Search Results (18)

The development of sustainable, smart food packaging materials that simultaneously provide antimicrobial protection and real-time monitoring of food quality is a critical frontier in food safety. This study reports the fabrication of a multifunctional amphiphilic emulgel designed for the detection of pathogen-induced metabolic pH changes in food systems. The system utilizes Pomegranate-derived nitrogen-doped quasi-spherical carbon dots (QS-CDs) as fluorescent nanoprobes and Rosemary Essential Oil (REO) as a natural antimicrobial agent, both encapsulated within a polyelectrolyte complex of chitosan and sugarcane bagasse-derived carboxymethyl cellulose (CMC). A low degree of substitution (DS = 0.4) was specifically engineered for the CMC to ensure an amphiphilic character, enabling nanocomposite complex stabilization of the REO droplets without synthetic surfactants. Structural characterization via Transmission Electron Microscopy (TEM) revealed well-dispersed QS-CDs (4.71–6.62 nm) and stable oil droplets (~605.49 nm) anchored within a zipped polymer network. Thermal analysis (TGA/DSC) using the Coats–Redfern model revealed a significant synergistic effect: the smart-emulgel exhibits a distinct two-stage degradation profile, with the high-temperature stage requiring an activation energy (E_a) of 95.19 kJ/mol, a substantial increase over the corresponding stage in the CD-emulgel baseline (18.69 kJ/mol). This enhanced stability is complemented by a slight increase in crystallinity (X_c from 0.11 to 0.14). While the smart-emulgel remains predominantly amorphous, this shift suggests that the integration of REO and QS-CDs into the polymer network promotes the formation of localized, more ordered domains, contributing to a more robust and structurally integrated matrix. The emulgel demonstrated a dual-mode optical response (colorimetric and fluorometric) sensitive to the metabolic byproducts (e.g., organic acids, amines, other alkaline compounds) produced by Escherichia coli and Staphylococcus aureus. These findings were corroborated by Density Functional Theory (DFT) calculations, which confirmed the thermodynamic stability and optimized electronic energy gaps for pH-responsive sensing. This research provides a green, high-performance platform for the real-time monitoring of food freshness and the prevention of foodborne illnesses. Full article

The food-packaging sector is undergoing a major transition driven by the environmental burden associated with petroleum-based plastics and the increasing demand for sustainable alternatives. In this context, biodegradable packaging materials capable of extending food shelf life through active preservation functions have attracted considerable interest. Cellulose is the most abundant natural polymer and an attractive candidate for sustainable packaging; however, it lacks intrinsic antimicrobial activity. In the present study, innovative carboxymethyl cellulose (CMC)-based composite films were developed by incorporating zinc oxide (ZnO) nanoparticles (NPs) and thyme essential oil (TEO) as antibacterial active agents. The obtained films exhibited strong antibacterial activity against both Escherichia coli and Staphylococcus aureus, completely eliminating planktonic cell viability after 3 h of contact and producing inhibition zones of up to 30 mm. In addition to their biological performance, the composite films showed improved mechanical and functional properties. ZnO NPs appear to act as multifunctional junctions within the CMC matrix, while the dispersed TEO droplets contribute, together with the inorganic phase, to reduced water-vapor transfer. The films retained good transparency in the visible range while exhibiting UV-A transmittance below 7%, indicating enhanced light-barrier performance. Preliminary tests on soft cheese indicated shelf-life extension up to 14 days at 4 °C, while in inoculated cheese slices packed in the composite films, S. aureus was not detected from the 3rd day. Overall, these results demonstrate the potential of CMC/ZnO/TEO composite films as biodegradable active packaging materials for perishable food products. Full article

The advancement of smart packaging technology demands high-performance and sustainable sensing materials. While starch is a biodegradable natural polymer, its inherent high crystallinity restricts charge transport capability. This study developed a novel smart sensing film by incorporating ellagic acid-derived blue, fluorescent carbon dots (CDs) into phosphate starch (PS), which is rich in phosphorus. The effects of silver ions (Ag⁺), sodium carboxymethyl cellulose (CMC), and CDs on the film properties were systematically investigated. Results indicate that CDs act as flexible nano-crosslinkers, forming hydrogen bonds with PS molecular chains and effectively balancing strength and toughness—achieving a tensile strength of 5.1 MPa and an elongation at break of 24.1%. Phosphorus, in synergy with CDs, facilitates an efficient dual conduction pathway for ions and electrons: phosphate groups enable ion transport, while the conjugated carbon cores of the CDs provide electron transport channels. This synergistic effect significantly reduces the film’s electrical impedance from 6.93 × 10⁶ Ω to 1.12 × 10⁶ Ω (a reduction of 84%) and enhances thermal stability, increasing the char residue from 1.1% to 18.3%. The PS/CDs composite film exhibits a strong linear current response to pH in the range of 2–7 (R² = 0.9450), and shows enhanced discrimination between fresh orange juice (pH = 3.38) and spoiled orange juice (pH = 2.68), with a current change of 0.62 × 10⁻⁵ A. Moreover, the film exhibits strong blue fluorescence at 427 nm, with an intensity that shows a pronounced pH-dependent response. This study elucidates the mechanism by which phosphorus and CDs synergistically enhance the sensing performance of starch-based films, offering a new strategy for developing high-performance starch-based materials for smart packaging. Full article

Carboxymethyl cellulose (CMC) films, derived from sugarcane bagasse agricultural waste (SCB) incorporated with Betalains-nitrogen-doped carbon dots (Betalains-N–CQDs), derived from beet root waste (BR), offer a sustainable, smart and naked-eye sensor for strawberry packaging due to their excellent fluorescent and shape memory properties. These CMC-Betalains-N–CQDs aim to enhance strawberry preservation and safety by enabling visual detection of common food contaminants such as bacteria, fungi and Pb(II). Crucially, the CMC-Betalains-N–CQD film also exhibits excellent shape memory properties, capable of fixing various shapes under alkaline conditions and recovering its original form in acidic environments, thereby offering enhanced physical protection for delicate produce like strawberries. Optical studies reveal the Betalains-N–CQDs’ pH-responsive fluorescence, with distinct emission patterns observed across various pH levels, highlighting their potential for sensing applications. Scanning Electron Microscopy (SEM) confirms the successful incorporation of Betalains-N–CQDs into the CMC matrix, revealing larger pores in the composite film that facilitate better interaction with analytes such as bacteria. Crucially, the CMC-Betalains-N–CQD film demonstrates significant antibacterial activity against common foodborne pathogens like Escherichia coli, Staphylococcus aureus, and Candida albicans, as evidenced by inhibition zones and supported by molecular docking simulations showing strong binding interactions with bacterial proteins. Furthermore, the film functions as a fluorescent sensor, exhibiting distinct color changes upon contact with different microorganisms and Pb(II) heavy metals, enabling rapid, naked-eye detection. The film also acts as a pH sensor, displaying color shifts (brown in alkaline, yellow in acidic) due to the betalains, useful for monitoring food spoilage. This research presents a promising, sustainable, and multifunctional intelligent packaging solution for enhanced food safety and extended shelf life. Full article

This study reports the synthesis and characterization of a novel carboxymethyl cellulose–N-fullerene–g-poly(co-acrylamido-2-methyl-1-propane sulfonic acid) (CMC–N-fullerene–AMPS) hydrogel for potential application in biosensing within food packaging. The hydrogel was synthesized via free radical polymerization and characterized using FTIR, SEM, and fluorescence microscopy. FTIR analysis confirmed the successful grafting of AMPS and incorporation of N-fullerenes, indicated by characteristic peaks and a shift in the N–H/O–H stretching frequency. Density Functional Theory (DFT) calculations revealed that the CMC–N-fullerene–AMPS hydrogel exhibited higher stability and a lower band gap energy (0.0871 eV) compared to the CMC–AMPS hydrogel, which means a high reactivity of CMC–N-fullerene–AMPS. The incorporation of N-fullerenes significantly enhanced the hydrogel’s antibacterial activity, demonstrating a 22 mm inhibition zone against E. coli and a 24 mm zone against S. aureus, suggesting potential for active food packaging applications. Critically, the hydrogel displayed a unique “turn-on” fluorescence response in the presence of bacteria, with distinct color changes observed upon interaction with E. coli (orange-red) and S. aureus (bright green). This fluorescence enhancement, coupled with the porous morphology observed via SEM (pore size 377–931 µm), suggests the potential of this hydrogel as a sensing platform for bacterial contamination within food packaging. These combined properties of enhanced antibacterial activity and a distinct, bacteria-induced fluorescence signal make the CMC–N-fullerene–AMPS hydrogel a promising candidate for developing intelligent food packaging materials capable of detecting bacterial spoilage. Full article

Background: Epizootics of largemouth bass ranavirus (LMBRaV) in largemouth bass (Micropterus salmoides) populations are associated with elevated mortality and significant financial losses. Given the lack of effective and safe medication to treat this disease, oral vaccination, which directly targets the intestinal mucosal immune system, is crucial for disease resistance. Methods: This study utilized carboxymethyl cellulose (CMC) to coat LMBRaV inactivated vaccine (LIV) (micro-CMC@LIV). The morphology and characteristics of the CMC microcapsules were determined. In vitro simulated gastric and intestinal conditions were used to validate that the microcapsules could tolerate gastric conditions and subsequently release their contents in the intestinal tract. This was confirmed using CMC-coated coumarin 6 (C6) fluorescence microcapsules. Results: After the oral administration of micro-CMC@LIV, the detection of LMBRaV major capsid protein confirmed effective antigen release and absorption in the midgut and hindgut. Neutralizing antibody titers were significantly higher (1:81.71) in the micro-CMC@LIV group compared to the uncoated vaccine group (1:21.69). The expression of genes linked to the innate and adaptive immune systems was upregulated post-micro-CMC@LIV treatment. Following the LMBRaV challenge, the micro-CMC@LIV group exhibited a relative percent survival (RPS) of 82.14%, significantly higher than the uncoated vaccine group (61.61%). Droplet digital PCR analysis revealed significantly lower viral loads in the liver, spleen, and head kidney of the micro-CMC@LIV group compared to the control group and the uncoated vaccine group. Conclusions: These results collectively suggest that the CMC-coated LIV can be effectively delivered to the intestinal tract and induce robust antibody and immune responses, providing a reliable method for preventing and controlling LMBRaV disease in the largemouth bass industry. Full article

Carboxymethyl cellulose (CMC) was prepared from sugarcane bagasse (SB) in minutes using a novel microwave method. Additionally, nitrogen-doped carbon dots (N–CDs) were synthesized from SB using the same microwave technique. These materials were crosslinked with CaCl₂ to prepare antibacterial/antifungal hydrogel sensors. In this regard, both CMC@Ca and CMC@Ca-N–CDs exhibited antibacterial activity against Escherichia coli (Gram negative), while only CMC@Ca-N–CDs demonstrated antibacterial activity against Staphylococcus aureus (Gram positive). Moreover, both materials showed antifungal activity against Candida albicans. The molecular docking study demonstrated that CMC@Ca-N–CDs showed good binding with proteins with short bond length 2.59, 2.80, and 1.97 A° for Escherichia coli, Staphylococcus aureus, and Candida albicans, respectively. These binding affinities were corroborated by the observed inhibition zone diameters. Furthermore, fluorescence microscope revealed distinct imaging patterns between Gram-positive and Gram-negative bacteria, as well as pathogenic yeast (fungi). CMC@Ca-N–CDs emitted blue light when exposed to Escherichia coli and Candida albicans (i.e., CMC@Ca-N–CDs/Escherichia coli and Candida albicans), whereas it emitted bright-red light when exposed to Staphylococcus aureus (i.e., CMC@Ca-N–CDs/Staphylococcus aureus). This disparity in the fluorescence-emitted colors is due to the difference in the cell wall of these microorganisms. Additionally, DFT calculations were conducted to substantiate the robust chemical interactions between CMC, Ca²⁺, and N–CDs. Full article

Skin wounds often form scar tissue during healing. Early intervention with tissue-engineered materials and cell therapies may promote scar-free healing. Exosomes and extracellular vesicles (EV) secreted by mesenchymal stromal cells (MSC) are believed to have high regenerative capacity. EV bioactivity is preserved after lyophilization and storage to enable use in remote and typically resource-constrained environments. We developed a bioprinted bandage containing reconstituted EVs that can be fabricated at the point-of-need. An alginate/carboxymethyl cellulose (CMC) biomaterial ink was prepared, and printability and mechanical properties were assessed with rheology and compression testing. Three-dimensional printed constructs were evaluated for Young’s modulus relative to infill density and crosslinking to yield material with stiffness suitable for use as a wound dressing. We purified EVs from human MSC-conditioned media and characterized them with nanoparticle tracking analysis and mass spectroscopy, which gave a peak size of 118 nm and identification of known EV proteins. Fluorescently labeled EVs were mixed to form bio-ink and bioprinted to characterize EV release. EV bandages were bioprinted on both a commercial laboratory bioprinter and a custom ruggedized 3D printer with bioprinting capabilities, and lyophilized EVs, biomaterial ink, and thermoplastic filament were deployed to an austere Arctic environment and bioprinted. This work demonstrates that EVs can be bioprinted with an alginate/CMC hydrogel and released over time when in contact with a skin-like substitute. The technology is suitable for operational medical applications, notably in resource-limited locations, including large-scale natural disasters, humanitarian crises, and combat zones. Full article

The excessive emission of iron will pollute the environment and harm human health, so the fluorescence detection and adsorption of Fe³⁺ are of great significance. In the field of water treatment, cellulose-based gels have attracted wide attention due to their excellent properties and environmental friendliness. If carbon dots are used as a crosslinking agent to form a gel with cellulose, it can not only improve mechanical properties but also show good biocompatibility, reactivity, and fluorescence properties. In this study, silicon-doped carbon dots/carboxymethyl cellulose gel (DCG) was successfully prepared by chemically crosslinking biomass-derived silicon-doped carbon dots with carboxymethyl cellulose. The abundant crosslinking points endow the gel with excellent mechanical properties, with a compressive strength reaching 294 kPa. In the experiment on adsorbing Fe³⁺, the theoretical adsorption capacity reached 125.30 mg/g. The introduction of silicon-doped carbon dots confers the gel with excellent fluorescence properties and a good selective response to Fe³⁺. It exhibits a good linear relationship within the concentration range of 0–100 mg/L, with a detection limit of 0.6595 mg/L. DCG appears to be a good application prospect in the adsorption and detection of Fe³⁺. Full article

In this article, the performance of brass electrode was investigated in a Zn-air (charcoal-based cathode) rechargeable battery. The construction of the battery was carried out with biodegradable materials, namely a cotton cloth diaphragm and carboxymethyl cellulose sodium salt (CMC-Na) viscosity modifier, while the battery skeleton was printed by 3D printing technology. The brass acted as a collector and a preferable surface for the metallic Zn deposition on the brass anode surface. The electrochemical behavior of the brass anode was investigated by cyclic voltammetry (CV). Cyclic performance tests were carried out, which showed stable cell operation even in the presence or absence of additives up to more than 100 cycles. Furthermore, high energy (E_eff) and Coulomb (C_eff) efficiencies, 80% (E_eff), 95% (C_eff), 75% (E_eff), and 95% (C_eff) were obtained, respectively. The Shepherd model was applied to describe the discharging processes of the Zn-air battery containing brass as anode in the presence of additive-free electrolyte or electrolyte with CMC-Na salt additive. It was found that the Shepherd equation described only approximately the resulting discharge curves. In order to attain a more precise mathematical description, stretched exponential function was implemented into the last term of the Shepherd equation. The need for such a correction shows the complexity of the electrochemical processes occurring in these systems. In addition, the surface of the brass anode was also investigated by scanning electron microscopy (SEM) and the composition of the brass alloys was determined by X-ray fluorescence spectroscopy (XRF). Importantly, the formation of dendritic deposition was successfully suppressed and a smooth and uniform surface was obtained after the cycling tests. Full article

The transformation of organic pollutants by stabilized nano-FeS in oxic conditions is far less understood than in anoxic states. Herein, carboxymethyl cellulose-stabilized FeS (CMC-FeS) nanofluids are prepared at a CMC-to-FeS mass ratio of 1/2 and their performance of tetracycline hydrochloride (TC) degradation under oxic conditions was investigated. Here, we showed that TC could be efficiently removed by oxygenation of CMC-FeS nanofluids at neutral initial pH. We found that CMC-FeS dosages as low as 15 mg/L can achieve the TC removal efficiency as high as 99.1% at an initial TC concentration of 50 mg/L. Oxidative degradation plays a predominated role in TC removal (accounting for 58.0%), adsorption has the second importance (accounting for 37.0%), and reduction has minor impact (accounting for 4.1%) toward TC removal. Electron spin resonance assays, fluorescent detection using coumarin as a probe, and radical scavenging experiments confirm that hydroxy radicals (•OH), both in free and surface-bound forms, contribute to oxidation of TC. Humic acids brought detrimental effects on TC removal and therefore should be biologically degraded in advance. This work offers a facile and cost-effective solution to decontaminate TC in natural and engineered water bodies. Full article

The residual acrylamide in food paper packaging can be transferred into water and food, which will cause harmful effects on human beings. In this paper, a rapid and easily available fluorescent probe based on carboxymethyl cellulose (CMC)/Eu (Ⅲ) nanocomposites was designed to detect the residue acrylamide with high sensibility. The probe could respond in 1 min. The concentration of acrylamide was linearly correlated to the fluorescence intensity of the probe at the emission wavelength of 615 nm in the concentration range of 0.1–100 μmol/L. The limit of detection (LOD) of the probe was 0.085 μg/L, which is lower than the guideline value of the European Union, the U.S. EPA, and the WHO. An experiment was performed to simulate the acrylamide migrating from food-contacting paper materials to different foods, including waterborne food, alcohol beverage, acidic food, and greasy food. The recoveries and RSDs of acrylamide in all samples indicated that the CMC/Eu (Ⅲ) fluorescent probe was efficient for acrylamide detection. The possible mechanism of the probe for acrylamide detection involved both dynamically quenching and static quenching by forming of non-fluorescent substances. Full article

In this work, a novel fluorescent probe CMC−GE−AQ with an effective sensitive detection ability for Cu²⁺ was synthesized and constructed by using carboxymethyl cellulose (CMC) as the skeleton and 8-aminoquinoline (AQ) as the fluorophore. This probe exhibited a highly specific “turn-off” fluorescence response to Cu²⁺, and the fluorescence color changed from bright orange to colorless after adding Cu²⁺. The probe could selectively detect Cu²⁺ in a complex environment and its detection limit (LOD), the binding constant (K_a) and the numbers of binding sites (n) were calculated to be 6.4 × 10⁻⁸ mol L⁻¹, 1.7 × 10⁶ mol⁻¹ L and 1.2, respectively. The sensing detection mechanism was confirmed by X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations. In addition, the probe CMC−GE−AQ was successfully applied to detect Cu²⁺ in real water samples, and CMC−GE−AQ-based fluorescent microspheres can serve as a convenient tool for the detection of Cu²⁺. Full article

The influences of interactions between carboxymethyl cellulose (CMC) and CMC/europium (III)–terbium (III) (CET) on the structure and properties of the resultant CMC/CET films were investigated by rheology at three stages of the film-drying process. According to the water content at different drying times, the kinetics curves during the film-drying process were drawn. Then, the rheology properties of film-forming solutions during the drying process were characterized by dynamic modulus, Han plots, zero shear complex viscosity and relaxation time. When the water content was 90%, the film contained either 0.1 or 0.2 g of CET, which had good fluidity, while the film with 0.3 g of CET was elastic-dominated. Han plots and XRD analyses showed that the interactions between the CMC and CET were not hydrogen bonds but random entanglements. The zero-shear complex viscosity and relaxation time spectrum confirmed that the entanglements enhanced as the CET content increased. Meanwhile, aggregation formed in the solution of CMC with 0.3 g of CET. When CMC-CET films with different CET additions were compared, the film with 0.2 g of CET had an even and tight sheet structure, the greatest fluorescence intensity, and superior tensile strength of 78.76 MPa. Full article

In order to minimize the pollution caused by the reuse of textile dyes, technologies and materials have been developed that purify waste water in an efficient and cost-effective manner before it is discharged into a water body. In this context, the presented research investigates the potential of two types of fully cellulose-based membranes as adsorbents for cationic dyes used in the textile industry. The first type combines cellulose nanofibrils (CNFs) and carboxymethylated cellulose (CMC) using the solvent casting process and an esterification coupling reaction, while the second type uses commercial bacterial cellulose (BC) in a native and sodium periodate-treated form (BCox). The corresponding membranes were comprehensively evaluated by means of Fourier Transform Infrared (FTIR) Spectroscopy. Results confirm the esterification process within the CNF/CMC membranes, as well as BC oxidation after periodate treatment, as shown by bands at 1726.2 cm⁻¹ and 895 cm⁻¹, respectively. The Potentiometric Titration shows the highest total negative charge of 1.07 mmol/g for 4CNF/4CMC, which is assigned to the presence of COO⁻ within CMC polymers, and lowest (0.21 mmol/g) for BCox. The Contact Angle Goniometry data confirm the hydrophilicity of all membranes, and the angle increased from 0 ° (in pure BC) to 34.5 ° in CMC-rich and to 31.4 ° in BCox membranes due to the presence of CH₂COO⁻ and CHO groups, respectively. Confocal Fluorescent Microscopy (CFM) demonstrated the highest µ-roughness in 4CNF/4CMC, while Scanning Electron Microscopy (SEM) depicted diverse morphological features between the membranes, from ultrafine nanofiber networks (in BC and BCox) to larger fiber bundles connected within the polymer phase in CNF/CMC membranes. The adsorption experiment followed by UV–VIS spectroscopy, showed ~100% dye removal efficiency in both CNF/CMC-based membranes, while BC and BCox adsorbed only 24.3% and 23.6%, respectively, when anthraquinone dye was used. Azo dye was only adsorbed with an efficiency of 7–9% on CMC/CNF-based membranes, compared with 5.57% on BC and 7.33% on BCox membranes. The adsorption efficiency at equilibrium was highest for BC (1228 mg/g) and lowest for 7CNF/1CMC (419.24 mg/g) during anthraquinone dye adsorption. In the case of azo dye, the BCox was most effective, with 445.7 mg/g. Applicability of a pseudo second-order model was confirmed for both dyes and all membranes, except for BCox in combination with azo dye, showing the fastest adsorption rate in the case of the 7CNF/1CMC membrane. Full article