Potential Of Silver Nanoparticles Research Articles

Silver Nanoparticles (AgNPs) as Effective Disinfectants with Natural Source: a New Inspiration

The antibacterial properties of silver nanoparticles have been well-proven. Various ways of modifying nanoparticles to get better activity have been reported. Metal crystals from micro to nano size produce excellent and promising properties in a wide range of applications. Various methods have been used in the production of nanoparticles, ranging from chemical to biological methods (green synthesis). Synthesis of metal nanoparticles with plant media brings advantages, one of which is not damaging the environment. The antibacterial ability of silver nanoparticles has been promised, so it is necessary to study its prospects as a disinfectant, especially in the use of plant-based hand sanitizers that are more skin-friendly. In this review, the potential of silver nanoparticles using the green synthesis method is described as a natural material-based disinfectant that is more environmentally friendly.

Green synthesis and antibiofilm potential of Silver Nanoparticles loaded with Narcissus tazetta L. Extract

Bacterial infections are the leading cause of mortality, due to the paucity of effective drugs. This study aimed to synthesize AgNPs loaded with fresh leaves & bulbs extracts of Narcissus tazetta and evaluate antimicrobial and antibiofilm potential against selected bacterial and fungal isolates using standard microbiological protocols. Different techniques like FTIR spectroscopy, GC-MS, electron microscopy and HPLC were used to characterize the AgNPs. The AgNPs synthesized from crude extract of leaves and bulb were checked and were found effective against all the bacterial isolates except E. coli however, strong biofilm inhibition potential was observed in case of E.coli. The synthesized AgNPs showed dose dependent zone of inhibition higher for methanol and lower for n-Hexane against both Gram + ve and Gram -ve bacterial strains, exhibiting the anti-microbial potential. Biofilm inhibition was recorded at sub-MIC values against Gram + ve and Gram -ve bacterial strains. Antifungal activity of AgNPs was observed only at a higher concentration against Aspergillus niger, Fusarium oxysporum and Alternaria alternata while Aspergillus terreus was resistant even at higher concentrations. In conclusion, we can say that the plant possesses pronounced antimicrobial potential with a wide range of the bioactive compounds, which can be explored for pharmaceutical purposes.

Antimicrobial potential of silver nanoparticles biosynthesized using aerial yam bulbils for control of selected phytopathogens

Silver nanoparticles as antimicrobial agent have vast potential in agriculture for the protection of plants from diseases and increasing crop productivity. In this study, the bulbils of aerial yam (Dioscorea bulbifera L.) were investigated for their potential for biosynthesis of silver nanoparticles. Variation in the absorption spectra of silver nanoparticles synthesized using different concentrations of 10 to 50% (v/v) of plant extract was observed. Phytochemical analysis of aerial yam bulbils revealed high content of flavonoid (4.06 ± 0.44 mg/g), phenols (3.36 ± 0.20 mg/g) and tannins (12.42 ± 0.22 mg/g) with potential role in the bioreduction process. Highest inhibition (98-100%) was recorded against Fusarium oxysporum and Colletotrichum gloeosporioides with 100 ppm silver nanoparticles. The inhibition zone against Bacillus sp. and Enterobacter cloacae ranged from 6.00 ± 0.41 to 11.00 ± 0.87 mm at 100 ppm concentration indicating antibacterial efficacy of biosynthesized silver nanoparticles. Silver nanoparticles biosynthesized using 20% (v/v) extract at higher temperature demonstrated the most effective inhibition of plant pathogenic fungi and bacteria.

Potential of Silver Nanoparticles in Overcoming the Intrinsic Resistance of Pseudomonas aeruginosa to Secondary Metabolites from Carnivorous Plants.

Carnivorous plants are exemplary natural sources of secondary metabolites with biological activity. However, the therapeutic antimicrobial potential of these compounds is limited due to intrinsic resistance of selected bacterial pathogens, among which Pseudomonas aeruginosa represents an extreme example. The objective of the study was to overcome the intrinsic resistance of P. aeruginosa by combining silver nanoparticles (AgNPs) with secondary metabolites from selected carnivorous plant species. We employed the broth microdilution method, the checkerboard titration technique and comprehensive phytochemical analyses to define interactions between nanoparticles and active compounds from carnivorous plants. It has been confirmed that P. aeruginosa is resistant to a broad range of secondary metabolites from carnivorous plants, i.e., naphthoquinones, flavonoids, phenolic acids (MBC = 512 µg mL−1) and only weakly sensitive to their mixtures, i.e., extracts and extracts’ fractions. However, it was shown that the antimicrobial activity of extracts and fractions with a significant level of naphthoquinone (plumbagin) was significantly enhanced by AgNPs. Our studies clearly demonstrated a crucial role of naphthoquinones in AgNPs and extract interaction, as well as depicted the potential of AgNPs to restore the bactericidal activity of naphthoquinones towards P. aeruginosa. Our findings indicate the significant potential of nanoparticles to modulate the activity of selected secondary metabolites and revisit their antimicrobial potential towards human pathogenic bacteria.

Formulation and Characterization of Anti-Bacterial Activity of Silver Nanoparticles Using Root and Leaf of Wedelia trilobata

In the present study one such species, Wedelia trilobata, has be chosen to review the In vitro antibacterial activity of the root extract by using solvent ethanol for the selected plant Wedelia triolobata. The deduction of nanoparticles used to be unalterable by UV-Visible spectroscopy, FTIR, particle size, and zeta potential. The anti-bacterial activity of Wedelia trilobata mediated synthesis silver nanoparticles was tested by disc diffusion assay against standard organisms like Escherichia coli and staphylococcus aureus bacteria. The formation of silver nanoparticles by Wedelia trilobata was initially demonstrated by color changes confirmed by UV-Visible root exhibited a specific absorbance peak around 450 nm and leaf exhibited a specific absorbance peak around 418nm respectively. The Zeta potential of silver nanoparticles was found to be root 0.1 and leaf 0.4, so it indicates the dispersion and stability. The antibacterial activity against Gram-positive Staphylococcus aureus was increased, which was indicated by an increase in the inhibition zone diameter from 3Mm for normal (9.5Mm), standard (12.3Mm), control (11.3Mm), extraction for AgNPs Wedelia trilobata (13.8). 5Mm for normal (7.3Mm), standard (19.4Mm), control (10.5Mm), extraction for AgNPs Wedelia trilobata (19.8). The antibacterial activity against Gram-negative E.coli was increased, which was indicated by an increase in the inhibition zone diameter from 3Mm for normal (7.8Mm), standard (8.5Mm), control (10.2Mm), extraction for AgNPs Wedelia trilobata (14.3). 5Mm for normal (13Mm), standard (19.6Mm), control (15.3Mm) extraction for AgNPs Wedelia trilobata (19.8). The present investigation revealed that the ethanolic Root and aqueous leaf extracts the chosen plant have potential to suppress the expansion of infective bacterial strains.

A New Comparison Between Ag-Nano Adsorbent and Walnut Shell Adsorbent

Silver nanoparticles were synthesised and used as a nano-adsorbent. Silver nanoparticles were added to adsorption system contain a (walnut husks – Manganese ions). The concept of this addition is to enhance the adsorption system due to high surface area to volume ratio of silver nanoparticles. Characterization of walnut husks was done by Fourier transformation infrared (FTIR). Characterization of silver nanoparticles was done also using many techniques, dynamic light scattering (DLS) and field emission scanning electron microscopy (FE-SEM) were used for determination of size and the potential of silver nanoparticles and also to identify the size and the shape of silver nanoparticles. The image showed an average particle diameter in the range (10-85 nm). Energy dispersive X- ray spectra (EDS) was used to examine the quantity of prepared silver nanoparticles. The optimum parameters were studied for this adsorption system such as contact time, weight of adsorpant, effect of pH, manganese concentration and the effect of addition of silver nanoparticles on the (walnut husks –Mn (II) ions) adsorption system. All the experiment parameters were fixed then silver nanoparticles were added to the system contain (walnut husks - Mn (II) ions). The results showed enhancement in the percentage of releasing by 2.2%. The data of the experiment has been investigated through Langmuir, Ferndelsch and Temkin. By evaluating the results, it can be concluded that the adsorption isotherm is most distinct through Freundlich.

Synthesis of Silver Nanoparticles with Reductant of Java Long Pepper Leaf Extract (Piper Retrofractum Vahl) and Its Application as a Mercury Detector

The synthesis of silver nanoparticles using the green chemistry concept utilizing Java long pepper leaf extract as a reducing agent has been successful. Silver nanoparticles were synthesized under optimum 1 mM silver nitrate concentration, 250 μL Java long pepper leaf extract, and 30 minutes under sunlight radiation. The silver nanoparticles formed can be confirmed by the change in the color of the solution from colorless to brownish red, indicating a reduction of Ag+ to Ag0. The Uv-vis spectrum showed a peak Surface Plasmon Resonance (SPR) at 441 nm. The FTIR spectrum showed that functional groups' vibrations in the Java Chili Leaf extract confirm that the phenol, alkaloid, and flavonoid compounds present in the extract act as reducing agents. TEM images show spherical silver nanoparticles with an average diameter of 17.65 nm. The potential of silver nanoparticles to detect Hg (II) metal is evidenced by a decrease in the color intensity of the silver nanoparticle solution along with the increasing concentration of Hg (II), which reacts back-oxidizing Ag0 to Ag+. The value of the correlation coefficient of the linear equation is 0.9807.

Potential of silver nanoparticles synthesized using low active mosquitocidal Lysinibacillus sphaericus as novel antimicrobial agents

Silver nanoparticles (AgNPs) were synthesized using extracellular filtrates of some Lysinibacillus sphaericus (Ls) strains under simple conditions. Ls synthesized AgNPs showed the optical absorption peaks at 388–412 nm as detected by UV-visible spectrophotometer. Transmission electron micrographs of bacterial synthesized AgNPs revealed that they were polycrystalline with spherical, hexagonal, cuboidal, rod and irregular shapes. The average diameter of the tested AgNPs were ranged from 14–21 nm and they were negatively charged as detected by DLS (−18.2 to −28.9). FTIR spectra showed the presence of nitrogenous biomolecules capping the synthesized AgNPs. The filtrates of tested Ls strains showed nitrate reductase activity (1.45–2.56 µmol/ml/min). Tested AgNPs showed bactericidal activity against Gram positive and Gram negative bacteria, fungicidal activity against yeast and filamentous fungi, and virucidal activity against rotavirus. In addition, it showed synergistic antimicrobial effect to cephradine and nizoarm against all tested microorganisms. Cytotoxicity test revealed the safety of the tested nanoparticles at tested concentrations. Finally, Ls strains represent microbial sources for ecofriendly, simple and economic biosynthesis of antimicrobial AgNPs. Also, this research may contribute to the medicinal chemistry and pharmaceutical industry for the development of new products used for the public health.

A Novel Green Biogenic Synthesis of Silver Nanoparticles using Tabebuia rosea (Bertol.) DC Fruit Extract and Its Antioxidant and Antibacterial Potential

Plant based synthesis of nanoparticles has generated worldwide interest because of cost-effectiveness, eco-friendly nature and abundance of applications. In the present investigation , antimicrobial potential of silver nanoparticles (AgNPs) of aqueous extract of Tabebuia rosea (Bertol.) DC (T. rosea) fruit extract has been investigated. Agar disc diffusion method was used for determining the antimicrobial activity of selected aqueous fruit extract AgNPs. Phytochemical analysis of aqueous fruit extract of T. rosea fruit revealed the presence of alkaloids, flavonoids, tannins, phenols, carbohydrates, glycosides, Vitamin-C, proteins and terpenoids. AgNPs synthesis using T. rosea aqueous fruit extract and characterized by UV-Visible spectroscopy showed a peak at 420 nm and average size of 82.9 nm, FT-IR analysis, dynamic light scattering, scanning electron microscope, EDX and X-ray diffraction analysis. Evaluation of antibacterial activity of green synthesized AgNPs recorded the more potent activity against selected human bacterial pathogens. The results obtained indicated that the fruit extract of T. rosea as well as AgNPs have strong and effective antibacterial potential that provide marvelous source for the development of new drug molecules of herbal origin which may be used for the welfare of humanity.

Preparation and characterization of cellulose/in situ generated silver nanoparticle composite films prepared using Pongamia pinnata leaf extract as a reducing and stabilizing agent

The present study is aimed at drawing the synergies by combining the microbial potential of Silver nanoparticles, the medicinally important plant and develop biodegradable nanocomposites. The silver nanoparticles (AgNPs) were in situ generated in Pongamia pinnata leaf extract infused cellulose. The cellulose, the matrix, and the resulting nanocomposite films were characterized. The Fourier transform infrared spectra, confirms that the amide groups present in the leaf extract are responsible for the formation of AgNPs through the reduction process, the energy dispersive X-ray analysis and the scanning electron microscopy revealed that the average AgNPs size is around 76 nm. These cellulose nanocomposites films showed enhanced tensile properties, indicating the reinforcing effect of AgNPs. The antibacterial studies shown good antibacterial activity against Escherichia coli. These studies validate the feasibility of using pinnata leaves for in situ generations of AgNPs in modified cellulose matrix, which makes these nanocomposite suitable for food and medical applications.

THERAPEUTIC EFFECT OF SILVER NANOPARTICLES AGAINST DIETHYL NITROSAMIN AND CARBON TETTRACHLORIDE-INDUCED HEPATOCELLULAR CARCINOMA IN RATS

Objective: Hepatic cancer is known as primary liver cancer and hepatocellular carcinoma (HCC). Newly silver nanoparticles gained importance due to its advantages and multiple potential such as molecular imaging agent, antimicrobial, wound healing, anti-inflammatory and anticancer activity. The current study deals to assess therapeutic property silver nanoparticles (AgNPs) against diethylnitrosamine (DENA), and carbon tetrachloride (CCL4) induced hepatic cancer.
 Methods: Thirty male albino rats (200-250g) were distributed into four groups and hepatic cancer was induced with a single intraperitoneal dose of 200 mg/kg body weight of DENA. Two weeks later, animals received subcutaneous injections of CCl4 once a week in a dose of 3 ml/kg body weight for 6weeks. Serum biomarkers, antioxidants enzymes, inflammatory markers were evaluated to find the anti-proliferative potential of silver nanoparticles. Histological evaluation and microscopic reports were also done to document the results of the current work.
 Results: AgNPs significantly recover the serum marker enzymes of hepatic parameter AST, ALT, ALP, and total bilirubin and also decreased the levels of NO, IL-6 and TNF-α. Histopathological features also exhibited recovery of a hepatic architecture in cancer-induced rats. Moreover, the immunohistochemical investigation demonstrated that the levels of PCNA, and Caspase-3, which are hepatocarcinogenic markers, were significantly improved by AgNPs.
 Conclusion: These results concluded that AgNPs showed promising curing effects on hepatocellular ailments.

Silver nanoparticles restrict microbial growth by promoting oxidative stress and DNA damage.

Bacterial infections remain a serious health issue; hence there is a need for continuous search for improved antimicrobials. In addition, it is important to understand the antibacterial mechanism of prospective antimicrobials to fully harness their benefits. In this study, the antimicrobial action of silver nanoparticles was investigated. The antimicrobial potential of silver nanoparticles against different strains of bacteria was evaluated after which Escherichia coli and Staphylococcus aureus were selected as model for gram-negative and gram-positive bacteria respectively. Additionally, to determine mechanism of action, some biochemical assays including determination of kynurenine level, DNA fragmentation, lipid peroxidation and antioxidant status were carried out. Results showed that silver nanoparticles caused DNA damage and induced oxidative stress as reflected in elevated nitric oxide production and lipid peroxidation level. In contrast silver nanoparticles increased the antioxidant capacity viz-a-viz, elevated levels of total thiol, superoxide dismutase (SOD), and total antioxidant capacity (TAC) compared to untreated cells. They also initiated inconsistent alteration to the kynurenine pathway. Taken together, the findings indicate that silver nanoparticles exhibited antimicrobial action through the promotion of oxidative stress.

Synthesis and characterization of silver nanoparticles as a potential sensor for volatile organosulfides for visual detection of postharvest storage in garlic

Garlic, one of the most popular spices used in manufacturing many food products, is subjected to fungal and bacterial diseases resulting to substantial losses in quantity and quality. Specific detection tools for garlic spoilage will be an asset in relieving these losses during postharvest storage. In this study, stable yellow-colored silver nanoparticle colloidal solution was studied as a potential sensor for volatile organosulfides in garlic. The silver nanoparticles (AgNPs) were synthesized by chemical reduction method where silver nitrate was taken as metal precursor, sodium borohydride as reducing agent, and polyethylene glycol as stabilizing agent. The silver nanoparticles were characterized by UV-Vis Spectroscopy and Dynamic Light Scattering (DLS). The spectral analysis revealed the formation of silver nanoparticles by exhibiting the typical surface plasmon absorption peak at around 395 nm. The DLS results show two populations of AgNPs with particle sizes of 3 nm and 50 nm. The volume ratio of sodium sulfite to be added in the silver nanoparticle and the reaction time was also determined. Synthesized AgNPs could detect sodium sulfite at 0.52 to 50 µM concentration range. This simple method indicated the potential of silver nanoparticles as a powerful detection tool for volatile organosulfides in garlic.

Silver nanoparticles in dye effluent treatment: A review on synthesis, treatment methods, mechanisms, photocatalytic degradation, toxic effects and mitigation of toxicity

The current scenario of water resources shows the dominance of pollution caused by the draining of industrial effluents. The polluted waters have resulted in severe health and environmental hazards urging for a suitable alternative to resolve the implications. Various physical and chemical treatment steps currently in use for dye effluent treatment are more time consuming, cost-intensive, and less effective. Alternatively, nanoparticles due to their excellent surface properties and chemical reactivity have emerged as a better solution for dye removal and degradation. In this regard, the potential of silver nanoparticles in dye effluent treatment was greatly explored. Efforts were taken to unravel the kinetics and statistical optimization of the treatment conditions for the efficient removal of dyes. In addition, the role of silver nanocomposites has also experimented with colossal success. On the contrary, studies have also recognized the mechanisms of silver nanoparticle-mediated toxicity even at deficient concentrations and their deleterious biological effects when present in treated water. Hence, the fate of the silver nanoparticles released into the treated water and sludge, contaminating the soil, aquatic environment, and underground water is of significant concern. This review summarizes the current state of knowledge regarding the use of silver nanoparticles and silver-based nanocomposites in effluent treatment and comprehends the recent research on mitigation of silver nanoparticle-induced toxicity.

Toxicity and application of nano-silver in multi-drug resistant therapy

Nano-silver toxicity is a major challenge in the field of nanotechnology and nanoscience. Silver nanoparticles have antibacterial activity against gram-negative and gram-positive bacteria. The level of nanotoxicity varies according to the size, shape, surface charge and cellular uptake. The size of nanoparticles influences their interaction and reactivity with cell membranes. Silver nanoparticles were investigated for the broad-spectrum antibacterial activities, especially against antibiotic-resistant bacteria. In the present scenario, pharmaceutical and biomedical sectors are facing the challenges of the continuous increase in multidrug-resistant human pathogenic microbes. The development of multidrug resistance has become a global issue with serious consequences in the management of infectious diseases caused by pathogenic bacteria. For the multi-drug resistant therapy, various combinations of antibiotics were used with silver nanoparticles. This review discusses the nanotoxicity and bactericidal potential of silver nanoparticles against the multi-drug resistant bacteria.

Potential of Silver Nano Particles Synthesized from <i>Ficus sycomorus</i> <i>Linn</i> Against Multidrug Resistant <i>Shigella species</i> Isolated from Clinical Specimens

Ficus sycomorus Plant was known traditionally for its medicinal properties, Shigella species as a bacterial was also known for their resistance to orthodox medicine. Hence the synthesis of silver nanoparticles from Ficus sycomorus. This study was carried out to investigate the anti-shigellosis potential of silver nanoparticles synthesized from Ficus sycomorus Linn stem bark aqueous extract against Multi-drug Resistant (MDR) Shigella species isolated from clinical specimen collected from patients attending Yobe State Specialist Hospital Damaturu, Nigeria. A total of 400 diarrhoeagenic stools were screened for isolation of Shigella species and determined their antibiotic susceptibility pattern using standard methods. Phytochemical constituents of Ficus sycomorus extract were used to synthesize silver nanoparticles using green synthesis approach. The nanoparticles was analyzed for transmittance, functional groups, sizes and shapes using Uv-vis, FTIR and Scanning Electron Microscopy (SEM), and was tested for antibacterial activities on MDR Shigella isolates. There is no significant difference in Shigella recovery relation to patients gender (P 30 years (21). Shigella were also found to be sensitive to Ciprofloxacin (92%), Augmentin (87%), Cefuroxime (85%), Streptomycin (83.5%) while the most frequent resistance was showcased against Nalidixic Acid (48%), and Tetracycline (27%). Phytochemicals detected include saponins, flavonoids, alkaloids, cardiac glycoside and tannin. Uv-vis showed broad peaks around 460nm, the FTIR showed C-H stretch of hydroxyl group of alkanes and the SEM showed nanoparticles with wide range of shapes and sizes. Anti-Shigella activities of silver nanoparticles is higher at zones of inhibition between 10mm and 30mm higher compared to the activities of crude aqueous extract and AgNO3 solution against the MDR Shigella species which showed an enhanced activities. The high prevalence of shigellosis among children in this study, indicated that improved hygiene is needed for children in the area and detailed examination is required for the treatment of diarrhoea in adults. Ciprofloxacin and Amoxicillin Clavulanate, Nalidixic acid could be used only where culture and sensitivity results prevailed. Enhanced traditional medicine should be given priority because of its potentials. This study have demonstrated feasibility of the green synthesis of F. sycomorus as a potent anti-shigellosis to combat the global burden of the disease. This is the first study On Stem bark aqueous extracts of F. sycomorus against Shigella species in the area.

Antifungal effect of engineered silver nanoparticles on phytopathogenic and toxigenic Fusarium spp. and their impact on mycotoxin accumulation

Cereal grains are essential ingredient in food, feed and industrial processing. One of the major causes of cereal spoilage and mycotoxin contamination is the presence of toxigenic Fusarium spp. Nanoparticles have immense applications in agriculture, nutrition, medicine or health but their possible impact on the management of toxigenic fungi and mycotoxins have been very little explored. In this report, the potential of silver nanoparticles (AgNPs) (size 14–100 nm) against the major toxigenic Fusarium spp. affecting crops and their effect on mycotoxin accumulation is evaluated for the first time. The studied Fusarium spp. (and associated mycotoxins) were F. graminearum and F. culmorum (deoxynivalenol, 3-acetyldeoxynivalenol and zearalenone), F. sporotrichioides and F. langsethiae (T–2 and HT–2 toxins), F. poae (nivalenol), F. verticillioides and F. proliferatum (fumonisins B1 and B2) and F. oxysporum (mycotoxins no detected). The factors fungal species, AgNP dose (range 2–45 μg/mL), exposure time (range 2–30 h) and their interactions significantly influence spore viability, lag period and growth rate (GR) in subsequent cultures in maize-based medium (MBM) of all the studied species. The effective lethal doses (ED50, ED90 and ED100) to control spore viability and GR were in the range 1–>45 μg/mL depending on the remaining factors. At high exposure times (20−30 h), the three effective doses ranged 1–30 μg/mL for all the studied species. At the end of the incubation period (10 days) mycotoxin levels in MBM cultures inoculated with fungal spores from treatments were strongly related with the size reached by the colony at that time. None of the treatments produced stimulation in conidia germination, GR or mycotoxin biosynthesis with respect to controls. Thus, the antifungal effect of the assayed AgNPs against the tested Fusarium spp. suggests that AgNPs could be a new antifungal ingredient in bioactive polymers (paints, films or coating) likely to be implemented in the agro-food sector for controlling these important toxigenic Fusarium spp. and their main associated mycotoxins.

Evaluation of the antibacterial potential of silver nanoparticles synthesized through the interaction of antibiotic and aqueous callus extract of Fagonia indica

Fagonia indica is a widely known medicinal plant. The extracts of Fagonia species contain secondary metabolites such as flavonoids, phenolic compounds, and terpenoids. Silver nanoparticles are known for antibacterial properties. In this study, AgNPs were synthesized using the callus extract of F. indica as a reducing agent. Characterization through different techniques suggests that the AgNPs absorbed light and gave SPR peaks at 414 nm while in case of ciprofloxacin supplemented callus mediated AgNPs the peak were recorded at 419 nm. Furthermore, FTIR analysis revealed the role of amides, acyl group, nitro group of callus extract of F. indica, and some functional groups of the ciprofloxacin in the reduction process as well as the capping and stabilization of AgNPs. Similarly, X-Ray Diffraction analysis indicate the structure of AgNPs as face-centered cubic crystalline particles. The antibacterial activity of AgNPs and ciprofloxacin and callus extract as control against resistant bacteria such as Escherichia coli, Citrobacter amalonaticus, Shigella sonnei, and Salmonella typhi was studied. The combination of AgNPs and antibiotic showed better antibacterial activity as compared to AgNPs alone and ciprofloxacin alone. Maximum inhibition zone of E. coli, C. amalonaticus, S. sonnei, and S. typhi in response to AgNPs and ciprofloxacin was 38.5 mm, 35.5 mm, 33 mm, and 35.5 mm, respectively. It can, therefore, be suggested that the AgNPs along with Ciprofloxacin might have worked in interaction and resulted in better antibacterial activity against all the tested pathogens.

Physicochemical characterization of 3,6-diHydroxyflavone binding BSA immobilized on PEG-coated silver nanoparticles

Studies based on silver nanoparticles (SNPs) and polyethylene glycols (PEGs) are mainly in the pharmaceutical field, with PEG as good “vehicle” to transport protein-based drugs. In this work, physicochemical characteristics of 3,6-diHydroxyflavone (3,6-diHF) binding bovine serum albumin (BSA) on PEG (Tween20, L64, and Myrj52)-coated SNPs have been investigated by steady-state and time-resolved fluorescence spectroscopy. These interactions give rise to the formation of intermolecular and intramolecular H bonds. As a subject of interest, the effect of temperature (30–60 °C) on the H bonds was studied by steady-state fluorescence. The size distribution and zeta potential of SNPs were determined by dynamic light scattering (DLS). Scanning electron microscopy (SEM) analysis revealed the spherical nature of particles with average diameter ~40–80 nm. The structure, stability, dynamics, and conformational changes in adsorbed BSA protein on the PEG-coated SNPs surface have been also investigated by steady-state/lifetime fluorescence and circular dichroism spectroscopy. The results have relevance in the oxidative stress and drug delivery processes.

Potential of Silver Nanoparticles Functionalized Polyaniline as an Electrochemical Transducer

Modification of commercial platinum (Pt) and glassy carbon (GC) electrodes with polyaniline (PANI) and silver nanoparticles doped polyaniline (PANI/Ag NPs) through electropolymerization of aniline in the absence and presence of Ag NPs in 1 M hydrochloric acid (HCl) was interrogated. Fourier transform infrared (FTIR) and transmission electron microscope (TEM) techniques were used for structural, compositional and morphological elucidation. FTIR spectra for PANI and PANI/Ag NPs had the characteristic PANI functional groups as well as desired bands for the conducting emeraldine (EM) form. The predominance of the PANI pattern in the spectra is indicative of the intact PANI structure in the presence of Ag NPs while the slight band shifts are signify interfacial interactions between PANI and Ag NPs. TEM micrograms depicts different size one dimensional nanofibric tubes of the supramolecular structures of PANI. Ag NPs functionalized PANI had larger smoother tubes, suggesting organized morphology arrangement. An increased energy dispersive spectroscopy (EDS)-TEM count from 256 to 277 confirms incorporation of Ag NPs in PANI. GC/PANI/Ag NPs exhibited outstanding electroactivity (higher conductivity and rate of electron transfer).This might be a result of the large surface coverage, film thickness and diffusion coefficient as a result of the large GC surface area. Possibly, the improvement might be due to the GC electrode properties. The electroactivity of the electrodes increased in the order: Pt < GC < Pt/PANI < Pt/PANI/Ag NPs < GC/PANI < GC/PANI/Ag NPs. The effect of Ag NPs in the polymer was demonstrated by ultimate band gap reduction of PANI and enhanced magnitudes of current response per electrode.