Search Results (2,577)

The fabrication of a real-time intelligent indication label for food freshness has emerged as an effective strategy to reduce food waste and improve food safety. In this study, utilizing polyvinyl alcohol (PVA) and arabinoxylan (AX) as the polymer matrices, and incorporating purple cabbage anthocyanins (PCAs) as natural pH-responsive agents, we fabricated a PVA/AX/PCA nanofiber-based intelligent indication label via electrospinning. The results confirmed that the nanofibers exhibited uniform morphology and good structural stability, with the PCA successfully embedded within the nanofibers. The nanofiber membrane exhibits a low water contact angle (54°) and demonstrates a tensile strength of 5.34 ± 0.09 MPa with an elongation at break of 32.43 ± 1.02%, while maintaining a certain degree of flexibility. The nanofiber labels exhibited distinct color changes within a wide pH range (2 to 12), which confirms their pH-responsive characteristics. After being stored at 4 °C and 25 °C for 14 days, the maximum color difference related to storage stability was 1.53 ± 0.02. In practical applications at 25 °C, this intelligent label demonstrated significant color changes when monitoring low-temperature-cooked sausages and fresh shrimp, with total color differences of 41.57 and 53.06, respectively. Degradation experiments showed that the nanofiber labels gradually decomposed, reflecting good biodegradability and environmental-protection characteristics. In conclusion, the green intelligent indication label developed in this study offers a feasible solution for real-time monitoring of food quality. Full article

Primary hepatocyte cultures serve as an ex vivo model of liver physiology. This study aims to employ poly(vinyl alcohol) (PVA) nanofiber membranes (NMs) to establish a three-dimensional (3D) culture system that supports the long-term functionality of primary hepatocytes. Primary hepatocytes were monocultured on a PVA NM or indirectly cocultured with NIH3T3 fibroblasts on a distinct polycaprolactone (PCL) NM layer. Monocultured and cocultured hepatocytes maintained prolonged survival without supplemental growth factors. Cocultured hepatocytes formed larger aggregates composed of cell clusters attached to untreated nanofibers than monocultured cells. However, most primary hepatocytes cultured on NaOH-treated PVA NM and Arg–Gly–Asp (RGD) peptide-blended PVA (RGD-PVA) NM, under monoculture and coculture conditions, formed non-aggregated cells in a single-cell layer. In a bioinert assay, unstimulated dendritic cells were activated on untreated but not NaOH-treated PVA NM. CYP3A4 activity was higher in cocultured cells on RGD-PVA NM with fibroblasts than in monocultured cells on PVA and RGD-PVA NM. Functional hepatocyte cultures were successfully maintained in a 3D single-cell layer on RGD-PVA NM, along with fibroblasts in a layer-by-layer coculture, for a prolonged period. The prolonged culture of hepatocytes in a 3D single-cell layer may facilitate further drug discovery, toxicity studies, and translational liver research. Full article

Polyvinyl alcohol (PVA)-based films are promising biodegradable alternatives to petroleum-derived plastics; however, their high rigidity and moisture sensitivity limit practical applications. In this study, PVA/carnauba wax (CW) films were prepared via solution casting and systematically modified using four plasticizers: glycerol (GLY), sorbitol (SOR), glucose (GLU), and sucrose (SUC), at concentrations of 0.1–0.5% (v/w, relative to PVA). Thermal analysis showed that GLY and SOR effectively reduced the glass transition temperature from 52.35 °C (control) to as low as 49.14 °C (0.2% GLY) and 50.70 °C (0.4% SOR), while SUC and SOR plasticized films exhibited improved thermal stability, with the highest melting temperature observed for 0.3% SUC (80.6 °C). SEM micrographs revealed that GLY at moderate concentrations (0.2–0.3%) produced the most homogeneous film morphology, whereas SUC at higher concentrations led to surface roughness and phase separation. Water contact angle measurements showed increased surface hydrophobicity at low plasticizer contents, with 0.1% GLY and 0.2% GLU exhibiting contact angles above 100° compared to the control film (<90°). Mechanical testing demonstrated that SUC at 0.2% had the highest tensile strength (3.03 MPa) compared to 0.73 MPa (control), while GLY at 0.3% yielded the highest elongation at break (9.26%), compared to 0.62% for the unplasticized film. These results demonstrate that precise control of plasticizer type and concentration enables effective tuning of PVA/CW film properties, offering a viable strategy for designing biodegradable films tailored for packaging and agricultural applications. Full article

Ensuring the simple, rapid, and real-time monitoring of the freshness of fresh food items is essential for maintaining food safety. By reacting with characteristic substances generated during spoilage, pH-responsive indicators can effectively reveal the degree of food freshness. In this study, a mixture of hydroxypropyltrimethyl ammonium chloride chitosan (HACC), polyvinyl alcohol (PVA), and blueberry anthocyanins (BAs) was adopted and, via an electrospinning strategy, changed into a membrane coupled with a pH-responsive ability to assess the freshness of shrimp. The results showed that HACC/PVA-BA membranes with a HACC: PVA ratio of 1:4 exhibited enhanced hydrophobicity, better WVP properties (4.32 × 10⁻⁹ g m⁻¹ s⁻¹ Pa⁻¹), a rapid pH-response ability within 5 s and super radical scavenging capacity (56.34% for DPPH and 54.74% for ABTS radicals). HACC’s immutable positive charge creates a strong electrostatic field that pre-concentrates spoilage-generated ammonia and intensifies the protonation state of BAs, which dramatically enhances colorimetric sensitivity and rapid response to volatile amines. Moreover, a satisfactory antibacterial ability for S. aureus and E. coli were also evidenced: HACC/PVA-BA (1:4) membranes achieved a maximum inhibition rate of 64.9% for E. coli and 62.2% for S. aureus. Once applied to monitor the freshness of shrimp stored at 4 °C, the HACC/PVA-BA (1:4) membranes were able to indicate shrimp freshness through visually recognizable color changes within 3 h, which correlated strongly with the spoilage indicators of total volatile basic nitrogen, total viable count, and pH value. It is suggested that the intelligent pH-responsive membranes show great potential for practical application in monitoring food freshness. Full article

The development of high-performance biocomposites based on poly vinyl alcohol (PVA) and lignin is often hindered by the limited interfacial compatibility. Herein, we reporte a synchronized crosslinking strategy to seamlessly integrate lignin and PVA into a uniform and robust composite film. The vinyl groups were introduced into both lignin and PVA molecular chains, which enable the formation of dense covalent bonds through reactions between these unsaturated carbon–carbon double bonds. This dual network structure combining covalent crosslinking with hydrogen bonding effectively strengthened the interfacial compatibility between lignin and PVA, which substantially enhanced film toughness, exhibiting an elongation at break of up to 4300%. Furthermore, the prepared composite film also demonstrated outstanding UV-blocking efficiency (>90%), strong antioxidant activity (82% DPPH scavenging), enhanced hydrophobicity (water contact angle of 97.9°), and improved thermal stability. The dramatic enhancements were attributed to the homogeneous dispersion of modified lignin within the covalently bonded network, which ensured efficient stress transfer and reduced the availability of hydrophilic groups. This synchronized crosslinking approach presents a versatile and effective route for fabricating high-value lignin-based composite materials. Full article

Bacterial cellulose (BC) is highly valued for biomedical and industrial applications due to its exceptional biocompatibility, strength, and biodegradability. Polyvinyl alcohol (PVA) exhibits favorable characteristics, making it an ideal candidate for hydrogel formulation. In this study, BC–PVA composite hydrogels were synthesized by dissolving 1% w/w BC in ZnCl₂ 3H₂O and 10% w/w PVA in ZnCl₂nH₂O, n = 6, 9, 12, and 15. These solutions were combined at BC:PVA weight ratios of 3:1, 1:1, and 1:3, then crosslinking using a glutaraldehyde–acetone solution before immersion in deionized water. The resulting hydrogels exhibited a dense, tightly packed structure with mild to moderate porosity. FTIR analysis confirmed molecular interactions via a broad, reduced O–H stretching band and the appearance of C-H bending vibrations. The water content and swelling ratio ranged from 88.13% to 94.67% and 437.93% to 997.22%, respectively. At a compressive strain of 30%, the compressive strength ranged from 62.28 kPa to 93.16 kPa. This work introduces a novel and efficient method for preparing BC-PVA hydrogels using ZnCl₂ hydrate solvents. Both the ZnCl₂ hydration level and the BC:PVA ratio significantly influenced the structural, water content, swelling, and mechanical properties, offering tunable materials for biomedical or industrial applications. Full article

In this work, a polypyrrole–tungsten disulfide (PPy–WS₂) nanocomposite was synthesized through oxidative polymerization and evaluated as an electrode material for supercapacitors. Structural and morphological analyses confirmed the successful integration of WS₂ within the PPy matrix. Electrochemical testing revealed a high specific capacitance of 816 F g⁻¹ at a scan rate of 1 mVs⁻¹, together with excellent cycling durability. To further assess device-level performance, an asymmetric supercapacitor was assembled using the PPy–WS₂ nanocomposite as the positive electrode, activated carbon as the negative electrode, and a PVA/KOH gel electrolyte. The device achieved an energy density of 41.6 Wh kg⁻¹ and a power density of 1500 W kg⁻¹, while maintaining 105% of its capacitance after 2500 charge–discharge cycles. The prototype was also able to power a light-emitting diode, highlighting its practical potential. These findings demonstrate that the synergistic coupling between polypyrrole and tungsten disulfide substantially improves electrochemical behaviour, positioning the PPy–WS₂ nanocomposite as a promising candidate for advanced energy storage applications. Full article

G protein-coupled receptors (GPCR) are targeted by more than one third of the clinically available drugs as specific ligands. Important as GPCR ligands may be, cases of ligand-independent GPCR activation are also abundant. In a recent article published in the journal ACS Nano, a series of cyanine skeleton-based plasmonic molecules, or molecular jackhammer, as the authors christened them, after insertion into the plasma membrane, was found after excitation by far-red light (730 nm) to vibronically-driven activate Gq-mediated calcium signaling in four different cell lines of both epithelial and muscle cell origin, which is normally activated after agonist stimulation of Gq-coupled GPCR, but the possible involvement of GPCR remains to be examined. This novel mode of activation of calcium signaling, normally associated with agonist-stimulated GPCR activation, is compared to nanoclustering activation of the neuropeptide Y2 receptor and photodynamic activation of the cholecystokinin 1 and 2 receptors. Full article

This research developed an active food packaging system featuring a tailored controlled-release mechanism. The system was fabricated using temperature-responsive poly(N-vinylcaprolactam) (PNVCL) nanofibers with a core-shell architecture. The resulting film incorporated cinnamon essential oil (CEO) as a natural preservative within a composite structure consisting of PNVCL, polyvinyl alcohol (PVA), polylactic acid (PLA) and CEO. The nanofiber film obtained via coaxial electrospinning exhibited a sandwich-like structure; the obtained fiber membrane is abbreviated as PP/PC, and the number represents the essential oil content. The PP/PC-4 composite demonstrated exceptional physical barrier properties and mechanical strength, with a WVP as high as 5.74 ± 0.37 (g·mm)/(m²·h·kPa). It also achieved the highest maximum force, elastic modulus, and tensile strength, recorded at 3.08 ± 0.31 N, 228.86 ± 15.46 MPa, and 5.26 ± 0.72 MPa, respectively, along with superior thermal stability. FTIR spectroscopy confirmed molecular interactions, specifically through C–H bonding, between the PLA/CEO core and the PNVCL shell layers. After 5 d of storage at 40 °C, the PP/PC-4 film retained substantial antibacterial efficacy. The antifungal efficacy demonstrated the highest performance, exceeding the control group by 32%. The weight loss rate on day four was 28%, significantly lower than other groups, while the hardness retention rate was 73% higher than the control group and 44% higher than PLA/CEO (4%). Application of this material prolonged the shelf life of Chinese bayberry (Myrica rubra) by 4 d while enhancing key preservation metrics. Owing to its advanced barrier properties, mechanical performance and temperature-modulated release characteristics, this PNVCL-based nanofiber film demonstrated strong potential as an intelligent packaging material for prolonging the freshness of perishable food products. Full article

The issue of cadmium (Cd(II)) contamination of the water is a serious concern of the environmental and health problem, and this requires effective technology to remove the problem of toxic element. It is the purpose of this review paper to give an overview of several techniques of cadmium removal, such as polymer membranes and composites, adsorption using green materials, and electrochemical methods. The important conclusions are presented regarding the effectiveness of the polymer and composite membranes; e.g., the efficacy of the PES/HPEI-SH membrane that reached 99% removal of Cd(II) in 20 min with adsorption capacity of 135.59 mg/cm², and the PVA/IC/PANI/GO nanofiber composite that indicates high adsorption of the 459 mg/g. The electrochemical process, i.e., electro-membrane extraction, exhibits 90% removal at 60 V, whereas the adsorption-based electro-membrane extraction contains an extraordinary capacity of 496.51 mg/g, using Fe@HC nanocomposites. Furthermore, the removal efficiencies of solar-powered electrocoagulation reached a percentage of 99.1% with respect to Cd(II). The review ends by stating that the tools to resolve cadmium removal problem include advanced materials and hybrid technologies and are promising, but various challenges such as membrane fouling and scalability are undeniable. Future studies ought to emphasize on improving reusability, expense effectiveness, and long-term applicability to address these challenges, thus contributing to the attainment of the United Nations Sustainable Development Goals (SDGs), particularly Goal 6: Clean Water and Sanitation, by guaranteeing the availability and sustainable management of water resources. Full article

This study reports the development and characterization of chitosan–poly(vinyl alcohol) (CH/PVA) nanofibers (NFs), functionalized with bioactive compounds (ACs) relevant for wound healing and tissue regeneration. CH/PVA NFs loaded with L-arginine (ARG), allantoin (ALA), royal jelly (RJ) and curcumin (CUR), either as single or co-loaded systems, were prepared by electrospinning. The polymer solutions were characterized in terms of key physicochemical properties relevant to electrospinning. The CH/PVA@ACs NFs were characterized morphologically and structurally through scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Additionally, surface-related, physical, and functional properties such as wettability, swelling behavior, and in vitro release profiles were examined. The NFs were successfully produced in a uniform and continuous manner, with the fiber diameter and morphology being influenced by the type of ACs. FTIR analysis validated the characteristic functional groups linked to both the polymeric matrix and ACs. The nanofibrous systems demonstrated a high swelling capacity and a release behavior that is dependent on pH. Analyses of surface free energy and wettability revealed favorable interfacial interactions between solid and liquid, indicating compatibility with aqueous biological environments. In summary, the developed CH/PVA@ACs NFs exhibited appropriate morphological, structural, surface, and functional properties, underscoring their potential as effective materials for wound dressings. Full article

The water absorption of polyvinyl alcohol (PVA) freeze-dried porous polymer is critically influenced by its molecular structure. The hydrolysis degree and molecular weight of PVA were identified as key factors in the design of freeze-dried porous polymers for enhanced structure and stability. The complex interactions between water absorption and structural characteristics in freeze-dried porous polymers were investigated. This was achieved by varying the degree of hydrolysis and molecular weight of the PVA. The results indicate that as the degree of PVA hydrolysis increases, the water absorption and structural stability of the freeze-dried porous polymer are significantly improved. These performance enhancements are attributed to the synergistic effects of hydrogen bonding interactions and molecular chain entanglement between PVA-sodium polyacrylate (PAAS) chains and PVA-PVA chains, collectively forming a denser and more stable three-dimensional network structure. Additionally, the incorporation of high molecular weight PVA significantly reduced the water absorption capacity of the freeze-dried porous polymer. However, freeze-dried porous polymers prepared using low molecular weight polyvinyl alcohol exhibit poor structural stability. Specifically, when the PVA molecular weight is 7200-8100, and the degree of hydrolysis is 99%, the freeze-dried porous polymer exhibits a maximum porosity of 92%, a density of 82 mg/cm³, and a water absorption capacity of 38 g/g. Overall, this work provides the theoretical basis and technical support for its application in absorbent pads. Full article

Potato virus X (PVX) and potato virus Y (PVY) are major pathogens that threaten seed potato quality and yield. To improve the efficiency of field screening, we developed monovalent PVX, monovalent PVY, and bivalent PVX/PVY nanozyme strips using Fe₃O₄ nanozymes as labels in a double-antibody sandwich lateral flow immunochromatographic assay. Western blot analysis demonstrated that four monoclonal antibodies (PVX 2, PVX 6, PVY 2, and PVY 5) specifically recognized their corresponding viral coat proteins. Specificity testing showed that the nanozyme strips reacted only with the target viruses and did not cross-react with other common potato viruses, including Potato virus A (PVA), Potato virus M (PVM), Potato virus S (PVS), and Potato leafroll virus (PLRV). The PVX nanozyme strip detected PVX-positive extracts diluted up to 10³-fold, the PVY nanozyme strip up to 10⁴-fold, and the bivalent strip detected PVX/PVY co-infected samples diluted up to 10³-fold. In addition, detection results by strips from 12 samples of plantlets in vitro were fully consistent with RT-PCR. These nanozyme strips provide rapid, simple, specific, and sensitive methods that can be stored at ambient temperature, enabling field surveys, warehouse screening, and on-site testing and supporting early detection of potato virus diseases. Full article

A novel low-cost poly(propylene carbonate-co-epichlorohydrin) (PPC-ECH) with mechanical properties similar to those of poly (butylene adipate-co-terephthalate) (PBAT) was developed and incorporated into a poly(propylene carbonate-co-phthalate) (PPC-P) matrix. Meanwhile, 4, 4′-diphenylmethane diisocyanate (MDI) was employed as a reactive compatibilizer and mixed with PPC-P and PPC-ECH to create a variety of PPC-P/PPC-ECH/MDI blends. The effects of PPC-ECH and MDI content on the mechanical, optical, thermal, morphological, and gas barrier properties of the blends were systematically investigated. Results demonstrated that MDI reacts with both PPC-P and PPC-ECH, forming a chemically bonded interface that significantly improves their compatibility. Notably, when 2 phr of MDI was incorporated, the elongation at break of the PPC-P/PPC-ECH/2MDI blend increased dramatically from 71% to 502%, while maintaining good tensile strength (~23 MPa) and light transmittance (~80%). To further enhance the gas barrier performance, a high-oxygen-barrier poly(vinyl alcohol) (PVA)/tannic acid (TA) complex coating was applied to the surface of the PPC-P/PPC-ECH/2MDI film. This coating synergistically leveraged the abundant hydroxyl groups in PVA and TA to form a dense hydrogen-bonded network, reducing oxygen permeability to an ultra-low value of 0.1 cm³·mm/(m²·day). This outstanding performance highlights the strong potential of PPC-P/PPC-ECH-based films for advanced packaging applications. Full article

As a widely used catalyst class, transition metal oxides (TMOs) face the challenges of detrimental nanoparticle agglomeration. The newly developing two-dimensional (2D) covalent triazine frameworks (CTFs) offer a promising solution as catalyst supports, capable of yielding composites with excellent dispersibility and synergistic catalytic enhancement. Building on this, and employing a hydroxylation functional modification strategy, this article introduces a binary oxide system to construct a CTF/CuO–NiO composite that exhibits excellent catalytic performance for the thermal decomposition of ammonium perchlorate (AP). Specifically, polyvinyl alcohol (PVA) was first employed to introduce -OH anchoring sites onto the CTF surface. A subsequent co-precipitation yielded a uniform dispersion of CuO–NiO nanoparticles across the functionalized CTF support. DSC analysis revealed that incorporating merely 2 wt% of the CTF/CuO–NiO composite into AP significantly alters its high-temperature decomposition (HTD) peak temperature, shifting it from 404.6 °C to 332.1 °C. This work highlights the construction of a binary oxide system through an effective dispersion strategy to enhance the synergistic catalytic performance of CTF-based composites. Full article