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In this study, semiconductive poly (lactic acid) (PLA)/carbon nanotube (CNT) nanocomposites have been simultaneously subjected to melt-compounding and foaming using a continuous and single-step extrusion foaming process. The extrusion foaming process with the ability to be developed on an industrial scale is a complex process for a biopolymer in the presence of nanoparticles, chemical foaming agent, and chain extender, and to control it, knowledge about the phenomena occurring during the process and the structural properties of the foam is required. Although the extrusion foaming of PLA has been studied before, the simultaneous effects of chain extender content and nanoparticle loading on the microstructure and phenomena during the PLA extrusion foaming process have not been thoroughly investigated. The results of this study show that the two investigated variables have a strong interaction with each other. Increasing the chain extender content has led to a change in the rheological properties of the melt, as a result, it has been significantly effective in the nanoparticle dispersion state. Besides, the loading of nanoparticles has a powerful effect on the intensity of the chain extension reaction of PLA chains by the chain extender additive. The lightest extruded foams (with a void fraction of 0.52) with the highest cell density (5 × 106 cells/cm3), the smallest cell size (about 50 and 200 µm for number- and volume-average cell diameters), and the most uniform cell size distribution have been obtained in the middle values of the chain extender content (5 phr) and the lowest values of the nanoparticle loading (0.25 phr). [ABSTRACT FROM AUTHOR]

The importance of biopolymer-based nanocomposites in food packaging is growing significantly. Therefore, in the present study, we aim to examine the impact of zinc oxide (ZnO), polyhedral oligomeric silsesquioxanes (POSS), and, for the first time, their hybrid on polycaprolactone (PCL) nanocomposites. For this matter, different concentrations of 1, 3, and 5 wt% of each nanoparticle and the hybrid were incorporated into the PCL nanocomposites via the solution casting method. Their chemical structures and interactions, crystalline structures, and morphology were investigated by FT-IR, WAXD, and SEM. Moreover, it was observed through contact angle and surface free energy experiments that an increase in the nanoparticle concentration corresponded to an increase in the contact angle values. The incorporation of hybrid POSS and ZnO equilibrated well between Young's modulus, tensile strength, and elongation of the samples in their single status. Accordingly, the addition of the hybrid nanoparticles up to 3 wt% significantly increased the modulus and yield strength of PCL nanocomposites without any significant sacrifice in toughness. Also, PPZ3 (containing an optimal 3%wt. of hybrid nanoparticles) demonstrated the lowest permeability against both water vapor and O2 gas, exhibiting reductions of approximately 30 and 55% when compared to pristine PCL. Finally, the antibacterial properties of the nanocomposite films were investigated for S. aureus and E. coli bacteria and revealed. In addition to the antibacterial properties of ZnO and POSS nanoparticles, increasing the concentration of hybrid nanoparticles up to 5 wt% expanded S. aureus's inhibitory zone. The balanced mechanical, and barrier characteristics, enhanced morphologies, and antibacterial effects of the novel hybrid nanocomposites present novel opportunities in the field of food packaging. [ABSTRACT FROM AUTHOR]

Regenerative medicine through the application of tissue engineering and cell transplantation has provided a new door for wound healing. In this study, the healing effect of human Wharton's jelly stem cells (WJSCs) labeled with superparamagnetic iron oxide nanoparticles (SPIONs) seeded onto polyvinyl alcohol/chitosan/carbon nanotubes (PVA/CS/CNTs) in burn wounds was investigated by performing magnetic resonance imaging (MRI) and Prussian blue staining. Human WJSCs were prepared from umbilical cord and characterized. PVA/CS/CNTs were fabricated via electrospinning. Forty-eight rats were divided into four groups. The control group underwent a third-degree burn injury and was left untreated. The second group received silver sulfadiazine after burn induction, the third group was treated with PVA/CS/CNTs after burn wounds, and the fourth group received WJSCs labeled with SPIONs seeded onto PVA/CS/CNTs following burn injury. Tensile strength was investigated, real-time polymerase chain reaction was used to evaluate apoptosis, and Prussian blue staining and MRI were performed to trace labeled cells. The mesenchymal properties of WJSCs were characterized. Histologically, healing was observed as complete granulation occurred and epithelial tissues were formed in the absence of inflammatory cells, with increased expression of Bcl-2 and a decrease in Bax genes in the fourth group. Internalization of SPIONs within WJSCs was confirmed by Prussian blue staining and MRI on day 14. WJSCs labeled with SPIONs seeded onto PVA/CS/CNTs could successfully participate in the healing of burn wounds and could be easily tracked by MRI as a noninvasive method, providing a new door in regenerative medicine for burn wounds., (© 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)