Formation Of Silver Nanoparticles Research Articles

Eco-friendly high-rate formation of silver nanoparticles in agave inulin and its bactericidal effect against Escherichia coli

Abstract A high rate of silver nanoparticle formation, effective against the Escherichia coli (E. coli) bacterium, was obtained for the first time by means of a simple, eco-friendly, and low-cost green method in a solution of agave inulin. The study was carried out using the traditional method, in which the effects of the concentration of agave inulin, AgNO3, temperature, and pH on the synthesis were analyzed by UV-Vis spectroscopy and transmission electron microscopy (TEM). Most of the nanoparticles produced were spherical with a size less than 10 nm. In a sample with 20 mg/mL of agave inulin, 1 mM of AgNO3, T = 23°C, and pH = 12, the highest percentage of Ag+ ions available in the solution were reduced for the formation of nanoparticles in less than 40 min, whereas a sample prepared with 60 mg/mL of agave inulin, 10 mM of AgNO3, T = 23°C, pH = 12, and a storage time of 40 min showed a significant bactericidal effect on the E. coli strain. Agave inulin is a good biological compound for the formation of small, spherical silver nanoparticles. A pH of 12 favors a higher production speed of the silver nanoparticles and better use of the available Ag+ ions. In addition to this, the concentration of AgNO3 is a determining factor for increased formation of the nanoparticles necessary to bactericidal effect.

Utilization of aqueous broccoli florets extract for green synthesis and characterization of silver nanoparticles, with potential biological applications

The process of creating nanoparticles using chemicals is not eco-friendly. However, a more environmentally conscious approach known as green chemistry, which involves using vegetable-mediated nanoparticle production, combines nanotechnology with biotechnology. In this study, the researchers aimed to assess the effectiveness of the green chemistry technique in producing silver nanoparticles using an liquid extract from broccoli florets (Brassica oleracea) under ideal environment. The successful production of silver nanoparticles was achieved through silver nitrate (AgNO₃) biological reduction with the help of an aqueous broccoli florets extract at a slightly acidic pH of 6–7. The silver nanoparticles occurrence was shown by a change of color that moved from colorless to reddish-brown. To characterize the green-produced nanoparticles, various analytical techniques such as Ultraviolet–Visible Spectroscopy (UV-VIS), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray Spectroscopy (EDAX) were employed. The antioxidant properties of the formed silver nanoparticles (AgNPs) were examined in vitro using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric Reducing Antioxidant Power (FRAP) tests. Additionally, the antibacterial properties of AgNPs against various pathogenic bacteria was evaluated. The reduction procedure was easy and simple manageable, with UV–Vis spectroscopy indicating the surface plasmon resonance (SPR) presence at 425 nm. FTIR was utilized to identify active chemical groups in the biomass before and after reduction. SEM and X-ray diffraction analyses indicated that the silver nanoparticles had an average the size of individual particles of 33 nm and exhibited a face-centered cubic (FCC) structure. EDAX analysis confirmed the occurrence of elemental silver in the nanoparticles. The study demonstrated that the biosynthesis of AgNPs led to significant variations in antioxidant activity, which was dose-dependent and showed a similar pattern to the testing of the scarfing action of the ascorbic acid against free radicals using DPPH and FRAP. The AgNPs also dispalyed firm deep-spectrum antibacterial action observed against the tested pathogenic bacteria, outperforming certain medications. Interestingly, the silver nanoparticles remained stable at ambient temperature for 25 days without precipitation, retaining their antioxidant and antibacterial properties. In conclusion, the research findings suggest that an aqueous extract of fresh broccoli florets can serve as a viable and environmentally friendly method for producing stable silver nanoparticles with beneficial antioxidant and antibacterial characteristics.

Ultrasonic-assisted Biosynthesis of Silver Nanoparticle using Green Seaweed Ulva lactuca Extract

Ulva lactuca, a green seaweed that is widely distributed in Indonesia, is abundant but still underutilized. Even though this seaweed contains a sulfated polysaccharide called ulvan as much as 30-40% of its dry biomass and secondary metabolite. These components can be applied in various fields including as a reducing agent for silver ions in the bottom up synthesis of silver nanoparticles. The utilization of seaweed extract combined with ultrasonication is expected to enhance the efficacy of environmentally friendly silver nanoparticle synthesis. The objective of this study was to obtain he crude extract of U. lactuca andto investigatethe impact of extract concentration and ultrasonication duration on the biosynthesis of silver nanoparticles. The study consists of two main phases 1) bio-synthesis employing different concentrations of the U. lactuca crude extract, and 2) bio-synthesis using selected extract concentrations combined with ultrasonic assistance for varying durations. The results of this study indicate that the crude extract of U. lactuca is a crude ulvan polysaccharide with a yield value and sulfate content of 26.9 ± 0.90% and 20.04 ± 1.02%, respectively. A reddish-brown color indicates the formation of silver nanoparticles. Based on the absorbance intensity, a 10% (v/v) concentration of ulvan crude extract produced the highest absorbance intensity (0.038 a.u). In addition, the ultrasonication duration of 60 minutes has succeeded in producing the smallest particle size (267.40 ± 6.52 nm) with a homogeneous particle distribution (PdI 0.265 ± 0.05). Scanning electron microscope (SEM) images depicted oval-shaped silver nanoparticles, while the Fourier-transform infrared (FTIR) spectrum indicated the degradation of sulfate and polysulfide functional groups in the crude extract during the biosynthesis process. These findings highlight the significant role of sulfate/sulfide groups present in the U. lactuca crude extract in the biosynthesis of silver nanoparticles.

In-situ formation of Azo dye capped-silver nanoparticles and their nanocomposite with reduced graphene oxide for dye degradation

This work entails a novel and simple chemical method for preparation of silver and reduced graphene oxide nanocomposite (Ag@rGO NCs). In nanocomposite fabrication, the silver salt was reduced through Eriochrome Black T (EBT) and Methylene Orange (MO) respectively in the presence of graphene oxide. The mechanism of interaction was understood by simulating the system using first-principle Density Functional Theory approach. The formation of silver nanoparticles was confirmed through UV–visible spectroscopy by observing the plasmonic peak. By X-Ray Diffraction (XRD) analysis, the crystallite size of silver nanoparticles was calculated to be 9.83 nm and 12.5 nm respectively, for two nanocomposites. Statistically, spherical surface morphology and average particles diameter of silver was assessed to be 38 nm and 42 nm from scanning electron microscopy (SEM) analysis. Energy dispersive spectroscopy (EDS) confirmed the presence of silver in the nanocomposites. Fourier Transform Infrared (FTIR) and RAMAN Spectroscopy confirmed the interaction mechanism of GO and Ag NPs by changes in surface groups. In photocatalysis, the dye degradation efficiency of Ag@rGO NCs have been studied against Methylene Blue (MB) and found to be 69.7% and 87.9% approximately.

Fluorophore-assisted green fabrication of flexible and cost-effective Ag nanoparticles decorated PVA nanofibers for SERS based trace detection

Detection and particularly quantitative analysis of organic pollutants such as rhodamine 6G (R6G), and p-nitrophenol (pNP) in water are very important for both human health and the ecological environment. In this study, we synthesized as a facile and low cost method silver nanoparticles on poly(vinyl alcohol) (PVA) nanofibers to prepare a film based surface enhancement Raman scattering (SERS) substrate for label free molecular detection. Detection of the R6G molecule with the obtained SERS substrate is possible even at concentrations as low as 10−12 M and therefore the obtained SERS substrate indicated excellent molecular sensitivity for R6G molecule. Limit of detection value (LOD) was determined as 1.07 × 10−13 M while the enhancement factor (EF) of the obtained SERS substrate was calculated as 1.06 × 109 for the R6G molecule. A fluorophore molecule named as 2,5-bis(4-hydroxyphenyl)thiazolo[5,4-d]thiazole (HPhTT) was effectively used for cross-linking of PVA nanofibers to use them as growth template for silver nanoparticles (AgNPs) formation on the surface without any reducing and stabilizing agent thanks to unique properties of HPhTT. Green and one pot preparation of such SERS substrates can pave the way for easily prepared commercial substrates.Moreover, AgNPs decorated PVA nanofiber-based SERS substrate has high reproducibility and good stability for SERS detection of organic pollutants. Obtained SERS substrate is expected to be applicable as a label-free sensor for various chemical and biological molecules.

Biosynthesises of Silver Nanoparticles of Beauveria bassiana and its Effect on Potato Tuber Moth (Zeller) Phthorimaea opercullella Lepidoptera: Gelechiidae

The study was conducted at the Atomic Energy Laboratory, plant Control Department / Baghdad for the year 2020-2021. The study aimed to synthesis of silver nanoparticles from Beauveria bassiana to control potato tuber moth Phthorimaea opercullella. The results showed the formation of silver nanoparticles of the supernatant B.b-SNPS of the fungal extract and biomass B.b-SNPS had the highest absorption at the longest wavelengths (380 and 435 nm) respectively. The scanning electron microscope images also showed that the silver nanoparticles were of irregular spherical shapes with average diameters of Bb-AgNPs for biomass and Bb-AgNPs for the supernatant (43.75 and 79.65) nanometers, respectively. The results showed that the silver nanoparticles prepared by the supernatant and the biomass of the fungus induced the highest egg mortality of 34.6% and 44.3%, while the egg mortality were 80.9 and 67.5%, respectively, when the fourth larval stage of the insect was treated. The overall results indicated that the prepared silver nanoparticles are highly efficient in affecting the eggs and larvae of the fourth instar, which can be used efficiently to reduce the rate of infection in the insect and can be a promising method for the insect control.

In Situ Formation of Silver Nanoparticles Induced by Cl-Doped Carbon Quantum Dots for Enhanced Separation and Antibacterial Performance of Nanofiltration Membrane.

Polyamide (PA) nanofiltration (NF) membranes suffer from biofouling, which will deteriorate their separation performance. In this study, we proposed a strategy to incorporate silver nanoparticles (Ag NPs) into PA NF membranes in situ, in order to simultaneously enhance water permeability and antibacterial performance. The chloride-doped carbon quantum dots (Cl-CQDs) with photocatalytic performance were pre-embedded in the PA selective layer. Under visible light irradiation, the photogenerated charge carriers generated by Cl-CQDs rapidly transported to silver ions (Ag+ ions), resulting in the in situ formation of Ag NPs. The proposed strategy avoided the problem of aggregating Ag NPs, and the amount of Ag NPs on the membrane surfaces could be easily tuned by changing silver nitrate (AgNO3) concentrations and immersion times. These uniformly dispersed Ag NPs increased membrane hydrophilicity. Thus, the obtained thin film nanocomposite Ag NPs (TFN-Ag) membrane exhibited an improved water flux (31.74 L m-2 h-1), which was ~2.98 times that of the pristine PA membrane; meanwhile, the sodium sulfate (Na2SO4) rejection rate was 96.11%. The sterilization rates of the TFN-Ag membrane against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were 99.55% and 99.52%, respectively. Thus, this facile strategy simultaneously improved the permeability and antibacterial property of PA NF membranes.

Silver Nanoparticles Incorporated PVA‐MC Blends: A Systematic Approach To Understand Its Properties For Food Packaging Applications

AbstractHither‐to‐unknown one‐pot method for the synthesis and stabilization of silver nanoparticles (AgNPs) from silver nitrate (AgNO3) through uncross‐linked and cross‐linked polyvinyl alcohol/methyl cellulose (PVA/MC) blend using solution casting method is discussed in detail. The formed films were characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive X‐ray spectroscopy (SEM‐EDX), transmission electron microscopy (TEM) and analyzed for its physical, mechanical, biodegradable and antibacterial properties (particle size, water vapour transmission rate, water contact angle, thermogravimetric analysis (TGA), UV‐Vis spectroscopy and migration). SEM and TEM results indicated that the formation of silver nanoparticles are spherical in shape as well as nano in size. FTIR spectroscopic analysis indicates the existence of hydrogen bonds in cross‐linked blend and complex of silver (Ag) in uncross‐linked blend. Further, enhanced mechanical, water barrier, and thermal properties are observed for the films containing AgNPs. Antibacterial test by disc diffusion method showed that, uncross‐linked and cross‐linked blend with AgNPs have more inhibition (mm) against L. Monocytogenes (10.33), Klebsiella (9.67) (Gram‐positive) and Salmonella (9.33), E. Coli (8.33) (Gram‐negative) strains respectively. Migration studies demonstrated that the developed films could be suitable for fatty food packaging.

Evaluation of antioxidant and antimicrobial properties of silver nanoparticles biosynthesized using weed (Dactyloctenium aegyptium) extracts for sustainable environment, agriculture and ethnomedicine

In order to maintain a sustainable environment, one of the strategies available for weed management is their conversion for use in pharmacological applications.Aqueous and ethanol extracts of Dactyloctenium aegyptium was utilized for silver nanoparticles (AgNPs) synthesis following established protocol. Techniques including Scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), UV–visible (UV–vis) spectroscopy, and Fourier Transform Infrared (FTIR) spectroscopy were used to analyze the synthesized AgNPs. The antioxidant as well as antibacterial activities of activity of aqueous (AE), ethanol (EE) extracts of Dactyloctenium aegyptium and the biosynthesized silver nanoparticles (AgNPs-AE and AgNPs-EE) were evaluated using standard methods.The first indication of successful AgNPs synthesis were the color changes observed after the addition of AgNO3 solution to the aqueous and ethanol extracts of Dactyloctenium aegyptium respectively. The UV spectrum of AgNPs-AE and AgNPs-EE were both observed to be 550 nm which is characteristic of silver nanoparticles.The reduction of silver ions (Ag+) to silver nanoparticles was revealed by the FT-IR analysis to involve biomolecules including flavonoids and phenolic acid. The SEM analysis revealed that the biosynthesized silver nanoparticles were irregularly spherical with diameters ranging from 14.35 μm-20 μm. The formation of silver nanoparticles were further confirmed by the EDX spectrum which revealed signals from Ag (0.3 and 3 keV).The result of the antioxidant activity of the samples (AE, EE, AgNPs-AE, and AgNP-EE) showed that AgNPs-EE had the highest total phenol and flavonoid content, as well as total antioxidant power followed by AgNPs-AE and ethanol extract and then the aqueous extracts. The antibacterial activity also revealed that for all the test pathogens,AgNPs-EE showed the greatest inhibitory capacity, followed by AgNPs-AE and then Levofloxacin. All the test pathogens used were however resistant to AE and EE. Silver nanoparticles biosynthesized using Dactyloctenium aegyptium can therefore be explored as an antioxidant and antibacterial agent after proper pharmacological evaluations.

Overcoming multidrug-resistant bacteria and fungi by green synthesis of AgNPs using Nepeta pogonosperma extract, optimization, characterization and evaluation of antibacterial and antifungal effects

This study explained a green synthesis of silver nanoparticles (AgNPs) using Nepeta pogonosperma extract and evaluated their antibacterial activity. Optimization of the temperature, concentration, pH, and reaction time was established to produce silver nanoparticles. The best condition was 10 mM AgNO3, pH = 14, temperature 85 °C, and reaction time 24 hours. The formation of silver nanoparticles was confirmed by colour-changing, UV-vis, FE-SEM, EDX, XRD, FT-IR, and DLS analysis. The prepared AgNPs had a spherical shape with an average size of 51.21±0.02 nm. In addition, our biofabricated nanoparticles displayed potential antibacterial activity against the tested strains. The MIC value of 1.17 µg/mL was determined against strains of Pseudomonas aeruginosa, Acinetobacter baumannii, and Escherichia coli and 2.34 µg/mL against Staphylococcus aureus, Klebsiella pneumoniae, Proteus mirabilis and Enterococcus faecalis. Furthermore, AgNPs exhibited excellent antifungal effects against Candida albicans strains (0.073 μg/mL). In general, N. pogonosperma played an important role in reducing Ag(+1) to Ag(0) and the production of Ag(0) with suitable surface features in combination with efficient biological activities.

Silver nanoparticles coated by Schiff base as an adsorbent of lead from polluted water.

Synthesis of silver nanoparticles coated with Schiff base was achieved . Silver nanoparticles are reduced and coated using Schiff base. Schiff base serves as a capping to stop silver oxide from overgrowing. Schiff base produces silver nanoparticles with a novel form and a distinctive appearance. The presence of Schiff base as a reducing and capping agent can give a new shape for prepared silver nanoparticles. The structure of Schiff base was analyzed based on spectral data (1 H nuclear magnetic resonance (H1NMR), Mass spectroscopy, and Fourier-transform infrared spectroscopy (FTIR). The formation of silver nanoparticles within a surface plasmon band at 461 nm was observed using UV-Vis Spectroscopy. Silver nanoparticles with a spherical shape and a particle size between 50 and 100 nm are visible in a scanning electron microscope image. For the first time, silver nanoparticles coated with Schiff base were used to adsorb lead from a sample of polluted water. The rate of adsorption was 69%.

Investigation of Antibiofilm and Antibacterial Properties of Green Synthesized Silver Nanoparticles from Aqueous Extract of Rumex sp.

The decrease in the effectiveness of conventional drugs as a result of the growth of resistance to antibiotics has increased the need for innovative tools to control the infections. At this point, metallic nanoparticles, in particular silver nanoparticles, have appeared as a promising method. In the current study, the extract of Rumex sp. (Labada, dock) leaves was used as a reducing agent for the formation of silver nanoparticles. Unlike similar studies, in this study the synthesis conditions were optimized by changing the extract ratio and silver nitrate concentration. Morphological investigations of synthesized silver nanoparticles showed that spherical homogeneous particles at size under 100nm had been produced. SEM/EDS and FTIR analyses showed that plant components are involved in the synthesis of nanoparticles. It was also determined that higher extract ratio reduced nanoparticle size. The antimicrobial effects of the synthesized nanoparticles against Gram-positive and Gram-negative bacteria were tested, and it was determined that all nanoparticles exhibited activity against both groups. Rumex sp. silver nanoparticles (NPs) were revealed to exhibit antibiofilm activity against three different isolates with moderate and strong biofilm-forming ability. The NPs reduced the biofilm-forming capacity of Acinetobacter baumannii and Klebsiella pneumonaie by 2.66-fold and 3.25-fold, whereas they decreased the Escherichia coli biofilm-forming capacity by 1.25-fold. The investigation of microbial biofilm could play an important role in developing new strategies for treatment options. Our results suggest that Rumex sp. silver NPs may have a high potential for use in the treatment of pathogenic strains.

Rutin Mediated Synthesis of Silver Nanoparticles derived from Melia dubia and Evaluation of Antioxidant and Antimicrobial Activity

Researches based on bio inspired synthesis of noble metal nano materials has become a promising one in today’s biomedical approach in therapy and diagnosis due to multidimensional applications. Furthermore, silver nanoparticles were reported to have several medicinal applications. Hence the present study was to explore the antioxidant and antimicrobial efficacy of silver nanoparticles (AgNPs) synthesized from rutin isolated from the methanolic extract of leaves of Melia dubia. The biosynthesized nanoparticles were analyzed using UV-Visible, FT-IR, XRD and SEM techniques. The band at 398.5nm in the UV-Visible spectra confirmed the formation of AgNPs. The characteristic shift in OH and C=O peak after the formation of silver nano particles shows the participation of biomaterial (Rutin) in the reduction process which is further supported by SEM report. The average size of the particle (19 nm) was determined from XRD analysis using the Scherrer’s equation. The antimicrobial and antioxidant efficacy of harvested nanoparticles were compared for their potential with rutin and silver salt. The synthesized material was shown to have good antimicrobial activity towards the tested bacteria and fungi and potentially active towards free radicals. Thus, the silver nanoparticles (AgNps) synthesized using bio-flavanoid viz. rutin are potentially good and therefore can be further studied for pharmacological activities.

Ganoderma lucidum-Mediated Green Synthesis of Silver Nanoparticles with Antimicrobial Activity.

"Green chemistry" is a simple and easily reproductible method that provides nanoparticles characterized by better stability and good dispersion in an aqueous solution. Nanoparticles can be synthesized by algae, bacteria, fungi, and plant extracts. Ganoderma lucidum is a commonly used medicinal mushroom with distinctive biological properties, such as antibacterial, antifungal, antioxidant, anti-inflammatory, anticancer, etc. In this study, aqueous mycelial extracts of Ganoderma lucidum were used to reduce AgNO3 to form silver nanoparticles (AgNPs). The biosynthesized nanoparticles were characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analysis. The maximum UV absorption was obtained at 420 nm, which represents the specific surface plasmon resonance band for biosynthesized silver nanoparticles. SEM images showed particles as predominantly spherical, while FTIR spectroscopic studies illustrated the presence of functional groups that can support the reducing of ion Ag+ to Ag(0). XRD peaks ratified the presence of AgNPs. The antimicrobial effectiveness of synthesized nanoparticles was tested against Gram-positive and Gram-negative bacterial and yeasts strains. The silver nanoparticles were effective against pathogens, inhibiting their proliferation, and thus reducing the risk to the environment and to public health.

Uncaria gambir Roxb. mediated synthesis of stable silver nanoparticles in the presence of triethanolamine as the capping agent

The study of silver nanoparticles (AgNPs) fabrication has gained great interest especially for pharmaceutical applications due to its excellent antibacterial properties. AgNps are well known for their inhibitory and bactericidal effects both on positive and negative gram bacteria. However, the utilisation of some chemical reducing agents in the synthesis process can be harmful to the environment and the human body. Green synthesis of silver nanoparticles has been successfully conducted using an aqueous extract of Uncaria gambir Roxb. (UGR) leaves as a bioreducing agent and triethanolamine as a capping agent, reacted with aqueous AgNO3 as the precursor. The formation of silver nanoparticles was visually revealed by colour change from yellow to brown. It was also confirmed by UV-visible (UV-Vis) spectrophotometer analysis by absorption peaks at 402–414 nm. The result of X-ray diffraction (XRD) analysis showed 5 peaks referring to face-centred cubic silver nanoparticles. Transmission electron microscope (TEM) analysis showed that spherical silver nanoparticles with a size range of 2–18 nm with a mean diameter of 8 nm have been formed. The result showed that the addition of 1/50 mL triethanolamine (TEA) could enhance the stability of colloidal nanoparticles and reduce the particle size up to 65%. This study confirmed that UGR aqueous leaf extract can be used to mediate rapid, environmentally friendly, and less expensive silver nanoparticles fabrication.

ПОЛІЛАКТИДНІ КОМПОЗИЦІЙНІ МАТЕРІАЛИ З ФУНГІБАКТЕРИЦИДНИМИ ВЛАСТИВОСТЯМИ

The regularities of obtaining polylactide film composite materials with simultaneous silver nanoparticles formation were researched. The influence of the nature of polylactide and its structure (amorphous and amorphous-crystalline), of the glycerin plasticizer on the solvent evaporationkinetics was determined. To give polylactide composites fungicidal properties, the silver reduction reaction by the interaction of argentum salts with polyvinylpyrrolidone was applied. A main technological scheme for obtaining films based on polylactide with fungicidal properties is proposed. Above mentioned provides effective practical usage of the films as packaging materials for food products and medicines.

PENENTUAN KANDUNGAN ANTIOKSIDAN DAN FENOLIK TOTAL DARI EKSTRAK TUMBUHAN SEBAGAI BIOREDUKTOR DALAM PEMBENTUKAN NANOPARTIKEL PERAK

The formation of metal nanoparticles (silver, gold, platinum) by biological methods (green synthesis) has advantages over chemical and physical methods because it is easier, faster, simpler, and environmentally friendly. One of the substances used in this method is plant extracts. The presence of secondary metabolites that act as antioxidants such as phenolics and flavonoids play roles in the formation of silver nanoparticles. In this study, phytochemical screening was carried out from several herbal plants as bioreductors in the formation of silver nanoparticles, such as Phyllanthus buxifolius, Pachira aquatica, Peperomia pellucida, Ageratum conyzoides, and Piper crocatum leaf extracts. The total antioxidant content was determined using the modified phenanthroline method, and the total phenolic content determined using the Folin-Ciocalteu method. The formation of silver nanoparticles was carried out by mixing silver nitrate solution with each plant extract. Colloidal silver nanoparticles formed were then measured for their absorption spectra. The results of the antioxidant content of the five consecutive samples were 26,90 ± 0,19; 26,09 ± 0,14; 18,25 ± 0,02; 42,76 ± 0,14; dan 30,94 ± 0,14 mg AA/g, while the total phenolic contents were 48,44 ± 0,45; 21,08 ± 0,92; 17,42 ± 0,27; 57,71 ± 0,47; dan 49,83 ± 0,60 mg GA/g. Silver nanoparticles mediated by Ageratum conyzoides leaf extracts provided the highest absorbance value compared to other plants. The antioxidants and phenolic contained in the extract acts as reducing agent from silver ions into silver nanoparticles.

Green synthesis of silver nanoparticles and their inhibitory efficacy on corrosion of carbon steel in hydrochloric acid solution

Silver nanoparticles were created by an easy green synthesis method using plant extract. The relationship between the size and form of silver nanoparticles and the concentration of silver nitrate salt was examined. Using plant extract (tobacco leaf extract) at concentrations of 3, 5, and 10 mill moles (mMol) of AgNO3, silver nanoparticles were produced. Using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively, the form and structure of the prepared samples were analyzed. The relation between salt concentrations and the size of silver nanoparticles is depicted linearly in SEM images. The capacity of these nanomaterials to prevent the corrosion of carbon steel used in the petroleum industry when exposed to 1.0 N hydrochloric acid, a corrosive medium, is being investigated. Using chemical, electrochemical, and analytical techniques, the effect of concentration (50–200 ppm) and temperature (303–333 K) on the ability of generated materials to inhibit growth was studied. It was revealed that the inhibitory efficacy decreased at higher temperatures and increased with higher doses. The maximum inhibition efficiency of 98% was achieved using 200 ppm of the nanomaterials 3. The inhibition is due to the Nano molecules’ adhesion and adsorption on the metal surface via Langmuir adsorption. There is a linear relationship between the size of nanoparticles and their inhibition efficiency, similar to the linear relationship observed between the size of silver nanoparticles and the salt concentration, as demonstrated by the order of inhibition efficiency for the three nanomaterial samples used: Nanomaterials Samples 3 > Nanomaterials Samples 2 > Nanomaterials Samples 1.

Silver nanoparticles production mediated by natural tetraploid Trifolium pratense L.: Characterization and potential biological activity

Abstract This study was aimed to present the green synthesis of silver nanoparticles through natural tetraploid Trifolium pratense L. containing high amounts of phenolic compounds and glycosidic bioactive macromolecules. Combinatorial optimization of AgNPs was achieved thanks to the stabilizing and reducing properties of the natural tetraploid T. pratense L. flowering herb extract. The biologically synthesized AgNPs were visualized by color change in UV–Vis spectroscopy. UV–Vis spectroscopy proved to be a fast and simple method to determine the synthesis of AgNPs. In addition, TEM, XRD, and FTIR analyses were performed to confirm and characterize the formation of crystalline silver nanoparticles. It was shown by the TEM analysis that AgNPs changed their size and shape when biosynthesized in different conditions. It was determined that smaller AgNPs were spherical and larger AgNPs had a truncated octahedron shape. The XRD analysis proved the presence of Ag0 in nanoparticles and showed its crystal structure and faced cubic shapes for AgNPs. Interactions between the plant bioactive compounds and the AgNPs were distinctly visible in the FTIR spectra. The biosynthesized AgNPs showed strong antioxidant activity against DPPH and ABTS; furthermore, the total phenol content was also high.

Mechanical and Physical Properties of an Experimental Chemically and Green-Nano Improved Dental Alginate after Proven Antimicrobial Potentials.

Impression materials could be a source of cross-contamination due to the presence of microorganisms from blood and saliva inside the oral cavity. Nevertheless, routinely performed post-setting disinfection could compromise the dimensional accuracy and other mechanical properties of alginates. Thus, this study aimed to evaluate detail reproduction, dimensional accuracy, tear strength, and elastic recovery of new experimentally prepared self-disinfecting dental alginates. Two antimicrobial-modified dental alginate groups were prepared by mixing alginate powder with 0.2% silver nitrate (AgNO3 group) and a 0.2% chlorohexidine solution (CHX group) instead of pure water. Moreover, a third modified group was examined by the extraction of Boswellia sacra (BS) oleoresin using water. The extract was used to reduce silver nitrate to form silver nanoparticles (AgNPs), and the mixture was used as well in dental alginate preparation (BS + AgNP group). Dimensional accuracy and detail reproduction were examined as per the ISO 1563 standard guidelines. Specimens were prepared using a metallic mold engraved with three parallel vertical lines 20, 50, and 75 µm wide. Detail reproduction was evaluated by checking the reproducibility of the 50 µm line using a light microscope. Dimensional accuracy was assessed by measuring the change in length between defined reference points. Elastic recovery was measured according to ISO 1563:1990, in which specimens were gradually loaded and then the load was released to allow for recovery from the deformation. Tear strength was evaluated using a material testing machine until failure at a crosshead speed of 500 mm/min. The recorded dimensional changes between all tested groups were insignificantly different and within the reported acceptable values (between 0.037-0.067 mm). For tear strength, there were statistically significant differences between all tested groups. Groups modified with CHX (1.17 ± 0.26 N/mm) and BS + AgNPs (1.11 ± 0.24 N/mm) showed higher tear strength values compared to the control (0.86 ± 0.23 N/mm) but were insignificant from AgNO3 (0.94 ± 0.17 N/mm). All tested groups showed elastic recovery values that met both the ISO standard and ADA specifications for elastic impression materials and tear strength values within the acceptable documented ranges. The CHX, silver nitrate, and green-synthesized silver nanoparticles could be promising, inexpensive alternatives for the preparation of a self-disinfecting alginate impression material without affecting its performance. Green synthesis of metal nanoparticles could be a very safe, efficient, and nontoxic method, with the advantage of having a synergistic effect between metal ions and active chemical constituents of plant extracts.