Antibacterial Activity Of Silver Nanoparticles Research Articles

Antibacterial activity of silver nanoparticles synthesized from latex and leaf extract of Ficus sycomorus

The development of green synthesis of nanoparticles has received increasing attention due to ease of preparation, less chemical handling, and eco-friendly. In the present study, crystalllization of silver ions to nanosized particles by latex and leaf aqueous extract of Ficus sycomorus through bioreduction process was assessed. Strong plasmon resonance of silver nanoparticles was observed around 435nm. UV–visible spectroscopy, transmission electron microscope (TEM) and energy dispersive X-ray fluorescence (EDXRF) were performed to examine the formation of silver nanoparticles (SNPs). The antibacterial activity of SNPs was tested against nine human pathogenic Gram −ve bacteria and one Gram +ve bacteria. Silver nanoparticles of extracts showed improved antibacterial activity on all the tested strains than for the extracts alone. This was confirmed either by optical density or zone of inhibition measurements. Silver nanoparticles was more effective in liquid than in solid medium probably because of better contact, for the higher silver content, with bacterial cells. It is concluded that fig (F. sycomorus) leaves and latex extracts can be used for the synthesis of SNPs that is environmentally friendly and cost effective. These preparations can be used for various biotechnology and medical applications for controlling pathogenic bacteria with better dispersion and, consequently, better efficiency in aqueous environment.

Potential antibacterial activity of crude extracts and silver nanoparticles synthesized from Sargassum wightii

The present work investigates the antibacterial activity of silver nanoparticles (Ag-NPs) synthesized by biological method using Sargassum wightii. The fresh live seaweed was collected from the Mandapam coast of Tamilnadu, India. Solvent extract was prepared using acetone, petroleum ether and methanol. Aqueous extract of the seaweed was also used for the synthesis of silver Ag-NPs. Seaweed extract is used as a reducing agent of 2mM silver nitrate solution for the synthesis of Ag-NPs. Periodical monitoring of reaction mixture was done using UV-vis spectroscopy at 300-750 nm. The scanning electron microscopy (SEM) of the sample confirms the presence of Ag-NPs. The antibacterial activity of solvent extract was done by Minimal inhibitory concentration (MIC) assay. The methanol extract of the seaweed at a concentration of 250µg/ml exhibited potent antimicrobial activity against the test microorganism. The zone of inhibition ranging from 8-14 mm was observed with different extracts. The antibacterial activity of the synthesized Ag-NPs against the organism was also done by MIC test. The MIC of Ag-NPs was found to be 130µg/ml for all pathogenic microorganisms selected for the study. The zone of inhibition against Bacillus cereus, Bacillus anhtracis, Staphylococcus aureus and Vibrio alginoyticus were found to be 10, 8, 10 and 9 mm, respectively. The synthesized Ag-NPs exhibited significant antimicrobial activity against the selected microorganisms than the solvent extract of seaweed.DOI: http://dx.doi.org/10.3329/icpj.v3i10.20337 International Current Pharmaceutical Journal, September 2014, 3(10): 322-325

Green synthesis of silver nanoparticles using marine algae Caulerpa racemosa and their antibacterial activity against some human pathogens

We present the synthesis and antibacterial activity of silver nanoparticles using Caulerpa racemosa ,a marine algae. Fresh C. racemosa was collected from the Gulf of Mannar, Southeast coast of India. The seaweed extract was used for the synthesis of AgNO3 at room temperature. UV-visible spectrometry study revealed sur- face plasmon resonance at 413 nm. The characterization of silver nanoparticle was carried out using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and transmission electron microscope (TEM). FT-IR measurements revealed the possible functional groups responsible for reduction and stabilization of the nanopar- ticles. X-ray diffraction analysis showed that the particles were crystalline in nature with face-centered cubic geom- etry.TEM micrograph has shown the formation of silver nanoparticles with the size in the range of 5-25 nm. The synthesized AgNPs have shown the best antibacterial activity against human pathogens such as Staphylococcus aureus and Proteus mirabilis. The above eco-friendly synthesis procedure of AgNPs could be easily scaled up in future for the industrial and therapeutic needs.

Anti-bacterial activities of silver nanoparticles synthesized from plant leaf extract of Abutilon indicum (L.) Sweet

Abutilon indicum (L.) Sweet is an Asian phytomedicinal plant and it has hypoglycemic and anti-bacterial activities. The nano silver was successfully synthesized from leaf extract using A. indicum (L.) Sweet. Nitrate reductase enzyme or other extra cellular proteins released from leaf extract involve in reduction of nitrate and formation of silver ions occurs. These proteins or enzymes act as template for the silver nucleation sites for the formation of silver nanocrystals and also act as capping agents (peptides or proteins) which control the size and shape of silver nanoparticles. FT-IR reveals that protein molecules can be bound to silver nanoparticles and XRD result confirmed crystal structure of nanoparticles. On the basis of our results, extract of A. indicum (L.) Sweet leaf protein molecules plays a vital role in reducing and capping of silver nanoparticles at 50 μl concentrations which act as anti-bacterial agent to control pathogenic microorganisms of Klebsiella pneumonia, Salmonella typhi, Bacillus subtilis, and Proteus vulgaris.

Room Temperature Synthesis and Evaluation of Antibacterial Activity of Silver Nanoparticles Using <I>Phyllanthus amarus</I> leaf extract

Room Temperature Synthesis and Evaluation of Antibacterial Activity of Silver Nanoparticles Using <I>Phyllanthus amarus</I> leaf extract

Antibacterial activity of silver nanoparticles: sensitivity of different Salmonella serovars.

Salmonella spp. is one of the main causes of foodborne illnesses in humans worldwide. Consequently, great interest exists in reducing its impact on human health by lowering its prevalence in the food chain. Antimicrobial formulations in the form of nanoparticles exert bactericidal action due to their enhanced reactivity resultant from their high surface/volume ratio. Silver nanoparticles (AgNPs) are known to be highly toxic to Gram-negative and Gram-positive microorganisms, including multidrug resistant bacteria. However, few data concerning their success against different Salmonella serovars are available. Aims of the present study were to test the antimicrobial effectiveness of AgNPs, against Salmonella Enteritidis, Hadar, and Senftenberg, and to investigate the causes of their different survival abilities from a molecular point of view. Results showed an immediate, time-limited and serovar-dependent reduction of bacterial viability. In the case of S. Senftenberg, the reduction in numbers was observed for up to 4 h of incubation in the presence of 200 mg/l of AgNPs; on the contrary, S. Enteritidis and S. Hadar resulted to be inhibited for up to 48 h. Reverse transcription and polymerase chain reaction experiments demonstrated the constitutive expression of the plasmidic silver resistance determinant (SilB) by S. Senftenberg, thus suggesting the importance of a cautious use of AgNPs.

Antibacterial activities of silver nanoparticles and antibiotic-adsorbed silver nanoparticles against biorecycling microbes.

Silver nanoparticles have a huge share in nanotechnology based products used in clinical and hygiene products. Silver nanoparticles leaching from these medical and domestic products will eventually enter terrestrial ecosystems and will interact with the microbes present in the land and water. These interactions could be a threat to biorecycling microbes present in the Earth's crust. The antimicrobial action towards biorecycling microbes by leached silver nanoparticles from medical waste could be many times greater compared to that of silver nanoparticles leached from other domestic products, since medical products may contain traditional antibiotics along with silver nanoparticles. In the present article, we have evaluated the antimicrobial activities of as-synthesized silver nanoparticles, antibiotics - tetracycline and kanamycin, and antibiotic-adsorbed silver nanoparticles. The antimicrobial action of silver nanoparticles with adsorbed antibiotics is 33-100% more profound against the biorecycling microbes B. subtilis and Pseudomonas compared to the antibacterial action of silver nanoparticles of the same concentration. This study indicates that there is an immediate and urgent need for well-defined protocols for environmental exposure to silver nanoparticles, as the use of silver nanoparticles in nanotechnology based products is poorly restricted.

Surface area or diameter – which factor really determines the antibacterial activity of silver nanoparticles grown on TiO2coatings?

Titanium dioxide coatings were prepared on Si wafers using the sol–gel method. Four different types of coatings with silver nanoparticles (AgNPs) were synthesized. The diameter and surface density of AgNPs were conditioned by the concentration of Ag+ ions in the initial solution, time and UV illumination source. The bactericidal activity of AgNPs on the titanium dioxide coatings against the S. aureus strain were calculated as the percentage of the inhibition of bacterial growth after 24 hour incubation of microorganisms at 37 °C on TiO2 coatings with AgNPs. Control samples were coated with titanium dioxide without AgNPs. We concluded that the titanium dioxide coatings modified with silver nanoparticles had a high antibacterial activity. Moreover, we demonstrated strong dependence between surface areas of AgNPs and inhibition of bacterial growth. The obtained results evidence that the surface area of AgNPs grown on titanium dioxide coatings is a major factor determining their antimicrobial potential.

The Antibacterial Activity of Silver Nanoparticles Produced in the Plant Sesamum indicum Seed Extract: A Green Method Against Multi-Drug Resistant Escherichia coli

Background: The nanoparticles synthesis through biological processes is evolving a new era of research interests in nanotechnology. In usual methods silver nanoparticles are synthesized through chemical methods, having extremely toxic and flammable natures. Objectives: The aim of the present study was to synthesize silver nanoparticles, through the green method of utilizing Sesamum indicum (S. indicum) extract and to determine the potential antibacterial effects of the product against multi-drug resistant Escherichia coli (E. coli). Materials and Methods: The formation and characterization of AgNPs (silver nanoparticles) were confirmed by UV-vis spectroscopy, energy-dispersive spectroscopy (EDX), X-ray diffraction (XRD) and transmission electron microscope (TEM). All 30 strains of E. coli were isolated from urine cultures of hospitalized patients (Amir Al-Momenin Hospital, Zabol, South-Eastern Iran) with urinary tract infection, 2011-2012. The minimum inhibitory (MIC) concentrations were investigated by microdilution method. Results: The results showed that isolated E. coli were resistant to four different antimicrobial agents including ceftazidime (26.6%), cefixime (40%), tetracycline (63.3%) and erythromycin (56.6%). The highest MIC value for produced nano silver in S. indicum seed extract, was 200 ppm, against five isolates of E. coli. Conclusions: Considering the sufficient antimicrobial activities of nanoparticles tested in this study, they are suggested for enterobacterial infection treatment, especially in hospital environment.

Eco-friendly synthesis and antibacterial activity of silver nanoparticles reduced by nano-wood materials

Hydrothermal treatment of nano-struc- tured wood, prepared by precision grinding, with cationic silver was found to give silver nanoparticles (Ag NPs) of 2-40-nm size range embedded in the wood tissue. The size and distribution of Ag NPs depended strongly on the starting silver ion concen- tration and reaction temperature. Higher temperature tended to give larger size and wider distribution. The obtained Ag NPs were characterized using various methods, including high-resolution transmission elec- tron microscopy, UV-visible spectroscopy, and X-ray diffraction. The antibacterial effect of the product against Escherichia coli was evaluated by static and

Synthesis and Antibacterial Activity of Silver Nanoparticles Capped with a Carboxylic Acid-terminated Generation 1 Oleodendrimer

Abstract This study investigated the potential of a novel carboxylic acid-terminated generation 1 oleodendrimer (E1A) as a novel biocompatible capping agent for the synthesis of silver nanoparticles (E1A@Ag). Synthesized E1A@Ag particles were spherical with an average size of 9 ± 3 nm and displayed antimicrobial activity against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. The current study, therefore, establishes E1A as an effective biocompatible material for the synthesis of silver nanoparticles.

Biogenic silver nanoparticles production and characterization from native stain of Corynebacterium species and its antimicrobial activity.

In the present study, synthesis, characterization, and the antibacterial activity of silver nanoparticles from native isolate of Corynebacterium glutamicum has been reported. Silver nanoparticles were synthesized by challenging the dried biomass of C. glutamicum with aqueous diamine silver ([Ag (NH3)2]+) containing 1 mM AgNO3. Synthesized silver nanoparticles (AgNPs) were characterized by ultraviolet–visible spectroscopy and energy-dispersive X-ray (EDX) spectroscopy analysis. Morphological study of silver nanoparticles was carried out using transmission electron microscopy (TEM) and scanning electron microscope (SEM). The spherical morphology of silver nanoparticles was confirmed from SEM image. The TEM image showed the average particle size of silver nanoparticles was about 15 nm. Silver nanoparticles synthesized from C. glutamicum were found to have enhanced antimicrobial activity against selected pathogenic strains. Silver nanoparticles from pure strains of Corynebacterium species was done by many investigators, but as per the present literature, this is the first report on the production of silver nanoparticles using a native strain of Corynebacterium.

Study on antibacterial activity of silver nanoparticles synthesized by gamma irradiation method using different stabilizers.

Colloidal solutions of silver nanoparticles (AgNPs) were synthesized by gamma Co-60 irradiation using different stabilizers, namely polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), alginate, and sericin. The particle size measured from TEM images was 4.3, 6.1, 7.6, and 10.2 nm for AgNPs/PVP, AgNPs/PVA, AgNPs/alginate, and AgNPs/sericin, respectively. The influence of different stabilizers on the antibacterial activity of AgNPs was investigated. Results showed that AgNPs/alginate exhibited the highest antibacterial activity against Escherichia coli (E. coli) among the as-synthesized AgNPs. Handwash solution has been prepared using Na lauryl sulfate as surfactant, hydroxyethyl cellulose as binder, and 15 mg/L of AgNPs/alginate as antimicrobial agent. The obtained results on the antibacterial test of handwash for the dilution to 3 mg AgNPs/L showed that the antibacterial efficiency against E. coli was of 74.6%, 89.8%, and 99.0% for the contacted time of 1, 3, and 5 min, respectively. Thus, due to the biocompatibility of alginate extracted from seaweed and highly antimicrobial activity of AgNPs synthesized by gamma Co-60 irradiation, AgNPs/alginate is promising to use as an antimicrobial agent in biomedicine, cosmetic, and in other fields.

Green synthesis of silver and gold nanoparticles using Zingiber officinale root extract and antibacterial activity of silver nanoparticles against food pathogens.

In the present study, we synthesized silver and gold nanoparticles with a particle size of 10-20nm, using Zingiber officinale root extract as a reducing and capping agent. Chloroauric acid (HAuCl4) and silver nitrate (AgNO3) were mixed with Z. officinale root extract for the production of silver (AgNPs) and gold nanoparticles (AuNPs). The surface plasmon absorbance spectra of AgNPs and AuNPs were observed at 436-531nm, respectively. Optimum nanoparticle production was achieved at pH 8 and 9, 1mM metal ion, a reaction temperature 50°C and reaction time of 150-180min for AgNPs and AuNPs, respectively. An energy-dispersive X-ray spectroscopy (SEM-EDS) study provides proof for the purity of AgNPs and AuNPs. Transmission electron microscopy images show the diameter of well-dispersed AgNPs (10-20nm) and AuNPs (5-20nm). The nanocrystalline phase of Ag and Au with FCC crystal structures have been confirmed by X-ray diffraction analysis. Fourier transform infrared spectroscopy analysis shows the respective peaks for the potential biomolecules in the ginger rhizome extract, which are responsible for the reduction in metal ions and synthesized AgNPs and AuNPs. In addition, the synthesized AgNPs showed a moderate antibacterial activity against bacterial food pathogens.

Extracellular Biosynthesis, Characterization and Antibacterial Activity of Silver Nanoparticles Synthesized by Bacillus subtilis (NCIM—2266)

Extracellular Biosynthesis, Characterization and Antibacterial Activity of Silver Nanoparticles Synthesized by <i>Bacillus subtilis</i> (NCIM—2266)

Combined effect of silver nanoparticles and therapeutical ultrasound on ovarian carcinoma cells A2780

Antibacterial activity of silver nanoparticles is widely known and used. The effect of application of therapeutical ultrasonic field in the presence of silver nanoparticles <100nm was examined on human ovarian carcinoma cell A2780. The cell's viability was examined by MTT assay and by life-time microscopy. The presence of nanoparticles in the cell was examined by using electron transmission microscopy. Experimental results indicate a significant decrease of viability of cell, which was affected by the combined action of ultrasound field and silver nanoparticles, compared to the separate exposure of silver nanoparticles or ultrasonic field. The experiments showed a significant effect of succession of application of these two factors. The presence of nanoparticles inside cells after incubation was showed. The results show the possibility of using of ultrasonic field as a factor that can significantly affect cell viability in the presence of silver nanoparticles.

Antibacterial Activity of Synthesized Silver Nanoparticles from Tinospora cordifolia against Multi Drug Resistant Strains of Pseudomonas aeruginosa Isolated from Burn Patients

In the present study, antibacterial activity of silver nanoparticles synthesized from stem of Tinospora cordifolia were analysed against multidrug-resistant strains of Pseudomonas aeruginosa isolated from burn patients. As Pseudomonas aeruginosa is a scourge of hospital burn units and its emergence as multidrug-resistant strains is a major problem in the control of nosocomial infections. Therefore, we tried to establish a combination of medicinal values of Tinospora cordifolia and nanotechnology possibly with the field of medicine for the development of antibacterial agents against these MDR strains.The synthesized silver nanoparticles were characterized by UV-visible spectroscopy, Energy Dispersive Spectroscopy and Fourier Transform Infrared Spectroscopy. Transmission Electron Microscopy and X-Ray Diffraction have revealed the size of silver nanoparticles 9 ± 36 nm and 12.49 nm respectively. Further antibacterial activity of silver nanoparticles prepared from Tinospora cordifolia against multidrug resistant strains was determined by agar well diffusion assay and Minimum Inhibitory Concentration (MIC) was estimated by qualitative experimentation by resazurin based micro broth dilution method. All experiments were done in triplicate. The silver nanoparticles of stem of Tinospora cordifolia showed the zone of inhibition ranges from 10 ± 0.58 to 21 ± 0.25mm. The MIC of AgNPs from stem extract was found to be 6.25 to 200 μg/ml against Pseudomonas aeruginosa strains. Silver nanoparticles from Tinospora cordifolia possess very good antibacterial activity which makes them a potent source of antibacterial agent.

Preparation and Antibacterial Activity of Silver Nanoparticles Coated by Poly(vinyl pyrrolidone)

Preparation and Antibacterial Activity of Silver Nanoparticles Coated by Poly(vinyl pyrrolidone)

Toxicity Mechanisms in Escherichia coli Vary for Silver Nanoparticles and Differ from Ionic Silver

Silver nanoparticles (Ag NPs) are commonly added to various consumer products and materials to impair bacterial growth. Recent studies suggested that the primary mechanism of antibacterial action of silver nanoparticles is release of silver ion (Ag(+)) and that particle-specific activity of silver nanoparticles is negligible. Here, we used a genome-wide library of Escherichia coli consisting of ∼4000 single gene deletion mutants to elucidate which physiological pathways are involved in how E. coli responds to different Ag NPs. The nanoparticles studied herein varied in both size and surface charge. AgNO3 was used as a control for soluble silver ions. Within a series of differently sized citrate-coated Ag NPs, smaller size resulted in higher Ag ion dissolution and toxicity. Nanoparticles functionalized with cationic, branched polyethylene imine (BPEI) exhibited equal toxicity with AgNO3. When we used a genome-wide approach to investigate the pathways involved in the response of E. coli to different toxicants, we found that only one of the particles (Ag-cit10) exhibited a pattern of response that was statistically similar to that of silver ion. By contrast, the pathways involved in E. coli response to Ag-BPEI particles were more similar to those observed for another cationic nanoparticle that did not contain Ag. Overall, we found that the pathways involved in bacterial responses to Ag nanoparticles are highly dependent on physicochemical properties of the nanoparticles, particularly the surface characteristics. These results have important implications for the regulation and testing of silver nanoparticles.

Synthesisof silver nanoparticles by some locallyLactobacillus spp.and detection of their antibacterial activity

The study included the rapid synthesis and antibacterial activity of silver nanoparticles synthesized by locally Lactobacillus spp.(Lactobacillus acidophilus, L. gasseri, L.rhamnosus, L. fermentum). The silver nanoparticles were characterized with Atomic Force Microscopy (AFM) and found theaverage size ranges from 33.71 to39.16 nm. Finally antibacterial activities of the silver nanoparticles were checked against pathogenic bacteria (Escherichia coli, Acinetobacter baumannii, Staphylococcus aureus and Listeria monocytogenes).The zone of inhibiton seems extremely good showing a relatively large zone of inhibition in both gram positive and gram negative bacterial isolates. To the best of our study this is the first report on synthesis of silver nanoparticles by locally Lactobacillus spp.