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Abstract Metal nanoparticles, synthesized using Phyto-constituents are the most economically and environmentally benign materials ever. Biogenic silver nanoparticles (AgNPs) from three fractions of Arisaema flavum tuber extract were synthesized and characterized by UV–visible spectroscopy, XRD (X-rays diffraction), FT-IR (Fourier transform infrared spectroscopy) TEM (transmission electron microscopy) and EDX (Energy dispersive Microscopy). XRD pattern show the face centred cubic crystalline (Fcc) structure of AgNPs. FTIR spectra confirmed the presence of different Polyphenolic compounds capping the AgNps. UV–visible spectroscopy result confirmed the presence of Ag because of the particular surface plasmon Resonance (SPR) in the area of 400-430 nm. The electron microscope studies revealed the formation of spherical AgNPs with diameter ranging from 12 nm to 20 nm. Strong signals of AgNPs were confirmed with EDX analysis. The antibacterial properties of the AgNPs prepared with various extracts were tested against multi-drug resistant bacteria. Which showed significant antibacterial activity against all the multidrug resistant bacterial strains and especially multidrug resistant engineered E.Coli QH4. AgNPs synthesized by methanolic, Ethyl Acetate and aqueous Extracts of Areseama Flavum exhibited significant Photocatalytic activity to reduce methylene blue. Small size, spherical shape and high dispersion are the key properties due to which the AgNPs are having significant biological and photocatalytic activity. To the best of our knowledge, it is the first report of biogenic AgNPs regarding antibacterial activity against multidrug resistant Engineered E.Coli QH4. Highlights • An Eco-benign synthesis of silver nanoparticles using extract of Arisaema Flavum Tuber. • Silver nanoparticles are highly dispersed and spherical shaped. • Silver nanoparticles have significant antibacterial activity against multidrug resistant engineered E.Coli QH4. • Silver nanoparticles have efficient photocatalytic activity in terms of photocatalytic degradation of methylene blue. [ABSTRACT FROM AUTHOR]

Plants mediated synthesis of noble metal nanoparticles is encountered as a clean, environment friendly, lucrative and benign loom. The current study consists of clean and green synthesis of Silver nanoparticles (AgNPs). Phytoconstituents from Longan (Euphorbia longana Lam . ) fruit peel were used to reduce Ag + into AgNPs. Different analytical techniques i.e. UV–vis Spectroscopy, X-ray diffraction spectroscopy (XRD), electron dispersive X-ray (EDX), High-resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the synthesized AgNPs. AgNPs have localized surface plasmon resonance (LSPR) peak at 445 nm which is confirmed by UV–vis spectroscopy. HRTEM showed that the prepared AgNPs are spheroid in shape and well dispersed while XRD results showed that the AgNPs are face centered cubic crystalline. EDX confirmed the elemental composition of AgNPs. The antiproliferative response of AgNPs was assayed by an exhaustive MTT assay. AgNPs showed potent anticancer activity (88%) against breast cancer cells MCF-7 . Moreover, the green produced AgNPs effectively scavenged 91% of the stable and harmful 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical which confirms its' efficient antioxidant nature. AgNPs have profound photocatalytic degradation (99%) of methylene blue in a short period of time (7 min). The noteworthy biological and photocatalytic responses of the green and cleanly produced AgNPs are encountered to their well dispersion, petite volume and round shaped structure . [ABSTRACT FROM AUTHOR]

Increase in the bacterial resistance to available antibiotics and water contamination by different toxic organic dyes are both severe problems throughout the world. To overcome these concerns, new methodologies including synthesis of nontoxic, human friendly and efficient nanoparticles is required. These nanoparticles not even inhibit the growth of microorganisms but are also effective in the degradation of toxic organics in waste water thus providing a clean and human friendly environment. The use of plants extracts to synthesize and stabilize noble metal nanoparticles have been considered as safe, cost-effective, eco-benign and green approach nowadays. In the present study, Longan fruit juice proficiently reduced ionic gold (Au + 3 ) to gold nanoparticles (AuNPs) as well as mediated the stabilization of AuNPs. The antibacterial activity of AuNPs was carried out against both gram positive and gram negative bacteria using agar well diffusion method, followed by the determination of Minimum inhibitory concentration (MIC) values. AuNPs were found to have significant antibacterial activity against Escherichia coli with MIC values of 75 μg/ml while outstanding MIC values of 50 μg/ml against Staphylococcus areous and Basilus subtilus . AuNPs revealed significant photocatalytic degradation (76%) of methylene blue in time period of 55 min, indicating the effective photocatalytic property of biosynthesized AuNPs (K = 0.29/min, r 2 = 0.95). The considerable antibacterial and photocatalytic activities of the photosynthesized AuNPs can be attributed towards their small size, spherical morphology and uniform dispersion. Our finding suggests the possible therapeutic potential of biogenic AuNPs in the development of new antibacterial agents as well as in the development of effective photocatalysts. [ABSTRACT FROM AUTHOR]

Phytosynthesis of metal nanoparticles is considered as a safe, cost-effective, and green approach. In this study, silver nanoparticles (AgNPs) were successfully synthesized using the aqueous extract of Lychee ( Litchi chinensis ) fruit peel and an aqueous solution of silver nitrate (AgNO 3 ). The synthesized nanoparticles were characterized by several analytical techniques i.e. UV–Vis Spectroscopy, XRD (X-ray diffraction spectroscopy), EDX (electron dispersive X-ray), SAED (selected area electron diffraction), HRTEM (high-resolution transmission electron microscopy), and FTIR (Fourier transform infrared spectroscopy). HRTEM and XRD results indicated that the prepared AgNPs are spherical in shape, well dispersed and face centered cubic crystalline. AgNPs showed potent antibacterial properties against Escherichia coli , Staphylococcus aureus , and Bacillus subtilis . The minimum inhibitory concentration (MIC) values were 125 μg against E. coli and 62.5 μg against both S. aureus and B. subtilis . AgNPs induce efficient cell constituent release from bacterial cells, which indicates the deterioration of cytoplasmic membrane. Moreover, antioxidant studies on the as-synthesized nanoparticles reveal efficient scavenging of the stable or harmful DPPH free radical. The cytotoxicity assay confirmed that biosynthesized AgNPs are nontoxic to normal healthy RBCs. AgNPs exhibited consistent release of Ag + determined by ICP-AES analysis. AgNPs exhibited extraordinary photocatalytic degradation (99.24%) of methylene blue. On the other hand, commercial silver nanoparticles have moderate biological activities against the tested bacterial strains and negligible photocatalytic degradation of methylene blue. The significant biological and photocatalytic activities of the biosynthesized silver nanoparticles are attributed to their small size, spherical morphology and high dispersion. [ABSTRACT FROM AUTHOR]

Iron oxide nanoparticles (Fe 2 O 3 NPs) are an interested and attractive area of research as they have numerous effective environmental and biomedical applications. Herein we have reported a simple and eco-benign synthesis Fe 2 O 3 NPs using Tamarix aphylla extract. The extract of the Tamarix aphylla acts both as a reducing and capping agent which leads to the fast and successful eco-benign synthesis of Fe 2 O 3 NPs.UV/Vis spectroscopy, XRD, EDX, SEM and TEM techniques were used to characterize and explore different features of Fe 2 O 3 NPs. UV/Vis studies showed asharppeak at 390 nm due to surface plasmon resonance absorption of Fe 2 O 3 NPs. XRD studies indicated that Fe 2 O 3 NPs were crystalline in nature. Structural features, elemental composition and geometry of Fe 2 O 3 NPswere confirmed by SEM, EDX and TEM. The as synthesized Fe 2 O 3 NPs showed efficient efficacy to degrade 100% of Methylene blue (MB) dye by 4 mg/25 ml MB and revealed 90% scavenging of the more stable DPPH free radical(1 mg/ml). Furthermore, Fe 2 O 3 NPs showed excellent antimicrobial activity against pathogenic multidrug resistant bacterial strains. The results of the present study explored the potential reducing, capping property of Tamarix aphylla extract, photocatalytic and biomedical applications of eco-benignly synthesized Fe 2 O 3 NPs which could be an alternative material for effective remediation of lethal organic pollutants and microbes. • An Eco-benign synthesis of novel Fe 2 O 3 nanoparticles using Tamarix aphylla extract. • Fe 2 O 3 have significant antibacterial activity against multidrug resistant E.Coli and Basilus subtilis. • Fe 2 O 3 nanocomposite have efficient photocatalytic activity in terms of photocatalytic degradation of methylene blue. [ABSTRACT FROM AUTHOR]

The development of eco-benign experimental procedures for the synthesis of nanomaterials is a fundamental developing branch of green nanotechnology. In this paper, green synthetic route was followed to synthesize novel Au@Fe 2 O 3 nanocomposite using Citrus sinensis fruit extract as a reducing and stabilizing agent. The as synthesized Au@Fe 2 O 3 nanocomposite was successfully characterized by UV–visible spectroscopy, X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy-dispersive X-ray (EDX), Fourier transform infrared (FT1R) spectrophotometry and Zeta potential. UV–vis spectroscopy showed two SPR peaks for Fe 2 O 3 and coated Au at 290 and 520 nm respectively. XRD confirmed the crystallinity of Au@Fe 2 O 3. Au@Fe 2 O 3 nanocomposite showed better antioxidant activity to effectively scavenge DPPH. The Au@Fe 2 O 3 has been also tested for antibacterial activity which showed an effective antibacterial activity against multi drug resistant E.coli and Bacillus subtilis. Furthermore, Au@Fe 2 O 3 also demonstrated better photo catalytic activity for methylene blue (MB) degradation. We proposed that the existence of organic acids (citric acids) also played a significant role in the stabilization of Au@Fe 2 O 3 , and plant (Citrus sinensis Var Kozan yerly) containing such component may be more effective for the green synthesis of Au@Fe 2 O 3 nanocomposite. The findings of this study prove the overwhelming therapeutic and photocatalytic potential of bio-inspired Au@Fe 2 O 3 nanocomposite which can be a novel candidate for the effective remediation of microbes and toxic organic pollutants. • An Eco-benign synthesis of novel Au@Fe 2 O 3 nanocomposite using Citrus sinensis fruit extract. • Au@Fe 2 O 3 have significant antibacterial activity against multidrug resistant engineered E.Coli QH4 and Basilus subtilis. • Au@Fe 2 O 3 nanocomposite have efficient photocatalytic activity in terms of photocatalytic degradation of methylene blue. [ABSTRACT FROM AUTHOR]

Abstract Synthesis of nanoparticles (NPs) through "green" chemistry is an exciting area of research with wide applications. Trianthema portulacastrum's extract containing greater amount of reducing agents has been explored first time for the synthesis of ZnO-NPs that characterized with UV/Vis, XRD, FT-IR, SEM,EDX, HR-TEM and XPS. The particles of ZnO-NPs are crystalline and having the size in the range of 25–90 nm. The cell viability of ZnO-NPs was studied using Mouse pre-osteoblast cell line MC3T3-E1 sub-clone 14 cells which confirmed its biocompatibility that render for biomedical applications. The antibacterial properties were evaluated against Staphylococcus aureus and Escherichia coli which showed high potency of synthesized ZnO-NPs against these species. The antifungal activities of ZnO-NPs were screened against Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus of fungal species. The antioxidant activity of the as-synthesized NPs was also studied using DPPH (2, 2-diphenyl-1-picrylhydrazyl) substrate. The ZnO-NPs were evaluated for catalytic activity through degradation of Synozol Navy Blue-KBF textile dye using solar irradiation that causes 91% degradation of the dye in 159 min. Mechanistic pathways for the degradation of Synozol Navy Blue-KBF dye using ZnO-NPs were also proposed from the pattern of the degradation of the dye and the resulting by-products. The results concluded that the ZnO-NPs synthesized by green method have high biological and photocatalytic applications. Graphical Abstract Unlabelled Image Highlights • Greener synthesis of Zinc Oxide Nanoparticles using Trianthema portulacastrum Extract. • Characterizations of ZnO-NPs by physical techniques like, XRD, FT-IR, SEM, HRTEM and XPS. • Antibacterial, antifungal and antioxidant application of green Synthesized ZnONPs. • use of ZnONPs to enhanced the photocatalytic activities of synozol navy blue K-BF water soluble dyes. • solar radiation, mechanistic investigation of synozol navy blue K-BF water soluble dyes. [ABSTRACT FROM AUTHOR]

Graphene-based materials have attracted a significant attention in constructing hybrid systems for drug delivery with enhanced antimicrobial activities. In our work, we demonstrated the formation of silver nanoparticles (AgNPs) on graphene oxide (GO) using tobramycin (TOB), an aminoglycoside antibiotic, as reducing and decorating agent. The TOB decorated GO AgNPs (TOB-GO-Ag) composite was used as an antibacterial agent against multi-drug resistant Gram-negative E-coli (BL21 DE3). The reversal of surface potential from −30 mV (GO) to +20 mV confirms the successful reduction of GO by TOB. Atomic force microscopy (AFM) and high-resolution transmission electron microscopic (HRTEM) analyses confirmed the formation of uniformly distributed AgNPs on the reduced GO with an approximate particle size of 5 nm. The as-synthesized nanocomposite displayed significant antibacterial activity as compared to pure AgNPs and TOB. The positively charged TOB-GO-Ag interacts with the negatively charged E. coli membrane and inhibit bacterial growth by the antibacterial actions of the released silver, GO and tobramycin from the TOB-GO-Ag composite. The significant loss of bacterial membrane potential from −52 ± 2 mV (control) to −2 ± 1 mV (treated) indicates a severe cell wall damage caused by TOB-GO-Ag composite. Furthermore, fluorescence study also demonstrated a severe membrane disruption in bacterial cells treated with TOB-GO-Ag composite as compared to pure AgNPs and GO. In conclusion, the development of such hybrid systems would help in enhancing the efficacy of available drugs and eradicating the emerging bacterial resistance. [ABSTRACT FROM AUTHOR]

The drug resistant bacteria and textile contaminations of water cause different sever health problem throughout the world. To overcome this issue, new environmental benign materials and methods are needed. Plant metabolites directed synthesis of nanoparticles is considered eco-friendly and easy in synthesis. Therefore, it was explicit for the synthesis of AgNPs. The prepared AgNPs were evaluated for antibacterial, antioxidant, photo-catalytic and electrochemical degradation properties as well as toxicity of degradation products on aquatic life. X-Ray Photoelectron Spectroscopy (XPS) has been used for analyzing the surface chemistry of prepared AgNPs. The particle size determines the interaction of nanoparticles with pathogens. Both Gram positive and negative bacteria ( Escherichia coli and Staphylococcus areous ) are used to determine the anti-microbial potency of the green synthesized AgNPs. The synthesized silver nanoparticles showed significant anti-bacterial applications against B. subtilus and S. aureus. The anti-oxidant applications of AgNPs also studied on comparison with vitamin C. The toxicity of the phenolic Azo dyes (PDA) has been studied against Fish, Daphnia and Green Algae . The electrode potential was studied in the electrochemical redox reaction of hydroxy phenol in aqueous media. Simple electrolyte was used to determine the current efficiency. For the stability of electrode multi cyclic voltammetry was also studied during redox reaction, which showed stability under the potential 0.4 to 0.2 V. [ABSTRACT FROM AUTHOR]

Synthesis of Nobel metal nanoparticles, play a key role in the field of medicine. Plants contain a substantial number of organic constituents, like phenolic compounds and various types of glycosides that help in synthesis of metal nanoparticles. Synthesis of metal nanoparticles by green method is one of the best and environment friendly methods. The major significance of the green synthesis is lack of toxic by-products produced during metal nanoparticle synthesis. The nanoparticles, synthesized by green method show various significant biological activities. Most of the research articles report the synthesized nanoparticles to be active against gram positive and gram negative bacteria. Some of these bacteria include Escherichia coli , Bacillus subtilis , Klebsiella pneumonia and Pseudomonas fluorescens . The synthesized nanoparticles also show significant antifungal activity against Trichophyton simii , Trichophyton mentagrophytes and Trichophyton rubrum as well as different types of cancer cells such as breast cancer cell line. They also exhibit significant antioxidant activity. The activities of these Nobel metal nano-particles mainly depend on the size and shape. The particles of small size with large surface area show good activity in the field of medicine. The synthesized nanoparticles are also active against leishmanial diseases. This research article explores in detail the green synthesis of the nanoparticles and their uses thereof. [ABSTRACT FROM AUTHOR]

The increase in the severe infectious diseases and resistance of the majority of the bacterial pathogens to the available drug is a serious problem now a day. In order to overcome this problem it is necessary to develop new therapeutic agents which are non-toxic and more effective to inhibit these microbial pathogens. For this purpose the plant extract of highly active medicinal plant, Taraxacum laevigatum was used for the synthesis of platinum nanoparticles (PtNPs) to enhance its bio-activities. The surface plasmon resonance peak appeared at 283 nm clearly represent the formation of PtNPs. The results illustrate that the bio-synthesized PtNPs were uniformly dispersed, small sized (2–7 nm) and spherical in shape. The green synthesized PtNPs were characterized by UV–vis spectroscopy, XRD, TEM, SEM, EDX, DLS and FTIR. These nanoparticles were tested against gram positive bacteria ( Bacillus subtilis ) and gram negative bacteria ( Pseudomonas aeruginosa ). The bio-synthesized PtNPs were examined to be more effective against both of the bacteria. The results showed, that the zone of inhibition of PtNPs against P. aeruginosa was 15 (± 0.5) mm and B. subtilis was 18 (± 0.8) mm. The most significant outcome of this examination is that PtNPs exhibited strong antibacterial activity against P. aeruginosa and B. subtilis which have strong defensive system against several antibiotics. [ABSTRACT FROM AUTHOR]

In this study, a simple and environmental friendly method was developed for the synthesis of silver nanoparticles (Ag-NPs) using Dimocarpus longan seed extract as a source of reducing and stabilizing agent. The appearance of a surface plasmon resonance peak at 432 nm confirmed the synthesis of silver nanoparticles (UV–visible spectroscopy). The biosynthesized Ag-NPs were face centered cubic structures (XRD) with an approximate particle size of 40 nm (TEM). Optimization study revealed that 10 mL of plant extract (2 mM AgNO 3 ) at 180 min of incubation resulted the optimum product synthesis. Poly-phenolic compounds were majorly involved in the reduction of silver ions into Ag-NPs (FT-IR). The catalytic activities of Ag-NPs were assessed against the photo-catalytic degradation of methylene blue and chemo catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The results indicated that the prepared Ag-NPs have strong chemo catalytic activity with a complete reduction of 4-NP to 4-AP within 10 min. Similarly, Ag-NPs displayed higher photo-catalytic activity (K = 0.12) as compared to commercial Ag-NPs (K = 0.003). In addition, the silver nanoparticles exhibited a promising antioxidant activity in scavenging DPPH radicals. The findings of this study conclude that the biosynthesized Ag-NPs are promising agent possessing strong catalytic and reducing properties. [ABSTRACT FROM AUTHOR]

There is a growing need to introduce eco-friendly and sustainable procedures for the synthesis of metal nanoparticles that include a mild reaction conditions, simple reaction setup, use of nontoxic medium such as water and plant extract, cost effectiveness as well as greater efficiency for biomedical and catalytic applications. For this purpose, small and highly dispersed palladium nanoparticles (PdNPs) were prepared by eco-friendly and cost effective green method using water soluble leaf extract of Sapium sebiferum as a reducing and capping agent. The formation of PdNPs was optimized at various temperatures i.e. (30 °C, 60 °C and 90 °C) and different leaves extract (5 mL and 10 mL) in order to control their size and shape. The results indicated that PdNPs synthesized at 10 mL leaf extract concentration and 60 °C temperature have small sized (5 nm) and spherical shape. The nanoparticles formation, their dispersion, size and shape were confirmed by various characterization techniques i.e. UV–Vis spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), thermo gravimetric analysis (TGA) and Dynamic light scattering technique (DLS) analysis. The biologically synthesized PdNPs were tested for size dependent photo degradation of methylene blue and inactivation of bacteria. The PdNPs synthesized at optimized condition (10 mL extract concentration and 60 °C) have strong photo catalytic activity and reduced 90% methylene blue in 70 min. The optimized PdNPs also showed strong bacterial inhibition against Staphylococcus aureus 29(± 0.8 mm), Bacillus subtilis 19(± 0.6 mm) and pseudomonas aeruginosa 11(± 0.6 mm). The results of this examination demonstrate effective applications of extremely active PdNPs. [ABSTRACT FROM AUTHOR]

Water purification is one of the worldwide problem and most of the conventional methods are associated with a number of drawbacks. Therefore it is the need of the day to develop new methods and materials to overcome the problem of water purification. In this research work we present a simple and green approach to synthesize silver decorated titanium dioxide (Ag/TiO 2 ) nanocomposite with an efficient photo catalytic activities. Phytochemicals of the Cestrum nocturnum leaf extract were used to synthesize silver nanoparticles (AgNPs), Titanium dioxide (TiO 2 ) and Ag/TiO 2 nanocomposite. To confirm the formation, crystal structure, particle size and shape of green synthesized nanoparticles and nanocomposite, they were characterized by UV–visible spectroscopy (UV–vis), X-ray diffraction spectroscopy (XRD), high resolution transmission electron microscopy (HRTEM), Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The AgNPs, TiO 2 and Ag/TiO 2 were evaluated for photo degradation of methylene blue (MB) and photo inhibition of Bacteria. The bio-synthesized Ag/TiO 2 nanocomposite was observed to have strong catalytic activities for photo reduction of MB and photo inactivation of bacteria as compared to bare AgNPs and TiO 2 . In the presence of Ag/TiO 2 , 90% of MB was degraded only in 40 min of irradiation. Alternatively the bare AgNPs and TiO 2 degraded less than 30% and 80% respectively of MB even in more than 100 min of irradiation. Similarly the Ag/TiO 2 has very strong photo inhibition efficiency towards Escherichia coli and Pseudomonas aeruginosa . The zone of inhibition of irradiated Ag/TiO 2 nanocomposites against E. coli and P. aeruginosa was 19 mm and 17 mm respectively which was two times higher than in dark. These promising photocatalytic activities of nanocomposite may be due to the highly decorated AgNPs over the surface of TiO 2 . [ABSTRACT FROM AUTHOR]

After malaria, Leishmaniasis is the most prevalent infectious disease in terms of fatality and geographical distribution. The availability of a limited number of antileishmanial agents, emerging resistance to the available drugs, and the high cost of treatment complicate the treatment of leishmaniasis. To overcome these issues, critical research for new therapeutic agents with enhanced antileishmanial potential and low treatment cost is needed. In this contribution, we developed a green protocol to prepare biogenic silver nanoparticles (AgNPs) and amphotericin B-bound biogenic silver nanoparticles (AmB-AgNPs). Phytochemicals from the aqueous extract of Isatis tinctoria were used as reducing and capping agents to prepare silver nanoparticles. Amphotericin B was successfully adsorbed on the surface of biogenic silver nanoparticles. The prepared nanoparticles were characterized by various analytical techniques. UV–Visible spectroscopy was employed to detect the characteristic localized surface plasmon resonance peaks (LSPR) for the prepared nanoparticles. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) studies revealed the formation of spherical silver nanoparticles with an average particle size of 10–20 nm. The cubic crystalline structure of the prepared nanoparticles was confirmed by X-ray diffraction (XRD) study. FTIR spectroscopic analysis revealed that plant polyphenolic compounds are mainly involved in metal reduction and capping. Under visible light irradiation, biogenic silver nanoparticles exhibited significant activity against Leishmania tropica with an IC 50 value of 4.2 μg/mL. The leishmanicidal activity of these nanoparticles was considerably enhanced by conjugation with amphotericin B (IC 50 = 2.43 μg/mL). In conclusion, the findings of this study reveal that adsorption of amphotericin B, an antileishmanial drug, to biogenic silver nanoparticles, could be a safe, more effective and economic alternative to the available antileishmanial strategies. [ABSTRACT FROM AUTHOR]

In the present research work a novel, nontoxic and ecofriendly procedure was developed for the green synthesis of silver nano particle (AgNPs) using Caruluma edulis ( C. edulis ) extract act as reductant as well as stabilizer agents. The formation of AgNPs was confirmed by UV/Vis spectroscopy. The small and spherical sizes of AgNPs were conformed from high resolution transmission electron microscopy (HRTEM) analysis and were found in the range of 2–10 nm, which were highly dispersion without any aggregation. The crystalline structure of AgNPs was conformed from X-ray diffraction (XRD) analysis. For the elemental composition EDX was used and FTIR helped to determine the type of organic compounds in the extract. The potential electrochemical property of modified silver electrode was also studied. The AgNPs showed prominent antibacterial motion with MIC values of 125 μg/mL against Bacillus subtilis and Staphylococcus aureus while 250 μg/mL against Escherichia coli . High cell constituents' release was exhibited by B. subtilis with 2 × MIC value of silver nanoparticles. Silver nanoparticles also showed significant DPPH free radical scavenging activity. This research would have an important implication for the synthesis of more efficient antimicrobial and antioxidant agent. The AgNP modified electrode (GC/AgNPs) exhibited an excellent electro-catalytic activity toward the redox reaction of phenolic compounds. The AgNPs were evaluated for electrochemical degradation of bromothymol blue (BTB) dyes which showed a significant activity. From the strong reductive properties it is obvious that AgNPs can be used in water sanitization and converting some organic perilous in to non-hazardous materials. The AgNPs showed potential applications in the field of electro chemistry, sensor, catalyst, nano-devices and medical. [ABSTRACT FROM AUTHOR]

The silver nanoparticles (AgNPs) were green synthesized using Cirsium arvense plant extract as a reducing and stabilizing agent, with superior photo inactivation activity against Escherichia coli ( E. coli ). The synthesized AgNPs had crystalline structure and were characterized by UV–vis spectroscopy, XRD, HRTEM, SEM, EDX and FT-IR. The formation of nanoparticles was observed at different pH and different plant extract concentrations and it was found that at higher pH (pH > 6) and at lower concentration (10 mL), the reducing and stabilizing efficiency of plant extract was increased. The synthesized AgNPs had small size (< 15 nm) and spherical shape. The AgNPs were evaluated for antibacterial activity against E. coli . Before transferring it to antibacterial activity, it was placed under visible light for 120 min. The same experiment was performed in dark as a control medium. The photo irradiated AgNPs were observed to be more effective against E. coli . The results showed, that the diameter of zone of inhibition of visible light irradiated AgNPs against E. coli was 23 (± 0.5) mm and in dark was 11 (± 0.4) mm. [ABSTRACT FROM AUTHOR]

The designing of new antibacterial agents with high and long-lasting activities are urgently needed in order to cope with the fast-emerging bacterial resistance. Zinc oxide nanoparticles (ZnO) have shown a significant promise as broad-spectrum antibacterial agents, and are efficient material in compromising bacterial membrane stability that leads to an increased cell permeability to nano-products. However, further engineering is required to improve their biological activities and to minimize their toxicity to healthy cells. In an attempt to resolve this issue, two semiconductor materials, ZnO and selenium (Se), were fabricated into a unique structural composite by a newly developed facile green method, and the designed composite was applied as an antibacterial nanomedicine. The developed methodology involves the initial preparation of ZnO, followed by its fabrication with Se at different temperatures (70 °C to 95 °C). Our experimental data showed that well defined interpenetrated crystalline Se network on ZnO (ZnO-Se) can be obtained at 80 °C for 180 min. The as-prepared ZnO-Se showed promising results in inhibiting the challenged bacterial strains under light irradiation (visible light) as compared to free ZnO. The enhanced biocidal property of ZnO-Se could be ascribed to its improved light-harvesting ability for sustainable induction of reactive oxygen species (ROS) and an active contact killing mechanism. Thus, ZnO-Se composite with a novel architecture could be a promising material in the treatment of bacterial infections by a mutual antibacterial synergy from the incorporated elements. Interestingly, the ZnO-Se has the ability to scavenge the overproduction of hydroxyl radicals, thus protecting the healthy cells from oxidative damage. Preparation of the ZnO and ZnO-Se composite and their antibacterial activity under visible light irradiation. Unlabelled Image • Preparation of ZnO-Se based composite with a novel architecture. • Visible light harvesting characteristics of the designed composite. • Enhanced antibacterial activity under visible light irradiation. • Scavenging of overproduced hydroxyl radicals. [ABSTRACT FROM AUTHOR]