Antibacterial Properties Research Articles

Improving the lubricity of titanium alloy joint by using tough, antibacterial and strongly adhesive hydrogel

Titanium alloy, especially Ti6Al4V, has gained widespread recognition as a material for joint implant. Aiming at the problems such as high friction and easy infection of Ti6Al4V implant materials in practical applications, a strategy of surface modification of Ti6Al4V was proposed. Inspired by the articular cartilage, a tough hydrogel integrated with lubricating and antibacterial properties was prepared in this work, and tightly applied to the Ti6Al4V surface with an adhesive agent. The strength of the hydrogel coating was similar to that of human articular cartilage, and play remarkable lubricating and antibacterial effects at the same time. This work presented new perspectives on the application of hydrogel coatings in biomedicine, underwater equipment, smart manipulation, and other fields.

The Impact of Titanium Hydroxyapatite Doping on the Mechanical and Biological Properties of Photocured Resin.

Photocured resin materials are widely used in various fields, such as 3D printing, medical applications, and dentistry. However, the strength, wear resistance, and antibacterial properties of photocured resin are relatively limited, rendering it susceptible to potential failures. In this recent study, photocured composite resins incorporating titanium-doped hydroxyapatite (Ti-HAp) were fabricated to investigate their mechanical and biological properties. It was found that the hardness and wear resistance increased with the addition of an appropriate amount of hydroxyapatite (HAp). Specifically, the 6wt%HAp resin demonstrated superior hardness. Compared with the 6wt%HAp resin, the acid resistance and wear resistance improved when an appropriate amount of Ti-HAp was added. Notably, the resin containing 0.56%Ti-HAp demonstrated superior wear resistance. Additionally, the antibacterial performance improved with higher titanium (Ti) content, showcasing a 71.9% improvement in the resin containing 1.37%Ti-HAp compared with the 6wt%HAp resin, alongside commendable remineralization capabilities. In summary, the Ti-HAp composite resin showed enhanced mechanical and biological properties, meeting clinical standards in terms of mechanical and antibacterial properties.

Potential Pharmacological Properties of Triterpene Derivatives of Ursolic Acid.

Ursolic acid (UA) and its derivatives have garnered significant attention due to their extensive pharmacological activity. UA is a pentacyclic triterpenoid found in a variety of plants, such as apples, rosemary, thyme, etc., and it possesses a range of pharmacological properties. Researchers have synthesized various derivatives of UA through structural modifications to enhance its potential pharmacological properties. Various in vitro and in vivo studies have indicated that UA and its derivatives possess diverse biological activities, such as anticancer, antifungal, antidiabetic, antioxidant, antibacterial, anti-inflammatory and antiviral properties. This review article provides a review of the biological activities of UA and its derivatives to show their valuable therapeutic properties useful in the treatment of different diseases, mainly focusing on the relevant structure-activity relationships (SARs), the underlying molecular targets/pathways, and modes of action.

Functional Cyperus esculentus L. Cookies Enriched with the Probiotic Strain Lacticaseibacillus rhamnosus SL42.

This study presents for the first time functional cookies for diabetics made with 100% organic Cyperus esculentus L. flour, either plain or enhanced with 5% polyfloral honey syrup containing the probiotic strain Lacticaseibacillus rhamnosus SL42. The flour's chemical composition and rheological and functional properties were analyzed, and 33 diabetic and semi-naive panelists assessed the cookies' sensory properties. MRS-cys agar cultures and SEM analysis evaluated SL42 survival and adhesion capacity over 21 days at 25 °C. Results showed that the flour and its extracts are rich in polyphenols and flavonoids, indicating strong antioxidant and antibacterial properties. Both cookie types met international standards when compared to commercial cookies and had similar physical properties. Sensory evaluation on day 1 revealed higher quality indicators for honey syrup-enriched cookies, but after 15 days, control cookies were preferred. The CIE LAB analysis confirmed the dietetic flour's typical dark color, with honey syrup-enriched cookies being darker. Despite textural differences, both cookies maintained detectable crispness over storage. Honey syrup-enriched cookies effectively carried L. rhamnosus SL42, remaining viable at 6.43 Log CFU per cookie after 21 days and adhering to the cookie's surface, as confirmed by SEM analysis. Further research is recommended to better understand the therapeutic value of these cookies.

Synthesis of Fe3O4@SiO2–branched polyethylenimine nanospheres for removal of Cr(VI) and anionic dyes

There is a need to design and prepare new sorbents for the effective elimination of toxic metal ions and textile dyes from the environment. In the presented study, the preparation of magnetic functionalized silica composite nanospheres for the removal of inorganic and organic pollutants from aqueous solutions is reported. Firstly, the surface of silica coated magnetic nanospheres was functionalized with epoxy groups via a reaction of 3-glycidoxypropyltriethoxysilane. Then, the branched polyethylenimine (BPEI) was attached to generate positive functional charged groups on the on the Fe3O4@SiO2. The performance of the Fe3O4@SiO2-BPEI nanospheres for the removal of Cr(VI) and Congo Red (CR) and Trypan Blue (TB) dyes was studied under various experimental conditions. The optimum pHs values for adsorption of Cr(VI) ions, CR and TB dyes on the Fe3O4@SiO2-BPEI nanospheres were found to be at pH 2.0, and at pH 4.0, respectively. The maximum adsorption capacities of the Fe3O4-@SiO2-BPEI nanospheres for Cr(VI), CR, and TB were obtained as 356.7, 395.3, and 561.8 mg/g within 90 min equilibrium time, an initial concentration of 500 mg/L, and at 25 ºC, respectively. The adsorption of the tested pollutants were well described by the Langmuir isotherm model and second-order kinetic model. After ten reuse cycles, the adsorption capacity of Fe3O4-@SiO2-BPEI nanospheres was not significantly changed for the tested pollutants. The adsorption mechanism of Cr(VI), CR, and TB by the Fe3O4-@SiO2-BPEI nanospheres was evaluated to be related to ion exchange and ion exchange and/or hydrogen bonding interactions, respectively. The results also suggested that the presented adsorbent may serve as a multi-functional adsorbent for the remediation of industrial effluents. In addition, compared to the unmodified Fe3O4@SiO2, the Fe3O4@SiO2-BPEI nanospheres have antibacterial activities against Escherichia coli (American Type Culture Collection (ATCC) 12435), Pseudomonas aeruginosa (ATCC 10145), Listeria monocytogenes (ATCC 7644), and Staphylococcus aureus (ATCC 43300). Based on the obtained results from this work, the branched polyethylene functionalized magnetic silica nanospheres with antibacterial properties can be used as a potential adsorbent for the removal of metal ions and anionic dyes from wastewater.

Phase Transformation and Mechanical Optimization of Eggshell-Derived Hydroxyapatite across a Wide Sintering Temperature Range.

Calcium phosphate, particularly hydroxyapatite (HA), bears a close resemblance to human bones, rendering it a prevalent material in biomedical applications. This study focuses on the successful preparation of HA using a precipitation method with eggshell as a raw material. Subsequently, the HA powder was press-formed and sintered at various temperatures to investigate the impact of sintering temperature on the mechanical properties, including hardness, compressive strength, and fracture toughness, of the sintered HA samples (E-HA). Statistical analyses, including one-way ANOVA and Tukey's post-hoc test, were conducted to determine significant differences in these properties at different sintering temperatures. Experimental findings revealed that as the sintering temperature increased, HA partially transformed into β-TCP between 800 and 1300 °C, with α-TCP observed at 1400 °C. The elimination of pores led to an increase in relative density, with a maximum relative density of 94.5% achieved at 1200 and 1300 °C. E-HA sintered at 1200 °C exhibited the highest hardness (5.08 GPa), compressive strength (255.79 MPa), and fracture toughness (1.21 MPa·m0.5). However, at 1400 °C, a slight decrease in apparent density (2.90 g/cm3) was noted due to the presence of α-TCP, along with significant grain growth. This study's objective is clearly aligned with the study design, incorporating detailed statistical analyses to validate the findings. Furthermore, bacterial culture experiments were conducted using sintered E-HA, Chem-HA (HA synthesized from reagent-grade calcium carbonate), and Comm-HA (commercial HA). Streptococcus mutans was cultured on the surfaces of sintered E-HA, Chem-HA, and Comm-HA samples for 20 h. After culturing, the OD values for all samples were below 0.2, indicating significant antibacterial efficacy. The comparable OD values and bacterial counts (p > 0.05) suggest that the source of HA does not impact its antibacterial properties. This underscores the potential of eggshell-derived HA as an effective material for biomedical applications.

Synthesis and Spectroscopic Investigation of N-(Morpholinofurfuryl) Maleimide and its Copper (II) Complex uses in Biological Applications

The Mannich base N-(morpholinofurfuryl) maleimide (MOFM) is synthesized through a Mannich reaction using Maleimide as one of the starting materials. The reaction likely involves the condensation of Maleimide with formaldehyde and a secondary amine. It is then complexed with copper (II) to form the copper complex. This complexation process might involve reacting the Mannich base with a copper (II) salt under appropriate conditions. Characterization techniques such as FT-IR, UV–visible spectroscopy, 1H, and 13C NMR spectroscopy are used to confirm the formation of the complex and determine its structural features. The antioxidant properties of both the Mannich base ligand and its copper (II) complex are evaluated using assays such as DPPH (2,2-diphenyl-1-picrylhydrazyl) and reducing power assay. These assays assess the ability of the compounds to scavenge free radicals and reduce oxidative stress. It was found that MOFM had an IC50 value of 4.1762 x 10-4 and its Cu(II) complex had 2.5772 x 10-4 which confirms the ability of the prepared compounds to scavenge free radicals and reduce oxidative stress. The antimicrobial activity of the copper (II) complex of MOFM and the ligand is tested against various microorganisms including Aspergillus niger, Candida albicans, Escherichia coli, and Staphylococcus aureus using the agar-well diffusion method. Both the compounds had good antibacterial and antifungal properties. By conducting these experiments and analyses, you can gain insights into the structural features, antioxidant properties, and antimicrobial efficacy of both the Mannich base ligand and its copper (II) complex, which could have potential applications in various fields such as pharmaceuticals, materials science, or environmental protection.

Antimicrobial Peptide Identified via Machine Learning Presents Both Potent Antibacterial Properties and Low Toxicity toward Human Cells.

Preventing infection is a critical clinical challenge; however, the extensive use of antibiotics has resulted in remarkably increased antibiotic resistance. A variety of antibiotic alternatives including antimicrobial peptides (AMPs) have been studied. Unfortunately, like most conventional antibiotics, most current AMPs have shown significantly high toxicity toward the host, and therefore induce compromised host responses that may lead to negative clinical outcomes such as delayed wound healing. In this study, one of the AMPs with a short length of nine amino acids was first identified via machine learning to present potentially low cytotoxicity, and then synthesized and validated in vitro against both bacteria and mammalian cells. It was found that this short AMP presented strong and fast-acting antimicrobial properties against bacteria like Staphylococcus aureus, one of the most common bacteria clinically, and it targeted and depolarized bacterial membranes. This AMP also demonstrated significantly lower (e.g., 30%) toxicity toward mammalian cells like osteoblasts, which are important cells for new bone formation, compared to conventional antibiotics like gentamicin, vancomycin, rifampin, cefazolin, and fusidic acid at short treatment times (e.g., 2 h). In addition, this short AMP demonstrated relatively low toxicity, similar to osteoblasts, toward an epithelial cell line like BEAS-2B cells.

The antimicrobial peptide Temporin-L induces vesicle formation and reduces the virulence in S. aureus

The evolution of methicillin-resistant Staphylococcus aureus (MRSA) has required the development of new antimicrobial agents and new approaches to prevent and overcome drug resistance. AntiMicrobial Peptides (AMPs) represent promising alternatives due to their rapid bactericidal activity and their broad-spectrum of action against a wide range of microorganisms. The amphibian Temporins constitute a well-known family of AMPs with high antibacterial properties against both Gram-positive and Gram-negative bacteria. In this paper, we evaluated the in vivo effect of Temp-L on S. aureus performing morphological studies using Transmission Electron Microscopy (TEM) that revealed the occurrence of protrusions from the cell surface. The formation of vesicle-like structure was confirmed by Dynamic Light Scattering (DLS). The global effect of Temp-L on Staphylococcus aureus (S. aureus) was deeply investigated by differential proteomics leading to the identification of up-regulated proteins involved in the synthesis of the cell membrane and fatty acids, and down-regulated virulence factors. GC-MS analysis suggested a possible protective response mechanism implemented by the bacterium after treatment with Temp-L, as the synthesis of fatty acids was increased. Adhesion and invasion assays on eukaryotic cells confirmed a reduced virulence of S. aureus following treatment with Temp-L. These results suggested the targeting of virulence factors as novel strategy to replace traditional antimicrobial agents that can be used to treat infections, especially infections caused by the resistant pathogen S. aureus.

Mechanisms of slow-release antibacterial properties in chitosan‑titanium dioxide stabilized perilla essential oil Pickering emulsions: Focusing on oil-water interfacial behaviors

Perilla essential oil (PLEO) offers benefits for food preservation and healthcare, yet its instability restricts its applications. In this study, chitosan (CS) and TiO2 used to prepare composite particles. TiO2, after being modified with sodium laurate (SL), was successfully introduced at 0.1 %–3 % into the CS matrix. The resulting CS-SL-TiO2 composite particles can be formed by intertwining and rearranging through intramolecular and intermolecular interactions, and form an O/W interface with stability and viscoelasticity. The Pickering emulsions stabilized by these particles exhibit non-Newtonian pseudoplastic behavior, shear-thinning properties, and slow-release characteristics, along with antibacterial activity. Emulsions with 0.5 % and 1 % CS-SL-TiO2 composites demonstrated superior antibacterial effects against Escherichia coli and Staphylococcus aureus. The study revealed that all emulsions undergo Fickian diffusion and a sustained release of PLEO, with the Ritger-Peppas model best describing this release mechanism. The slow-release behaviors positively correlates with interfacial pressure, composite particle size, composite particle potential, composite contact angle, emulsion particle size and emulsion potential, but negatively correlates with diffusion rate, penetration rate, release kinetics and release rate. The findings lay groundwork for developing slow-release antimicrobial emulsions within polysaccharide matrices, showcasing promise for antimicrobial packaging solutions and enhanced food preservation techniques.

Enhanced sunlight-driven photocatalysis of non-metal doped zinc oxide via wet impregnation for the removal of organic compounds

Zinc oxide (ZnO), a commonly used photocatalyst, suffers from the rapid recombination of photogenerated charge carriers, and the inability to harvest visible light. Therefore, the green synthesized ZnO from Garcinia mangostana pericarp is modified via non-metal (X) doping of N, P, S, Br, and B with a mass content of 5 % to tackle the aforementioned. The obtained materials were characterized through various modern characterization techniques. The results reveal that amongst the X-doped sample, ZnO-B demonstrates the highest photocatalytic performance. The characteristics of ZnO include good crystallinity as well as a low band gap energy of 2.094 eV, revealing an enhanced visible light absorption activity of the sample. The photoactivity of surveyed ZnO-B was investigated through the degradation of malachite green, methyl orange, and tetracycline, achieving a removal rate of 96.29, 86.59, and 90.32 %, respectively. Simultaneously, the antibacterial properties of the ZnO-X were evaluated for Staphylococcus aureus under sunlight illumination. Moreover, the photocatalysis mechanism of the studied materials was elucidated through the band structure, toxicity, and total organic carbon removal of the post-catalysis solution. The selected boron-doped zinc oxide catalyst also showed excellent reusability after 10 cycles of photocatalysis, retaining ∼ 80 % of its original activity. The obtained results reveal the potential application of non-metal-doped zinc oxide in environmental remediation and water disinfection.

Kigelia pinnata fruit extract mediated green synthesis of Ce11O20/CeCu/CuO nanocomposites and their anticancer and antibacterial properties

In the current study, we used green synthesis techniques to conjugate additional metals into native nanoparticles, with an emphasis on how this altered its surface morphology and biological capabilities. It is an important turning point in the field of nanotechnology since it opens up new, dependable, environmentally friendly and manageable ways to prepare nanocomposites. This work employs a green synthetic technique to synthesize CuO nanparticles (KpCuO NPs), Ce11O20/CeCu/CuO nanocomposites (KpCe@CuO-5 and KpCe@CuO-10 NCs) using aqueous extract of Kigelia pinnata fruit. The materials were characterized by Fourier-Transform Infrared Spectroscopy (FTIR), surface area and porosity of nanocomposites analyzed with the Scanning Electronic Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), UV-visible spectroscopy (UV–visible), X-ray Powder Diffraction (XDR), XPS (X-ray photoelectron spectroscopy), and High-Resolution Transmission Electron Microscopy (HRTEM). The synthesized KpCuO NPs, KpCe@CuO-5 and KpCe@CuO-10 nanocomposites exhibited anticancerous activity against MDA-MB-231, HEK-293 and antimicrobial properties against E. Coli bacteria. These samples also demonstrated their bio-potency by preventing the migration and proliferation of cells, decreasing the number of colonies, and triggering cell cycle arrest and programmed cell death. All of these findings suggest that KpCuO NPs and KpCe@CuO NCs have therapeutic potential to treat triple negative breast cancer (TNBC).

Antibacterial rice protein nanoparticles with a high curcumin loading for fruit preservation

Curcumin (Cur) exhibits potential as a food preservative because of its natural antibacterial and antioxidant properties. Nevertheless, its practical application is challenging due to poor water solubility and physicochemical instability. In this study, we prepared Cur-loaded protein nanoparticles (RCs) with a high loading capacity. The water-dispersible nanoparticles (10–30 nm) enclosing Cur with a loading capacity of up to 302 mg/g protein were formed by neutralizing rice proteins (RPs) from alkali-unfolded RPs utilizing cation exchange resin in the presence of Cur. Compared to free Cur, RCs improved the heat-stability and photo-stability of Cur by 26.7% and 23.2%, respectively. The RCs demonstrated significantly higher antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) compared to free Cur, with inhibition rates exceeding 94.45% and 91.00%, respectively. Additionally, RCs exhibited superior antioxidant activities across multiple assays, with RCs5 showing increases of 122.22% (DPPH), 64.99% (ABTS), and 94.72% (FRAP) compared to free curcumin. RCs significantly preserved freshly-cut apples, with the RCs5 group showing the lowest bacterial count (1.46 log CFU/g) and the highest total soluble solid content (10.45%) after 7 days of storage. RCs also reduced weight loss to 34.35% of the control and effectively minimized browning by at least 5.83% compared to the control group. These findings highlight the potential use of RCs to improve the antimicrobial and antioxidant activities of encapsulated phytochemicals, which may have numerous applications in, for example, food preservations.

Preparation and antibacterial evaluation of silver-doped zirconia for enhanced dental restoration performance

Because of its superior strength, esthetic properties, and excellent biocompatibility, zirconia is preferred for dental prosthetic such as crowns and bridges. However, zirconia crowns and bridges are susceptible to secondary caries owing to margin leakage. Silver is a well-known antibacterial agent, making it a desirable additive to zirconia crowns and bridges for secondary caries prevention. This study focuses on imparting zirconia composite with antibacterial properties to enhance its protective capacity in dental restorations. We used the sol-gel method to dope Ag into zirconia. Silver-doped zirconia powders were prepared at Zr:Ag molar ratios of 100:0,100:0.1, 100:0.5, 100:1, 100:3, and 100:5 (respective samples denoted as Ag-0, Ag-0.1, Ag-0.5, Ag-1, Ag-3, and Ag-5) and were subjected to firing at various temperatures (400 °C-1000 °C). We performed x-ray diffraction to investigate the crystal phase of these powders and x-ray fluorescence and field emission scanning electron microscopy to analyze their elemental composition and surface morphology, respectively. Moreover, we performed spectrophotometry to determine theL*a*b* color values, conducted dissolution tests, and quantified the Ag content through inductively coupled plasma optical emission spectroscopy. In addition, we studied the antibacterial activity of the samples. Analyses of the samples fired at ⩽600 °C revealed a predominantly white to grayish-white coloration and a tetragonal crystal phase. Firing at ⩾700 °C resulted in gray or dark gray coloration and a monoclinic crystal phase. The Ag content decreased after firing at 900 °C or 1000 °C. Ag-0.5 and above exhibited antibacterial activity against bothEscherichia coliandStaphylococcus aureus. Therefore, the minimum effective silver-doped zirconia sample was found to be Ag-0.5. This study allows the exploration of the antimicrobial potential of silver-doped zirconia materials in dental applications such as prosthdontical lining materials, promoting the development of innovative restorations with protective capacity against secondary caries.

Antimicrobial coating of biologically synthesized silver nanoparticles on surgical fabric and surgical blade to prevent nosocomial infections

In this study, biologically synthesized AgNPs were found to be effective against six hospital prevalent bacterial species (Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, Methicillin-resistant Staphylococcus aureus and Enterococcus faecalis). AgNPs were deposited on the fabric and surgical blades using layer-by-layer and electrochemical deposition methods, respectively. The coated objects were characterized using scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy and energy dispersive X-ray. Coated fabric samples and blades when tested against six above mentioned bacterial species were found to be effective for all of them. Antibiofilm activity of AgNPs coated blade and fabric was tested against P. aeruginosa and SEM images of post-treated fabrics and blades showed clear bacterial cell distortion and inhibition. Furthermore, washing durability test revealed that AgNPs were strongly attached to the surface of fabric even after 20 cycles of hospital laundering. This unlocks the way to several technologically relevant applications of AgNPs coated surfaces to reduce the risks of nosocomial infections and as a proof of concept; we demonstrated efficient antibacterial properties of AgNPs coated cotton fabric and surgical blades.

Development of a graphene oxide/hydroxyapatite-containing orthodontic primer: An in-vitro study

Fixed orthodontic appliances increase the risk of enamel demineralization and the development of white spot lesions (WSLs). This study aimed to develop a novel orthodontic primer that incorporates graphene oxide (GO) and hydroxyapatite (HA), investigate their cell viability, bonding strength, and enamel damage, and evaluate their antibacterial and remineralization properties. Nine groups were prepared by adding different concentrations of GO (0.1, 0.25, and 0.5 wt%) and HA (2, 5, and 7 wt%) to Transbond™ XT orthodontic primer. After observing the surface morphology of the material by a Field Emission Scanning Electron Microscope (FESEM), the phase of the materials by X-ray diffraction (XRD), and their chemical compositions by Energy Dispersive X-ray spectroscopy (EDX). The prepared primers were compared to the control primer group in terms of cell viability, shear bond strength (SBS), adhesive remnant index (ARI), enamel damage index (EDI), and antibacterial test. Then the groups with higher antibacterial properties (GOHA 0.1–2, GOHA 0.1–5, GOHA 0.25–2) were selected to evaluate their remineralization properties. Primers with all the prepared concentrations of GO/HA revealed acceptable cell viability levels within the limit of the ISO standards with comparable SBS and ARI values with the control primer (p > 0.05). Simultaneously, the EDI significantly reduced, and the antibacterial properties enhanced when compared to the control group (p < 0.05). The result of remineralization properties revealed that the selected groups had significantly higher remineralization ability than the control group which was more pronounced in GOHA 0.25–2 group. All the prepared orthodontic primers with different concentrations of GO/HA are safe biologically with adequate SBS, ARI, and EDI values for clinical application with enhanced antibacterial properties. The GOHA 0.25–2 experimental primer reveals the best antibacterial and remineralization properties which require further in-vitro and in-vivo investigation as a preventive measure of WSL.

Injectable natural hydrogel with spatiotemporal self-strengthening, antibacterial and anti-inflammatory properties for treating diabetic wound

Injectable hydrogel dressings provide a promising approach for treating diabetic wounds as they conform to irregular surfaces and foster new tissue development in a moist environment. Nevertheless, post-injection mechanical performance is often mediocre, coupled with inadequate antibacterial protection. Herein, we prepared an injectable hydrogel dressing (CBGT@PDA) consisting of double-network hydrogel (CBGT) and polydopamine nanoparticles (PDA NPs) as a multi-targeted combination therapy system oriented to chronic diabetic wound healing. Efficient enzymatic reactions combined with a slow quaternization procedure regulate the mechanical attributes of injectable hydrogels, offering spatiotemporal self-strengthening and exceptional antibacterial capabilities. The hydrogel system is also equipped with scavenged ROS function, bioadhesion characteristics and remarkable biocompatibility, thus exhibiting high improvement in the healing of the diabetic wound. We believe such injectable hydrogels with spatiotemporal self-strengthening capabilities in both of mechanical and antibacterial properties will provide new insight into the hydrogel-based wound dressing and broaden the application of the bioinspired hydrogels in biomedical fields.

Zein film loaded with Fructus Ligustri Lucidi essential oil: Preparation, characterization and application in fresh-cut apple preservation

Fresh-cut fruits and vegetables are a type of convenient, ready-to-use food that offers consumers a healthy choice. However, the peeling and slicing operations make them susceptible to microbial contaminations and oxidation. In this study, zein was used as the film-forming substrate, and Fructus Ligustri Lucidi essential oil (FEO), a natural bacteriostatic agent, was incorporated into zein film to prepare a film with antibacterial and antioxidant properties to prolong the shelf life of fresh-cut fruits and vegetables. Polyethylene glycol 400 (PEG400) and glucose were used as plasticizers, and the optimal formulation of the film (FZF) was obtained by orthogonal experiment: 10% PEG400, 5% glucose and 10% FEO. The films were characterized by scanning electron microscope (SEM), Fourier transform infrared spectrum (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA), and the influence of FEO on the physical, chemical, and biological characteristics of the films was explored. The results demonstrated that FEO was successfully loaded into zein film and distributed evenly. The FZF film exhibited excellent antioxidant activity, when the concentration of FEO was 200 μg/mL, the scavenging rate of DPPH and ABTS was 81.63 ± 0.69% and 91.44 ± 0.55% respectively. Furthermore, the FZF film showed antibacterial properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) and low cytotoxicity in vitro. Moreover, the FZF film demonstrated anti-browning capabilities, effectively prolonging the shelf life of fresh-cut apple slices. Thus, the FZF film possesses considerable potential for utilization in food packaging.

Preparation of multi-barrier and multi-functional paper-based materials by chitosan, ethyl cellulose and green walnut husk biorefinery products for sustainable food packaging

The growing interest in paper-based materials for packaging is driven by their renewable and eco-friendly characteristics. However, their poor barrier performance against water, oil, and gas limits their application in the food packaging industry. In this study, we developed a simple dual-layer coating method to create water- and oil-repellent, gas barrier, antioxidant, and antibacterial paper-based materials using naturally-derived materials, including chitosan (CS), ethyl cellulose (EC), and cascade biorefinery products from green walnut husk (GWHE and CNC). The bottom CS/CNC oil-resistant coating and the top EC/GWHE water-resistant coating were applied to the paper surface. The synergistic effect of these coatings enhances the gas barrier and imparts functional properties to the paper. Compared to uncoated paper, the dual-layer-coated paper demonstrated a 239.1 % increase in tensile index, a higher kit rating value of 12/12, a lower Cobb 60 value of 3.21 mg/m2, a 44.0 % decrease in water vapor permeability (WVP), and a 90.7 % reduction in air permeability (AP). Additionally, this coated paper exhibited good antioxidant and antibacterial properties and favorable biodegradability. This study provides novel insights into the valorization of GWH waste and presents a sustainable strategy for producing high-performance paper-based materials for food packaging applications.

Effects of quaternization sites and crossing methods on the slow-release and antibacterial effects of hydroxypropyltrimethyl ammonium chloride chitosan/dialdehyde chitosan-based film

In this study, the active food packaging film were prepared using hydroxypropyltrimethyl ammonium chloride chitosan with different substitution sites (O-HACC & N-HACC) and dialdehyde chitosan (DCS) grafted with protocatechuic acid (PA). To explore the effect of chitosan quaternization positions and crosslinking approaches on the slow-release and antibacterial properties, the double-crosslinked film were fabricated through the self-coupling reaction of PA and Schiff base reaction between amino groups on HACC and aldehyde groups on DCS. The HACC/DCS-based film exhibited stable porous three-dimensional networks with high nisin loading ratios (>90 %). With the participation of the catechol-catechol structure, the dense double-crosslinked film effectively restricted the diffusion of the water molecules, resulting in excellent slow-release properties fitting with the Korsmeyer-Peppas kinetic model. Especially, O-HACC/PA-g-DCS film, which had more reaction sites for Schiff base crosslinking than N-HACC, exhibited the equilibrium swelling ratio of 800 % at 60 h and could sustainably release nisin via non-Fickian diffusion behavior until 48 h. Moreover, the HACC/DCS-based double-crosslinked film performed good long-time antibacterial activity and preservation effects on salmon. On the 10th day of storage, the TVBN of N-HACC/PA-g-DCS and O-HACC/PA-g-DCS groups were only 28.26 ± 1.93 and 29.06 ± 1.68 mg/100 g and still lower than the thresholds.