Anticancer, Enhanced Antibacterial, and Free Radical Scavenging Potential of Fucoidan- (Fucus vesiculosus Source) Mediated Silver Nanoparticles.

The present research displays the green synthesis of stable silver nanoparticles (AgNPs). The aqueous solution of Fucoidan from Fucus vesiculosus source (brown marine algae) is used as a reducing and capping agent. UV-Vis spectroscopy, XRD, FT-IR, SEM, EDX, and TEM with selected area electron diffraction are used to characterize the synthesized silver nanoparticles (AgNPs). The synthesized AgNPs exhibit a surface plasmon resonance at 430 nm after 24 h. The characterization results showed that AgNPs are crystalline in nature and exhibit mostly spherical shapes with an average diameter of 4-45 nm. Silver nanoparticles showed effective antibacterial activity against representative pathogens of bacteria. The activities of commercial antibiotics were enhanced by impregnation with the synthesized AgNPs. It also shows good fungicidal and anticancer activity against liver and lung cell lines and shows significant antioxidant efficacy (84%) at 10 µg/ml AgNP concentration against DPPH. The utilization of environmentally synthesized AgNPs offers numerous benefits of ecofriendliness and compatibility for biomedical applications.

In-situ synthesis of polypyrrole/silver for fabricating alginate fabrics with high conductivity, UV resistance and hydrophobicity.

In this research, the polypyrrole/silver (PPy/Ag) composite was first in-situ prepared on alginate fabrics by chemical oxidative polymerization of pyrrole (Py) monomer using silver nitrate as oxidant and sodium dodecyl sulfate (SDS) as the dopant. The effects of mole ratio of Py to silver nitrate, reaction time and dopant concentration on the preparation of PPy/Ag composite were optimized. It was found the optimal molar ratio of Py to silver nitrate was 1:1.5 with 0.02 M SDS under the reaction time of 10 h. Then, the microstructure and properties of resultant PPy/Ag composite were analyzed by scanning electron microscope (SEM), Fourier infrared spectrometer (FT-IR), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and the thermogravimetry analysis (TGA), respectively. Finally, the influences of PPy/Ag coating on the performance of alginate fabrics including electrical conductivity, hydrophilicity, antistatic property and anti-ultraviolet capability were determined. It was found that the electrical conductivity of alginate fabric could be intensively increased after PPy/Ag coating. Meantime, the anti-ultraviolet capability and hydrophobicity could be largely improved by PPy/Ag coating especially under high Py dosage. This paper introduced a simple method for preparing PPy/Ag composite direct on alginate fabric to make it a good functional substrate which could be applied in many fields.

Sugar-Mediated Green Synthesis of Silver Selenide Semiconductor Nanocrystals under Ultrasound Irradiation.

Silver selenide (Ag2Se) is a promising nanomaterial due to its outstanding optoelectronic properties and countless bio-applications. To the best of our knowledge, we report, for the first time, a simple and easy method for the ultrasound-assisted synthesis of Ag2Se nanoparticles (NPs) by mixing aqueous solutions of silver nitrate (AgNO3) and selenous acid (H2SeO3) that act as Ag and Se sources, respectively, in the presence of dissolved fructose and starch that act as reducing and stabilizing agents, respectively. The concentrations of mono- and polysaccharides were screened to determine their effect on the size, shape and colloidal stability of the as-synthesized Ag2Se NPs which, in turn, impact the optical properties of these NPs. The morphology of the as-synthesized Ag2Se NPs was characterized by transmission electron microscopy (TEM) and both α- and ß-phases of Ag2Se were determined by X-ray diffraction (XRD). The optical properties of Ag2Se were studied using UV-Vis spectroscopy and its elemental composition was determined non-destructively using scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS). The biological activity of the Ag2Se NPs was assessed using cytotoxic and bactericidal approaches. Our findings pave the way to the cost-effective, fast and scalable production of valuable Ag2Se NPs that may be utilized in numerous fields.

Aqueous synthesis of PEGylated Ag2S quantum dots and their in vivo tumor targeting behavior.

With significantly decreased light scattering and tissue autofluorescence, fluorescence imaging in the second near infrared (NIR-II, 1000-1700 nm) region has been heavily explored in biomedical field recently. Silver sulfide quantum dots (Ag2S QDs) with unique optical properties were one of the most classic NIR-II imaging probes. However, the Ag2S QDs for in vivo purpose were mainly obtain by oil phase-based high-temperature route at present. Here, we proposed a mild aqueous route to prepare NIR-II emissive Ag2S QDs for in vivo tumor imaging. Original Ag2S QDs was obtained by mixing sodium sulfide and silver nitrate in a thiol-terminated polyethylene glycol (mPEG-SH) solution. Treating the original Ag2S QDs with extra mPEG-SH ligands produced highly PEGyalted Ag2S QDs. These re-PEGylated Ag2S QDs exhibited much better blood circulation and tumor accumulation in vivo comparing with the original ones, which can serve as excellent tumor imaging probes. The whole-body blood vessel imaging of living mice was achieved with high resolution, the bio-distribution of these QDs were studied by NIR-II imaging as well. This work also highlighted the importance of ligand density for tumor targeting.

A clinical mimicker of melanoma with distinctive histopathology: Topical silver nitrate exposure.

Exposure to silver-containing compounds can result in reversible discoloration of the skin, presenting as an irregular brown or black macule, which can have a clinical appearance similar to melanoma. Both the clinical scenario and the histopathology are unique. Silver nitrate darkens with exposure to light, and the area can appear to change over time. On microscopic examination, there are coarse pigmented granules dispersed throughout the corneal layer, and largely absent from the remainder of the epidermis-although the precise location may depend on the duration of topical exposure. While argyria, its irreversible counterpart, has been well-characterized, only a single source has previously reported the histopathology of transient topical silver nitrate exposure. We present two cases, review the clinical and histopathologic differentials, and detail the distinctive histopathology that enables a diagnosis to be suggested in this clinical mimicker of melanoma.

Radiation-induced synthesis of tween 80 stabilized silver nanoparticles for antibacterial applications.

Recently, Silver nanoparticles (AgNPs) have become widely applied nanomaterial in human contacting areas such as cosmetics, food and medicine due to their antibacterial property. On the other hand, surfactants are essential ingredient of several industrial and consumer formulations. Based on these important applications, the current research was aimed to carry out the synthesis and characterization of Tween 80 capped silver nanoparticles (T80-AgNPs) using gamma radiation reduction method. Characterization of T80-AgNPs was occurred by using UV-Vis, XRD, FTIR and TEM techniques. UV-Visible spectra showed surface plasmon resonance (SPR) peak in the range of 420 nm signifying the synthesis of colloidal AgNPs. TEM confirmed the formation of spherical and uniformly distributed AgNPs with average size of 18 nm. XRD analysis illustrated the formation of pure crystalline AgNPs. The FTIR analysis provides evidence for the stabilization of AgNPs by Tween 80. The synthesized T80-AgNPs were evaluated for antibacterial activity against both Escherichia coli (E. coli) as gram negative (G -ve) bacteria and Staphylococcus aureus (S. aureus) as gram positive (G + ve) bacteria and anti-biofilm activity to P. aeruginosa. The results show that T80-AgNPs exhibits excellent antibacterial and antibiofilm activities.

Suppressing growth, migration, and invasion of human hepatocellular carcinoma HepG2 cells by Catharanthus roseus­silver nanoparticles.

Application of silver nanoparticles serves as a new approach in cancer treatment due to its unique features. Biosynthesis of silver nanoparticles using plant is advantageous since they are easily accessible, nontoxic and produce quicker reaction compared to other methods. To evaluate the cytotoxicity, mechanism of cell death and DNA damage of biosynthesized Catharanthus roseus-silver nanoparticles on human liver cancer (HepG2) cells. The antiproliferative activity of Catharanthus roseus­silver nanoparticles was measured using MTT assay. The cytotoxic effects were further evaluated by measuring nitric oxide and reactive oxygen species (ROS). The mechanism of cell death was determined by annexin-FITC/propidium iodide, mitochondrial membrane potential (MMP) and cell cycle assays. The assessment of DNA damage was evaluated using Comet assay method. The uptake of the nanoparticles were evaluated by Transmission Electron Microscopy (TEM). Catharanthus roseus­silver nanoparticles has inhibited the proliferation of HepG2 cells in a time-dependent manner with a median IC50 value of 3.871 ± 0.18 µg/mL. The concentration of nitrite and ROS were significantly higher than control. The cell death was due to apoptosis associated with MMP loss, cell cycle arrest, and extensive DNA damage. TEM analysis indicated the presence of free nanoparticles and endosomes containing the nanoparticles. The findings show that Catharanthus roseus­silver nanoparticles have produced cytotoxic effects on HepG2 cells and thus may have a potential to be used as an anticancer treatment, particularly for hepatocellular carcinoma.

Synthesis of Silver Nanoparticles Using a Novel Cyanobacteria Desertifilum sp. extract: Their Antibacterial and Cytotoxicity Effects.

BACKGROUND: The emergence of multi drug-resistant (MDR) bacterial infections and cancer has necessitated the development and discovery of alternative eco-safe antibacterial and anticancer agents. Biogenic fabrication of metallic nanoparticles is an emerging discipline for production of nanoproducts that exert potent anticancer and antibacterial activity, and do not suffer from the limitations inherent in physiochemical synthesis methods. METHODOLOGY: In this study, we isolated, purified, and characterized a novel cyanobacteria extract (Desertifilum IPPAS B-1220) to utilize in biofabrication of silver nanoparticles (D-SNPs). D-SNPs were produced by adding Desertifilum extract to silver nitrate solution under controlled conditions. Biofabrication of D-SNPs was confirmed using a UV-Vis spectrophotometer. The resultant D-SNPs were characterized using XRD, FTIR, SEM, and TEM. The toxicity of D-SNPs against five pathogenic bacteria and three cancer cell lines (MCF-7, HepG2, and Caco-2) was evaluated. RESULTS: Formation of D-SNPs was indicated by a color change from pale yellow to dark brown. The peak of the surface plasmon resonance of the D-SNPs was at 421 nm. The XRD detected the crystallinity of D-SNPs. FTIR showed that polysaccharides and proteins may have contributed to the biofabrication of D-SNPs. Under SEM and TEM, the D-SNPs were spherical with diameter ranges from 4.5 to 26 nm. The D-SNPs significantly suppressed the growth of five pathogenic bacteria, and exerted cytotoxic effects against MCF-7, HepG2, and Caco-2 cancer cells with IC50 values of 58, 32, and 90 µg/mL, respectively. CONCLUSION: These findings showed for the first time the potentiality of novel cyanobacteria strain Desertifilum IPPAS B-1220 to fabricate small SNPs that acted as potent anticancer and antibacterial material against different cancer cell lines and pathogenic bacterial strains. These findings encourage the researchers to focus on cyanobacteria in general and especially Desertifilum sp. IPPAS B-1220 for synthesizing different NPs that opening the window for new applications.

Protocol optimization for a fast, simple and economical chemical reduction synthesis of antimicrobial silver nanoparticles in non-specialized facilities.

OBJECTIVE: Silver nanoparticles (AgNPs) can be difficult or expensive to obtain or synthesize for laboratories in resource-limited facilities. The purpose of this work was to optimize a synthesis method for a fast, facile, and cost-effective synthesis of AgNPs with antimicrobial activity, which can be readily implemented in non-specialized facilities and laboratories. RESULTS: The optimized method uses a rather simple and rapid chemical reduction process that involves the addition of a polyvinylpyrrolidone solution to a warmed silver nitrate solution under constant vigorous stirring, immediately followed by the addition of sodium borohydride. The total synthesis time is less than 15 min. The obtained AgNPs exhibit an aspect ratio close to 1, with an average size of 6.18 ± 5 nm. AgNPs displayed potent antimicrobial activity, with Minimal Inhibitory Concentration values of ≤ 4 µg mL-1 for Staphylococcus aureus and ≤ 2 µg mL-1 for Candida albicans. The resulting method is robust and highly reproducible, as demonstrated by the characterization of AgNPs from different rounds of syntheses and their antimicrobial activity.

Synthesis and biological characterization of silver nanoparticles derived from the cyanobacterium Oscillatoria limnetica.

Using aqueous cyanobacterial extracts in the synthesis of silver nanoparticle is looked as green, ecofriendly, low priced biotechnology that gives advancement over both chemical and physical methods. In the current study, an aqueous extract of Oscillatoria limnetica fresh biomass was used for the green synthesis of Ag-NPs, since O. limnetica extract plays a dual part in both reducing and stabilizing Oscillatoria-silver nanoparticles (O-AgNPs). The UV-Visible absorption spectrum, Fourier transforms infrared (FT-IR), transmission electron microscopy (TEM) and scanning electron microscope (SEM) were achieved for confirming and characterizing the biosynthesized O-AgNPs. TEM images detected the quasi-spherical Ag-NPs shape with diverse size ranged within 3.30-17.97 nm. FT-IR analysis demonstrated the presence of free amino groups in addition to sulfur containing amino acid derivatives acting as stabilizing agents as well as the presence of either sulfur or phosphorus functional groups which possibly attaches silver. In this study, synthesized Ag-NPs exhibited strong antibacterial activity against multidrug-resistant bacteria (Escherichia coli and Bacillus cereus) as well as cytotoxic effects against both human breast (MCF-7) cell line giving IC50 (6.147 µg/ml) and human colon cancer (HCT-116) cell line giving IC50 (5.369 µg/ml). Hemolytic activity of Ag-NPs was investigated and confirmed as being non- toxic to human RBCs in low concentrations.

A paper-based length of stain analytical device for naked eye (readout-free) detection of cystic fibrosis.

The test of sweat chloride is routinely performed as a worldwide newborn screening (NBS) to the diagnosis of cystic fibrosis (CF) in infants. However, the available methods for measurement of chloride in sweat suffer from such limitations as either low selectivity and/or requiring relatively large sample size. In this work, we have designed an analytical ruler that can measure chloride ion in sweat and hence can be used for the diagnosis of cystic fibrosis. This micro-pad (µ-PAD) device is fabricated by making hydrophilic micro-channel on a filter paper impregnated with silver dichromate. After addition of chloride ion-containing sweat sample, it moves through the channel, leading to the formation of an AgCl sediment, which deposits as a white color stain, the length of which in the channel being proportional to the amount of chloride ion in sweat. A well-defined linear relation was observed between the length of white color stain and the concentration of chloride ion in the sample solutions with a relative standard deviation of 3.6% (n = 3) for an artificial sweat sample containing 100 mM chloride ion. The possible interfering effects of several different cations and anions on the detection of chloride ion were investigated and the results well-confirmed the selectivity of the proposed method. With the use of only 2.0 µL of the sample solution, the µPAD was able to measure the chloride content of sweat over a concentration range of 20.0-100.0 mM, which covers both the healthy range (˂ 40 mM) and the risky range (˃60 mM) of chloride ion. Analysis of chloride content of sweat samples by the µPAD agreed well with those obtained by a standard electrochemical method (with relative errors of lower than 10%).

Gamma radiation-induced crosslinked composite membranes based on polyvinyl alcohol/chitosan/AgNO3/vitamin E for biomedical applications.

Crosslinked hydrogel composite membranes based on polyvinyl alcohol (PVA) and chitosan-loaded AgNO3 and vitamin E were prepared using gamma irradiation. Chitosan has been used as antimicrobial blend materials to provide further biocompatibility for the prepared composite hydrogel membranes. The crosslinking reaction between PVA and chitosan owing to gamma irradiation was verified and characterized by FTIR analysis, while the morphology of hydrogel composite membranes was investigated by SEM. Important parameters affecting on hydrogel membranes formation, such as copolymer concentration, irradiation dose, AgNO3 concentration, plasticizer, and vitamin E of PVA/chitosan membranes were evaluated and discussed in details. In addition, the mechanical and thermal properties of hydrogel composite membranes were examined to evaluate the possibility of its application for wound dressings. The results revealed that the gelation (%) of hydrogel membranes increased dramatically with PVA composition, irradiation dose and glycerol content up to 20%; however, it decreased with AgNP incorporation due to the viscosity of copolymer composition is hyper-increased. The swelling ratio of composed hydrogel membranes decreased notably with increasing the radiation dose and incorporation of AgNP, due to reducing of the crosslinking degree of formed hydrogel membranes. PVA-Cs-Ag composed hydrogel membranes showed significant antimicrobial activity in particular against Streptococcus mutans due to the presence of AgNP in membranes, compared to other bacteria and fungi microbes. Thus, the PVA/chitosan/AgNO3-Vit.E hydrogel composite membranes showed satisfactory properties for use as wound dressing materials.

Toward ultrasensitive and fast colorimetric detection of indoor formaldehyde across the visible region using cetyltrimethylammonium chloride-capped bone-shaped gold nanorods as "chromophores".

Plasmonic nanostructures have been broadly used for chemical detections, but their applications are limited by slow detection rates, insufficient visual resolution and sensitivity due to the chemical and structural stability of conventional plasmonic nanomaterials. It is thus essential to develop strategies to enhance the detection kinetics while promoting their excellent plasmonic properties. In this work, a colorimetric assay for HCHO measurement is developed based on the fact that HCHO can react with Tollens' reagent to anisotropically deposit a layer of silver shells onto the bone-shaped gold nanorod (Au NR) cores. Compared to the routine rod-shaped Au NRs, the bone-shaped Au NRs facilitate the deposition of Ag onto the sunken section due to their unique concave structures, giving rise to fast reaction kinetics and detection rate. It is also important to point out that the surface ligand exchange from CTAB to CTAC is helpful to accelerate the deposition of silver onto Au NRs, which significantly shortens the reaction time. The preferential deposition of Ag on the concave Au NRs induces more dramatic morphology changes and therefore promotes the plasmonic shift of the bone-shaped Au NRs and improves the sensing efficiency. Correspondingly, the apparent color of the solution changes from light gray to dark blue, purple, red, orange and finally to yellow as the longitudinal localized surface plasmon resonance (LSPR) band shifts from 710 to 500 nm along with the emergence of a new LSPR band at 400 nm almost covering the full visible region. The colorimetric method developed enables sensitive detection of HCHO with a low detection limit (1 nM), wide linear range (0.1-50 µM), high visual resolution and good specificity against other common indoor gases. It was successfully applied to the detection of gaseous HCHO present in the air collected from a furniture plaza, showing its potential practicality for on-site HCHO analysis.

Comparative and Mechanistic Study on the Anticancer Activity of Quinacrine-Based Silver and Gold Hybrid Nanoparticles in Head and Neck Cancer.

Using oral cancer cells ( in vitro) and in vivo xenograft mice model, we have systematically studied the detailed mechanism of anticancer activity of quinacrine-based hybrid silver (QAgNP) and gold (QAuNP) nanoparticles (NPs) and compared their efficacies. Both the NPs showed characteristic anti-cell proliferation profile in various cancer cells with minimally affecting the normal nontransformed breast epithelial MCF-10A cells. The IC50 values of QAuNP in various cancer cells were less compared to QAgNP and also found to be the lowest (0.5 µg/mL) in SCC-9 oral cancer cells. Although both NPs caused apoptosis by increased DNA damage, arresting at S phase and simultaneously inhibiting the DNA repair activity in cells, efficacy of QAuNP was better than that of QAgNP. NPs intercalated with DNA and inhibited the topoisomerase activity in cells. Alteration in expression of cell cycle regulatory (cyclins B1, E1, A2, etc.) and replication-related (MRE11, RPA, RFC, etc.) proteins were also observed after NP exposure to the cells. Accumulation of cells resulted in extended G/M phase after prolonged exposure of QAuNP in SCC-9 cells. Interestingly, depletion of geminin and increase of Cdt-1 along with CDC-6 suggest the formation of re-replication. Recovery of body weight and reduction in tumor volume were found in NP-treated xenograft mice. Induction of Bax/Bcl-xL, PARP-1 cleavage, p53, and p21 were noted in NP-treated xenograft mice tissue samples. Thus, data suggest that NP inhibits topoisomerase activity, thereby inhibiting DNA replication and inducing re-replication, which causes S-phase arrest, DNA damage, and finally apoptosis of the oral cancer cells. Also, it was found that anticancer activity of QAuNP is better than that of QAgNP.

Silver(I) Complexes of the Pharmaceutical Agents Metronidazole and 4-Hydroxymethylpyridine: Comparison of Cytotoxic Profile for Potential Clinical Application.

In previous papers, we have reported on the high antifungal and significant antibacterial activity against Gram-positive and Gram-negative bacteria of the water-soluble silver(I) complexes of metronidazole and derivatives of pyridine compared to silver nitrate. In the present study, the cytotoxic activity of the silver(I) complexes of metronidazole and 4-hydroxymethylpyridine was compared with that of silver nitrate. Metronidazole and 4-hydroxymethylpyridine were investigated using Balb/c 3T3 and HepG2 cell lines in order to evaluate the potential clinical application of silver(I) complexes. The cells were exposed for 72 h to compounds at eight concentrations. The cytotoxic concentrations (IC50) of the study compounds were assessed within four biochemical endpoints: mitochondrial activity, lysosomal activity, cellular membrane integrity, and total protein content. The investigated silver(I) complexes displayed comparable cytotoxicity to that of silver nitrate used in clinics. Mean cytotoxic concentrations calculated for investigated silver(I) complexes from concentration-response curves ranged from 2.13 to 26.5 µM. HepG2 cells were less sensitive to the tested complexes compared to fibroblasts (Balb/c 3T3). However, the most affected endpoint for HepG2 cells was cellular membrane damage. The cytotoxicity of both silver complexes was comparable for Balb/c 3T3 cells. The cytotoxic potential of the new silver(I) compounds compared to that of silver nitrate used in medicine indicates that they are safe and could be used in clinical practice. The presented results are yet more stimulating to further studies that evaluate the therapeutic use of silver complexes.

Pyrrole-Hemoglobin Adducts, a More Feasible Potential Biomarker of Pyrrolizidine Alkaloid Exposure.

Pyrrolizidine alkaloids (PAs) are naturally occurring phytotoxins widely distributed in about 3% of flowering plants. The formation of PA-derived pyrrole-protein adducts is considered as a primary trigger initiating PA-induced hepatotoxicity. The present study aims to (i) further validate our previous established derivatization method using acidified ethanolic AgNO3 for the analysis of pyrrole-protein adducts and (ii) apply this method to characterize the binding tendency, dose-response, and elimination kinetics of pyrrole-protein adducts in blood samples. Two pyrrole-amino acid conjugates, (±)-6,7-dihydro-7-hydroxy-1-hydroxymethyl-5 H-pyrrolizine (DHP)-cysteine (7-cysteine-DHP) and 9-histidine-DHP, were synthesized and used to demonstrate that acidified ethanolic AgNO3 derivatization can cleave both S-linkage and N-linkage of pyrrole-protein adducts. Subsequently, using precolumn AgNO3 derivatization followed by ultra-high-pressure liquid chromatography/mass spectrometry analysis, we quantified pyrrole-protein adducts in monocrotaline-treated rat blood protein fractions, including hemoglobin (Hb), plasma, albumin, and plasma residual protein fractions, and found that the amount of pyrrole-Hb adducts was significantly higher than that in all plasma fractions. Moreover, elimination half-life of pyrrole-Hb adducts was also significantly longer than pyrrole-protein adducts in plasma fractions (12.08 vs 2.54-2.93 days). In addition, we also tested blood samples obtained from five PA-induced liver injury patients and found that the amount of pyrrole-protein adducts in blood cells was also remarkably higher than that in plasma. In conclusion, our findings for the first time confirmed that the AgNO3 derivatization method could be used to measure both S- and N-linked pyrrole-protein adducts and also suggested that pyrrole-Hb adducts with remarkably higher level and longer life span could be a better biomarker of PA exposure.

Physiological, ultrastructural and proteomic responses of tobacco seedlings exposed to silver nanoparticles and silver nitrate.

Since silver nanoparticles (AgNPs) are a dominant nanomaterial in consumer products, there is growing concern about their impact on the environment. Although numerous studies on the effects of AgNPs on living organisms have been conducted, the interaction of AgNPs with plants has not been fully clarified. To reveal the plant mechanisms activated after exposure to AgNPs and to differentiate between effects specific to nanoparticles and ionic silver, we investigated the physiological, ultrastructural and proteomic changes in seedlings of tobacco (Nicotiana tabacum) exposed to commercial AgNPs and ionic silver (AgNO3) from the seed stage. A higher Ag content was measured in seedlings exposed to AgNPs than in those exposed to the same concentration of AgNO3. However, the results on oxidative stress parameters obtained revealed that, in general, higher toxicity was recorded in AgNO3-treated seedlings than in those exposed to nanosilver. Ultrastructural analysis of root cells confirmed the presence of silver in the form of nanoparticles, which may explain the lower toxicity of AgNPs. However, the ultrastructural changes of chloroplasts as well as proteomic study showed that both AgNPs and AgNO3 can affect photosynthesis. Moreover, the majority of the proteins involved in the primary metabolism were up-regulated after both types of treatments, indicating that enhanced energy production, which can be used to reinforce defensive mechanisms, enables plants to cope with silver-induced toxicity.

Evaluating microwave-synthesized silver nanoparticles from silver nitrate with life cycle assessment techniques.

Silver Nanoparticles (AgNPs) are well known for applications in electronics and as antimicrobial agents because of their unique optical, electrical, cytotoxic and thermal properties. These nanoparticles can be synthesized via a wide variety of techniques; however, they require the use of hazardous solvents which have very high environmental impacts. Nanoscience researchers have attempted novel synthesis routes that reduce resource requirements and use benign chemicals, while maintaining control over their unique properties. The present study evaluates the potential environmental impacts of one such benign method using Life Cycle Assessment (LCA) techniques which are used to assess the environmental impacts of a product's life through all the stages from raw material extraction to disposal/ recycling. This research evaluates AgNPs which were synthesized using glucose as the reducing agent and food grade corn starch as the stabilizing agent in a microwave-assisted reaction system. GaBi 6.0 software was used to carry out the Life Cycle Impact Assessment on a declared unit of 1 kg of 3.0 ±â€¯1.2 nm diameter AgNPs. The results indicate that the impacts are predominantly on acidification (AP), human health particulate air (HHAP) and human toxicity non-cancer (HTNCP) potentials. These impacts are mainly from the production of silver metal and electricity used. The starch and glucose used to produce AgNPs of 3.0 ±â€¯1.2 nm is shown to have negligible environmental impacts and is therefore considered to be environmentally benign.