed PLA exposed to a 3.5 wt% NaCl solution, simulating marine conditions. PLA specimens with raster angles of 0°, 45°, and 90° were fabricated by fused deposition modeling (FDM) and coated with a polyurethane/carbon nanotube (PU/CNT) composite to enhance interlayer strength and environmental resistance. The PU/CNT coating effectively mitigated saline-induced degradation, improving tensile, impact, and flexural strength by up to 28% and maintaining over 80% of the initial strength after 21 days of immersion. Moreover, the coated PLA exhibited a shape recovery ratio of ~ 91%, compared to 82% for uncoated samples, confirming improved functional stability. These findings demonstrate that PU/CNT coatings successfully address the key mechanical and environmental limitations of PLA, providing a viable route for the reliable use of PLA-based composites in marine engineering, adaptive smart structures, and biodegradable biomedical sensors.

Researchers have been attentive in modifying the inherent properties of biopolymers by incorporating nanocarrier schemes, involving metal nanoparticles into the matrix to achieve higher potentials. Herein, fabricated in situ generation of silver nanocomposites (AgNC) NC1, NC3, and NC5 using different concentrations of AgNPs using vegetal carboxy methyl chitosan (CMCs) and Curcuma longa debranched starch, which facilitated the formation of AgNC films. UV–visible spectroscopy revealed surface plasmon resonance peaks at 413, 404, and 403 nm for NC1, NC3, and NC5, respectively, confirming the formation of AgNPs. XRD analysis demonstrated characteristic silver peaks at 2θ = 31.94°, 37.82°, and 45.92°, indexed to the (101), (111), and (200) planes, respectively and showed the plane of face-centered cubic Ag. AFM revealed that the average roughness (Ra) increased from 3.29 nm in NC0 to 42.33 nm in NC5. SEM-EDX revealed a rough surface and successful incorporation of Ag (up to 3.14 wt% in NC5), while TEM confirmed spherical AgNPs morphology with an average particle size of 24.42 ± 9.04 nm. XPS analysis further verified the presence of Ag, C, O, and N with high-resolution peaks matching Ag and Cs elemental states. TGA showed improvements in thermal stability: NC5 exhibited lower weight loss (8.61% between 326 and 600 °C) than NC0 (16.70%). The microbial efficacy was evaluated against Gram-positive, Gram-negative bacteria, and fungi. The NC5 films exhibited significant inhibition zones against S. aureus (6–9 mm), E. coli (8–10 mm), and Candida albicans (6–9 mm). MIC values for NC5 ranged from 0.025 to 0.2 cm²/mL for all the tested pathogens. The NC5 film reduced S. aureus biofilm cell counts from 10,747 ± 592 (control) to 4,416 ± 348, with biofilm cell viability decreasing from > 98% to 45–55%. In vitro release studies of Ag ions were performed at 37 °C for 36 h. Due to its improved performance, the fabricated nanocomposite films could be suitable for active food packaging, reducing environmental impacts and ensuring food safety, and should be converted into nanomedicine to meet future biomedical requirements.

This study focuses on the novel investigation of the individual and combined effects of fucoidan, ulvan, and carrageenan on growth parameters, immune responses, and digestive and antioxidant enzyme activities in common carp, emphasizing the simultaneous use of these three polysaccharides. A total of 405 common carp (50.27 ± 1.39 g) were divided into nine treatment groups: control (CTRL); fucoidan (F 0.5% and 1%); ulvan (U 0.5% and 1%); carrageenan (K 0.5% and 1%); and a combination of all three (FUK 0.5% and 1%). The results indicated that the F1, U1, K1 FUK0.5 and FUK 1% treatment significantly enhanced final weight, weight gain and specific growth rates while decreasing the feed conversion ratio compared to CTRL. Sulfated polysaccharides did not significantly affect hemoglobin and hematocrit levels; however, only the FUK1% group showed a significant increase in white and red blood cell counts compared to the CTRL. Immune parameters, including serum C3, serum and mucus lysozyme, and immunoglobulin levels, increased notably across various treatments. Expression of IL-1β decreased significantly in the F, U, K, and FUK 1% groups, while IL-10 expression increased in all treated groups. Digestive enzymes such as α-amylase, lipase, and trypsin showed remarkable increases in most treatments compared to the CTRL. Additionally, serum antioxidant parameters, including superoxide dismutase (all doses except F 0.5%, U 0.5%, and K 0.5%) and catalase (all doses except U 0.5% and K 0.5%), showed significant increases relative to the CTRL. Overall, these sulfated polysaccharides, especially FUK 0.5% and FUK 1%, positively influenced growth, immune function, digestive efficiency, and antioxidant activity in common carp.

Mucosal drug delivery offers an attractive approach for localized and systemic therapy while bypassing first-pass metabolism; however, its success is often hindered by poor drug permeability, rapid clearance, and low bioavailability. In this study, we developed a sustainable cannabidiol (CBD)-loaded nanocarrier system based on poly(D, L-lactide-co-glycolide) (PLGA) nanoparticles surface-modified with chitosan (CS), a renewable biopolymer, to enhance mucosal and neurodegenerative therapeutic performance. CS-coated PLGA nanoparticles (50–2000 µg/mL) exhibited increased particle size, a positive surface charge, and improved hydrophilicity, enabling stronger mucoadhesive interactions and storage stability for at least six months. Although CS modification slightly reduced encapsulation efficiency and drug loading, it markedly improved sustained and controlled CBD release by reducing burst effects and prolonging drug retention, consistent with first-order and Higuchi kinetics. Enhanced mucoadhesion was confirmed through stronger electrostatic interactions with mucin and improved rheological behaviour, promoting longer mucosal residence time and greater bioavailability. All formulations were highly biocompatible in HT-29 cells and exhibited significant anti-inflammatory activity, with CS-modified systems showing superior nitric oxide inhibition. Remarkably, CS-modified PLGA-CBD nanoparticles demonstrated potent, dose-dependent anti-amyloidogenic activity, outperforming curcumin at low to moderate concentrations, highlighting their promise as multifunctional, environmentally responsible nanocarriers for mucosal drug delivery and neuroinflammatory disease management.

Graphical Abstract