Antimicrobial Activity Of Silver Nanoparticles Research Articles

Biosynthesis of DLLAE blended silver nanoparticles and their response against periodontitis triggering bacteria

Facts over microorganisms to predominate periodontitis, shifting of human microbiota by Dimocarpus longan (D. longan) plant, and potentiation of antimicrobial activity by biosynthetic silver nanoparticles (SNPs) intended present study to biosynthesize, optimize, characterize and evaluate the antimicrobial potential of silver nanoparticles (SNPs) obtained using D. longan leaves aqueous extract (DLLAE). Study involved preparation of DLLAE using decoction method. The DLLAE was subjected to biosynthesis of SNPs followed by optimization (using UV-Visible spectrometry), characterization (by FTIR, FESEM, XRD, and EDX), stability, and antimicrobial activity of SNPs against periodontitis triggering human microflora. Biosynthesized SNPs exhibited signal between 416-453 nm. Optimization study established AgNO3 concentration (5 mM), pH 4, DLLAE and AgNO3 ratio (1:9) and temperature (60°C) as parametric requirement for SNPs biosynthesis using DLLAE. Stability study exhibited signal between 489-553 nm supporting SNPs stability. Characterization data of FESEM showed that SNPs were poly dispersed, and spherical shaped. Biosynthesized SNPs size ranged from 74.82 nm to 131.5 nm. The XRD data revealed presence of signals at 38.08°, 44.33°, 64.47°, and 78.83° 2θ values indexed to silver cubic structure planes. In EDX study, silver exhibited strong signal (55.54%). Antimicrobial investigation explored the high inhibitory potential of SNPs against B. subtilis and P. aeruginosa; and low inhibitory potential against S. aureus and E. coli. Present study conclude that biosynthesis of SNPs using DLLAE is an efficient method and biosynthetic SNPs possess high antimicrobial potential against P. aeruginosa and B. subtilis the periodontitis triggering pathogens.

Enhanced antimicrobial activity of silver nanoparticles conjugated with synthetic peptide by click chemistry

Strategies to design novel antibacterial materials may rely on the combination of materials to achieve synergistic effects. The coupling of antibacterial peptides to nanoparticles, however, needs to be directed conveniently to avoid structural changes within the peptide and/or degradation of the nanoparticle. Here, we present the results of the attachment of a synthetic peptide (VIHGW-alkyne-G-NH2) containing the amino terminal copper and nickel (ATCUN) motif to silver nanoparticles. In order to direct the peptide-nanoparticle coupling, the peptide was functionalized with an alkyne, whereas the nanoparticles were functionalized with azide groups using thiol-polyethylene glycol-azide (HS-PEG-N3) chains, so that the acetylide and the azide can undergo a click reaction. The reaction was conducted at room temperature and the steps in the construction of the nanoparticle-PEG-ATCUN array were followed by a combination of UV-Vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy. Evidence of the attachment of the PEG molecules through the thiol termination indicates that the nanoparticle is functionalized with azide groups, although only partially. The click reaction with the synthetic peptide is evidenced by the loss of the N3-vibrational signal with infrared spectroscopy. Throughout the steps of the synthesis, the behavior of the nanoparticles was followed by UV-Vis spectroscopy, dynamic light scattering, and zeta potential measurements, observing that during the process there are no significant changes in the size of the nanoparticle and that the stability of the nanoparticles increases. Antibacterial tests, conducted using E. coli, showed that the activity of the Ag-PEG-ATCUN nanocomposites is higher than that of nanoparticles and ATCUN peptides separately.

Performance on Bone Regeneration of a Silver Nanoparticle Delivery System Based on Natural Rubber Membrane NRL-AgNP

NRL-AgNP was developed bringing important properties of natural rubber as occlusive membrane with antimicrobial activity of silver nanoparticles. Biological aspects, such as cell viability, tissue reaction, and occlusive membrane performance of NRL-AgNP, are presented. In addition, in vivo degradation was investigated by Fourier Transform Infrared Spectroscopy (FTIR). The cell viability test was performed in mesenchymal stem cells of human deciduous dental pulp seeded with the new material. Tissue reaction was tested through subcutaneous implant of NRL-AgNP and compared to Polytetrafluoroethylene (PTFE) at the dorsum of rats. The performance of the NRL-AgNP as an occlusive membrane in Guided Bone Regeneration (GBR) was tested in full thickness critical size bone defects (8 mm) in rat calvaria. Cell viability was 98.8% for NRL-AgNP and did not result in statistically significant differences compared to negative control (p > 0.05 Kruskal–Wallis). All materials presented similar tissue reaction (p > 0.05). In the GBR experiment, the defects covered with NRL-AgNP presented a more advanced stage of bone regeneration in comparison with non-treated defects. The FTIR spectra of NRL-AgNP before and after implantation showed no degradation of NRL-AgNP membranes. These results are in favor of the NRL-AgNP use as an occlusive membrane for GBR.

Antibacterial and biofilm inhibition activity of biofabricated silver nanoparticles against Xanthomonas oryzae pv. oryzae causing blight disease of rice instigates disease suppression.

Antimicrobial activity of silver nanoparticles (AgNPs) has been well documented in earlier studies. As their efficient role in combating phytopathogens has begun recently, there is ahuge scope to explore their effectiveness in agriculture. Considering the strong antifungal activity of biosynthesized AgNPs (as reported in our previous study), our main aim is to elucidate their antibacterial activity against bacterial plant pathogens to authenticate their wide range of agricultural applications. The present manuscript highlights the potential role of biosynthesized AgNPs against Xanthomonas oryzae pv. oryzae (Xoo) causing disastrous sheath blight disease of rice worldwide. We observed strong antibacterial activity of biosynthesized AgNPs (size ~ 12nm) against Xoo at 20, 30 and 50µg/mL concentrations. The significant inhibitory impact of AgNPs on biofilm formation by Xoo was noted even at the lower dose of 5µg/mL (p = 0.001). Maximum biofilm inhibition (p = 0.000) was caused at 50µg/mL concentration of AgNPs in comparison to control. Furthermore, disease suppression by biosynthesized AgNPs was authenticated under greenhouse conditions. Foliar spray of AgNPs significantly reduced the blight symptoms in rice sheaths as shown by 9.25% DLA (% Diseased leaf area) as compared to 33.91% DLA in Xoo inoculated rice plants. Altogether, our data suggest that biosynthesized AgNPs based nanoformulation can be applied for successful management of blight disease of rice. In addition, the antibiofilm strategies instigated by AgNPs can be exploited against a wide range of bacterial phytopathogens. In light of rapidly emerging antibiotic-resistant microbial strains, the current work provides an alternate effective platform for the application of nanoformulation for augmenting sustainability in the agriculture.

Comparative analysis of biofabricated silver nanoparticles as antibiofilm agents on Pseudomonas aeruginosa

Microbial cells in the biofilm were characterized with significant features like antimicrobial resistance and bio fouling properties, which make them distinguishable from their planktonic forms. Although many antimicrobial drugs and antibiotics were reported for biofilm inhibition and dispersal, these compounds had limited applications because of drug resistance. Development of antibiofilm agents which could overcome the drug resistant bacteria had been a challenge over the years. In order to overcome development of drug resistance, silver nanoparticles were being used, to coat the medical devices. This strategy, though successful to some extent, suffer with toxic effects on eukaryotic cells in application. Hence there arises a need to explore natural compounds with antibiofilm activity. Natural products established as antibacterial agents were also found to have quorum quenching activity. Garcinia (Garcinia cambogia) and Ginger (Zingiber officinale) extracts were observed to possess quorum quenching activity in the lab, therefore used for biofabrication to enhance the antimicrobial activity of silver nanoparticles. Pseudomonas aeruginosa being a most potent biofilm forming bacteria in various environments, like infections, food spoilage and bio fouling in medical devices etc. The study aimed to figure out a novel antibiofilm agent, which could inhibit or eliminate biofilms by using a combination of biologically synthesized nanoparticles and natural quorum quenching agents. Comparative analysis of bio fabricated nanoparticles on the inhibition and dispersal of Pseudomonas biofilms was performed with non fabricated nanoparticles using microtiter based assay, followed by SEM and Flow cell cytometry techniques. Fabricated GNP (fGNP) had showed 17.9% more inhibition which indicates - 2 fold enhancement in biofilm inhibition activity. Similarly 9.45% enhancement was found in dispersal activity by fGNP. These results were encouraging us to improve upon the combinatorial approach and to formulate an ideal antibiofilm agent with minimal scope for emergence of antimicrobial resistance.

Evaluation of the antimicrobial activity of silver nanoparticles obtained by microwave-assisted green synthesis using Handroanthus impetiginosus (Mart. ex DC.) Mattos underbark extract.

We describe here a green method for the preparation of silver nanoparticles (AgNPs), by a microwave-assisted synthesis route using Handroanthus impetiginosus underbark extract, with antibacterial activity. After optimizing the synthesis parameters with a Box–Benhken designed experiment, samples were characterized by powder XRD, TEM, UV-Vis spectroscopy, FTIR and zetametry. Using the overall optimized conditions of synthesis – time of reaction 15 min at 200 °C and plant extract/AgNO3 volume ratio equal to 10% – highly crystalline ∼13.4 nm-sized spherical AgNPs in a well-dispersed colloidal state were obtained. It was also proved that the plant extract compounds act as reductant and capping agents during synthesis to functionalize AgNPs, resulting in a negatively charged surface with high values of zeta potential in a wide range of pH, from acidic to alkaline media. Biological activity tests against Staphylococcus aureus and Escherichia coli and cell viability experiments showed that synthesized AgNPs were not toxic to HaCaT mammalian cells and presented a high efficiency against Gram-positive bacteria (S. aureus). This was associated with the synergistic combination of AgNP silver cores with the capping layer containing natural compounds with antimicrobial properties and considered an alternative to the AgNPs commonly obtained from conventional routes that present antibacterial effectiveness preferentially against Gram-negative strains.

Antimicrobial Activity of Silver Nanoparticles with Antibiotics Against Clinically Isolated Acinetobacter baumannii

Antibiotic-resistant bacteria are among the major healthcare problem worldwide and Acinetobacter baumannii is a leading threat among them. In this study, the combined effects of different antibiotics with silver nanoparticles (AgNPs) were assessed against the growth of a clinical isolate of A. baumannii. The bacterial strain was isolated from a hospitalized burned patient in Sulaimanyah- Iraq. Identification of the isolated bacterium was done based on the partial sequence of the 16S rRNA gene and phylogenetic analysis. The growth of the bacterium was totally inhibited by AgNPs at the concentration of (0.2 mg/ml). AgNPs treatment showed a partial synergistic effect with azithromycin (Fractional Inhibitory Concentration Index (FICI) = 0.6) and an additive effect with kanamycin (FICI = 1.67). Not a significant difference in the antimicrobial activities of either ampicillin or tetracycline was observed when they used alone or in combination with AgNPs. Overall, this study may provide a promising future use of azithromycin with AgNPs to treat A. baumannii superficial infections; however, a combination of kanamycin with AgNPs together should be avoided.

Silver Decorated Mesoporous Carbons for the Treatment of Acute and Chronic Wounds, in a Tissue Regeneration Context.

IntroductionSilver decorated mesoporous carbons are interesting systems that may offer effective solutions for advanced wound care products by combining the well-known anti-microbial activity of silver nanoparticles with the versatile properties of ordered mesoporous carbons. Silver is being used as a topical antimicrobial agent, especially in wound repair. However, while silver shows bactericidal properties, it is also cytotoxic at high concentrations. Therefore, the incorporation of silver into ordered mesoporous carbons allows to exploit both silver’s biological effects and mesoporous carbons’ biocompatibility and versatility with the purpose of conceiving silver-doped materials in light of the growing health concern in wound care.MethodsThe wound healing potential of an ordered mesoporous carbon also doped with two different loadings of silver nanoparticles (2 wt% and 10 wt%), was investigated through a biological assessment study based on different assays (cell viability, inflammation, antibacterial tests, macrophage-conditioned fibroblast and human keratinocyte cell cultures).ResultsThe results show silver-doped ordered mesoporous carbons to positively condition cell viability, with a cell viability percentage >70% even for 10 wt% Ag, to modulate the expression of inflammatory cytokines and of genes involved in tissue repair (KRT6a, VEGFA, IVN) and remodeling (MMP9, TIMP3) in different cell systems. Furthermore, along with the biocompatibility and the bioactivity, the silver-doped ordered mesoporous carbons still retain an antibacterial effect, as shown by a maximum of 13.1% of inhibited area in the Halo test. The obtained results clearly showed that the silver-doped ordered mesoporous carbons exhibit both good biocompatibility and antibacterial effect with enhanced re-epithelialization, angiogenesis promotion and tissue regeneration.DiscussionThese findings suggest that the exceptional properties of silver-doped ordered mesoporous carbons could be exploited in the treatment of acute and chronic wounds and that such carbon materials could be potential candidates for use in medical devices for wound healing purposes, in particular, the 10 wt% loading, as the results showed to be the most effective.

Antimicrobial activity of silver nanoparticles synthesised by using microbial biosurfactant produced by a newly isolated Bacillus vallismortis MDU6 strain.

Microbial biosurfactants has evolved as green molecules and their chemical diversity has gained momentum in recent time not only in the field of environmental and industrial sectors but also in the pharmaceutical sector. In this study, an effort was made for the biosynthesis of silver nanoparticle (AgNPs) having antimicrobial and non-cytotoxic activities with the help of microbial biosurfactant extracted from a novel Bacillus vallismortis strain MDU6 (Genbank accession no. MH382951) from petroleum oil logged soil sample in Dibrugarh, Assam. The isolate shows excellent potential for the production of biosurfactant by reducing the surface tension of diesel supplemented medium up to 56.57% only within 5 days. FTIR spectra of the crude biosurfactant show the presence of ʋCH2 (asymmetric stretching), ʋCH2 (symmetric stretching), ʋC=C (stretch), ʋC-C (stretch), ʋC-H (bending), ʋC-O (stretch) and ʋC-H (bending) functional groups and LC-MS/MS analysis confirms it as a cyclic lipopeptide which is a mixture of surfactin and iturin. The synthesized AgNPs showed excellent antimicrobial activities against Escherichia coli (ATCC no. 25922), Listeria monocytogenes (ATCC No. BAA-751), Staphylococcus aureus (ATCC No. 9542) and Bacillus subtilis (ATCC no. 6051) and showed no cytotoxicity against primary mouse liver cell lines.

Novel honey mediated green synthesis of Graphene@Ag Nanocomposite and its two-dimensional application in photovoltaic and anti-microbial activity

The green and facile method were successfully employed for the fabrication of Graphene/Ag nanocomposite (Gr@AgNCs) with graphite oxide (GO) as graphene precursor and AgNO3 as precursor for Ag nanoparticles. Honey was used as a reducing and stabilizing agentwhich is known to be environment-friendly in nature. The characterization of synthesized Gr@AgNCs was done using x-ray diffraction (XRD),scanning electron microscopy (SEM),Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectra (RS),Thermogravimetric analysis (TGA), and UV analysis. The results showed that Honey effectively reduced GO to graphene and silver ions to silver nanoparticles (AgNPs) which makes present synthesis more suitable for synthesizing other metals like gold (Au) on graphene sheets. This active synthesis perhaps can have wide applications in medical, technological and industrial field. In addition to this, enhanced antimicrobial activity of silver nanoparticles (AgNPs) was retained in the Gr@AgNCs along with the photovoltaic activity signifyingtheir potential use as a graphene-based nanomaterial.

Comparative Antimicrobial Activity of Silver Nanoparticles Synthesized by Corynebacterium glutamicum and Plant Extracts

Biosynthesis of nanoparticles has received considerable attention due to the growing need to develop environmentally benign nanoparticle synthesis processes that do not use toxic chemicals. Therefore, biosynthetic methods employing both biological agents such as bacteria and fungus or plant extracts have emerged as a simple and a viable alternative to chemical synthetic and physical method .It is well known that many microbes produce an organic material either intracellular or extracellular which is playing important role in the remediation of toxic metals through reduction of metal ions and acting as interesting Nano factories. As a result, in the present study Ag NPs were synthesized by two methods biosynthetic technique using supernatant of Corynebacterium glutamicum that isolated from soil and green synthesis method by using plant extracts of fresh green plants.Ag NPs which synthesized by two methods were investigated visually by monitoring the color shift of reaction mixture from pale yellow to brown color, UV-Visible spectrophotometer was used to measure maximum absorbance of synthesized Ag NPs. The nanoparticles synthesized from Corynebacterium glutamicum exhibited maximum antimicrobial activity against selected pathogenic and environmental strains more than Ag NPs synthesized by green synthesis method from Spinacia oleracea, Malva parviflora and Eruca sativa. plant extracts

Antimicrobial activity of silver nanoparticles fabricated from some vegetable plants

In the recent years green synthesis of silver nanoparticles is being have become more advantage than over other biological process because they avoid elaborating process of culturing and maintaining the cells. Also, nanoparticles synthesized from plant extracts is favourite because it is less cost, environmental -friendly, rapid and facile method. Therefore, the present study we chosen some plant extracts represented with Petroselinum crispum, Beta vulgaris and Lepidium aucheri for fabrication Ag NPs which was treated with silver nitrate solution( 1mM ) at two temperatures (60-100)C°. Ag NPs synthesized was investigated visually by colour shift for reaction mixture from yellowish green to brown colour. synthesized Ag NPs was characterise by UV-Visible spectroscopy that revealed a characteristic surface Plasmon resonance peak between( 405- 422 )nm. Also using Fourier transform infra-red spectroscopy( FTIR) indicated the role of the functional groups that participated in synthetic process. These Ag NPs showed antimicrobial activity against some bacterial strains.

Green Synthesis, Characterization and Antimicrobial Activity of Silver Nanoparticles Using Dudoa (Hydnocarpus alcalae C.DC.) Leaf Extract As a Reducing and Stabilizing Agent

Background and Objective: In this study, dudoa (Hydnocarpus alcalae C.DC.) leaf extract was used as a reducing and stabilizing agent in a novel one-step green synthesis of silver nanoparticles. Dudoa is an endemic plant in the province of Legazpi, Philippines and its seed oil was used as an anti-leprotic drug. Method: Therefore, the dudoa leaf extract was used to synthesize silver nanoparticles. Moreover, optimization of various parameters greatly affected the size and morphology of the synthesized AgNPs as indicated by the Ultraviolet-visible (UV-vis) spectrophotometry. The synthesized AgNPs were further characterized using spectral analyses such as XRD, EDX, SEM, FT-IR, TGA and DLS. The antimicrobial activity of synthesized AgNPs was also demonstrated. Results and Discussions: The synthesized AgNPs exhibited a diffraction pattern and a particle size ranging from 22-48 nm. The AgNPs also showed complete inhibitory and mild reactivity against representative pathogenic gram-positive (S.aureus) and gram-negative (E.coli) bacteria. Conclusion: Silver nanoparticles were successfully synthesized using H. alcalae leaf extract. Furthermore, this green synthesis approach appeared to be cost-effective, non-toxic, and eco-friendly which is a best alternative to the conventional chemical methods.

Antimicrobial Activity Of Silver Nanoparticles Synthesized with Extract of Tomato plant Against Bacterial and Fungal Pathogens

Objective: Silver nanoparticles (AgNPs) have a wide range of applications. Environmental-friendly synthesis methods for these nanoparticles are more preferable due to their various advantages. This study aimed to synthesize AgNPs using the extract of the tomato plant in an easy and economical way. and testing this AgNPs against some human pathogens.Methods: Silver nanoparticles were synthesized using aqueous silver nitrate and reducing tomato plant extract. The characterization of AgNPs was determined by ultraviolet-visible spectrophotometry (UV-Vis), X-ray crystallography (XRD) Scanning electron microscopy (SEM), Fourier transform infrared Spectroscopy (FT-IR), energy dispersive X-ray spectrum (EDAX), thermogravimetric - differential thermal analysis (TGA-DTA) data. The effects of the particles on pathogenic microorganisms were determined by minimum inhibition concentration (MIC).Results: These data, with a maximum absorbance of 450.51 nm, in the spherical view, with the peaks and values of 111o, 200o, 220o and 311o (38.08, 44.28, 64.42 and 77.34), AgNPs showed a cubic crystal structure and, using the Debye-Scherrer equation, it was determined that they had a crystal size of 21.11 nm AgNPs had an antimicrobial activity on hospital pathogens gram negative, gram positive and Candida albicans yeast. Conclusion: We found that these particles showed antimicrobial activity on various microorganisms even at very high concentrations. As a solution to the antimicrobial search, it can be developed in medical industry.

Green synthesis, characterization and antimicrobial activity of silver nanoparticles (AgNPs) using leaves and stems extract of some plants

Green synthesis of silver nanoparticles using the aqueous extract of Ferula gumosa, Ferula latisecta, Teucrium polium and Trachomitum venetum leaves and stems extract as the reducing and stabilizing agents. This synthesis shows attractive characteristics such as; the use of inexpensive and available plant extracts, non-toxicity, eco-friendly biological materials, and operational simplicity. The extracts incubated with AgNO3 solution showed gradual change in color of the extracts to yellowish brown, with intensity increasing during the period of incubation. The nanoparticles were characterized by UV–visible absorption spectroscopy, X-ray diffraction (XRD) spectroscopy, Dynamic Light Scattering (DLS), and Transmission Electron Microscope (TEM). The silver nanoparticles synthesized were generally found to be spherical in shape with variable size ranging from 5 to 30 nm, as evident by TEM. The biosynthesized silver nanoparticles (AgNPs) showed good antibacterial activity against clinical strains of two bacteria Staphylococcus aureus and Escherichia coli.

Biosynthesis of gold and silver nanoparticles using Parkinsonia florida leaf extract and antimicrobial activity of silver nanoparticles

In this work, the biosynthesis of gold and silver nanoparticles from a leaf extract of Parkinsonia florida (P. florida) is reported. The P. florida leaf extract was analyzed by a phytochemical screening, by measuring the DPPH radical scavenging activity, and by Fourier-transform infrared spectroscopy (FT-IR). The phytochemical screening results indicated that biomolecules like carbohydrates, phenols, proteins, aminoacids, saponins, and flavonoids present in P. florida leaf extract might have participated in the chemical reduction of the metallic salts and further colloidal stabilization. The FT-IR results from leaf extract functional groups support the role of surface modification with the presence of residues of phenols, proteins, aminoacids, saponins, and flavonoids. The formation of metallic nanoparticles was confirmed by optical absorption spectroscopy with characteristic absorption bands at 550 nm and 430 nm, for gold and silver nanoparticles, respectively. Zeta potential for gold nanoparticles presents negative values in the range of −10 ± 1 to −16 ± 1 mV, depending on the amount of leaf extract used during the synthesis reaction. Similarly, zeta potential values for silver nanoparticles were in the range of −5 ± 1 to −16 ± 1 mV. STEM images revealed the average particles sizes in the range from 10 to 15 nm, and 10 to 57 nm, for gold and silver nanoparticles respectively. The silver nanoparticles presented good antibacterial activity, inhibiting the growth of Staphylococcus aureus and Escherichia coli.

Antimicrobial Activity of Silver Nanoparticles Synthesized Using Goat Milk against Pathogens of Selected Vegetables

This study was carried out to determine the antimicrobial activity of silver nanoparticles synthesized using goat milk against pathogens of selected vegetables. Synthesis of Silver nanoparticles was done using Goat milk, and characterized using Ultra Violet-Visible absorption spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X- ray diffraction (XRD) and Transmission Electron Microscopy (TEM). Maximum absorbance of Goat milk synthesized AgNPs was observed at 417 nm, with FTIR peaks at 3455 cm−1, 1628 cm−1, 1402 cm−1, 1081 cm−1 and 517 cm−1, indicating that proteins in Goat milk (GM) were the capping and stabilization molecules involved the synthesis of AgNPs. Transmission electron microscopy analysis showed that the biosynthesized particles were spherical in shape having a size of 10-100 nm, X- ray diffraction (XRD) pattern agreed with the crystalline nature and face-centered cubic phase of AgNPs. Evaluation of the antimicrobial activity of AgNPs synthesized using GM against the indicator strains (Staphylococcus aureus CIP 9973, Pectobacterium carotovorum Pec1, Enterobacter cloacae AS10, Klebsiella aerogenes OFM28, Proteus mirabilis UPMSD3 and Escherichia coli 2013C-3342) isolated from selected vegetables, was carried out using the Agar diffusion assay at different concentrations of 25, 75 and 100 µl/ml. The present study demonstrated that the AgNPs synthesized using Goat milk have potent biological activities, which can find applications in diverse areas.

Antimicrobial activity of silver nanoparticles supported by magnetite

AbstractAntibacterial and antifungal ability of silver nanoparticles (Ag NPs) supported by functionalized magnetite (Fe3O4) with 5‐aminosalicylic acid (5‐ASA) was tested against Gram‐negative bacteria Escherichia coli, Gram‐positive bacteria Staphylococcus aureus and yeast Candida albicans. Characterization of materials including transmission electron microscopy, X‐ray diffraction analysis, and inductively coupled plasma optic emission spectroscopy technique followed each step during the course of nanocomposite preparation. The synthesized powder consists of 30–50 nm in size silver particles surrounded by clusters of smaller (∼10 nm) Fe3O4 particles. The content of silver in the nanocomposite powder was found to be slightly above 40 wt.–%. Concentration‐dependent and time‐dependent bacterial reduction measurements in dark indicated that use of Ag NPs leads to the complete reduction of E. coli and S. aureus even at the concentration level of silver as low as 40 μg/mL. However, the negligible antifungal ability of synthesized nanocomposite was found against yeast C. albicans in the entire investigated concentration range (0.1‐2.0 mg/mL of the nanocomposite, i. e., 40–800 μg/mL of silver). Complete inactivation of E. coli and S. aureus was achieved in five repeated cycles indicated that synthesized nanocomposite can perform under long‐run working conditions. From the technological point of view, magnetic separation is the additional advantage of synthesized nanocomposite for potential use as an antibacterial agent.

Enhance the Antimicrobial Activity of Silver Nanoparticles by Manipulating a Redox Process and Controlling the Size of the Particles

Enhance the Antimicrobial Activity of Silver Nanoparticles by Manipulating a Redox Process and Controlling the Size of the Particles

Characterization of silver nanoparticle produced by Pseudopediastrum boryanum (Turpin) E. Hegewald and its antimicrobial effects on some pathogens

The aim of this research was to investigate the antimicrobial activity of silver nanoparticles (AgNPs) biosynthesized by Pseudopediastrum boryanum (Turpin) E. on several human pathogen microorganisms. AgNPs were isolated from P. boryanum. The biosynthesis of AgNPs was carried out using a UV–visible spectrophotometer and FTIR spectroscopy analysis. The antimicrobial activity of AgNPs was evaluated against various pathogen microorganisms using the well diffusion method, and MIC was estimated by qualitative experimentation by microbroth dilution method. The antimicrobial activities of AgNPs at three different concentrations (1 mM, 2 mM and 3 mM) were measured using the diameter of the inhibition zone (DIZ) of the pathogen microorganisms. AgNPs demonstrated various antimicrobial effects on pathogen microorganisms at different concentrations. The highest antimicrobial activity was determined in Proteus vulgaris [DIZ = 30 ± 0.2 mm (2 and 3 mM)], followed by Candida parapsilosis (M006) [DIZ = 25 ± 0.1 mm (3 mM)], followed by Pseudomonas aeruginosa [DIZ = 20 mm (2 and 3 mM)] and Candida parapsilosis (M006) [DIZ = 20 mm (1 and 2 mM)]. The lowest antibacterial effects of AgNPs were observed on Aeromonas hydrophila [DIZ = 5 ± 0.1 mm (3 mM)], Staphylococcus epidermidis [DIZ = 5 ± 0.1 mm (1 mM)], Candida parapsilosis [DIZ = 5 ± 0.1 mm (2 mM)] and Candida albicans [DIZ = 5 ± 0.1 mm (3 mM)]. Gram-negative bacteria Proteus mirabilis, Enterobacter aerogenes, Salmonella typhimurium, Shigella dysenteriae, Escherichia coli and Serratia marcescens and Gram-positive bacteria Listeria monocytogenes and Enterococcus faecalis exhibited no zone of inhibition. Our results confirm that AgNPs biosynthesized from P. boryanum may be used as an effective antimicrobial agent against human pathogens.