Smaller AgNPs Research Articles

A yeast-based biosensor for silver nanoparticle accumulation and cellular dissolution

Silver nanoparticles (AgNPs) are now being increasingly applied in many fields, thus it is critical to quantify these nanoparticles as well as their cellular dissolution for biological assessment. In this study, we developed a novel technique to quantify the concentration of ultra-small AgNPs based principally on the finding that dissolved Ag+ decreased the Zn2+ directed fluorescence increase of an adenine deficient yeast [Ade(−) yeast]. To obtain the highest sensitivity to AgNPs, the biomass and addition of Zn2+ were optimized to be 0.005 and 0.05 μM, respectively. The lowest detectable Ag+ dissolved from the internalized AgNPs was 3.77 ng Ag/μg P. The lowest detectable concentration of AgNPs (7 nm) was 8.9 μg/L, while the bio-response induced by larger AgNPs (20 nm) did not change with increasing AgNPs concentration. Thus, Ade(−) yeast selectively collected the ambient ultra-small AgNPs and acted as a screener to differentiate small AgNPs (4.5–9 nm) and large ones (16–26 nm). The method was further employed to determine the cellular dissolution of these ultra-small AgNPs once they were internalized by the yeast cells. Over 78% of the internalized 7 nm-AgNPs was dissolved to Ag+. Our study provided a novel biosensing system using Ade(−) yeast in screening ultra-small AgNPs from the large ones and monitoring the cellular dissolution processes of these ultra-small AgNPs.

Neutrally charged nanosilver antimicrobial effects: A surface thermodynamic perspective

Nanosilver (AgNP) has a large surface area that contributes to enhanced interactions with bacteria, as well as silver ion release. The actual AgNP antimicrobial effect is determined by the AgNP size. AgNPs with smaller diameters showed better antimicrobial effects because smaller AgNPs had larger surface areas, which led to greater silver ion release and stronger attachment to bacteria. The attachment of AgNPs to bacterial surfaces is attributed to the attractive interactions between the AgNPs and bacteria, which is also a function of the size of AgNPs. Although the antimicrobial activity of AgNPs has been extensively studied, there is a gap between antimicrobial effects of AgNPs on bacteria and their subsequent attachment. To fully understand the antimicrobial effectiveness of different-sized AgNPs, this study investigated the dynamic process of AgNP-bacteria interactions in aqueous media, including AgNP aggregation, AgNP attachment, and antimicrobial effects. AgNP-AgNP and AgNP-bacteria interactions were quantified based on DLVO and surface chemistry theories, which were used to interpret subsequent AgNP aggregation, AgNP-bacteria attachment and AgNP antimicrobial observations.

Anti-Cancer and Anti-Bacterial Effects of Terfezia boudieri-Derived Silver Nanoparticles.

The use of nanoparticles has markedly increased in biomedical sciences. The silver nanoparticles (AgNPs) have been investigated for their applicability to deliver chemotherapeutic/antibacterial agents to treat cancer or infections disease. However, the existing chemical and physical methods of synthesizing AgNPs are considered inefficient, expensive and toxic. Natural products have emerged as viable candidates for nanoparticle production, including the use of Terfezia boudieri (T. boudieri), a member of the edible truffle family. Accordingly, our goal was to synthesize AgNPs using an aqueous extract of T. boudieri (green synthesized AgNPs). Since certain infectious agents are linked to cancer, we investigated their potential as anti-cancer and antibacterial agents. The synthesis of AgNPs was confirmed by the presence of an absorption peak at 450nm by spectroscopy. The physico-chemical properties of green synthesized AgNPs were analyzed by UV-Vis, FT-IR, XRD, SEM, and TEM. In addition, their potential to inhibit cancer cell (proliferation and the growth of infectious bacteria were investigated. The size of nanoparticles ranged between 20-30nm. They exerted significant cytotoxicity and bactericidal effects in a concentration and time-dependent manner compared to T. boudieri extract alone. Interestingly, the synthesis of smaller AgNPs was correlated with longer synthesis time and enhanced cytotoxic and bactericidal properties.

Facile encapsulating Ag nanoparticles into a Tetrathiafulvalene-based Zr-MOF for enhanced Photocatalysis

A facile and efficient synthetic strategy was used to prepare a silver nanoparticles-doped MOF (Ag NPs@Zr-TTFTB, TTFTB = tetrathiafulvalene tetrabenzoate) catalyst. Considering the stability of Zr6 cluster-based MOFs and the confinement of small Ag NPs (below 5 nm), title hybrids can be used for the photocatalytic degradation of sulfamethoxazole (SMZ). The prepared Ag NPs@Zr-TTFTB were found to efficiently remove SMZ (k = 0.009 min−1) and remain active in the wide range of pH values (3.0 ~ 9.0) and four cycles. The leaching amount of Ag and Zr under different pH values were only accounted for 0.18% ~ 0.61% and 0.01% ~ 0.05% of used Ag NPs@Zr-TTFTB, respectively, which indicated its excellent stability. Studies on the catalytic mechanism revealed that the proposed heterostructure of Ag NPs and Zr-TTFTB led to the electron transfer and the generation of active oxygen species, resulting in its remarkable photocatalytic activities.

Interfacial heterogeneous precipitation of Ag nanoparticles in soda-lime silicate glass for improved toughness and conductivity

The fracture toughness and thermal conductivity of soda-lime glass were enhanced by an interfacial precipitation of Ag. Large quantities of silver nanoparticles (AgNPs) are formed on the surface and subsurface layers of the Ag–Na ion exchanged glass powders during the heat-treatment in H2 for various times, and are fully densified by subsequent spark plasma sintering (SPS). The AgNPs with particle sizes above 50 nm are mainly located near the interfaces with the original glass particles, whereas smaller AgNPs are observed inside the glass particles. Moreover, the thickness of the precipitated Ag layer is seen to increase with increasing heat-treatment time. The incorporation of AgNPs is shown to enhance the fracture toughness of the soda-lime glass due to ductile deformation, crack deflection, and crack bridging. Finally, a maximum fracture toughness of 1.14 MPa m1/2, and a maximum thermal conductivity of 1.20 W m−1K−1, are obtained for the glass powders that were subjected to the entire process of ion-exchange, heat-treatment, and SPS densification.

Synthesis of Colloidal Silver Nanoparticles in Various Liquid Media Using Pulse Laser Ablation Method and Its Antibacterial Properties

The silver nanoparticles (AgNPs) have been applied as an antibacterial agent in consumer products, cosmetics, and food industries. In this present work, AgNPs were synthesized in various mediums of polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), and chitosan using the pulse laser ablation synthesis method. Experimentally, a pulse Nd:YAG laser beam (1064 nm, 7 ns, 30 mJ) was directed using a silver mirror and focused using a quartz lens with a focal length of 30 mm on a silver metal plate placed in a petri dish containing liquid mediums for 120 min to produce colloidal silver nanoparticles. The results certified that All AgNPs have a spherical shape with polydisperse size in all media, including PVP, PEG, and chitosan. The smallest AgNPs have been produced in PVP medium with an averaged smallest size of 11.62 nm. Based on this result, PVP is the preferred medium to produce AgNPs with the smallest size and good stability. The produced silver nanoparticles have been successfully employed as an antibacterial agent, which is experimentally demonstrated by using Escherichia coli and Staphylococcus aureus. The result certified that the produced silver nanoparticles could effectively kill the bacteria with a killing percentage of 99.6 to 100%.

Phase Transition Behavior and Catalytic Activity of Poly(N-acryloylglycinamide-co-methacrylic acid) Microgels.

Poly(N-acryloyl glycinamide) is a well-known thermoresponsive polymer possessing an upper critical solution temperature (UCST) in water. By copolymerizing N-acryloyl glycinamide (NAGA) with methacrylic acid (MAA) in the presence of a crosslinker, poly(N-acryloyl glycinamide-co-methacrylic acid) [P(NAGA–MAA)] copolymer microgels with an MAA molar fraction of 10–70 mol % were obtained. The polymerization kinetics suggests that the copolymer microgels have a random structure. The size of the microgels was between 60 and 120 nm in the non-aggregated swollen state in aqueous medium and depending on the solvent conditions, they show reversible swelling and shrinking upon temperature change. Their phase transition behavior was studied by a combination of methods to understand the process of the UCST-type behavior and interactions between NAGA and MAA. P(NAGA–MAA) microgels were loaded with silver nanoparticles (AgNPs) by the reduction of AgNO3 under UV light. Compared with the chemical reduction of AgNO3, the photoreduction results in smaller AgNPs and the amount and size of the AgNPs are dependent on the comonomer ratio. The catalytic activity of the AgNP-loaded microgels in 4-nitrophenol reduction was tested.

Highly Efficient Silver Catalyst Supported by a Spherical Covalent Organic Framework for the Continuous Reduction of 4-Nitrophenol.

Developing new materials and novel technologies for the highly efficient treatment of toxic organic pollutants is highly desirable. Chemical reduction based on heterogeneous substrate/noble metal catalysts and the reducing agent NaBH4 has become an effective method in recent years. Here, a spherical covalent organic framework (SCOF) was designed to provide basic sites for Ag ions, by which small Ag NPs were immobilized on the SCOF to form Ag NPs@SCOF microspheres. The prepared microspheres exhibited a high catalytic reduction ability toward 4-nitrophenol (4-NP). An optimized permeation flux of 2000 L m-2 h-1 (LMH) and a more than 99% 4-NP reduction efficiency were obtained with flow-through experiments, which are far better than the reported results (below 200 LMH). Moreover, the microspheres could maintain stable catalytic performance under a continuous flow-through process. Our work provides an efficient material and technology that can be applied to easily treat toxic organic pollutants.

The effects of solubility of silver nanoparticles, accumulation, and toxicity to the aquatic plant Lemna minor.

The use of silver nanoparticles (AgNPs) in commercial products has increased due to their antibacterial properties and their impacts on the environment must be investigated. This scenario has motivated the conduction of this study, which relates different factors that affect the toxicity of AgNPs to the aquatic plant Lemna minor such as size, accumulation, concentration, and dissolution of AgNPs. To this end, synthesized AgNPs measuring 30, 85, and 110 nm were added into the culture medium to observe toxicity for 30 days. The mapping by SEM showed that the smallest AgNPs can translocate from roots to leaves due to its mobility and internalization. As predicted by the Ostwald equation, the solubility for 30-nm AgNPs increased almost 3 times at the end of 30 days, while for 85 and 110 nm size nanoparticles, after 7 days, the solubility decreased due to "Ostwald ripening" process. Plant mortality was assessed and, after 1 month, the size of 30 nm was the most toxic with negative growth in all studied concentrations, with 60% mortality in the worst case. The concentration of 50 μg mL-1 was toxic in all sizes with negative growth in the period. Therefore, the investigation of AgNPs' toxicity needs to consider a different factor to better understand their effects on aquatic plants and the environment.

Small AgNP in the Biopolymer Nanocomposite System.

In this work, ultra-small and stable silver nanoparticles (AgNP) on chitosan biopolymer (BP/AgP) were prepared by in situ reduction of the diamminesilver(I) complex ([Ag(NH3)2]+) to create a biostatic membrane system. The small AgNP (3 nm) as a stable source of silver ions, their crystal form, and homogeneous distribution in the whole solid membrane were confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The X-ray photoelectron spectroscopy (XPS) and Auger analysis were applied to investigate the elemental composition, concentration, and chemical state of surface atoms. It was found that ultra-small metallic nanoparticles might form a steady source of silver ions and enhance the biostatic properties of solid membranes. Ultra-small AgNP with disturbed electronic structure and plasmonic properties may generate interaction between amine groups of the biopolymer for improving the homogeneity of the nanometallic layer. In this work, the significant differences between the typical way (deposition of ex-situ-prepared AgNP) and the proposed in-situ synthesis approach were determined. The improved thermal stability (by thermogravimetry and differential scanning calorimetry (TG/DSC) analysis) for BP/AgP was observed and explained by the presence of the protective layer of a low-molecular silver phase. Finally, the antibacterial activity of the BP/AgP nanocomposite was tested using selected bacteria biofilms. The grafted membrane showed clear inhibition properties by destruction and multiple damages of bacteria cells. The possible mechanisms of biocidal activity were discussed, and the investigation of the AgNP influence on the bacteria body was illustrated by AFM measurements. The results obtained concluded that the biopolymer membrane properties were significantly improved by the integration with ultra-small Ag nanoparticles, which added value to its applications as a biostatic membrane system for filtration and separation issues.

Evaluation of the Effects of Particle Sizes of Silver Nanoparticles on Various Biological Systems.

Seven biological methods were adopted (three bacterial activities of bioluminescence, enzyme, enzyme biosynthetic, algal growth, seed germination, and root and shoot growth) to compare the toxic effects of two different sizes of silver nanoparticles (AgNPs). AgNPs showed a different sensitivity in each bioassay. Overall, the order of inhibitory effects was roughly observed as follows; bacterial bioluminescence activity ≈ root growth > biosynthetic activity of enzymes ≈ algal growth > seed germination ≈ enzymatic activity > shoot growth. For all bacterial activities (bioluminescence, enzyme, and enzyme biosynthesis), the small AgNPs showed statistically significantly higher toxicity than the large ones (p < 0.0036), while no significant differences were observed among other biological activities. The overall effects on the biological activities (except shoot growth) of the small AgNPs were shown to have about 4.3 times lower EC50 (high toxicity) value than the large AgNPs. These results also indicated that the bacterial bioluminescence activity appeared to be an appropriate method among the tested ones in terms of both sensitivity and the discernment of particle sizes of AgNPs.

An effective weapon against biofilm consortia and small colony variants of MRSA.

Objective(s):This study was designed to investigate the effect of AgNPs (10 nm and 30 nm) on different phenotypes of Staphylococcus aureus biofilm consortia.Materials and Methods:A total of eighteen biofilm-producing isolates of Methicillin-Resistant S. aureus (MRSA) were used in the present study. Tube methods, Congo-red agar method, and scanning electron microscopy (SEM) were used to study biofilm phenotypes. Population analysis assay on a tryptone soya agar (TSA) plate was applied to study the different phenotypes of biofilm consortia. The effect of AgNPs was evaluated by broth dilution assay. Results:Results showed that biofilm consortia harbour different phenotypes, i.e., planktonic, metabolically inactive cells, and small colony variants (SCVs) or persister cells. The focus of the present study is the effect of AgNPs on biofilm consortia of MRSA, particularly on the SCVs population. Large size AgNPs (30 nm) were unable to diffuse through extracellular matrix material coverings of the biofilm consortia; they were only active against the planktonic population that occupies the outer surface of consortia. The smaller AgNPs (10 nm), on the other hand, were found to diffuse through the matrix material and hence were effective against planktonic as well as metabolically inactive population of consortia. Moreover, 30 nm AgNPs take 6 hr to disperse off and kill planktonic and upper surface indwellers. The 10 nm AgNPs disperse and kill the majority of biofilm indwellers within 20 min. Conclusion:The present study showed that 10 nm AgNPs can easily penetrate inside the biofilm and are active against all of the indwellers of consortia.

In vitro and in vivo evaluation of structurally-controlled silk fibroin coatings for orthopedic infection and in-situ osteogenesis

Biomedical device-associated infections (BAI) and osteosynthesis are two main complications following the orthopedic implant surgery, especially while infecting bacteria form a mature biofilm, which can protect the organisms from the host immune system and antibiotic therapy. Comparing with the single antibiotics therapeutic method, the combination of silver nanoparticles (AgNPs) and conventional antibiotics exert a high level of antibacterial activity. Nevertheless, one major issue that extremely restricts the potential application of AgNP/antiviotics is the uncontrolled release. Moreover, the lack of osteogenic ability may cause the osteosynthesis. Thus, herein we fabricated a structure-controlled drug-loaded silk fibroin (SF) coating that can achieve the size and release control of AgNPs and high efficient osteogenesis. Three comparative SF-based coatings were fabricated: α-structured coating (α-helices 32.7%,), m-structured coating (β-sheets 28.3%) and β-structured coating (β-sheets 41%). Owning to the high content of α-helices structure and small AgNPs (20 nm), α-structured coating displayed better protein adsorption and hydrophilicity, as well as pH-dependent and long-lasting antibacterial performance. In vitro studies demonstrated that α coating showed biocompatibility (cellular attachment, spreading and proliferation), high ALP expression, collagen secretion and calcium mineralization. Moreover, after one month subcutaneous implantation in vivo, α-structured coating elicited minimal, comparable inflammatory response. Additionally, in a rabbit femoral defect model, α-structured coating displayed a significant improvement on the generation of new-born bone and bonding between the new bone and the tissue, implying a rapid and durable osteointegration. Expectedly, this optimized structure-controlled SF-based coating can be an alternative and prospective solution for the current challenges in orthopedics. Statement of SignificanceIn this study, an AgNPs/Gentamycin-loaded structured-controlled silk fibroin coatings were constructed on Ti implant's surface to guarantee the success of implantation even in the face of bacterial infection. In comparison, the α-structured coating had the lowest content of β-sheets structure (19.0%) and the smallest particle size of AgNPs (~ 20 nm), and owned pH-responsive characteristic due to reversible α-helices structural. Thanks to pH-responsive release of Ag+, the α-structure coating could effectively inhibit adhesive bacteria and kill planktonic bacteria by releasing a large amount of reactive oxygen radicals. Through in vitro biological results (cell proliferation, differentiation and osteogenic gene expression) and in vivo rabbit femur implantation results, the α-structure coating had good biocompatible and osteogenic properties.

The influence of the Gemini surfactants hydrocarbon tail on in-situ synthesis of silver nanoparticles: Characterization, surface studies and biological performance

Three different Gemini compounds containing different lengths of multi-carbonyl groups were synthesized, and the effect of their hydrocarbon tail length on the AgNPs synthesis was investigated. The Gemini surfactants with the long hydrocarbon chain tail produces small AgNPs with a narrow size distribution and high colloidal stability in an aqueous phase. The surface parameters of the aqueous solution were affected by the hydrocarbon chain length as well as phase temperature. The critical micelle concentration, assessed by surface tension and conductometric measurements, decreases with both increasing solution temperature and increasing hydrocarbon tail length. Thermodynamic calculations predicted the ability of the synthesized Gemini surfactant to adsorb on the phase surface and aggregate in a cluster.

Comparative evaluation of silver nanoparticles biosynthesis by two cold-tolerant Streptomyces strains and their biological activities.

The present study reflected on high-priority biological activities of novel silver nanoparticles (AgNPs) synthesized via two cold-tolerant strains; namely, Streptomyces sp.OSIP1 and Streptomyces sp.OSNP14. These AgNPs were synthesized through a green method using culture supernatant of bacteria at 20°C and characterized by several instrumental techniques. The TEM results revealed that the NPs obtained from OSIP1 were smaller (8nm, average) than those taken from OSIP14 (15nm, average). Both AgNPs-OSP1 and AgNPs-OSNP14 also posed the strongest growth inhibitory effect against several pathogenic bacteria alone and especially in combination with antibiotics. Smaller NPs especially at 3.9-31.25µg/ml concentrations were assumed more effective biofilm inhibitors of Pseudomonas aeruginosa. Cytotoxic activity of both AgNPs (at 25 and 50µg/mL concentrations) on mouse colorectal carcinoma cells (CT26) were then studied using methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. The findings demonstrated that smaller AgNPs at a 50µg/mL concentration had 7% more cytotoxicity effects. In conclusion; although AgNPs produced by diverse strains of cold-adapted Streptomyces had close characteristics and biological activities, they showed some multifarious properties.

Generation of High Quality, Uniform and Stable Plasmonic Colorants via Laser Direct Writing

AbstractBrilliant plasmonic colors with long‐standing stability are generated via laser direct writing. This plasmonic coloring system is made of silver nanoparticles (Ag NPs) layer embedded in the quartz glass formed by ion implantation. The laser‐induced plasmonic heating merges the small Ag NPs into larger ones, which modifies the plasmon resonances. The plasmon resonances can be further tuned via changing the irradiation time and power, which shows scattering colors ranging from red to green and cyan. By scanning the laser across the Ag NPs layer, sophisticated plasmonic patterns and images with high resolution (≈105 DPI) can be obtained and preserved over long time (several months). This plasmonic coloring system via laser printing is facile, cost‐effective, accurate, and highly stable with rich hue, compared to other plasmonic color systems, which bears significant potentials for industrial applications such as optics, displays, decorations, data storage, and anti‐counterfeiting.

Graphene Oxide-Silver Nanoparticle Nanohybrids: Synthesis, Characterization, and Antimicrobial Properties.

Drug resistance of pathogenic microorganisms has become a global public health problem, which has prompted the development of new materials with antimicrobial properties. In this context, antimicrobial nanohybrids are an alternative due to their synergistic properties. In this study, we used an environmentally friendly one-step approach to synthesize graphene oxide (GO) decorated with silver nanoparticles (GO–AgNPs). By this process, spherical AgNPs of average size less than 4 nm homogeneously distributed on the surface of the partially reduced GO can be generated in the absence of any stabilizing agent, only with ascorbic acid (L-AA) as a reducing agent and AgNO3 as a metal precursor. The size of the AgNPs can be controlled by the AgNO3 concentration and temperature. Smaller AgNPs are obtained at lower concentrations of the silver precursor and lower temperatures. The antimicrobial properties of nanohybrids against Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, Gram-positive Staphylococcus aureus, and the yeast Candida albicans were found to be concentration- and time-dependent. C. albicans and S. aureus showed the highest susceptibility to GO–AgNPs. These nanohybrids can be used as nanofillers in polymer nanocomposites to develop materials with antimicrobial activity for applications in different areas, and another potential application could be cancer therapeutic agents.

Synthesis of silver nanoparticles in context of their cytotoxicity, antibacterial activities, skin penetration and application in skincare products

ABSTRACT The benefits of silver nanoparticles (AgNPs) have been known in many fields from catalysis through optics to medicine due to their unique size-dependent properties. Recently, there is also a growing interest in novel skincare formulations containing AgNPs. In this work, AgNPs were successfully synthesised and were characterised by UV-Vis spectroscopy and Transmission Electron Microscopy (TEM). In addition, an analysis of particle size distribution (measured by Dynamic Light Scattering – DLS) and zeta potential (using the method Electrophoretic Light Scattering – ELS) were made. The obtained AgNPs were in two sizes: small (20 nm ± 5 nm) and large (100 nm ± 5 nm). The assessment of the cytotoxic effect on human skin cells was done. Smaller AgNPs showed less cytotoxicity and thus greater safety for skin, so they were introduced into new skincare formulations such as oil/water (O/W) emulsion, water/oil (W/O) emulsion and hydrogel. Moreover, the study of release AgNPs from emulsions and hydrogel using Franz diffusion chamber with pig skin as a membrane has been conducted. The receptor fluid measurements were performed by Atomic Absorption Spectroscopy (AAS). The last point of the research was the performance of microbiological tests to determine the antibacterial effect of the smaller AgNPs in both solution and cosmetic.

The 3D Design of Multifunctional Silver Nanoparticle Assemblies Embedded in Dielectrics

Many applications as optical spectroscopy, photothermal therapy, photovoltaics, or photocatalysis take advantage of the localized surface plasmon resonance of noble metal nanoparticles (NPs). Among them, AgNPs are multifunctional nano‐objects that can be used not only as efficient plasmonic antennae but also as electron reservoirs for charge transfer or ion reservoirs with strong biocide activity. Herein, the 10 years’ efforts on the safe‐by‐design synthesis of multifunctional nanocomposites consisting of 3D patterns of small AgNPs embedded in dielectrics are presented by coupling low‐energy ion implantation and stencil masking techniques. Their multifunctional coupling with different objects deposited on top of the dielectric surface is also presented through three examples. The twofold role of this single plane of AgNPs as the embedded plasmonic enhancer and charge carrier reservoir is first tested on few‐layer graphene deposited in specific areas at a controlled nanometer distance from the AgNPs. These buried AgNPs are also coupled to light emitters coimplanted in the dielectric matrix in specific regions, showing light emission enhancement. Finally, these AgNPs also provide an efficient biocide activity on green algae when submerged in water, with the amount of Ag+ release simply controlled by the thickness of the silica cover layer.

Simplified synthesis of silver nanoparticles on graphene oxide and their applications in electrocatalysis

In this work the possibility of synthesizing in situ silver nanoparticles (AgNPs) on graphene oxide (GO) surfaces without commonly used additional reducing or alkalizing agents or increased temperature was investigated. Using diverse microscopic (atomic force microscopy, transmission electron microscopy) and spectroscopic methods, it was proved that very small AgNPs were formed on GO by simple incubation for 2 h in a mixture of GO dispersion and AgNO3. The prepared nanomaterial (GO_Ag) was also assessed using electrochemical methods, and it exhibited electrochemical behavior similar to the GO_Ag nanomaterial prepared with a help of citric acid as a reducing agent. Furthermore, it was found that (i) the electrochemical reduction of the GO_Ag on the electrode surface decreased the voltammetric response even though this step increased the surface conductivity and (ii) GO_Ag can be employed for the sensing of chlorides with a detection limit of 79 μM and a linear range of up to 10 mM. It could also provide an electrochemical response toward the chloroacetanilide herbicide metazachlor. Hence, the reducing capabilities of GO were proved to be applicable for in situ synthesis of metal nanoparticles with the highest possible simplification, and the as-prepared nanomaterials could be employed for fabrication of different electrochemical sensors.