Silver Nanocomposites Research Articles

Fabrication of MIL-101(Cr)/silver nanocomposites as SERS substrate for sensitive determination of malachite green and crystal violet in tilapia

Fabrication of MIL-101(Cr)/silver nanocomposites as SERS substrate for sensitive determination of malachite green and crystal violet in tilapia

Antiviral Activity of Chitosan Nanoparticles and Chitosan Silver Nanocomposites against Alfalfa Mosaic Virus.

Plant viruses are a global concern for sustainable crop production. Among the currently available antiviral approaches, nanotechnology has been overwhelmingly playing an effective role in circumventing plant viruses. Alfalfa mosaic virus (AMV) was isolated and identified from symptomatic pepper plants in Egypt using symptomatology, serological tests using the direct ELISA technique, differential hosts and electron microscopy. The virus was biologically purified from a single local lesion that developed on Chenopodium amaranticolor. The AMV infection was further confirmed using an AMV coat protein-specific primer RT-PCR. We further evaluated the antiviral potential of chitosan nanoparticles (CS-NPs) and chitosan silver nanocomposites (CS-Ag NC) in different concentrations against AMV infections in pepper plants. All tested concentrations of CS-NPs and CS-Ag NC induced the inhibition of AMV systemically infected pepper plants when applied 24 h after virus inoculation. The foliar application of 400 ppm CS-NPs or 200 ppm CS-Ag NC produced the highest AMV inhibitory effect (90 and 91%) when applied 24 h after virus inoculation. Treatment with CS-NPs and CS-Ag NC considerably increased the phenol, proline and capsaicin contents compared to the infected plants. Moreover, the agronomic metrics (plant height, fresh and dry pod weights and number of pods per plant) were also significantly improved. According to our results, the potential applications of CS-NPs and CS-Ag NC may provide an effective therapeutic measure for better AMV and other related plant virus management.

Unraveling the electrochemical properties and charge storage mechanisms of lactobacillus-mediated synthesized RGO-titanium silver nanocomposite as a promising binder-free electrode for asymmetric supercapacitor device

A sustainable and scalable technique was developed to synthesize RGO-TiAg nanocomposites at room temperature, utilizing Lactobacillus sp. as an environmentally friendly reducing and stabilizing agent. This approach offers a cost-effective solution for large-scale production. The unique properties of Lactobacillus sp. allow for the reduction of metal ions while inhibiting agglomeration and preserving the stability of the resulting nanocomposites. The addition of reduced graphene oxide (RGO) sheets to the TiAg-based electrode increases its specific surface area, thereby enhancing the electrode's charge-storage capacity by promoting the formation of conductive networks. Furthermore, the hydrophilic oxygen groups of chemically reduced graphene oxide in the RGO-TiAg nanocomposites facilitate the electrolyte's access to the electrode's pores. Electrochemical analysis revealed that the RGO-TiAg NCs demonstrated the highest specific capacitances of 816.92 F/g at 1.5 A/g. An asymmetric supercapacitor device was fabricated by utilizing a composite electrode composed of RGO-TiAg NCs and activated carbon (AC). Polyvinyl alcohol-Na2SO4 (PVA-Na2SO4) was employed as the electrolyte and electrode separator. The RGO-TiAg NCs//ACarbon assisted ASC supercapacitor device demonstrated a specific capacitance of 256 F/g at 4 A/g, along with tremendous energy and power densities of 53.33 Wh kg− 1 and 2 kW kg− 1, respectively, at the same current density. The device exhibited a high-power density of 6 kW kg− 1 and an energy density of 25 Wh kg− 1, with a capacitance retention of 82% even at an ultrahigh current density of 12 A/g, after 10,000 cycles. Additionally, this work illustrates an effective method for synthesizing nanocomposites that may be used for developing prospective, high-performance supercapacitors for energy storage.

Synthesis, Characterization, Antioxidant and Biological Activities of Polyglucose Based Hydrazides and their Metal Nano Composites

The interaction of carbon (C) and nitrogen (N) single, double, and triple bonds with an aliphatic and aromatic carbon skeleton is widely used for medications and polymer synthesis. Many scientists have employed these compounds as target structures to determine their diverse chemical synthesis and use in various fields. The synthesis of polyglucose-hydrazide metal nanocomposites is a novel area of chemistry research. Polyglucose metal nanocomposites are widely used for drug delivery to target cancer and other lethal diseases. The major interests of this research were to synthesize, characterize, and find out the antibacterial properties of hydroxyl groups present in polyglucose-hydrazide metal nanocomposites. These nanocomposites were synthesized by acidification, esterification, and hydrazination of glucose and mixing of metal nanoparticles with polyglucose, respectively. The characterization of proposed nanocomposites was done by using scanning electron microscopy (SEM) and, energy dispersive X-Ray (EDX) spectroscopy. The biological activities of polyglucose-hydrazides cobalt, silver, and iron nano-composites were tested against Xanthomonas campestris malvacearum (a bacterial strain) by agar disc diffusion method. Amongst all, polyglucose-hydrazides cobalt nanocomposite yielded the highest antibacterial activity. Silver and iron nanocomposites also showed good activity. These results indicate that the antibacterial activities of metal nanoparticles are remarkably enhanced by combining with polyglucose hydrazide. These polyglucose-hydrazide metal nanocomposites have great potential as biocompatible antibacterial agents.

Antimicrobial properties of green synthesized silver and chitosan nanocomposites.

An eco-friendly and simple approach was carried out for the synthesis of silver-chitosan nanocomposites using Azadirachta indica and fluconazole-mediated aqueous extract. This extract acted as a reducing agent as well as a capping agent for the green synthesis of silver nanoparticles. Chitosan nanoparticles on the other hand were synthesized from the deacetylation of the chitin matrix. To confirm the nanoparticle synthesis, a UV- A visible spectrophotometer was used and FTIR analysis confirmed the presence of functional groups in the prepared extract. The morphological characteristics of silver and chitosan nanoparticles and as nano-composites were studied and confirmed using scanning electron microscopy (SEM) analysis. The synthesized silver-chitosan nanocomposites were subjected to well-loaded agar plates for the evaluation of antibacterial properties against the Streptococcus mutans and Candida albicans for their antifungal properties. The synthesized silver and chitosan nanoparticles showed antibacterial and antifungal activities against common oral micro flora such as Streptococcus mutans and Candida albicans which were measured using the zone of inhibition method. This approach is a one-step, economical and eco-friendly, biocompatible, and effective alternative for nanoparticle synthesis for various prosthetic applications.

Novel alginate-amino fatty acid amide composite hybrid gel beads as nanocarriers for in vitro release of silver nanoparticles

Nanosilver has been found to be a more effective alternative to conventional antibiotics due to its unique mechanisms of action. To facilitate prolonged topical drug delivery, a highly efficient 2,6-diaminopyridine-based silver nanocomposite gels, extended 22DAP/alginate hybrid gels and core-shell shaped hybrid gel beads are developed for prolonged topical drug delivery applications. The research revealed the benefits of in situ formation of nanosilver within the 22DAP gel and gel beads. A comparative study was conducted on silver uptake and release in a single component 22DAP gel, extended 22DAP/alginate hybrid gel, and gel beads. The study showed that the 22DAP/alginate hybrid gel beads had better efficiency of silver uptake (∼10 equivalents) due to their large surface area. These nanocomposites have also demonstrated excellent control and slow release of nanosilver, making them ideal for prolonged drug release and antimicrobial applications. The nanosilver composite 22DAP/alginate gel beads were tested against S. aureus and E. coli to evaluate their antibacterial activity, and the results were promising. The bead shape of these nanocomposites is anticipated to increase their usability for wound repair, biosensors, bone healing, and surgical interventions.

Paper-Based Electrodes Decorated with Silver and Zinc Oxide Nanocomposite for Electro-Chemical Sensing of Methamphetamine

We present the development of an electrochemical paper-based analytical device (ePAD) for the detection of methamphetamine. Methamphetamine is a stimulant that young people use as an addictive narcotic, and it must be detected quickly since it may be hazardous. The suggested ePAD has the advantages of being simple, affordable, and recyclable. This ePAD was developed by immobilizing a methamphetamine-binding aptamer onto Ag-ZnO nanocomposite electrodes. The Ag-ZnO nanocomposites were synthesized via a chemical method and were further characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, and UV-vis spectrometry in terms of their size, shape, and colloidal activity. The developed sensor showed a limit of detection of about 0.1 μg/mL, with an optimum response time of about 25 s, and its extensive linear range was between 0.01 and 6 μg/mL. The application of the sensor was recognized by spiking different beverages with methamphetamine. The developed sensor has a shelf life of about 30 days. This cost-effective and portable platform might prove to be highly successful in forensic diagnostic applications and will benefit those who cannot afford expensive medical tests.

Synthesis, Characterization, and Docking Study of Novel Thioureidophosphonate-Incorporated Silver Nanocomposites as Potent Antibacterial Agents.

Newly synthesized mono- and bis-thioureidophosphonate (MTP and BTP) analogues in eco-friendly conditions were employed as reducing/capping cores for 100, 500, and 1000 mg L-1 of silver nitrate. The physicochemical properties of silver nanocomposites (MTP(BTP)/Ag NCs) were fully elucidated using spectroscopic and microscopic tools. The antibacterial activity of the nanocomposites was screened against six multidrug-resistant pathogenic strains, comparable to ampicillin and ciprofloxacin commercial drugs. The antibacterial performance of BTP was more substantial than MTP, notably with the best minimum inhibitory concentration (MIC) of 0.0781 mg/mL towards Bacillus subtilis, Salmonella typhi, and Pseudomonas aeruginosa. Among all, BTP provided the clearest zone of inhibition (ZOI) of 35 ± 1.00 mm against Salmonella typhi. After the dispersion of silver nanoparticles (AgNPs), MTP/Ag NCs offered dose-dependently distinct advantages over the same nanoparticle with BTP; a more noteworthy decline by 4098 × MIC to 0.1525 × 10-3 mg/mL was recorded for MTP/Ag-1000 against Pseudomonas aeruginosa over BTP/Ag-1000. Towards methicillin-resistant Staphylococcus aureus (MRSA), the as-prepared MTP(BTP)/Ag-1000 displayed superior bactericidal ability in 8 h. Because of the anionic surface of MTP(BTP)/Ag-1000, they could effectively resist MRSA (ATCC-43300) attachment, achieving higher antifouling rates of 42.2 and 34.4% at most optimum dose (5 mg/mL), respectively. The tunable surface work function between MTP and AgNPs promoted the antibiofilm activity of MTP/Ag-1000 by 1.7 fold over BTP/Ag-1000. Lastly, the molecular docking studies affirmed the eminent binding affinity of BTP over MTP-besides the improved binding energy of MTP/Ag NC by 37.8%-towards B. subtilis-2FQT protein. Overall, this study indicates the immense potential of TP/Ag NCs as promising nanoscale antibacterial candidates.

Methylene blue removal from aqueous solution using modified Met-SWCNT-Ag nanoparticles: optimization using RSM-CCD

Abstract The presence of residual organic dyes in water resources results in a threat for both environment and human health due to their adverse health effects such as mutagenicity, carcinogenicity, and teratogenicity. Thus, they must be removed from industrial wastewater. Among these dyes, methylene blue (MB) is a toxic, carcinogenic, and almost non-biodegradable dye and can pose a significant threat to human health and environmental safety. Thus, it is removed from industrial effluents by a variety of methods, including adsorption, prior to discharge into the environment. This study aims to optimize the adsorption conditions of MB from an aqueous solution with nanocomposite of silver onto single-wall carbon nanotube metronidazole (Met-SWCNTs/Ag). Response Surface Methodology (RSM) based on Central Composite Design (CCD) is used to optimize and model the adsorption of MB dye (as pollutant) on Met-SWCNTs/Ag. The Met-SWCNTs/Ag is synthesized using Met-SWCNT impregnated with silver nitrate. The produced Met-SWCNT/Ag nanocomposite is characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The effect of four independent variables including nanoparticle (NP)/dye ratio, temperature, pH and contact time on MB removal on the specific surface area of SWCNT/Ag and Met-SWCNTs/Ag is evaluated. The accuracy and fit of the model for MB removal using Met-SWCNTs/Ag are estimated by ANOVA with R 2 > 0.99 and P-value < 0.0001. RSM results indicates that the NP/Dye ratio has the most significant influence on the adsorption of MB onto Met-SWCNTs/Ag. The optimal condition of the adsorption process takes place at NP/Dye ratio of 2.21, contact time of 65.57 min, and pH = 6.15 at 25.79 °C temperature leading into a 98.94 % MB removal. Isotherms and kinetic studies are performed to characterize the adsorption behavior of the adsorbent for MB removal. The adsorption behavior of the MB onto Met-SWCNTs/Ag is best described by the Langmuir isotherm model with regression coefficient R 2 of 0.9935 with the Q max of 112.42 mg/g. Adsorption kinetics of Met-SWCNT/Ag is investigated and modelled by means of the pseudo-first-order, pseudo-second-order models which is best fitted to the pseudo-second-order model. The thermodynamic study reveals that the adsorption of MB dye is spontaneous and exothermic. Experimental results suggest that the modified SWCNTs/Ag with Met achieves a higher removal efficiency of (∼98 %) when compared to SWCNTs/Ag (∼93 %).

Evaluation of chitosan and chitosan silver nanocomposites against bacterial pathogens of tropical tasar silkworm, Antheraea mylitta Drurry

Aim: The present research work was carried out to evaluate the effect of commercially available shrimp chitosan and chitosan silver nanocomposites (CSN) on the inhibition of bacterial pathogens of tropical tasar silkworm. Methodology: Synthesis of chitosan silver nanocomposite was by carried by using chemical precipitation method. The synthesized nanocomposites were characterized using different techniques. Further, antimicrobial potential of the chitosan and chitosan silver nanocomposites was evaluated by in vitro inhibition assay. The minimum inhibitory concentration of both chitosan and chitosan nanocomposites was estimated against bacterial pathogens of tasar silkworm. Results: Chitosan at different concentrations showed antibacterial activity against the bacterial pathogens (Bacillus spp., Micrococcus spp., and Serratia spp.) of tropical tasar silkworm under in vitro conditions. The 0.2% concentration of chitosan and CSN was identified as a minimum inhibitory concentration (MIC) against bacterial pathogens. Interpretation: Based on the findings of this study, the 0.2% concentration of CSNs may be considered as minimum inhibitory concentration against bacterial pathogens infecting tropical tasar silkworms. Key words: Bacterial pathogens, Chitosan silver nanocomposites, Tropical tasar silkworm

Novel Silver Nanocomposites as Effective Antitumor Agents

AbstractNovel silver nanocomposites based on copolymers of N,N‐diallyl‐N'‐acylhydrazines and diallylaminophosphonium salts with N‐vinylpyrrolidone and sulfur dioxide have been developed. There have been conducted studies of the cytotoxicity of the synthesized copolymers and nanocomposites toward lung carcinoma A549, rhabdomyosarcoma RD TE32, melanoma MS, and non‐cancerous embryonic kidney HEK 293. The nanocomposites have a significant cytotoxic activity against tumor RD TE32 and MS cell lines. There is the absence of a cytotoxic effect with respect to non‐cancerous HEK293 cell line. This indicates a high selectivity of silver nanocomposites with respect to RD TE32 and MS cell lines. The mechanism of cytotoxic effect of nanocomposites is determined. The nanocomposites cause apoptotic death of tumor cells with chromatin condensation and the reduction of mitochondrial fluorescence. The newly developed nanocomposites may be considered as promising for developing drugs to treat malignant cancer tumors.

Application Study of Novel Eggshell/Ag Combined with Pit and Fissure Sealants.

The study aims to enhance the anti-caries performance of pit and fissure sealants through the synthesis of novel silver nanocomposites, and to evaluate their mechanical properties and biological safety in vitro and in vivo. The antibacterial properties of synthetic eggshell/Ag were detected by bacterial inhibition zone, minimum bacteriostatic concentration, fluorescence staining and scanning electron microscopy. The synthetic products were then combined with pit and fissure sealants to prepare specimens, and their effects on mechanical properties, antibacterial properties and cytotoxicity were evaluated. Furthermore, an oral mucosal contact model of golden hamsters was established according to the ISO10933 standard to evaluate local stimulation and systemic effects. The novel nanocomposite eggshell/Ag was confirmed to exhibit strong broad-spectrum antibacterial activity, and that the eggshell/Ag-modified pit and fissure sealant had strong antibacterial properties against common dental caries bacterial biofilms, without any significant change in mechanical properties. The gradient dilution extract showed acceptable cytotoxicity, and in the golden hamster oral contact model, there were no visible abnormalities in local mucosal tissues, blood indices, or liver and kidney histopathology. These findings suggest that eggshell/Ag combined with pit and fissure sealants has strong antibacterial activity and excellent biosafety in vitro and in vivo, making it a promising candidate for clinical applications.

Synthesis, characterization and application of BR@Ag nanocomposite material for high degree reduction of p-nitro phenol under a suitable condition

ABSTRACT One of the most essential chemical processes that is utilized in the manufacturing of a great deal of contemporary goods is called heterogeneously catalyzed reactions, and it is also one of the most fascinating. Metallic nanostructures are heterogeneous catalysts for range reactions due to their huge surface area, large assembly of active surface sites, and quantum confinement effects. Unprotected metal nanoparticles suffer from irreversible agglomeration, catalyst poisoning, and limited life cycle. To circumvent these technical disadvantages, catalysts are frequently spread on chemically inert materials like as mesoporous Al2O3, ZrO2, and different types of ceramic material. In this research, plentiful bauxite residue is used to create a low-cost alternative catalytic material. We have hydrogenated p-Nitrophenol to p-Aminophenol on bauxite residue (BR) supported silver nanocomposites (Ag NCs). The phase and crystal structure, bond structure and morphological analysis of the developed material will be done XRD, FTIR, and SEM-EDX respectively. The ideal conditions were 150 ppm of catalyst, 0.1 mM of p-NP, and 10 minutes overall up-to 99% conversion of p-NP to p-AP. A multi-variable predictive model created using Response Surface Methodology (RSM) and a data-based Artificial Neural Network (ANN) model were found to be the best ways to predict the maximum conversion efficiency. ANN models predicted efficiency more accurately than RSM models, and the strong agreement between model predictions and experimental data was indicated by their low relative error (RE0.10), high regression coefficient (R2>0.97), and Willmott-d index (dwill-index > 0.95) values.

A novel optimized polyoxometalate-modified silver nanocomposite. Application to the development of antibacterial textiles

Antimicrobial textiles are used in various settings ranging from households to different industries, health areas, and shops. These materials are used in the manufacture of air filters, food packaging, sportswear; and hygiene, medical, storage, ventilation, and water purification systems. In healthcare medical centers, textiles like bed sheets and curtains are surfaces prone to contamination with microorganisms. The growth of microbes on the surface of textile materials can be inhibited by biocidal and biostatic compounds to prevent the spread of microbes. This work describes the development and characterization of a new antibacterial nanocomposite composed of silver nanoparticles functionalized with polyoxometalates. The experimental conditions for the synthesis were optimized using design of experiment tools. The resulting nanocomposite (formulation) was extensively characterized by UV-Vis spectroscopy, Fourier-transformed infrared spectroscopy, cyclic voltammetry, dynamic light scattering, X-ray diffraction, and transmission electron microscopy, and the bioactivity of the material was tested against Gram-positive and Gram-negative models. The novel formulation was supported in an eco-friendly fabric to obtain a textile material with broad applicability and lasting antibacterial properties.

ПОЛУЧЕНИЕ НАНОКОМПОЗИТОВ СЕРЕБРА ТЕРМОЛИЗОМ МЕТАЛЛСОДЕРЖАЩИХ МОНОМЕРОВ

A number of new metal-containing monomers have been obtained by direct interaction of unsaturated mono- and dicarboxylic acids with silver nitrate. The study of their thermal properties showed that thermolysis proceeds in two or three (for crystalline hydrates) stages. The end products of thermolysis are silver nanocomposites containing metallic silver nanoparticles stabilized by a carbon matrix. Silver particles are located relatively evenly in the object, the amplitude during scanning in a given direction allows us to state that the particles have a shape close to spherical, while some of the large particles, about 30 nm, are aggregates of smaller particles formed during thermolysis.

Selective sensing of free ammonia in aqueous medium by uniformly distributed silver nanoparticles composite of poly(meta-aminophenol)

The purpose of this communication is to develop a nanocomposite of poly(meta-aminophenol)/silver for chemiresistive sensing of free ammonia selectively in aqueous medium. Uniformly distributed silver nanoparticles was formed within the poly(meta-aminophenol) matrix by thermal reduction of silver mono-positive complexes with the functional groups of polymer. The silver loading within the poly(meta-aminophenol) matrix was optimized with respect to size and dispersion of the nanoparticles. The surface morphology and the interfacial interaction between the components of the prepared nanocomposite were characterized by various standard characterization techniques. The highest average DC-conductivity of the nanocomposite with ∼5 % silver loading with an average diameter of 50 nm ranging from 10 to 80 nm was achieved as 1.3 × 10−4 S cm−1 without using any other dopant. This poly(meta-aminophenol)/silver nanocomposite was found to have chemiresistive type sensing response towards ammonia in aqueous medium. The poly(meta-aminophenol)/silver nanocomposite film was responded significantly towards free ammonia in water with response time of 15–20 s, recovery time of 2.5–3 min and limit of detection or quantification of 5 mM. The selectivity of the ammonia sensing by the nanocomposite was also confirmed over ammonium sulfate, ammonium chloride, sodium nitrate and urea in aqueous medium.

Construction, characterization and application of locust bean gum/Phyllanthus reticulatus anthocyanin - based plasmonic silver nanocomposite for sensitive detection of ferrous ions

Iron is a transition metal of tremendous eco-physiological significance. This work aimed at constructing a simple plasmonic Ag-nanocomposite (LBG/PRAg-NC) based on locust bean gum and Phyllanthus reticulatus anthocyanin in a sustainable manner for the optical detection of ferrous ions (Fe2+) in aqueous solution. LBG/PRAg-NC was prepared via a green chemistry route and thoroughly characterized for its physico-chemical and plasmonic attributes. Successful synthesis of LBG/PRAg-NC under room temperature with Phyllanthus reticulatus anthocyanin as reductant and locust bean gum as stabilizer was accomplished within 15 min. LBG/PRAg-NC exhibited small size (∼8.04 nm), spherically shaped nanosilver, with good colloidal dispersion, stability and prominent SPR absorption peak at 420 nm. XPS analysis revealed the existence of both Ag0 and Ag + species embedded in the biopolymer support. Furthermore, LBG/PRAg-NC was highly selective for Fe2+ as opposed to other interferents including Fe3+. The presence of Fe2+ engendered a redox oxidation of the analyte by the Ag+ species, prompting a rapid, concentration dependent increase in color and SPR absorption band intensity of LBG/PRAg-NC colloidal solution. In aqueous solution, the probe displayed a good linear range for Fe2+ (0.1–100 μM), and a low detection limit (LOD of 0.38 μM). The obtained detection limit is much lower than the guideline limit of Fe2+ content in drinking water, ∼5 μM. Additionally, the probe was successfully applied in determination of Fe2+ in aqueous solutions of apple juice, iron supplement tablet, and tap water, with commendable analytical performances. Therefore, our research findings demonstrate a facile, efficacious, cost-effective, and eco-friendly approach for the sustainable synthesis of plasmonic Ag-nanocomposites based solely on locust bean gum and Phyllanthus reticulatus anthocyanin. Importantly, these results validate the capacity of plasmonic Ag-nanocomposite constructed via green chemistry route as a simple, rapid, and selective probe for effective monitoring of trace amounts of Fe2+ in aqueous environment.

Photoactive MOF-Derived Bimetallic Silver and Cobalt Nanocomposite with Enhanced Antibacterial Activity

Conventional antibiotic-based treatment of bacterial infections remains one of the most difficult challenges in medicine because of the threat of multidrug resistance caused by indiscriminate abuse. To solve these problems, it is essential to develop an effective antibacterial agent that can be used at a small dose while minimizing the occurrence of multiple resistance. Metal-organic frameworks (MOFs), which are hyper-porous hybrid materials containing metal ions linked by organic ligands, have recently attracted attention because of their strong antibacterial activity through metal-ion release, unlike conventional antibiotics. In this study, we developed a photoactive MOF-derived cobalt-silver bimetallic nanocomposite (Ag@CoMOF) by simply depositing silver nanoparticles on a cobalt-based MOF through nanoscale galvanic replacement. The nanocomposite structure continuously releases antibacterial metal ions (i.e., Ag and Co ions) in the aqueous phase and exhibits a strong photothermal conversion effect of Ag nanoparticles, accompanied by a rapid temperature increase of 25-80 °C under near-infrared (NIR) irradiation. Using this MOF-based bimetallic nanocomposite, superior antibacterial activities were achieved by 22.1-fold for Escherichia coli and 18.3-fold for Bacillus subtilis enhanced inhibition of bacterial growth in a liquid culture environment compared with the generally used chemical antibiotics. In addition, we confirmed the synergistic enhancement of the antibacterial ability of the bimetallic nanocomposite induced by NIR-triggered photothermal heating and bacterial membrane disruption even when using a small amount of the nanocomposites. We envision that this novel antibacterial agent using MOF-based nanostructures will replace traditional antibiotics to circumvent multidrug resistance and present a new approach to antibiotic development.

Electrosynthesis of silver metallonanocomposites in the 1-vinyl-1.2.4-triazole copolymer matrix with methacrylic acid

Silver nanocomposites were synthesized by the electrochemical method in the matrix of a copolymer of 1-vinyl-1,2,4-triazole with methacrylic acid, by combining the process of electrochemical polymerization with cathodic precipitation of metals on metal electrodes. In the electronic spectra of nanocomposites, absorption bands appear with a maximum in the region of 417–421 nm, which is typical for systems with zero valence silver. The IR spectra show that the polymer structure hardly changes during the formation of nanocomposites and films. The presence of silver in the amorphous polymer phase is indicated by the results of X-ray diffraction studies. The silver content in nanocomposites is 0–9%, which leads to an increase in the viscosity of nanocomposite solutions compared to solutions of the initial copolymers. Transmission electron microscopy data show that the synthesized nanocomposites consist of particles with a diameter of 1–12 nm, predominantly spherical.

Silver Nanoparticles Capped with Poly[(maleic anhydride)-co-(vinyl acetate)

Anhydride containing functional co-polymer, Poly[(maleic anhydride)-co-(vinyl acetate)] (pMAVAc) was synthesized by free radical polymerization reaction presence of methyl ethyl ketone (MEK) media with benzoyl peroxide radical initiation at 80 ◦C. Surface modification of pMAVAc was carried out with silver to obtain size specific silver nanocomposites by well-known chemical-reduction approach. Structural characterizations of the samples were performed spectroscopic measurement and surface morphology identification using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy (SEM), respectively. Results obtained from the ATR-FTIR analysis, detection of the characteristic spectrum data of the co-polymer composition in pMAVAc-AgNPs nanocomposite is proof that the co-polymer structure remains unchanged after treatment. The size and morphological properties of the silver nanoparticles were compatible with the characteristic nanomaterial structure and their average size was found to be 35 nm. In addition, as expected, MAVA-AgNPs nanocomposite, the detection of 79.73% Ag by mass is evidence of the high silver content in the material, and it was concluded that the co-polymer was successfully coated with silver. In recent years, considering the increasing importance of biocompatible nanomaterials in drug delivery systems and in pharmaceutical industry, the synthesized nanocomposites are thought to be a useful drug carrier system with potential antibacterial activity.