Size Of Silver Nanoparticles Research Articles

Particle Size Modulates Silver Nanoparticle Toxicity during Embryogenesis of Urchins Arbacia lixula and Paracentrotus lividus.

Silver nanoparticles represent a threat to biota and have been shown to cause harm through a number of mechanisms, using a wide range of bioassay endpoints. While nanoparticle concentration has been primarily considered, comparison of studies that have used differently sized nanoparticles indicate that nanoparticle diameter may be an important factor that impacts negative outcomes. In considering this, the aim of the present study was to determine if different sizes of silver nanoparticles (AgNPs; 10, 20, 40, 60 and 100 nm) give rise to similar effects during embryogenesis of Mediterranean sea urchins Arbacia lixula and Paracentrotus lividus, or if nanoparticle size is a parameter that can modulate embryotoxicity and spermiotoxicity in these species. Fertilised embryos were exposed to a range of AgNP concentrations (1−1000 µg L−1) and after 48 h larvae were scored. Embryos exposed to 1 and 10 µg L−1 AgNPs (for all tested sizes) showed no negative effect in both sea urchins. The smaller AgNPs (size 10 and 20 nm) caused a decrease in the percentage of normally developed A. lixula larvae at concentrations ≥50 µg L−1 (EC50: 49 and 75 μg L−1, respectively) and at ≥100 µg L−1 (EC50: 67 and 91 μg L−1, respectively) for P. lividus. AgNPs of 40 nm diameter was less harmful in both species ((EC50: 322 and 486 μg L−1, for P. lividus and A. lixula, respectively)). The largest AgNPs (60 and 100 nm) showed a dose-dependent response, with little effect at lower concentrations, while more than 50% of larvae were developmentally delayed at the highest tested concentrations of 500 and 1000 µg L−1 (EC50(100 nm); 662 and 529 μg L−1, for P. lividus and A. lixula, respectively. While AgNPs showed no effect on the fertilisation success of treated sperm, an increase in offspring developmental defects and arrested development was observed in A. lixula larvae for 10 nm AgNPs at concentrations ≥50 μg L−1, and for 20 and 40 nm AgNPs at concentrations >100 μg L−1. Overall, toxicity was mostly ascribed to more rapid oxidative dissolution of smaller nanoparticles, although, in cases, Ag+ ion concentrations alone could not explain high toxicity, indicating a nanoparticle-size effect.

THE EFFECT OF SHAPE AND SIZE OF SILVER NANOPARTICLES ON ELECTROCHEMICAL ACTIVITY OF SENSOR TO HYDROGEN PEROXIDE

The work considers the influence of the morphological characteristics of the AgNPs (form, sizes of silver nanoparticles (AgNPs), the average size of the area) from the composition of the reducing agent and their influence on the optical characteristics and electrochemical activity of the sensor based on the AgNPs to H2O2. The intensity of the optical spectra of absorption AgNPs and the electrochemical activity of the sensors based on them correlate with the size and shape of the particles. It is shown that the greatest electrochemical activity of H2O2 is possessed by AgNPs-based sensors obtained by using sodium citrate. The reason for increasing the electrochemical activity of the sensor based on the AgNPs obtained in the presence of the soft restorer of sodium citrate is an increase in the area of their active surface 1.3–2.7–3.3 μm2 due to the non-spherical form of particles (triangular, prismatic, pyramidal form), compared with spherical particles obtained using borhydridicitrate and borohydride-based reducing agents.

Effect of caffeine-loaded silver nanoparticles on minerals concentration and antibacterial activity in rats

Background: Caffeine boosts metabolism and the neurological system. When extreme weakness or sleepiness occurs, it is used recreationally and medicinally to reduce physical and mental fatigue. Caffeine initially stimulates the central nervous system, increasing intellect, speed, accuracy, focus, and coordination. Objective: To evaluate how caffeine nanoparticles affect potassium, calcium, zinc, and magnesium levels, in addition, the anti-bacterial activity of the samples has been employed. Methods: Eighteen male albino rats were divided into three separate groups. The first group (G1) was made up of six animals that served as a control group. The second group (G2) was made up of six animals that were given caffeine, and the third group (G3) was made up of six animals that were given silver nanoparticles from a caffeine solution. The particle size and structural morphology of Caffeine and silver nanoparticles were analyzed using Brookhaven Instruments Corp., XRD and SEM respectively. Results: The structural results showed after addition, caffeine was tube-shaped and silver was spherical granular. Caffeine has more silver nanoparticles than caffeine solution. Caffeine solution affects potassium, calcium, zinc, and magnesium levels. Additionally, the solution has antibacterial activity against the following bacteria: Staphylococcus aureus (Gram +ve), E. coli (Gram –ve), and Pseudomonas aeruginosa (Gram-ve), but it has no effect against yeast (Candida albicans). Conclusions: To determine the biological effects of caffeine-synthesized Ag NPs on zinc, magnesium, calcium, and potassium levels in male albino mice's serum, this is antibacterial against staphylococcus.

Directing the size and dispersity of silver nanoparticles with kudzu leaf extracts.

Kudzu is an abundant and invasive species in the Southeastern United States. The prospective use of kudzu as a non-toxic, green and biocompatible reducing and stabilizing agent for one-pot Ag nanoparticle synthesis was investigated. Ag nanoparticles were synthesized using aqueous and ethanolic kudzu leaf and stem extracts. The size and dispersity of the synthesized nanoparticles were found to depend on the extract used. Ultraviolet-visible and Fourier transform infrared spectroscopies were used to characterize the extracts. Surface-enhanced fluorescence and Raman scattering were used to characterize the surface species on synthesized Ag nanoparticles. The primary reducing and stabilizing agents in aqueous kudzu leaf extracts were determined to be reducing sugars and saponins which result in Ag nanoparticles with average diameters of 21.2 ± 4.8 nm. Ethanolic kudzu leaf extract was determined to be composed of chlorophyll, reducing sugars and saponins, producing Ag nanoparticles with average diameters of 9.0 ± 1.6 nm. Control experiments using a chlorophyllin standard as the reducing and stabilizing agent reveal that chlorophyll has a key role in the formation of small and monodisperse Ag nanoparticles. Experiments carried out in the absence of light demonstrate that reducing sugars and saponins also contribute to the formation of Ag nanoparticles in ethanolic kudzu leaf extracts. We propose a mechanism by which reducing sugars donate electrons to reduce Ag+ leading to the formation of Ag nanoparticles, forming carboxylic acid sugars which stabilize and partially stabilize Ag nanoparticles synthesized with aqueous and ethanolic kudzu leaf extracts, respectively. In the ethanolic extract, photoexcited chlorophyll serves as a co-reducing and co-stabilizing agent, leading to small and monodisperse Ag nanoparticles.

Spectroscopic analyses of particle and energy aggregations at the interface of silver nanoparticles and fluorescent carbon nanodots.

We study the change in the surface electromagnetic field provided by photoexcited silver nanoparticles as the field is disturbed by fluorescent carbon nanodots. Fluorescent carbon nanodots with an appropriate quantity and quality of surface functional groups are used to mediate the aggregation of silver nanoparticles of matching size and shape to form available nano-size conical structures. Carbon nanodots in the composite absorb and transfer additional photoenergy to the silver surface, resulting in energy aggregation within the cone structure and enhancement of the electromagnetic field in proximity to the silver surface. This elevated energy state is manifested in the strengthening of the SERS signal of the analytical probe 4-aminophenyl disulfide and the mechanism involved is elucidated by additional molecular spectroscopy studies.

Fabrication and properties of Sn(iv) porphyrin-linked porous organic polymer for environmental applications.

A robust porous organic polymer cross-linked by Sn(iv) porphyrin (SnPOP) was fabricated by reacting trans-dihydroxo-[5,15,10,20-tetrakis(phenyl)porphyrinato]tin(iv) (SnP) with fluorinated polyimide (FPI) via sol-gel formation, followed by supercritical CO2 drying. The structural and porous properties of SnPOP were characterized using FT-IR, UV-vis, and fluorescence spectroscopies, along with field-emission scanning electron microscopy and gas sorption experiments. The reaction between the SnP's oxophilic Sn(iv) center and FPI's carboxylic acid moiety resulted in a controllable cross-linked porous texture. This material features the desirable physical properties of porphyrin and exhibits mesoporous structures with a relatively high surface area. SnPOP is thermally stable at temperatures up to 600 °C and highly resistant to boiling water, strong acids, and bases, owing to its assembly via formation of covalent bonds instead of typically weaker hydrogen bonds. The modified chemical and morphological structures of SnPOP showed an impressive CO2 uptake capacity of 58.48 mg g-1 at 273 K, with a preference for CO2 over N2. SnPOP showed significant efficiency in removing pollutant dyes, such as methylene blue and methyl orange, from dye-contaminated water. Additionally, SnPOP was a photocatalyst for fabricating silver nanoparticles of regular shape and size. All these properties make SnPOP a potential candidate for environmental applications like pollutant removal, gas storage, and separation.

Synthesis of Silver Nanoparticle-Based Chitosan Nanocomposites Using Neowestiellopsis persica Strain A1387 and Characterization of Their Potential Antimicrobial Activity Against Oral Pathogen

Today, overuse and unregulated application of antibiotics and antimicrobial agents have resulted in a substantial increase in drug-resistant pathogens. Therefore, there is a great need for innovative therapeutic methods that can replace ineffective antibiotics. Cyanobacteria are one of the most useful natural candidates in the biosynthesis of nanoparticles to face antibiotic resistance in pathogens. In this study, the antimicrobial effect of different concentrations of silver (AgNPs) nanoparticles based chitosan nanocomposites biosynthesized by <i>Neowestiellopsis persica </i>against oral pathogens was investigated. The NPs biosynthesis were characterized through UV-visible spectroscopy, scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR) and X-ray diffraction analysis (XRD). Results of UV-visible Spectroscopy showed that the amount of absorption increased significantly with increasing time. The SEM and TEM images depict the size of the nanocomposite to be 78.74 to 74.29 and 100 nm respectively and spherical in shape. According to the results of the FT-IR spectrum, the peaks located at a wave number less than 800 cm<sup>-1</sup> are related to the stretching vibration of metal-oxygen bonds in a crystal structure, where due to the presence of silver nanoparticles, these peaks can be related to the symmetric and asymmetric stretching vibration of Ag-O bonds. The results of XRD crystallography confirmed the success of the synthesis of microcoated silver nanoparticles by chitosan. The average crystal size of silver nanoparticles covered by chitosan was 17.6 nm. The antimicrobial efficacy of the biosynthesized AgNP nanocomposite showed that with the increase in the concentration of nanoparticles and nanoparticles coated with chitosan, the diameter of the growth halo increased significantly (<i>p</i> < 0.05). Totally the results of this study confirmed that nanoparticle-based chitosan nanocomposites biosynthesized by cyanobacteria species can be converted into nanomedicine to meet future biomedical needs.

The Impact of Temperature on the Synthesis of Silver Nanoparticles by Candida macedoniensis

Nanoparticles are widely used in medical diagnosis and treatment, as carriers of drug preparations, in cosmetics, production packaging and transportation of foods and etc. Special attention is paid to the use of biological structures in the production of nanoparticles. The aim at the presented work was to investigate the influence of temperature on the formation of silver nanoparticles by Candida macedoniensis BSU-MI44. Wet biomass of yeast at AgNO3 solution, was incubated at 25, 30, 35, 40°C. The samples have been analyzed on the UV spectrometer, the scanning electron microscope and the X-ray spectroscope. Spectrophotometric analyses showed 410 nm wavelength (peak), characteristic for silver nanoparticles in samples incubated at 25 and 30°C. By increasing temperature, the formation of silver nanoparticles has weakened and has finally stopped. The optimum temperature was between 25-30°C for the production of silver nanoparticles and the formed nanoparticles were spherical at both temperatures. The sizes of silver nanoparticles formed at 25°C and 30°C were 65.6 and 14.2-22.9 nm. The sizes of the first ones have been 2.8-4.7 times larger than the sizes of the others. Correspondingly X- ray spectroscopic analyses of the obtained samples showed the characteristic absorption peak for silver nanoparticles formed at temperatures 25 and 30°C.

An overview of synthesis and applications of silver nano-particles

Nanoparticles have different characteristics than their larger counterparts. The mechanical, magnetic, as well as optical properties, add uniqueness to the silver nanoparticles, as the changes in mechanical attributes of substances at the nanoscale are about four times those of macro-sized materials, whereas the magnetic nature of these nanoparticles varies with temperature. These nanoparticles are helpful in several industries, such as medicine, electronics, and environmental restoration, as silver nanoparticles surpass other metal nanoparticles in some qualities and applications. A major advantageous property is microbe resistance, which serves the medicinal field, but these nano-sized particles have their limitations because of nanotoxicity. There are a lot of methods for synthesizing nano silver, and these are listed under chemical, physical, and biological categories. Since the synthesis listed requires physical and chemical methods, which are expensive, the majority of synthesis now takes place through biological pathways involving plant extracts and microorganisms. The technique of production in a biological manner is called the biogenic process of production. The review aims at analyzing the proper synthesis techniques, properties, and application fields of nano-sized silver particles.

Tailoring the size and magnetic property of biogenic silver nanoparticles

By exploring biological sources, the area of nanotechnology is currently thriving and offers a fresh method. Plant extract-mediated green nanomaterial synthesis has gained appeal as a result of its cost-effectiveness and environmentally beneficial characteristics. In this study, Ag NPs were successfully synthesized from reducing Ag+ ions using Mangifera indica leaf extracts as a source of reducing and capping agents. Several different microscopic and spectroscopic approaches were used in order to characterize the produced Ag NPs. Analyses using XRD and SEM have been carried out to look into the morphology of the generated Ag NPs. The (XRD) pattern peaks are associated with the metallic silver in the (FCC) shape. Silver nanoparticles average grain size is in the 10–100 nm range for all concentrations of AgNO3. The shape of the produced silver nanoparticles was determined to be round and spherical by (SEM), and their total size was determined to be between 50 and 100 nm. Analysis using EDX spectroscopy also demonstrated the production of silver and the presence of components that performed the function of a capping agent. (FT-IR) spectra were performed in order to determine the organic groups like carbonyl, hydroxyl, amine, and protein molecules. Analysis using (FT-IR) spectroscopy publicized the presence of flavonoids, polyphenols, and amide groups, all of which are candidates for being responsible for the environmentally friendly creation of silver nanoparticles. From (VSM) analysis, the biosynthesized Ag NPs were weak ferromagnetic in nature, which would be a potential research arena, especially for device application and medical equipment construction using these magnetic crystalline AgNPs. Keywords: Ag NPs, synthesized, X-ray Diffraction, TGA, magnetization

Preparation and properties of Ag-loaded zinc oxide antibacterial coating on medical cobalt-chromium alloy

Medical cobalt-chromium alloy has been widely used in oral implants due to its excellent mechanical properties, corrosion resistance, etc. However, its antibacterial properties should be improved as an implant. In this paper, nano-zinc oxide and Ag-loaded zinc oxide coating were prepared on cobalt-chromium alloy using the hydrothermal and photoreduction methods, and the influencing factors of the preparation process were studied. The effects of pH, hydrothermal temperature and time on the morphology of nano-sized zinc oxide were investigated. The results show that the zinc oxide has satisfactory morphology when the hydrothermal time is 3.0 h, hydrothermal temperature is 100 ℃, and pH value is 9.5. The effects of light intensity, illumination duration and AgNO3 concentration on the size and dispersion of silver nanoparticles on the Ag-loaded zinc oxide were studied. The results show that the Ag-loaded zinc oxide has satisfactory morphology under the illumination intensity of 0.6 W/m2 , illumination duration of 60 min and AgNO3 concentration of 1.0 mol/L. By analyzing the morphology, phase, quality and thickness of zinc oxide and Ag-loaded zinc oxide coating, it is found that the needle-like zinc oxide array is uniformly loaded with silver particles. The average thickness of the coatings is 6.80 μm, and the average weight is 1.67 mg. The antibacterial test shows that the Ag-loaded zinc oxide coating has better antibacterial performance than the pure zinc oxide coating, both of which were better than the blank control sample.

Silver-Decorated Silicon Nanostructures: Fabrication and Characterization of Nanoscale Terraces as an Efficient SERS-Active Substrate

Rich and highly dense surface-enhanced Raman (SERS) hotspots available in the SERS-active platform are highly anticipated in SERS measurements. In this work, conventional silicon wafer was treated to have wide exposure to terraces available within the silicon nanostructures (Si-NSs). High-resolution field emission scanning electron microscopic (FESEM) investigations confirmed that the terraces were several microns wide and spread over different steps. These terraces were further decorated with silver nanoparticles (Ag-NPs) of different shapes and sizes to achieve SERS-active hotspots. Based on more than 150 events, a histogram of the size distribution of Ag-NPs indicated a relatively narrow size distribution, 29.64 ± 4.66 nm. The coverage density was estimated to be ~4 × 1010 cm-2. The SERS-activity of Ag-NPs -decorated Si-NSs was found to be enhanced with reference to those obtained in pristine Si-NSs. Finite difference time domain models were developed to support experimental observations in view of electromagnetic (EM) near-field distributions. Three archetype models; (i) dimer of same constituent Ag-NPs, (ii) dimer of different constituent Ag-NPs, and (iii) linear trimer of different constituent Ag-NPs were developed. EM near-field distributions were extracted at different incident polarizations. Si-NSs are well-known to facilitate light confinement, and such confinement can be cascaded within different Ag-NPs-decorated terraces of Si-NSs.

Synthesis of Green Chitosan – Silver Nanoparticle Composite Material: Parameter Optimization and Physicochemical Characterization

In this study, response surface methodology (RSM) was carried out with four parameters: chitosan concentration, AgNO3 concentration, ascorbic acid concentration and time with the objective to obtain minimum mean particle size of silver nanoparticles (response Y). The chitosan-silver nanoparticle composite material (CTS-AgNPs nanocomposite) obtained experimentally from the optimal conditions was characterized by evaluating some of their physical-chemical properties using combined technique including visible ultraviolet spectroscopy (UV -Vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), infrared spectra (IR) and X-ray diffraction. The optimal conditions were chitosan concentration of 19.2 %, silver nitrate of 26 mM, ascorbic concentration of 33 mM and time of 4.25 hours. Spherical Ag particles obtained experimentally were well dispersed in chitosan matrix with the average diameter of around 2÷8 nm with a narrow size distribution and homogeneous dispersion

Rapid Detection of Mercury Ions Using Sustainable Natural Gum-Based Silver Nanoparticles

Fabrication of metal nanostructures using natural products has attracted scientists and researchers due to its renewable and environmentally benign availability. This work has prepared an eco-friendly, low-cost, and rapid colorimetric sensor of silver nanoparticles using tree gum as a reducing and stabilizing agent. Several characterization techniques have been exploited to describe the synthesized nanosensor morphology and optical properties. Ultraviolet−Visible (UV−Vis) spectroscopy has been used for monitoring the localized plasmon surface area. High-resolution transmission electron microscopy (HR-TEM) illustrated the size and shape of silver nanoparticles. X-ray diffraction spectra showed the crystallography and purity of the product. Silver nanoparticles decorated with almond gum molecules (AgNPs@AG) demonstrated high sensitivity and colorimetric detection of mercury ions in water samples. The method is based on the aggregation of AgNPs and the disappearing yellow color of AgNPs via a spectrophotometer. The detection limit of this method was reported to be 0.5 mg/L. This work aimed to synthesize a rapid, easy-preparation, eco-friendly, and efficient naked-eye colorimetric sensor to detect toxic pollutants in aqueous samples.

Near field and far field plasmonic enhancements with bilayers of different dimensions AgNPs@DLC for improved current density in silicon solar

The effect of a bilayer of different dimension silver nanoparticles (Ag NPs) on light trapping in silicon solar cells is investigated. Here, we report on the improved performance of silicon solar cells by integrating two layers of silver nanoparticles of different sizes. We experimentally examine the plasmonic near-field and far-field effects of bilayer Ag NPs embedded within an anti-reflective DLC layer on silicon solar cells' optical and electrical characteristics. Field-Emission Scanning Electron Microscopy drove the two-dimensional differences in the size of Ag NPs. The surface plasmon resonance of the two-dimensional nanoparticles was estimated from the absorption optical spectra. External quantum efficiency measurements showed that near-field or far-field plasmonic effects altered with the Ag NPs size. The development of far fields was confirmed by measuring the solar cell performance under AM 1.5 G illumination. The impact of the far-field in the cell containing two layers of Ag NPs, which outer layer is larger dimensions NPs, improves the current density up to 38.4 mA/cm2 (by 70% compared to the bare reference cell).

Size-tunable silver nanoparticle synthesis in glycerol driven by a low-pressure nonthermal plasma

Silver nanoparticles (NPs) are extensively used in electronic components, chemical sensors, and disinfection applications, in which many of their properties depend on particle size. However, control over silver NP size and morphology still remains a challenge for many synthesis techniques. In this work, we demonstrate the surfactant-free synthesis of silver NPs using a low-pressure inductively coupled nonthermal argon plasma. Continuously forming droplets of silver nitrate (AgNO3) precursor dissolved in glycerol are exposed to the plasma, with the droplet residence time being determined by the precursor flow rate. Glycerol has rarely been studied in plasma-liquid interactions but shows favorable properties for controlled NP synthesis at low pressure. We show that the droplet residence time and plasma power have strong influence on NP properties, and that improved size control and particle monodispersity can be achieved by pulsed power operation. Silver NPs had mean diameters of 20 nm with geometric standard deviations of 1.6 under continuous wave operation, which decreased to 6 nm mean and 1.3 geometric standard deviation for pulsed power operation at 100 Hz and 20% duty cycle. We propose that solvated electrons from the plasma and vacuum ultraviolet (VUV) radiation induced electrons produced in glycerol are the main reducing agents of Ag+, the precursor for NPs, while no significant change of chemical composition of the glycerol solvent was detected.

Sodium borohydride mediated synthesis of nano-sized silver particles: Their characterization, anti-microbial and cytotoxicity studies

This work reports the one-step, fast, easy, simple and economical process for the synthesis of nano-sized and stable silver particles. AgNPs were synthesized at six (0.02 M, 0.04 M, 0.06 M, 0.08 M, 0.10 M and 1.00 M) different concentrations of metal precursor and reducing agent. Sodium borohydride was used as both reducing and stabilizing agent. Characterization studies revealed that all the silver nanoparticles (AgNPs) synthesized were in the range of 10 nm–50 nm, spherical shaped, crystalline nature and with high negative surface charge (−30 mV to −47 mV). Among the AgNPs evaluated for their anti-microbial activity through well diffusion method against Escherichia coli (Gram negative bacteria), Bacillus subtilis (Gram positive bacteria) and Candida albicans (fungi), AgNPs-1.00 showed maximum zone of inhibition with 11.5 mm, 18.5 mm and 10 mm at highest test concentration (100 mg/L), respectively. Cytotoxicity of the AgNPs was determined against MCF-7, PVA1 and Caco-2 cancer cell lines through standard MTT assay. AgNPs-0.08 showed highest mortality% with 90% and 80% against MCF-7 and PVA1 at maximum test concentration (100 mg/L), respectively. However, none of the AgNPs showed toxicity towards Caco-2 cancer cell line. Therefore, AgNPs can be used as anti-microbial agents in the biomedical applications.

Green Synthesis and Characterization of Silver Nanoparticles Synthesized Using Leaf Extract of Passiflora Foetida Linn

The silver nanoparticles (SNPs) are applied in nanomedicine, health, food safety and other applications. The topical methods are based on chemicals that are toxic in nature, thus to minimize the hazardous effects the natural sources need to be explored forsynthesizing SNPs. The contemporary work reports the greener way of silver nanoparticles (SNPs) fabrication using phytochemical, functional groups and secondary metabolites from Passifloraaqueous leaf extract. The optimized condition for SNPs synthesis was 1 mM AgNO3 95ml + leaf extract 5 ml at alkaline pH 11 yields stable NPs. Various parameters such as temperature, pH, sunlight, dark, different concentration of AgNO3were evaluated. The UV-spectroscopic analysis confirms SNPs synthesis at 420 nm for sunlight based, 428 nm at room temperature and 425 nm for microwave-based conditions. The FTIR determines alkanes, alkyne, amines, aliphatic amine, carboxylic acid; nitro-compound from the leaf extract have been used for reducing silver nitrate for SNPs synthesis. The SEM and TEM analysis confirms the 14.96 nm size SNPs under sun light condition shows antimicrobial activity against E. coliand S. aureouspathogens at 50 ug/ml concentration, which may have applicability to raised SNPs based green sustainable products in treating pathogens.

Green synthesis of pectin‐silver nanocomposite: Parameter optimization and physico‐chemical characterization

AbstractIn our present reports, an eco‐friendly approach of green‐synthesis of silver nanoparticles without using any toxic reducer or organic solvent was investigated. Pectin, a biopolymer, was used both as a reducing agent and a stabilizer. Response surface methodology (RSM) was carried out with four parameters: pectin concentration, AgNO3 concentration, temperature, and time to obtain the minimum mean particle size of silver nanoparticles (response Y). The optimal conditions were pectin concentration of 1.64 mg/ml, silver nitrate of 3.26 mM, temperature of 36.6°C and time of 9.6 h. A silver particle size of 6.82 nm was obtained by Design Expert Software and silver particle size obtained experimentally was 6.62 nm. The physico‐chemical properties of the pectin‐silver nanocomposite were characterized by combined techniques including visible ultraviolet spectroscopy (UV‐Vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), infrared spectra (IR), and X‐ray diffraction.

Preparation of Biocidal Nanocomposites in X-ray Irradiated Interpolyelectolyte Complexes of Polyacrylic Acid and Polyethylenimine with Ag-Ions.

Due to the presence of cationic units interpolyelectrolyte complexes (IPECs) can be used as a universal basis for preparation of biocidal coatings on different surfaces. Metallopolymer nanocomposites were successfully synthesized in irradiated solutions of polyacrylic acid (PAA) and polyethylenimine (PEI), and dispersions of non-stoichiometric IPECs of PAA–PEI containing silver ions. The data from turbidimetric titration and dynamic light scattering showed that pH 6 is the optimal value for obtaining IPECs. Metal polymer complexes based on IPEC with a PAA/PEI ratio equal to 3/1 and 1/3 were selected for synthesis of nanocomposites due to their aggregative stability. Studies using methods of UV–VIS spectroscopy and TEM have demonstrated that the size and spatial organization of silver nanoparticles depend on the composition of polymer systems. The average sizes of nanoparticles are 5 nm and 20 nm for complexes with a molar ratio of PAA/PEI units equal to 3/1 and 1/3, respectively. The synthesized nanocomposites were applied to the glass surface and exhibited high antibacterial activity against both gram-positive (Staphylococcus aureus) and gram-negative bacteria (Salmonella). It is shown that IPEC-Ag coatings demonstrate significantly more pronounced biocidal activity not only in comparison with macromolecular complexes of PAA–PEI, but also coatings of PEI and PEI based nanocomposites.