Antibacterial Nanocomposites Based on Thermosetting Polymers Derived from Vegetable Oils and Metal Oxide Nanoparticles

Optically amended biosynthesized crystalline copper-doped ZnO for enhanced antibacterial activity

The emergence and re-emergence of antibiotic-resistant bacteria is a potential threat to treating infectious diseases. This study employed a nanometer-scale green synthesis using an extract of Solanum incanum leaves to obtain nanoparticles (NPs) and nanocomposites (NCs) possessing antibacterial properties. The FESEM-EDS elemental mapping analysis proved the novelty of the green synthesis approach in synthesizing a copper-doped ZnO NCs with good dopant distribution. The crystallinity and ZnO bandgap were adjusted by extrinsic copper doping in the ZnO lattice. The optical property adjustments from 3.04 to 2.97 eV for indirect Kubelka-Munk functions were confirmed from DRS-UV-vis analysis. The dopant inclusion in the host lattice was also confirmed by the angle shift on the XRD pattern analysis relative to single ZnO. In addition to doping, the XRD pattern analysis also showed the development of CuO crystals. The lattice fringe values from HRTEM analysis confirmed the existence of both CuO and ZnO crystals with local heterojunctions. Doping and heterojunctions have crucial values in charge transfer and visible light harvesting behaviour, as proved by the PL analysis. The synergistic effects of the doped NCs showed greater antibacterial activity against both Gram-positive and Gram-negative bacteria as a result of more ROS generation through the bacteria-cell-catalyst interaction and release of metal ions. The antioxidant potential of the doped NCs was found to be higher than that of single NPs, using the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay and is expected to impart protective effects to the host cells by scavenging destructive free radicals. Thus, the overall analysis leads to the conclusion that the potentiality of synthesized materials has a future outlook for biological applications, especially in the development of antimicrobials to combat antibiotic-resistant bacteria and microbes.

Metal Oxide Nanoparticles in Food Packaging and Their Influence on Human Health

It is a matter of common knowledge in the literature that engineered metal oxide nanoparticles have properties that are efficient for the design of innovative food/beverage packages. Although nanopackages have many benefits, there are circumstances when these materials are able to release nanoparticles into the food/beverage matrix. Once dispersed into food, engineered metal oxide nanoparticles travel through the gastrointestinal tract and subsequently enter human cells, where they display various behaviors influencing human health or wellbeing. This review article provides an insight into the antimicrobial mechanisms of metal oxide nanoparticles as essential for their benefits in food/beverage packaging and provides a discussion on the oral route of these nanoparticles from nanopackages to the human body. This contribution also highlights the potential toxicity of metal oxide nanoparticles for human health. The fact that only a small number of studies address the issue of food packaging based on engineered metal oxide nanoparticles should be particularly noted.

Anti-diabetic efficacy and selective inhibition of methyl glyoxal, intervention with biogenic Zinc oxide nanoparticle

Non-enzymatic glycation of biomolecules results in advanced glycation end products (AGEs), which are responsible for secondary complications in diabetes. Inhibiting methyl glyoxal (MGO) induced advanced glycation end product (AGE) formation is the only way to alleviate diabetic complications. This study aimed to look into the abilities of herbal extract Kigelia africana and K. africana synthesized zinc oxide nanoparticles (ZnONPs) to inhibit the emergence of MG-derived AGEs. The study intended to determine antioxidant and AGE inhibition of the plant extract and ZnONPs. ZnONPs were tested for the efficiency of anti-diabetic activity in streptozotocin-induced diabetic Wister rats. We discovered that the MGO-trapping effects on the prevention of AGE production were mediated by the downregulation of the amplification of MGO-trapping impacts on the hypoglycemic and antihyperlipidemic mechanisms of ZnONPs. According to histological findings, the treatment with ZnONPs also successfully lowers inflammation in the hepatic and renal tissues. Overall, future mechanistic research could establish ZnONPs potential anti-diabetic properties.

Thermoplastic Starch Composites Reinforced with Functionalized POSS: Fabrication, Characterization, and Evolution of Mechanical, Thermal and Biological Activities

Rapid advancements in materials that offer the appropriate mechanical strength, barrier, and antimicrobial activity for food packaging are still confronted with significant challenges. In this study, a modest, environmentally friendly method was used to synthesize functionalized octakis(3-chloropropyl)octasilsesquioxane [fn-POSS] nanofiller. Composite films compared to the neat thermoplastic starch (TS) film, show improved thermal and mechanical properties. Tensile strength results improved from 7.8 MPa to 28.1 MPa (TS + 5.0 wt.% fn-POSS) with fn-POSS loading (neat TS). The barrier characteristics of TS/fn-POSS composites were increased by fn-POSS by offering penetrant molecules with a twisting pathway. Also, the rates of O₂ and H₂O transmission were decreased by 50.0 cc/m²/day and 48.1 g/m²/day in TS/fn-POSS composites. Based on an examination of its antimicrobial activity, the fn-POSS blended TS (TSP-5.0) film exhibits a favorable zone of inhibition against the bacterial pathogenic Staphylococcus aureus and Escherichia coli. The TS/fn-POSS (TSP-5.0) film lost 78.4% of its weight after 28 days in natural soil. New plastic materials used for packaging, especially food packaging, are typically not biodegradable, so the TS composite with 5.0 wt.% fn-POSS is therefore of definite interest. The incorporation of fn-POSS with TS composites can improve their characteristics, boost the use of nanoparticles in food packaging, and promote studies on biodegradable composites.

Biosafety Construction Composite Based on Iron Oxide Nanoparticles and PLGA

Nanocomposites based on polymers and nanoparticles are used in agriculture for photoconversion of solar radiation, as a basis for covering material, as a packaging material, and as functional films. At the same time, nanocomposites are almost never used in agriculture as biosafe structural materials. In this work, we have developed a technology for obtaining a nanocomposite based on PLGA and iron oxide nanoparticles. The nanocomposite has unique physical and chemical properties and also exhibits pronounced antibacterial properties at a concentration of iron oxide nanoparticles of more than 0.01%. At the same time, the nanocomposite does not affect the growth and development of pepper and is biocompatible with mammalian cells. Nanocomposites based on PLGA and iron oxide nanoparticles can be an attractive candidate for the manufacture of structural and packaging materials in agriculture.

Acrylated Biopolymers Derived via Epoxidation and Subsequent Acrylation of Vegetable Oils

Chemically modified vegetable oils have become commercially attractive nowadays because they can be utilized as specialized components for the production of bioplasticizers and biopolymers due to their characteristics as being inexpensive, nontoxic, biodegradable, and renewable products. Due to the presence of unsaturation sites in the vegetable oils, they can be chemically modified and transformed into polymeric monomers such as acrylated epoxidized vegetable oils through well-known processes like epoxidation and acrylation processes. Acrylated epoxidized vegetable oil is a biopolymer that has a multitude of applications and is used mainly as a coating material for plastic, paper, and wood. There is an enormous demand for this biopolymer, and the market growth prospects are huge in some regions of the world. However, there are some challenges in the synthesis of acrylated epoxidized vegetable oils in achieving the performance of similar acrylated polymer derived from petroleum sources. In this paper, the chemical structure, properties, and chemical modifications of different types of vegetable oils were reviewed where the emphasis was given on epoxidation and its subsequent acrylation processes. This paper also highlights four types of epoxidation and their subsequent acrylation processes involving five different vegetable oils.

Composite Materials Based on Iron Oxide Nanoparticles and Polyurethane for Improving the Quality of MRI

Polyether urethane (PU)-based magnetic composite materials, containing different types and concentrations of iron oxide nanostructures (Fe₂O₃ and Fe₃O₄), were prepared and investigated as a novel composite platform that could be explored in different applications, especially for the improvement of the image quality of MRI investigations. Firstly, the PU structure was synthetized by means of a polyaddition reaction and then hematite (Fe₂O₃) and magnetite (Fe₃O₄) nanoparticles were added to the PU matrices to prepare magnetic nanocomposites. The type and amount of iron oxide nanoparticles influenced its structural, morphological, mechanical, dielectric, and magnetic properties. Thus, the morphology and wettability of the PU nanocomposites surfaces presented different behaviours depending on the amount of the iron oxide nanoparticles embedded in the matrices. Mechanical, dielectric, and magnetic properties were enhanced in the composites’ samples when compared with pristine PU matrix. In addition, the investigation of in vitro cytocompatibility of prepared PU nanocomposites showed that these samples are good candidates for biomedical applications, with cell viability levels in the range of 80–90%. Considering all the investigations, we can conclude that the addition of magnetic particles introduced additional properties to the composite, which could significantly expand the functionality of the materials developed in this work.

State of the Art in the Antibacterial and Antiviral Applications of Carbon-Based Polymeric Nanocomposites

The development of novel approaches to prevent bacterial infection is essential for enhancing everyday life. Carbon nanomaterials display exceptional optical, thermal, and mechanical properties combined with antibacterial ones, which make them suitable for diverse fields, including biomedical and food applications. Nonetheless, their practical applications as antimicrobial agents have not been fully explored yet, owing to their relatively poor dispersibility, expensiveness, and scalability changes. To solve these issues, they can be integrated within polymeric matrices, which also exhibit antimicrobial activity in some cases. This review describes the state of the art in the antibacterial applications of polymeric nanocomposites reinforced with 0D fullerenes, 1D carbon nanotubes (CNTs), and 2D graphene (G) and its derivatives such as graphene oxide (GO) and reduced graphene oxide (rGO). Given that a large number of such nanocomposites are available, only the most illustrative examples are described, and their mechanisms of antimicrobial activity are discussed. Finally, some applications of these antimicrobial polymeric nanocomposites are reviewed.

Synthesis and Characterization of Antibacterial Carbopol/ZnO Hybrid Nanoparticles Gel

This study recommends Carbopol/zinc oxide (ZnO) hybrid nanoparticles gel as an efficient antibacterial agent against different bacterial species. To this end, ZnO nanoparticles were synthesized using chemical precipitation derived from a zinc acetate solution with ammonium hydroxide as its precipitating agent under the effect of ultrasonic radiation. The synthesized ZnO nanoparticles were stabilized simultaneously in a freshly prepared Carbopol gel at a pH of 7. The chemical composition, phase identification, particle size and shape, surface charge, pore size distribution, and the BET surface area of the ZnO nanoparticles, as well as the Carbopol/ZnO hybrid Nanoparticles gel, were by XRD, SEM, TEM, AFM, DLS, Zeta potential and BET instruments. The results revealed that the synthesized ZnO nanoparticles were well-dispersed in the Carbopol gel network, and have a wurtzite-crystalline phase of spherical shape. Moreover, the Carbopol/ZnO hybrid nanoparticles gel exhibited a particle size distribution between ~9 and ~93 nm, and a surface area of 54.26 m2/g. The synthesized Carbopol/ZnO hybrid nanoparticles gel underwent an antibacterial sensitivity test against gram-negative K. pneumonia (ATCC 13883), Bacillus subtilis (ATCC 6633), and gram-positive Staphylococcus aureus (ATCC 6538) bacterial strains, and were compared with ampicillin as a reference antibiotic agent. The obtained results demonstrated that the synthesized Carbopol/ZnO hybrid nanoparticles gel exhibited a compatible bioactivity against the different strains of bacteria.

Design and Characterization of a Novel ZnO-Ag/Polypyrrole Core-Shell Nanocomposite for Water Bioremediation

Incorporating nanostructured metal and metal oxide in a polymer matrix is a strategic way to develop a novel candidate for water bioremediation. In this study, under microwave irradiation, a ZnO–Ag/polypyrrole (PPy) nanocomposite with a core/shell structure was prepared by interfacial polymerization of pyrrole in the presence of ZnO nanoparticles and AgNO₃ as an oxidant. The antimicrobial behavior of the ZnO–Ag core combined with the electrical properties of the conducting PPy shell created a special ZnO–Ag/PPy nanocomposite with inherent adsorption behavior and antimicrobial properties. More impressively, the as-prepared ZnO–Ag/PPy displayed enhanced adsorption of Cd²⁺ and PO₄³⁻ ions in the mixed solution. At pH 8, it had overall removal efficiencies of 95% and 75% for Cd²⁺and PO₄³⁻ ions, respectively. The Freundlich adsorption model, rather than the Langmuir adsorption model, better fits the adsorption isotherm results. The adsorption kinetics also followed the pseudo-second-order kinetic model. Additionally, the engineered nanocomposite demonstrated antifungal activity against different fungi, as well as remarkable antibacterial activity against Gram-negative and Gram-positive bacteria. The synergistic combination of crystallinity, coherence of the ZnO–Ag core in the PPy matrix, and the negative zeta potential all contribute to this nanocomposite’s high efficiency. Our results have significant consequences in the wastewater bioremediation field using a simple operation process.

Antibacterial Activity of Polymer Nanocomposites Incorporating Graphene and Its Derivatives: A State of Art

The incorporation of carbon-based nanostructures into polymer matrices is a relevant strategy for producing novel antimicrobial materials. By using nanofillers of different shapes and sizes, and polymers with different characteristics, novel antimicrobial nanocomposites with synergistic properties can be obtained. This article describes the state of art in the field of antimicrobial polymeric nanocomposites reinforced with graphene and its derivatives such as graphene oxide and reduced graphene oxide. Taking into account the vast number of articles published, only some representative examples are provided. A classification of the different nanocomposites is carried out, dividing them into acrylic and methacrylic matrices, biodegradable synthetic polymers and natural polymers. The mechanisms of antimicrobial activity of graphene and its derivatives are also reviewed. Finally, some applications of these antimicrobial nanocomposites are discussed. We aim to enhance understanding in the field and promote further work on the development of polymer-based antimicrobial nanocomposites incorporating graphene-based nanomaterials.

QTMP, a Novel Thiourea Polymer, Causes DNA Damage to Exert Anticancer Activity and Overcome Multidrug Resistance in Colorectal Cancer Cells

Colorectal cancer (CRC) is one of the most common malignancies, and multidrug resistance (MDR) severely restricts the effectiveness of various anticancer drugs. Therefore, the development of novel anticancer drugs for the treatment of CRC patients with MDR is necessary. Quaternized thiourea main-chain polymer (QTMP) is a self-assembled nanoparticle with good water solubility. Notably, QTMP is not a P-glycoprotein (P-gp) substrate, and it exhibits potent cytotoxic activity against CRC cells, including HCT116/DDP and P-gp-mediated multidrug-resistant Caco2 cells. QTMP also exhibits a strong anticancer activity against SW480 cells in vivo. Interestingly, reactive oxygen species (ROS) and reactive nitrogen species (RNS) production were increased in a concentration-dependent manner in QTMP-treated HCT116, SW480 and Caco2 cells. Importantly, QTMP causes DNA damage in these CRC cells via direct insertion into the DNA or regulation of ROS and/or RNS production. QTMP also induces caspase-dependent apoptosis via overproduction of ROS and RNS. Therefore, QTMP is a promising anticancer therapeutic agent for patients with CRC, including those cancer cells with P-gp-mediated MDR. The present study also indicates that the design and synthesis of anticancer drugs based on thiourea polymers is promising and valuable, thereby offering a new strategy to address MDR, and provides reference resources for further investigations of thiourea polymers.

The Prospering of Macromolecular Materials Based on Plant Oils within the Blooming Field of Polymers from Renewable Resources

This paper provides an overview of the recent progress in research and development dealing with polymers derived from plant oils. It highlights the widening interest in novel approaches to the synthesis, characterization, and properties of these materials from renewable resources and emphasizes their growing impact on sustainable macromolecular science and technology. The monomers used include unmodified triglycerides, their fatty acids or the corresponding esters, and chemically modified triglycerides and fatty acid esters. Comonomers include styrene, divinylbenzene, acrylics, furan derivatives, epoxides, etc. The synthetic pathways adopted for the preparation of these materials are very varied, going from traditional free radical and cationic polymerizations to polycondensation reactions, as well as metatheses and Diels-Alder syntheses. In addition to this general appraisal, the specific topic of the use of tung oil as a source of original polymers, copolymers, and (nano)composites is discussed in greater detail in terms of mechanisms, structures, properties, and possible applications.

Sustainable plant and microbes-mediated preparation of Fe3O4 nanoparticles and industrial application of its chitosan, starch, cellulose, and dextrin-based nanocomposites as catalysts

Iron oxide nanoparticles (Fe₃O₄ NPs) attracted significant scientific interest, considering their immense diversity of usage and biocompatibility. Perceiving the growing importance of sustainable chemistry, many efforts have been made to prepare these NPs using naturally occurring materials mostly plant extracts and microbes. Magnetic NPs (MNPs) are commonly used as composites and are considered in two matters: synthesis and modification of their functional groups. Biopolymeric nanocomposites are a group of hybrid materials composed of natural polymers and inorganic nanomaterials. Biopolymers such as alginate, cellulose, starch, gelatin, chitosan, etc. have been considered extensively and provided composites with better electrical and mechanical thermal properties. Fe₃O₄ NPs incorporated in a polymer and biopolymer matrix is a good instance of the functional nanostructure, which has been able to enhance the properties of both ingredients. These hybrids can have impressive applications in various scopes such as magneto-optical storage, electromagnetic interference shielding, catalyst, water remediation, biomedical sensing, and so on. In this study, we have tried to briefly introduce Fe₃O₄ NPs, investigate the green and sustainable methods that have been suggested for its synthesis and review recent utilization of their biopolymeric nanocomposite (NC) including starch, chitosan, dextrin, etc. as catalysts and photocatalysts.

Antibacterial activity and reinforcing effect of SiO2–ZnO complex cluster fillers for dental resin composites

The regular-shaped SiO₂-ZnO complex clusters constructed by spray-draying technology can enhance antibacterial activity while maintaining the mechanical and aesthetic properties of dental resin composites.