In the present work, a bio-derived biopolymer electrolyte based on a neem gum–chitosan (70:30 wt.
Balancing mechanical integrity, optical transparency, and bioactive functionality remains challenging for polymer films containing plant-derived particles. Here, Apocynum venetum extract (AVE) particles were sequentially treated with KH-550 and poly(ε-caprolactone) (PCL) and incorporated into poly(lactic acid) (PLA) films at 5 and 10 wt
Electrospun bio-based polymer mats require simultaneous control of blend composition and processing-induced architecture. In this study, the processing–structure relationships of a ternary system composed of hydrolyzed salmon skin collagen (HSSC), chitosan (CS), and poly(vinyl alcohol) (PVA) were investigated during electrospinning using a rotating drum collector. A 3² full factorial design was applied to evaluate how applied voltage and collector rotational speed modulate fiber morphology and organization. Scanning electron microscopy and image-based analysis showed that collector speed promoted directional fiber organization, while the combined increase in voltage and rotational speed produced more ordered nonwoven networks. Effect analysis showed that voltage and collector rotational speed significantly increased fiber coherency (p = 0.011 and p = 0.020, respectively), whereas voltage was the dominant factor controlling fiber diameter, which decreased by approximately 113 nm between 10 and 15 kV (p < 0.001). The condition of 15.0 kV and 1500 rpm showed the highest model-predicted coherency within the experimental domain (close to 0.30). ATR-FTIR spectra showed the characteristic bands of HSSC, CS, and PVA in all mats. The selected scaffold supported MEF and C2C12 cell growth during 3 days of culture, providing biological characterization of the scaffold obtained under this condition. Overall, these results quantify how voltage and drum speed affect fiber diameter and orientation of HSSC/CS/PVA mats within the studied domain.
Polyethylene-based materials are widely used in fields such as wire and cable, film, and others. They are typically subjected to irradiation treatment prior to application to significantly enhance their overall performance. Therefore, research on the application of irradiation oxidation and post-irradiation oxidation to polyethylene is of importance. To explore the ionizing radiation induced oxidation, three types of polyethylene (LDPE, UHMWPE and HDPE) were irradiated by gamma rays in Ar or air, and subsequently exposed to air. The evolution of carbonyl group and free radicals were studied by Fourier transform infrared microscopy measurement (FTIR) and electron paramagnetic resonance spectroscopy (EPR) techniques, respectively. It was found that all types of PE were rapidly oxidized during irradiation in air (i.e., direct irradiation oxidation) compared with storage in air after irradiation (i.e., post-irradiation oxidation). The oxidation product of carbonyl group on UHMWPE and HDPE for a 17-hour direct irradiation oxidation exceeded that for a 52-day post-irradiation oxidation. The carbonyl group on HDPE and UHMWPE increased gradually with time in the post-irradiation oxidation, while there was almost no such product formation on LDPE. EPR testing showed that the free radical decay on irradiated LDPE was much faster than that on HDPE and UHMWPE, indicating that the post irradiation oxidation was related to free radical oxidation. Additionally, ozone oxidation experiment and shielding irradiation oxidation experiment were designed and confirmed that the direct irradiation oxidation of PEs may be attributed to the highly active oxidative species induced in situ by gamma irradiation. Based on these findings, it was proposed that the rapid direct irradiation oxidation was a three-pathway oxidation reaction, including irradiation oxidation, active oxygen species oxidation, and ozone oxidation. This work would provide new insight to understand the direct irradiation oxidation of other polymers. Irradiation oxidation rate is much higher than post-irradiation oxidation. Irradiation oxidation has stimulative effect on post-irradiation oxidation. Ozone oxidation has a weak contribution to irradiation oxidation. A new irradiation oxidation pathway by in-situ active oxidative species was proposed.
Polycaprolactone (PCL) is widely used in tissue engineering because of its mechanical strength and biodegradability. However, its hydrophobicity limits cell affinity, necessitating surface modifications such as surface coating to improve cell adhesion and growth. Despite investigations of different surface coating materials, there is a lack of directly comparable data on their efficacy under identical conditions. Here, 3D printed PCL scaffolds were prepared using fused deposition modeling, followed by dip coating with hyaluronic acid (HA), collagen (COL), gelatin (GL) and oxidative self-polymerization coating with polydopamine (PDA). The effectiveness of these materials in enhancing the cell compatibility of PCL scaffolds was compared. To evaluate cytocompatibility, the scaffolds were co-cultured with human umbilical cord mesenchymal stem cells (hUCMSCs), followed by a series of assays including CCK-8 viability assay, live/dead staining, and cytoskeleton staining. The results demonstrated that all coatings enhanced the cytocompatibility of PCL scaffolds, with the following ranking of effectiveness: HA ≈ COL < GL < PDA. Notably, the PDA and GL coatings significantly outperformed the HA and COL coatings, indicating that simple gelatin dip coating and PDA oxidation self-polymerization effectively improved the cytocompatibility of PCL scaffolds. This information provides a basis for selecting an appropriate surface-coating approach for tissue engineering.
