Among various metal nanoparticles, palladium nanoparticles (Pd NPs) are one of the most important and fascinating nanomaterials. An important concern about the preparation of Pd NPs is the formation ...of toxic by-products, dangerous wastes and harmful pollutants. The best solution to exclude and/or minimize these toxic substances is plant mediated biosynthesis of Pd NPs. Biogenic Pd-based NPs from plant extracts have been identified as valuable nanocatalysts in various catalytic reactions because of their excellent activities and selectivity. They have captured the attention of researchers owing to their economical, sustainable, green and eco-friendly nature. This review attempts to cover the recent progresses in the fabrication, characterization and broad applications of biogenic Pd NPs in environmental and catalytic systems. In addition, the stability of biosynthesized Pd NPs and mechanism of their formation are investigated.
Display omitted
•Recent advances in plant-assisted biosynthesis of Pd NPs are described.•Environmental and catalytic applications of biosynthesized Pd NPs have been presented.•Stability, characterization and antibacterial properties of biosynthesized Pd-based NPs are highlighted.•Future challenges on biosynthesis of Pd-based NPs using plant extracts are discussed.
Plant extracts are increasingly becoming important additives in food industry due to their antimicrobial and antioxidant abilities that delay the development of off-flavors and improve the color ...stability in ready-to-eat (RTE) meat products. Due to their natural origin, they are excellent candidates to replace synthetic molecules, which are generally considered to have toxicological and carcinogenic effects. The efficient extraction of these antioxidant molecules from their natural sources, along with the determination of their activity in the commercialized products, have been a great challenge for researchers and food chain contributors. The objective of this review is to highlight the application of plant extracts to improve the shelf-life, nutritional and health-related properties of RTE meat products. The sensory effects of these extracts on RTE meat products as well as the possible synergistic effects of a combination of extracts are discussed.
Peri-implantitis is an inflammatory process around dental implants that is characterised by bone loss that may jeopardize the long-term survival of osseo integrated dental implants. The aim of this ...study was to create a surface coating on titanium abutments that possesses cellular adhesion and anti-microbial properties as a post-implant placement strategy for patients at risk of peri-implantitis.
Titanium alloy Grade V stubs were coated with gold particles and then subjected to ceramic conversion treatment (CCT) at 620 °C for 3, 8 and 80 h. The surface characteristics and chemistry were assessed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analysis. The leaching profile was investigated by inductively coupled plasma mass spectroscopy (ICP-MS) for all groups after 7, 14 and 28 days in contact with distilled water. A scratch test was conducted to assess the adhesion of the gold coating to the underlying titanium discs. Two bacterial species (Staphylococcus aureus (SA) &Fusobacterium nucleatum (FN)) were used to assess the antibacterial behaviour of the coated discs using a direct attachment assay test. The potential changes in surface chemistry by the bacterial species were investigated by grazing angle XRD.
The gold pre-coated titanium discs exhibited good stability of the coating especially after immersion in distilled water and after bacterial colonisation as evident by XRD analysis. Good surface adhesion of the coating was demonstrated for gold treated discs after scratch test analysis, especially titanium, following a 3-hour (3 H) ceramic conversion treatment. All coated discs exhibited significantly improved antimicrobial properties against both tested bacterial species compared to untreated titanium discs.
Ceramic conversion treated titanium with a pre-deposited gold layer showed improved antimicrobial properties against both SA and FN species than untreated Ti-C discs. Scratch test analysis showed good adherence properties of the coated discs the oxide layer formed is firmly adherent to the underlying titanium substrate, suggesting that this approach may have clinical efficacy for coating implant abutments.
This work aims to evaluate the antimicrobial potential of ethanolic and water extracts of roselle (
, rosemary (
, clove (
), and thyme (
) on some food pathogens and spoilage microorganisms. Agar ...well diffusion method has been used to determine the antimicrobial activities and minimum inhibitory concentrations (MIC) of different plant extracts against Gram-positive bacteria (
), Gram-negative bacteria (
, and
), and one fungus (
). The extracts exhibited both antibacterial and antifungal activities against tested microorganisms. Ethanolic roselle extract showed significant antibacterial activity (
< 0.05) against all tested bacterial strains, while no inhibitory effect on
(CA) was observed. Only the ethanolic extracts of clove and thyme showed antifungal effects against CA with inhibition zones ranging from 25.2 ± 1.4 to 15.8 ± 1.2 mm, respectively.
(BC) appears to be the most sensitive strain to the aqueous extract of clove with a MIC of 0.315%. To enhance our understanding of antimicrobial activity mechanism of plant extracts, the changes in internal pH (pH
), and membrane potential were measured in
(SA) and
(EC) cells after exposure to the plant extracts. The results indicated that the plant extracts significantly affected the cell membrane of Gram-positive and Gram-negative bacteria, as demonstrated by the decline in pH
as well as cell membrane hyperpolarization. In conclusion, plant extracts are of great value as natural antimicrobials and can use safely as food preservatives.
It is still a great challenge to develop soybean protein adhesives with high strength and antimildew properties through a sustainable and facile strategy. Herein, water-soluble dialdehyde chitosan ...(DCS) was obtained by oxidizing chitosan (CS) and used to crosslink soybean meal (SM) to fabricate protein adhesives via the Schiff base reaction. This strategy is simple, all-biomass, and without additional crosslinkers. Owing to the covalent imine bonds and non-covalent hydrogen bonds interactions, the adhesion strength of SM/DCS-4 adhesive reached 1.47 MPa, satisfying the requirement for Type II interior plywood (≥ 0.7 MPa). More importantly, the protein adhesives showed excellent antimildew properties due to the amino and aldehyde groups of DCS and the Schiff base formation. The SM/DCS-4 adhesive exhibited long shelf life (7 d), which is beneficial for industrial applications. This study helps in preparing green and fully bio-based adhesives from agricultural and fishery wastes.
Display omitted
•Dialdehyde chitosan (DCS) acted as a functional crosslinker.•Highly dense imine bonds and hydrogen bonds strengthened the adhesive network.•DCS can improve the bonding strength and antimildew properties of the adhesive.•The soybean meal (SM)/DCS adhesive exhibited long shelf life (7 d).•The SM/DCS adhesive made full use of agricultural and fishery wastes.
Coatings are widely used as protective and decorative layers on various substrates. However, the use of large quantities of solvent-based coatings can lead to environmental pollution. Although ...waterborne coatings are eco-friendly owing to their low toxicity and low emission of volatile organic compounds, the main raw materials for fabricating waterborne polyurethane are derived from unsustainable petroleum resources. In this study, a series of bio-based waterborne polyurethanes (BWPUs) were synthesised using bio-based poly(trimethylene ether) glycol (PO3G) to reduce dependence on petrochemical resources. The structures and performances of the prepared BWPUs were systematically characterised. The results showed that WPUs exhibit obvious microphase separation and possess excellent mechanical properties, high transparency, wear resistance, and antimicrobial properties, which can be controlled by adjusting the equivalent ratio of the isocyanate component to that of the hydroxyl component. This study provides new ideas for designing BWPUs with excellent properties, limiting the dependence on petrochemical resources.
Display omitted
•A waterborne polyurethane (WPU) is synthesised by bio-based materials.•The WPU exhibits apparent microphase separation.•The WPU possesses excellent mechanical properties, high transparency, wear resistance, and antimicrobial properties.
Display omitted
•It’s first time to prepare the natural cellulose-based nonionic antimicrobial biopolymers.•Indole-3-acid-functionalized biopolymers had favorable solubility and antibacterial ...properties.•The minimum inhibitory concentration of soluble nonionic biopolymers was 5 μg disk−1.•Cellulose-based nonionic biopolymers showed good antimicrobial activity, non-leachability, and biocompatibility.
Novel soluble cellulose-based nonionic biopolymers (CIs) with enhanced antimicrobial properties and nonleachability were successfully produced using a sustainable one-pot synthesis method. Fourier transform infrared spectroscopy (FTIR), Nuclear magnetic resonance H-spectrometer (1H NMR), X-ray Photoelectron Spectroscopy (XPS), and Energy Dispersive Spectroscopy (EDS) results demonstrated that the cellulose (MCC) molecules combined with indole-3-acetic acid (IAA) via esterification to produce CIs with abundant terminal indole groups. The degree of substitution of the prepared CI3 reached 1.85 when the molar ratio of IAA to MCC molecules was 4:1. The prepared CI samples were characterized using X-ray diffractometer (XRD), Scanning Electronic Microscopy (SEM), Thermogravimetric Analysis (TGA), and other analysis techniques. Results indicated that after the MCC was grafted with IAA, its crystallinity decreased and solubility increased. After blending CI3 with polycaprolactone (PCL) to form cellulose-based antimicrobial (PCL–CI) films, the films showed good compatibility, preferable biological cell activity, and low water vapor permeability. When the CI3 content was 10%, the tensile strength of the produced PCL–CI10 film reached 9.96 MPa. Moreover, the prepared PCL–CI films exhibited good nonleachability after being immersed in water for 5 d. The disk diffusion assay revealed that the CIs and PCL–CI films had good antimicrobial and bactericidal effects against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). The minimal inhibitory concentration was 5 μg disk−1, significantly lower than that of traditional antibiotics and chitosan. The nonionic biopolymers are simple and efficient to prepare and ecofriendly as well as exhibit nontoxicity, good solubility, enhanced antimicrobial properties, and nonleachability, which can provide new ideas for developing natural biomass-based nonionic antimicrobial materials with potential applications in wound dressing, medical devices, and food packaging.
The aim of the present research was to investigate the interaction effect of incorporating titanium dioxide (TiO2) (0 %, 0.5 %, and 1 %) nanoparticles and manipulating the proportion of tomato seed ...mucilage (TSM) and gelatin (Ge) (1: 0, 0.33:0.67, 0.67:0.33, and 0:1) on the physical, mechanical, and microbial characteristics of the film. The findings indicated that the incorporation of TiO2 engendered an augmentation in the surface roughness of the film and an elevation in the film's thickness. The mechanical evaluation results revealed that the incorporation of TiO2 into the TSM-Ge films significantly enhanced (p˂0.05) the tensile strength (TS), (up to 300 %), an elevation of Young's modulus, while concurrently leading to a reduction in the elongation at break (EB). The incorporation of TiO2 resulted in a significant enhancement in various properties of the film (p˂0.05), including opacity, contact angle, oxygen permeability (OP), water vapor permeability (WVP), moisture absorption, moisture content, solubility, and swelling. The rise in the proportion of TSM resulted in a concomitant increase in the color differences (ΔE), and yellowness index (YI). Conversely, there was a decrease in the lightness (L*) and the whiteness index (WI). Additionally, an increase was found in opacity, solubility, moisture content, WVP, OP, swelling, and moisture absorption. It was observed that films without TiO2 exhibited no inhibitory effect. However, upon augmenting the concentration of TiO2 to 1 %, notable inhibitory and lethal effects were observed against various microorganisms, including Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Candida glabrata. The results showed that the TSM-Ge composite film containing TiO2, exhibited potential as a viable choice for food packaging susceptible to microbial spoilage.
•TSM-Ge film containing TiO2, exhibited potential as a viable choice for food packaging•Incorporation of TiO2 into TSM-Ge films exhibited enhancements in the film's physical, permeability, and antimicrobial characteristics.•Incorporation TiO2 and in TSM-Ge films caused the changed film's surface characteristics
Biodegradable edible films for sour cream packaging were developed based on chitosan (CS), hydroxyethyl cellulose (HEC), Olive leaf extract (OE), and titanium dioxide nanoparticles (TiO2-NPs). The ...prepared CS/HEC/TiO2-OE bionanocomposite films were evaluated for their antimicrobial and antioxidant activities as well as using FT-IR, mechanical, permeability, and contact angle. The effect of developed films on the lipid oxidation, microbiological load, and chemical properties of sour cream was investigated. The fabricated films had an antimicrobial impact against all tested strains. The film containing 8 % OE showed effective protection against fat oxidation, with a peroxide value of 3.21 meq O2/kg, a para-anisidine value 5.40, and free fatty acids of 0.82 mg KOH/kg. The films with OE 4 % and 8 % have a good effect on the microbiological load of sour cream for 90 days. These films did not influence the chemical composition of sour cream and therefore can be used in this sort of dairy product.
To effectively extend the shelf life of fruits meanwhile facilitating consumers to judge their freshness, in this work, a double-layer multifunctional film combining CO2 sensitivity and antibacterial ...properties was successfully prepared by adding methyl red (MR), bromothymol blue (BTB) into gellan gum (GG) as the sensing inner layer, and doping tannic acid (TA) into sodium alginate with sodium carboxymethyl cellulose (CMC) as the antimicrobial outer layer, which was applied to the freshness indication of strawberries. Microscopic morphology and spectral analysis demonstrated that the bi-layer films were fabricated successfully. The mechanical characteristics, thermal stability, water vapor resistance, and antibacterial capabilities of the bilayer films improved as TA concentration rose. They exhibited noticeable color changes at pH = 2–10 and different concentrations of CO2. Application of the prepared films to strawberries revealed that the GG-MB@SC-6%TA film performed most favorably under 4 °C storage conditions, not only monitoring strawberry freshness but also retaining high soluble solids and titratable acidity, resulting in a slight decrease in hardness and weight loss. Therefore, taking into account all of the physical-functional characteristics, the GG-MB@6%TA film has a broad application prospect for intelligent food packaging.
Display omitted
PDF
