Search Results (1,667)

Active packaging supports sustainable development by extending food shelf life and reducing spoilage, contributing to global food security. In this study, cellulose dialdehyde was synthesized and blended with polyvinyl alcohol in varying ratios to produce composite films. The incorporation of dialdehyde cellulose into films tended to increase puncture strength and Young’s modulus, decrease elongation, reduce water solubility, and enhance resistance to water vapor transmission because of crosslinking. Carbon quantum dots were subsequently incorporated into composite films to enhance their antibacterial property. This represents a novel combination of a natural bio-based crosslinker and fluorescent nanomaterials in a single packaging system. Carbon quantum dots were synthesized by an electrochemical method and incorporated as functional agents. The addition of carbon quantum dots influenced the mechanical properties of the films due to interactions between polymers and carbon quantum dots. This interaction also slightly reduced the antibacterial effectiveness of the films, consisting of dialdehyde cellulose and PVA in ratios of 3:1 and 4:0. Nevertheless, the composite films maintained sufficient antimicrobial activity against common foodborne bacteria, including Staphylococcus aureus, Escherichia coli, and Salmonella Typhimurium. Overall, the findings demonstrate that multifunctional material made from dialdehyde cellulose, polyvinyl alcohol, and carbon quantum dots are a promising alternative to conventional plastic packaging. Full article

Background/Objectives: Lidocaine is a widely used local anesthetic, but injections and topical creams are often painful or slow in onset. This study aimed to develop dissolving microneedles incorporating lidocaine hydrochloride for rapid and convenient local anesthesia. Methods: Six formulations were prepared with polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) and evaluated for mechanical strength, skin insertion, drug release, and transdermal permeability. Results: Sharp pyramidal microneedles were successfully fabricated, with PVP–PVA mixtures producing stronger needles than single polymers. The optimized F5 formulation showed high strength (>32 N), efficient skin insertion (four parafilm layers), and rapid release (>80% within 15 min). In ex vivo studies, F5 delivered >600 µg/mL lidocaine in 15 min, over three times the therapeutic level and much faster than Emla cream (5%). Conclusions: PVP–PVA microneedles represent a promising platform for painless, rapid local anesthesia, combining the benefits of injections and topical creams while minimizing their drawbacks. Full article

Thyme oil (TO), an aromatic compound derived from Thymus species, exhibits potent antioxidant and antibacterial properties. To address its defects of high volatility and susceptibility to oxidation, TO was encapsulated in chitosan oligosaccharide (COS)-stabilized oil-in-water emulsions using a two-step emulsification method with ultrasound assistance. The droplet size of TO-in-water emulsions decreased significantly with increasing ultrasound power and treatment time, achieving sizes below 240 nm with an encapsulation efficiency exceeding 90%. The COS interface layer, combined with polyvinyl alcohol (PVA), effectively enhanced emulsion stability by preventing phase separation and maintaining droplet size and zeta potential during storage. Compared to its free form, the encapsulation of TO in the emulsion significantly improved the antioxidant activities, as evidenced by the enhanced ABTS (1.25-fold) and DPPH (1.33-fold) radical scavenging activities, at equivalent concentrations. Additionally, the TO emulsions exhibited superior antibacterial and antifungal properties, with minimum inhibitory concentration (MIC) values reduced by half and effective inhibition of Escherichia coli, Staphylococcus aureus, and Penicillium italicum growth. These findings highlight the potential of TO emulsions as an effective delivery system for improving the functionality and stability of TO in fresh food preservation applications. Full article

Microneedles represent an emerging transdermal drug delivery platform offering painless, minimally invasive penetration of the stratum corneum. This study addresses limitations of conventional lidocaine hydrochloride formulations, such as slow onset and poor patient compliance, by developing lidocaine hydrochloride-loaded dissolvable microneedles (LH-DMNs) for rapid local anesthesia. LH-DMNs were fabricated via centrifugal casting using polyvinyl alcohol (PVA) as the matrix material in polydimethylsiloxane (PDMS) negative molds, which imparts high mechanical strength to the microneedles. Biocompatibility assessments showed negligible skin irritation, resolving within 3 min. And drug-loading capacity reached 24.0 ± 2.84 mg per patch. Pharmacodynamic evaluation via mouse hot plate tests demonstrated significant analgesia, increasing paw withdrawal latency to 36.11 ± 1.62 s at 5 min post-application (p < 0.01). The results demonstrated that the LH-DMNs significantly elevated the pain threshold in mice within 5 min, surpassing the efficacy of conventional anesthetic gels and providing a rapid and effective solution for pain relief. These findings validate the system’s rapid drug release and efficacy, positioning dissolvable microneedles as a clinically viable alternative for enhanced transdermal anesthesia. Full article

Anthropomorphic CT phantoms are essential training tools for interventional radiology. Given the high technical demands and stringent safety requirements in this field, realistic CT phantoms are vital simulation tools that support effective hands-on training, procedural planning, and risk mitigation. However, commercially available phantom geometries are limited in their scope. This study investigates the use of polyvinyl alcohol (PVA) to fabricate customizable training phantoms. PVA, a non-toxic material, can be processed into PVA cryogels (PVA-C) with tissue-like mechanical properties. We modified PVA-C (10 wt.% PVA) by incorporating various additives to adjust X-ray attenuation and achieve Hounsfield units (HUs) similar to different soft tissues. HU values were measured at X-ray tube voltages of 70, 120, and 150 kV. The inclusion of barium sulfate (e.g., U = 120 kV; 0.1–2 wt.%: 33.29 ± 5.45–323.72 ± 12.64 HU) and iohexol (e.g., U = 120 kV; 0.1–2 wt.%: 26.05 ± 4.74–161.99 ± 5.69 HU) significantly increased HU values. Iohexol produced more homogeneous HU distributions than barium sulfate and cellulose derivatives, with the latter having air gaps and inconsistencies. The tested formulations encompassed a wide range of soft tissue densities, with HU values varying significantly across the energy range (p < 0.001). While cellulose derivatives showed variable HU modulation, their primary role appears to be in modifying phantom texture and morphology rather than precise attenuation control. In conclusion, PVA-C demonstrates strong potential for use in interventional radiology training phantoms. Further studies may enhance phantom realism by replicating tissue textures, for example, through the incorporation of cellulose-based substances. Full article

Using ultrasound-assisted extraction, we obtained a chlorophyll-rich extract from Opuntia ficus-indica cladodes (OFI) characterized through thin-layer chromatography (TLC), Fourier-transform infrared spectroscopy (FTIR), and spectrophotometric absorption analysis. The dye exhibited a strong fluorescence response in the visible range (400–800 nm) with a pronounced red emission when excited with a UV source. Antioxidant ability was evaluated via DPPH assay, showing an IC₅₀ of 185 µg/mL, highlighting its potential for reactive oxygen species scavenging. The extract was incorporated into polymethyl methacrylate (PMMA), polyvinylpyrrolidone (PVP), and polyvinyl alcohol (PVA), leading to fluorescence intensity enhancements of up to 40 times compared to the dye alone depending on matrix polarity, consistent with aggregation and polarity effects. Stability tests confirmed the dye’s resistance to CO₂ exposure, pH variations, and prolonged storage, positioning it as a viable alternative to synthetic fluorophores. These findings suggest that the OFI extract provides a functionally relevant, bio-derived dye platform promoting the valorization of agricultural by-products in high-value technological applications, highlighting a circular and scalable approach to developing ecofriendly fluorescent materials, aligning with sustainability and green technology goals. Full article

Background: Postoperative ocular inflammation is a frequent complication of eye surgeries commonly managed using corticosteroids or nonsteroidal anti-inflammatory drug (NSAIDs) eye drops. However, poor ocular bioavailability and patient non-adherence due to frequent dosing limit the therapeutic efficacy of conventional eye drops. This study aimed to develop a sustained-release ocular insert containing bromfenac sodium (BS)-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles (MPs) with an initial 3% (w/w) free BS fraction incorporated into a poly(vinyl alcohol) (PVA) matrix designed to achieve a dual-phase release profile for improved postoperative therapy. Methods: PLGA-based MPs were fabricated using a double emulsion solvent evaporation technique and incorporated into PVA films to produce ocular inserts with varying MP content. Formulations were characterized for morphology, particle size, zeta potential, drug loading, entrapment efficiency, mucoadhesion, drug distribution, and in vitro release. Data were analyzed by an ANOVA and t-tests with p < 0.05 as significance. Results: MPs were smooth, spherical, and well-dispersed in the PVA inserts. Particle sizes ranged from 3.7 to 5.6 µm, with drug loading 7–8% and entrapment efficiencies 47–52%. Multiphoton imaging confirmed uniform drug distribution. In vitro release showed a dual-phase profile with an initial burst followed by sustained release for up to 4 days, with only negligible further release through Day 6 in one formulation (M1-7525). Conclusions: The developed BS-loaded PLGA MP/PVA insert demonstrated a dual-phase release profile relevant to postoperative ocular inflammation. Its biodegradable, single-application design holds promise for enhancing compliance and therapeutic outcomes in ophthalmic care. Full article

Conventional conductive hydrogels are susceptible to swelling in aquatic environments; which compromises their mechanical integrity; a limitation that poses a potential challenge to their long-term stability and application. In this study, a zwitterionic ion-conductive hydrogel was fabricated from polyvinyl alcohol (PVA), acrylic acid (AA), and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SMBA), forming a dual-network structure. A copolymer of zwitterionic SBMA and AA formed the first network, and PVA formed the second network by repeated freeze–thawing. The equilibrium state of zwitterionic SBMA was modulated by AA to protonate the SBMA, which resulted in the conversion of -SO₃⁻ to -SO₃H; thus, hydrogels had the anti-swelling property driven by electrostatic repulsion. In addition, the prepared hydrogels possessed excellent mechanical properties (tensile strength of 0.76 MPa, elongation at break of 322%, and compressive strength of 0.97 MPa at 75% compressive strain) and remarkable anti-swelling properties (80% swelling after 120 h of immersion). Owing to the zwitterionic nature of SBMA, the hydrogel also showed inherent antimicrobial properties and high electrical conductivity, which could be capable of monitoring human movement and physiological signals. This work provides a facile strategy for designing hydrogels with remarkable mechanical properties and anti-swelling characteristics, expanding the application environment of hydrogels in flexible sensing Full article

Packaging demand currently exceeds 144 Mt per year, of which >90% is conventional plastic, generating over 100 Mt of waste and 1.8 Gt CO₂-eq emissions annually. In this review, we systematically survey three classes of lignocellulosic feedstocks, agricultural residues, fruit and vegetable by-products, and forestry wastes, with respect to their physicochemical composition (cellulose crystallinity, hemicellulose ratio, and lignin content) and key processing pathways. We then examine fabrication routes (solvent casting, extrusion, and compression molding) and quantify how compositional variables translate into film performance: tensile strength, elongation at break (4–10%), water vapor transmission rate, thermal stability, and biodegradation kinetics. Highlighted case studies include the reinforcement of poly(vinyl alcohol) (PVA) with 7 wt% oxidized nanocellulose, yielding a >90% increase in tensile strength and a 50% reduction in water vapor transmission rate (WVTR), as well as pilot-scale extrusion of rice straw/polylactic acid (PLA) blends. We also assess techno-economic metrics and life-cycle impacts. Finally, we identify four priority research directions: harmonizing pretreatment protocols to reduce batch variability, scaling up nanocellulose extraction and film casting, improving marine-environment biodegradation, and integrating circular economy supply chains through regional collaboration and policy frameworks. Full article

In this study, composite films based on phosphorylated polyvinyl alcohol (PVA-P), Ti₃C₂T_x MXene, and cholesteryl acetate (ChLC) were designed and characterized to explore their potential in flexible electronic applications. The incorporation of phosphate groups and ChLC enhanced intermolecular interactions, as confirmed with FTIR spectroscopy. Morphological and optical analyses revealed a transition from homogeneous to phase-separated structures with birefringent textures in ChLC-rich films. Thermal studies demonstrated improved stability and increased glass transition and melting temperatures, particularly in samples with higher ChLC content. Mechanical and dielectric evaluations highlighted the tunability of stiffness, flexibility, permittivity, and dielectric losses depending on MXene and ChLC ratios. These multifunctional films exhibit flame-retardant behavior and show promise for use in stimuli-responsive, sustainable electronic devices such as flexible displays and sensors. Full article

The objective of this paper was to determine the interactive effects of multiple synthesis parameters on annealed PVA hydrogel properties and assess these hydrogels for the application of cartilage replacement. PVA hydrogels were synthesized at two different molecular weight ranges (89–98 kDa and 146–186 kDa), two polymer concentrations (10% PVA and 20% PVA), and four different annealing temperatures (120 °C, 135 °C, 150 °C, and 165 °C). The compressive, tensile, and wear mechanical properties were measured, and the crystalline structure of these hydrogels was assessed via differential scanning calorimetry. Hydrogels showed increasing polymer weight percent, tensile modulus, and compressive modulus with increasing annealing temperature. Depending on synthesis parameters, the hydrogels matched or exceeded the previously published compressive and tensile properties of native cartilage. Higher molecular weight PVA hydrogels (146–186 kDa) exhibited less wear, but greater friction, compared to lower molecular weight PVA (89–98 kDa). The PVA hydrogels exhibited crystallinity in the range of 53–78%, but no consistent differences in crystallinity were detected between hydrogel variants. It was concluded that the (10% PVA, 146 kDa, 165 °C) annealed PVA hydrogel demonstrated the most appropriate balance of high tensile strength and compressive compliance comparable to cartilage. Full article

In this study, a bio-nanocomposite integrating calcium caseinate, modified starch, and bentonite nanoclay was formulated and synthesized into film form via solution casting. Glycerol was incorporated for plasticization, and polyvinyl alcohol (PVA) was used to enhance the structural and chemical attributes of the material. The addition of PVA and bentonite notably improved the mechanical strength of the casein-based matrix, showing up to a 30% increase in tensile strength compared to similar biopolymer formulations. Water vapor permeability was significantly reduced when compared to previously reported casein–starch formulations, evidencing the barrier-positive effects of bentonite nanostructures. The microbial analysis confirmed that the quantity of bacterial colonies remained within permissible levels for non-antimicrobial biodegradable films; however, further antibacterial evaluations are advised. Biodegradability testing showed a consistent degradation trend, with full disintegration extrapolated to occur around 13 weeks under natural soil conditions. This study offers exploratory insight into the development of functional and biodegradable films using biopolymer blends and nanoclay suspensions, highlighting their potential in sustainable food packaging applications. Full article

Mixtures containing polyvinyl alcohol (PVA) and methylcellulose (MC) were obtained and used to synthesize hydrogels in various ratios of components. The swelling kinetics of the resulting hydrogels were studied, revealing that the equilibrium swelling degree in artificial saliva is nearly twice as high as in water. It was found that increasing the volumetric content of PVA in the mixture leads to a higher swelling degree. The kinetics of active pharmaceutical ingredient (API) sorption and release from the hydrogels were also investigated. It was demonstrated that hydrogels with a higher PVA content exhibit greater sorption capacity; however, the release of the API from such samples occurs at a slower rate. For the first time, the mucoadhesive properties of PVA-MC-based hydrogels were studied. It was established that the PVA-MC hydrogel with a ratio of 6:4 vol.% remained on the surface of the porcine cheek mucosa for two days, the 5.5:4.5 vol.% sample detached after 24 h, and the 5:5 vol.% sample adhered for approximately 10 h. These findings confirm the mucoadhesive potential of the hydrogels and their suitability for buccal drug delivery forms. The synthesized PVA-MC hydrogels are promising for applications in medicine and pharmacology. Full article

The objective of this study was to evaluate the physical, chemical, mechanical, thermal, and topological properties of polyvinyl alcohol (PVA) and gelatin (GL) films after incorporating three different fractions of blueberry extract: crude extract (EB, without purification), phenolic portion (EF), and concentrated anthocyanins (EA). Additionally, the study aimed to analyze the efficiency of these colorimetric indicator films in monitoring the freshness quality of shrimp. The experiment followed a completely randomized design with one factor—different types of films—studied at six levels: film incorporated with crude blueberry extract (FB), film incorporated with phenolic extract (FF), and film incorporated with anthocyanin extract (FA), in addition to the control films: the plasticized blend containing glycerol, PVA, and GL (FC), the pristine gelatin film (FG), and the pristine PVA film (FPVA). To evaluate the colorimetric sensitivity of the indicators applied to shrimp, storage time was studied at two levels: T0 (before storage—on the day of collection) and T7 (after 7 days of storage at 6.5 ± 1 °C) for the FB and FA films. Regarding thermal properties, the degradation profile occurred in three stages, with the FC film being the most thermally stable. In terms of mechanical behavior, the isolated anthocyanin content increased the elasticity of FA, while the crude extract and other phenolic compounds contributed to the stiffness of FB (Young’s modulus, YM = 22.52) and FF (YM = 37.33). Structurally, the FC film exhibited a smooth and well-blended polymeric surface, whereas FF, FB, and FA displayed heterogeneous and discontinuous phases. The incorporation of blueberry extracts reduced water absorption, leading to decreased swelling and solubility. FF showed the lowest solubility (S = 16.14%), likely due to hydrogen bonding between phenolic compounds and the polymer matrix. Notably, FB demonstrated superior physical, chemical, and mechanical performance, as well as the highest thermal stability among the extract-containing films. It also showed a visible color change (from purple to green/brown) after 7 days of shrimp storage, corresponding with spoilage and pH values unsuitable for consumption. Both FA and FB effectively monitored shrimp freshness, offering a sustainable approach to quality assurance and food waste reduction. Among them, FB was the most practical for visual detection. Overall, these films demonstrated strong potential as pH-sensitive indicators for evaluating the freshness of shrimp. Full article

This study presents an environmentally benign composite hydrogel system by combining polyvinyl alcohol (PVA) with carboxymethyl cellulose derived from jackfruit peel waste (JCMC), subsequently reinforced with graphene oxide (GO) and Kaolin nanoparticles for enhanced Congo red (CR) adsorption. The structural properties of the synthesized hydrogels were comprehensively characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). FTIR analysis confirmed hydrogel formation through hydrogen bonding interactions, while XRD and SEM revealed the uniform dispersion of GO and Kaolin within the polymer matrix, resulting in an improved adsorption performance. Furthermore, the adsorption efficiency of the composite hydrogels was systematically evaluated under varying conditions, including solution pH, contact time, temperature, and initial CR concentration. Optimal CR removal (92.3%) was achieved at pH 8.0, with equilibrium attained within 90 min. The adsorption kinetics were best fitted by the pseudo-second-order model (R² = 0.9998), confirming a chemisorption-dominated process. The equilibrium adsorption data were accurately described by the Langmuir isotherm model, indicating monolayer coverage with an exceptional maximum capacity of 200.80 mg/g. These findings highlight the superior adsorption performance of the PVA/JCMC/GO/Kaolin hydrogels, attributed to their tailored physicochemical properties and synergistic interactions among components. This study offers both sustainable jackfruit peel waste valorization and an effective solution for anionic dye removal in wastewater treatment. Full article