Search Results (456)

This study developed high-oxygen-barrier active bilayer packaging films by combining corona-treated low-density polyethylene (LDPE) with chitosan/glycerol (CS/Gl) and carvacrol@natural zeolite (CV@NZ) nanohybrid layers using industrially scalable processes. LDPE film was surface-activated via ambient-pressure corona treatment (0.75 s/cm² at 45 kV, 30 W) and assembled with solution-cast CS/Gl or CS/Gl/CV@NZ monolayers via hot-pressing (110 °C, 1 min). Corona treatment enabled robust interfacial adhesion, evidenced by statistical equivalence between monolayer and bilayer mechanical properties. Incorporation of 10 wt.% CV@NZ nanohybrid increased elastic modulus by 60% (to ≈2970 MPa) and tensile strength by 30% (to ≈50 MPa). The LDPE-CS/Gl film achieved a 64-fold reduction in oxygen permeability; CV@NZ incorporation maintained excellent barrier performance (22-fold reduction). Antioxidant potency increased 16-fold upon CV@NZ incorporation. The LDPE-CS/Gl/CV@NZ film demonstrated exceptional antibacterial activity (5.08–5.30 log reductions; >99.999% kill) against both Listeria monocytogenes and Escherichia coli—substantially exceeding additive effects—confirming synergistic action between chitosan and carvacrol. In fresh minced pork preservation (8 days, 4 °C), the active film achieved a 1.73 log reduction in Total Viable Count (98.2% inhibition) and extended microbiological shelf life from 6 to beyond 8 days (33% increase). The bilayer configuration utilizes only 40% of the total thickness as biopolymer, aligning with circular economy principles. Unlike conventional high-barrier films (e.g., PA/PE) which require complex compatibilization for recycling, the water-soluble chitosan layer in this bilayer design can be readily separated from the LDPE backbone, enabling recovery of a pure polymer stream. This work demonstrates a feasible pathway for developing next-generation active packaging that combines a high oxygen barrier, potent antioxidant activity, and exceptional antimicrobial efficacy through industrially scalable manufacturing. Full article

Background: Baicalein (BA) is a poorly soluble flavonoid with limited oral bioavailability. This study aimed to enhance the solubility and nasal absorption of the compound using a dual-carrier system that combines cyclodextrin inclusion complexes and thermosensitive hydrogels. Methods: The inclusion complexes of BA with hydroxypropyl-β-cyclodextrin (HP-β-CD) or sulfobutyl-β-cyclodextrin (SBE-β-CD), namely BA-HP-β-CD and BA-SBE-β-CD, were prepared via solution stirring and characterized by solubility, dissolution, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis-differential scanning calorimetry (TG-DSC), and Madin-Darby canine kidney (MDCK) cell permeation. The optimal complexes were incorporated into chitosan/β-glycerophosphate thermosensitive hydrogels (BA/HP-Gel and BA/SBE-Gel), followed by evaluations of gelation properties, in vitro release, and in vivo pharmacokinetics in rats. Results: The water solubility of BA-HP-β-CD and BA-SBE-β-CD increased 572 and 582 times, with MDCK permeability enhanced by 5.3 and 2.9 times, respectively. Both hydrogels showed rapid solution-gel transition at nasal temperature and sustained release. Following intranasal administration, BA/HP-Gel and BA/SBE-Gel achieved relative bioavailabilities of 623.5% and 697.8%, respectively, compared with BA-Gel. Conclusions: The dual-carrier platform effectively improved BA solubility, permeability, and nasal bioavailability, offering a promising strategy for nasal delivery of poorly soluble drugs. Full article

In the present study, innovative active gelatin–chitosan films enriched with blackberry (ACTIVE-BF) and sage flower (ACTIVE-SF) extracts were developed and comprehensively characterised with regard to their physicochemical, functional and environmental properties. The incorporation of phenolic compounds increased the film’s UV–Vis (ultraviolet–visible spectroscopy) absorbance, confirming the presence of chromophoric groups and the improvement of light-barrier properties. FTIR (Fourier Transform Infrared Spectroscopy) analysis revealed hydrogen bond formation and intermolecular interactions between polyphenols and the –OH/–NH groups of the biopolymer matrix, which enhanced the structural stability of the films. Adding blackberry and sage extracts slightly increased the hydrophilicity and solubility of the films (40–48%), without significantly affecting their water vapour transmission rate (531–547 g/m²·d). The obtained films exhibited strong antioxidant activity, with FRAP (Ferric Reducing Antioxidant Power) values ranging from 17.75 to 40.83 mM Trolox/mg, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging capacity between 42.58 and 46.88%, and metal chelating ability up to 50.82%. During the nine-day storage of salmon fillets at 4 °C, the active films effectively inhibited microbial growth (reduction of 1.5–2.1 log CFU/g) while maintaining pH stability (6.2–6.4). Respiration activity confirmed environmental safety. The developed materials represent biodegradable, multifunctional films with high potential for application as sustainable active packaging for perishable food products. Full article

The aim of this study was to use lemon balm extract (Melissa officinalis L.), prepared via microwave-assisted extraction, for the development of novel formulations of functional edible films based on chitosan, gum arabic, and gelatine (simple and blended formulations). This study focused on changes in the antioxidant properties of enriched films, in addition to their physicochemical and barrier performance for potential applications. Thickness, colour, transparency, water solubility, gas and water vapour permeability, total polyphenol content, and antioxidant capacity were evaluated. The addition of lemon balm extract resulted in an increased polyphenol content (of about 30%) and enhanced antioxidant properties (approximately three-fold), without influencing hydration-related properties (solubility, moisture content and water absorption). These parameters were significantly influenced by the matrix structure (neat chitosan vs. blends with gelatine and gum arabic). Significant increases in the oxygen (three-fold for neat chitosan and five-fold for blends) and carbon dioxide (21-fold for blends) permeability coefficients were also observed in all films with extracts. However, all values remained below 30 × 10⁻⁵ cm³ m⁻¹ d⁻¹ bar⁻¹, indicating that all films retained good gas barrier properties. The results indicate the potential of the developed material for applications in active food packaging as a sustainable alternative to traditional packaging materials, which should be further validated through studies on real food systems and shelf-life evaluation. Full article

Polyelectrolyte complexes (PECs) are recognized as promising materials for the development of sustainable food packaging. In this study, eco-friendly PECs based on pectin (P) and chitosan (C) were prepared by solvent casting at different pH values and volume ratios (C, P, 1C:1P, 1C:2.5P, and 1C:5P) (v/v). The resulting films were characterized for numerous features, including thickness, opacity, moisture content, swelling degree, and water solubility, while mechanical performance (elongation at break and tensile strength), water vapor transmission rate (WVTR), surface energy, and anti-adhesive activity were evaluated for the most promising formulation. The results revealed that blending chitosan with pectin significantly improved the films’ physicochemical properties, notably by increasing thickness (up to 100 µm) and opacity (slightly above 2) while reducing the swelling degree (from over 1800% for pure chitosan to below 600% for 1C:2.5P film at pH 3.2) and the water solubility (from 100% for pectin films to around 45–50% for the blended films). The film 1C:2.5P at pH 3.2 showed improved barrier performance, with a lower WVTR (approximately 20 g/h·m²) compared to the single polymer films (more than 30 g/h·m²), and exhibited significant anti-adhesive activity by reducing bacterial adhesion to below 5% compared to 65% for the conventional packaging film. However, these improvements were accompanied by reduced tensile strength (From ~4.2 MPa to ~1.3 MPa) and in elongation at break (from ~50% to ~20%). Overall, PEC films demonstrate strong potential as sustainable packaging materials by combining improved barrier properties and anti-adhesive activity, despite some limitations in mechanical resistance. Full article

Sunset Yellow is a water-soluble synthetic dye resistant to degradation and stable under various conditions, posing an environmental challenge. In the present study pure chitosan hydrogel (PCH) films were synthesized, followed by the assessment of sorption capacity and recyclability compared to chitosan-based films doped with niobium oxide (CHN) or activated carbon (CHC). The aim was to promote the application of sorption methods for Sunset Yellow dye using these films as a treatment option for the pollutant, with the analysis of the effectiveness of the method and its behavior using adsorption kinetic models and thermodynamic analysis. Equilibrium was reached at 240 min for all films tested, with the adsorbed amounts ranging from 18.58 to 18.79 mg g⁻¹ at 30 °C, when the highest kinetic rate constants were observed. The pseudo-first-order kinetic model best described the experimental data, with the lowest Bayesian information criterion, Akaike information criterion, and mean absolute error values. Thermodynamic analysis indicated a spontaneous, exothermic process, with interactions ranging from electrostatic interactions in CHC and PCH to physisorption in CHN. Recycling tests showed 80% efficiency after the third cycle for all three films. These findings highlight the potential of chitosan-based films as an efficient option for removing Sunset Yellow dye from water, thus improving water quality and enhancing wastewater treatment. Full article

Poly(vinyl alcohol)/chitosan (PVA/CS) biodegradable films reinforced with acid-functionalized multi-walled carbon nanotubes (f-MWCNTs) were fabricated via solution casting to investigate the effects of nanotube incorporation on structural, mechanical, thermal, dielectric, and physicochemical properties. Unlike conventional CNT-reinforced systems, this study focuses on the role of acid functionalization in improving nanotube dispersion and interfacial interactions, enabling simultaneous enhancement of multiple performance characteristics. Fourier transform infrared spectroscopy (FTIR) analysis confirmed strong intermolecular interactions between PVA/CS functional groups and carboxyl groups on f-MWCNTs, while scanning electron microscopy (SEM) revealed homogeneous nanotube dispersion at low loadings and partial aggregation at higher contents. X-ray diffraction (XRD) indicated that crystallinity was modified in a non-monotonic manner with increasing nanotube concentration due to competing nucleation and chain-restriction effects, while dielectric measurements showed an increase in dielectric constant from 3.78 to 4.27 as a result of enhanced interfacial polarization. The thermal conductivity improved from 0.195 to 0.247 W·m⁻¹·K⁻¹, and tensile strength increased from 19.8 to 24.5 MPa at 0.2 wt.% f-MWCNT, with elongation at break decreasing from 37.9% to 25.1%, reflecting increased stiffness. The degree of swelling and water solubility decreased with higher nanotube content, indicating reduced hydrophilicity and enhanced structural compactness. The results provide new insights into how surface-functionalized nanofillers can be used to tailor the multifunctional performance of biodegradable polymer nanocomposite films, highlighting their potential in advanced applications such as sustainable packaging, flexible electronics, sensors, and membrane technologies. Full article

To address inherent limitations of chitosan-based edible films, including inadequate mechanical strength and poor moisture resistance, cellulose nanofibers (CNF) were employed as a synergistic film-forming component to partially substitute chitosan in the fabrication of ternary composite films (denoted as CSTF-CNFs). This approach was based on a previously developed chitosan matrix modified with tannin-Fe³⁺ nanoparticles (TF). It was hypothesized that CNF could function as a reinforcing scaffold to improve the dispersion of TF within the film matrix and, through hydrogen bonding and physical entanglement, form an interpenetrating fiber network with chitosan, thereby enhancing the structural and barrier properties of the films. The present study systematically evaluated the influence of varying CNF substitution ratios (0–30%) on the physicochemical characteristics of the resulting composite films and their performance in tomato preservation. The results demonstrated that an appropriate CNF incorporation facilitated the formation of a dense, cross-linked network with chitosan and TF via hydrogen bond interactions, significantly improving both mechanical strength and water resistance. Among all formulations, the CSTF-CNF20 film exhibited optimal comprehensive performance, achieving the highest tensile strength of 27.60 MPa. Moreover, its swelling ratio markedly decreased from 675.5% (CSTF-CNF0) to 120.9%, while the water contact angle increased to 113.7°, and the DPPH radical scavenging activity remained above 85%. Tomato preservation assays revealed that, in comparison with the untreated control and polyethylene film-wrapped groups, the application of CSTF-CNF20 coating effectively mitigated the decline in weight loss and firmness, preserved surface color integrity, and resulted in the highest L* value alongside the lowest soluble solids content. These findings suggest that the synergistic integration of CNF with nano-scale metal–phenolic networks offers a viable strategy for developing high-performance chitosan-based edible films. The CSTF-CNF20 composite film holds significant promise for application in the postharvest preservation of fruits and vegetables. Full article

This study investigates the valorisation of Salicornia ramosissima agro-industrial by-product by using cellulose nanofibers (CNFs) extracted from this halophyte to reinforce chitosan-based films. The physical, mechanical, and thermal properties of chitosan films containing 0% (control), 1%, and 2% (w/w) CNF were evaluated. Films were produced by solvent casting with glycerol as a plasticiser. At the 2% CNF concentration, films exhibited a reduced moisture content and increased solubility in aqueous solutions. The water vapour transmission rate (WVTR) decreased as CNF content increased under constant humidity but increased at higher temperature and humidity. Control films were more transparent, yet CNF-reinforced films had higher tensile strength and Young’s modulus, reflecting greater stiffness. Maximum elongation at break decreased markedly with the addition of CNFs. SEM revealed that reinforced films had more heterogeneous, rougher surfaces, particularly at 2% CNF. Thermogravimetric analysis showed that 2% CNF adversely affected the thermal stability of the chitosan film. ATR-FTIR spectra indicated that CNF reinforcement protected against UV-induced degradation. Degradability tests in soil and seawater confirmed that the chitosan–CNF mixture preserved degradability, especially at 1% CNF. These findings demonstrate that reinforcing chitosan-based films with CNFs from S. ramosissima can improve functional properties and suggest the potential of this approach for biomaterials development in food packaging applications. Full article

Polymer–drug conjugates (PDCs) represent an advanced drug delivery strategy designed to address critical limitations of conventional therapeutics, including poor water solubility, rapid systemic clearance, and off-target toxicity. By covalently linking therapeutic agents to polymeric carriers through rationally designed linkers, PDCs enable improved pharmacokinetic profiles, enhanced stability, and controlled drug release. This review provides a comprehensive overview of the key design principles governing PDC systems, with a particular focus on the role of biofunctional polymers. Essential parameters for polymer selection, including biocompatibility, biodegradability, molecular weight, and functional group availability, are discussed in relation to their influence on drug loading, release kinetics, and biological performance. In addition, both natural and synthetic polymers are evaluated for their ability to improve solubility, modulate biodistribution, and reduce systemic toxicity. An overview of stimuli-responsive PDCs is provided, including pH-, redox-, and temperature-sensitive systems, which enable site-specific and spatiotemporally controlled drug release in response to pathological microenvironments. We emphasize the special role of bioactive polymers such as poly-lysine, hyaluronic acid, chitosan, and gelatin for their intrinsic biological activity, including receptor-mediated targeting, antimicrobial activity, and synergistic therapeutic effects. These properties support the development of dual-active conjugates with enhanced specificity and efficacy. Overall, this review underscores the transition of polymers from passive carriers to active therapeutic components and outlines current challenges and future perspectives for the clinical translation of next-generation PDCs. Full article

In this study, a multicomponent composite film system based on alginate, chitosan, κ-carrageenan, agar, and Rapana venosa protein hydrolysate (RVPH) was developed, and the effect of RVPH incorporation (0–1.5%) on molecular interactions, microstructure, and functional performance was evaluated using FTIR, SEM, mechanical testing, optical analysis, and water-related measurements. FTIR results indicated that RVPH interacted with the polysaccharide matrix mainly through hydrogen bonding and ionic interactions without causing chemical degradation. SEM analysis revealed concentration-dependent microstructural changes, with smoother morphologies at low RVPH levels and increased roughness and heterogeneity at higher concentrations. These structural differences were reflected in the functional properties. All films exhibited high swelling and water solubility. Optical properties were significantly affected by RVPH. Mechanical properties exhibited a non-linear response, with numerical variations observed but no statistically significant differences (p > 0.05). The EDAS and SWARA methods were employed to determine the optimal incorporation level of RVPH in the film formulations. Among the RVPH-containing films, the formulation incorporating 1% RVPH was identified as the most suitable alternative. Full article

Paclitaxel is a first-line anticancer drug, but its low water solubility impedes bioavailability. The purpose of this study is to estalish a delivery strategy via carboxymethyl chitosan (CMCS)-encapsulated 6-deoxy-6-mercapto-β-cyclodextrins (dmβCDs)-modified concave cubic gold (CCGs) to achieve PTX release. CCGs were initially synthesized by the one-pot method and further modified by dmβCDs, the dmβCDs can effectively capture PTX molecules, followed by encapsulation with CMCS, and then prepare pH-responsive CMCS/dmβCDs/CCGs nanocarriers after lyophilization. Results indicated that desirable hexagonal CCGs with 50 ± 5 nm size can be obtained by adjusting H₂O₂ and HClO concentration. FT-IR, Raman and XRD spectra had confirmed dmβCDs successfully grafted to the surface of CCGs. Drug loading experiments demonstrated that the nanocarrier encapsulated PTX in amorphous powder or molecular form have a capacity of 55.05 µg/mL. Drug release experiments revealed PTX release from CMCS/dmβCDs/CCGs nanocarriers carrying a typical pH-responsive profile and indicating earlier release in an acidic environment than in a neutral or alkaline environment. The proposed method can be utilized to effectually achieve high-efficiency solubilization and targeted release inside tumor cells of PTX. Full article

Algae extracts have emerged as a sustainable and eco-friendly alternative to synthetic dyes and functional additives in the textile industry, particularly for dyeing and functionalizing of cotton fabrics. Herein, two types of water-soluble algae extracts from Arthrospira platensis and Porphyridium cruentum were characterized in terms of thermal, structural, and functional properties and used as dye and/or functional agents. Cotton samples were pre-treated with chitosan and alum mordants and compared with commercially treated cationic cotton. The algae extracts were applied through the exhaust method, with variations in temperature, pH, liquor ratio, temperature rise gradient, and extract percentages. The resulting colours, assessed through CIE L*a*b* coordinates and K/S values using UV–Vis spectroscopy, displayed green and pink coloration, with commercial cationic cotton exhibiting more intense colours. Colour fastness measurements were also performed on functionalized cotton fabrics. The water-based algae extracts and functionalized samples were additionally characterized for functional features, displaying an antioxidant activity exceeding 60% (68.13 ± 3.60 and 60.76 ± 1.18, for A. platensis and P. cruentum, respectively). This work highlights their dual role in providing both aesthetic dyeing and functional enhancement of cotton. By using renewable marine resources and eco-friendly water-based processes, this approach supports the development of greener, more sustainable textile technologies. Full article

‘Barhi’ dates (Phoenix dactylifera L.) are highly prized and widely consumed at the khalal stage, but they are only available for a short time, which highlights the importance of extending their storage life. This study examined the effectiveness of edible coatings in delaying ripening and maintaining fruit quality during cold storage (2 °C). The treatments tested were gelatin alone or gelatin combined with chitosan, Aloe vera gel (AVG), or gum arabic, and applied in a layer-by-layer (LbL) approach. A fifth treatment consisting of deionized water was used as a reference untreated control. The fruit parameters measured included weight loss, decay, moisture content, ripening (rutab transformation), firmness, color (lightness and hue angle), total soluble solids (TSS), titratable acidity (TA), TSS/TA ratio, total sugars, total polyphenols, and enzymatic activity. Results indicated that the LbL edible coating was more effective in preserving postharvest quality. Regarding weight loss and decay rate, the results showed that the control treatment consistently had 1.5–5-fold higher deterioration indicators than the coated fruits. Among the tested treatments, the gum arabic and gelatin coating was the most effective compared to the untreated control, reducing weight loss by over 40%, lowering decay by approximately 80%, and maintaining significantly higher moisture content throughout storage. Concerning carotenoid levels, the untreated fruits exhibited approximately 1.2–1.4-fold higher carotenoid content than the coated fruits. Fruits treated with gum arabic and gelatin exhibited the best preservation effect Sby limiting TSS increase and maintaining higher TA compared with the control. This treatment best maintained antioxidant capacity and phenolic content while significantly suppressing the activities of polyphenol oxidase and peroxidase. Overall, the LbL coating strategy successfully maintained the quality of ’Barhi’ dates by mitigating oxidative and enzymatic degradation throughout storage. Principal component analysis and hierarchical cluster analysis demonstrated that treatments gum arabic and gelatin exhibited superior effectiveness in extending the date storage life in terms of physicochemical properties and antioxidant activity, followed by chitosan and gelatin, and Aloe vera and gelatin, compared to the control fruits over a 60-day storage period. Full article

With the increasingly stringent environmental regulations, the development of high-performance and eco-friendly shale inhibitors for water-sensitive formations has become an urgent priority. Chitosan, a renewable biopolymer derived from chitin, has inherent potential as a shale inhibitor but is limited by low water solubility and suboptimal inhibition efficiency. To overcome these limitations, cationic quaternary ammonium groups were grafted onto chitosan through etherification with 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHA), yielding chitosan quaternary ammonium chloride (QASC). Systematic evaluation through linear swelling, rolling recovery, and bentonite inhibition tests revealed QASC’s superior performance. Notably, 1% QASC reduced bentonite swelling to 28.1% after 16 h, outperforming 5% KCl (48.2%) and 1% polyetheramine (41.1%). Remarkably, QASC achieved 88.4% shale recovery at 150 °C significantly exceeding the values for polyetheramine (52%) and pure water (13.2%). Mechanistic analysis revealed that QASC inhibits clay hydration through dual mechanisms: (1) electrostatic and hydrogen-bond mediated adsorption on clay surfaces, effectively neutralizing surface charges and diminishing hydration films; (2) intercalation into clay interlayers to create a physical barrier against water invasion. This synergistic combination ensures stable inhibitory performance under elevated temperatures. Given its enhanced biodegradability, QASC emerges as a sustainable alternative to conventional inhibitors, effectively addressing the dual challenges of technical performance and environmental compatibility in shale gas drilling operations. Full article