Graphene Oxide-silver Nanoparticle Research Articles

Enhanced Antibacterial Activity through Silver Nanoparticles Deposited onto Carboxylated Graphene Oxide Surface.

The strong bactericidal action of silver nanoparticles (AgNPs) is usually limited by their degree of aggregation. Deposition of AgNPs onto a graphene oxide (GO) surface to generate GO-Ag hybrids has been shown to be an effective method of controlling these aggregation problems. In this sense, a novel carboxylated graphene oxide–silver nanoparticle (GOCOOH-Ag) material has been synthesized, and their antibacterial and biofilm formation inhibitions have been studied. AgNPs decorating the GOCOOH surface achieved an average size of 6.74 ± 0.25 nm, which was smaller than that of AgNPs deposited onto the GO surface. In addition, better distribution of AgNPs was achieved using carboxylated material. It is important to highlight the main role of the carboxylic groups in the nucleation and growth of the AgNPs that decorate the GO-based material surface. In vitro antibacterial activity and antibiofilm-forming action were tested against Gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli). Both GO-Ag and GOCOOH-Ag reduced bacterial growth, analyzed by time–kill curves. However, the minimum inhibitory concentration and the minimum bactericidal concentration of GOCOOH-Ag were lower than those of GO-Ag for all strains studied, indicating that GOCOOH-Ag has better antibacterial activity. In addition, both nanomaterials prevent biofilm formation, with a higher reduction of biofilm mass and cell viability in the presence of GOCOOH-Ag. The carboxylation functionalization in GO-based materials can be applied to improve the bactericidal and antibiofilm-forming action of the AgNPs.

In Situ Green Synthesis of Graphene Oxide-Silver Nanoparticles Composite with Using Gallic Acid.

The adoption of plant-derived natural products to synthesize metal nanoparticles and their complexes has the advantages of mild reaction conditions, environmental protection, sustainability and simple operation compared with traditional physical or chemical synthesis methods. Herein, silver nanoparticles (AgNPs) were in situ synthesized on the surface of graphene oxide (GO) by a “one-pot reaction” to prepare graphene oxide-silver nanoparticles composite (GO-AgNPs) based on using AgNO3 as the precursor of AgNPs and gallic acid (GA) as the reducing agent and stabilizer. The size and morphology of GO-AgNPs were characterized by ultraviolet-visible spectrophotometer (Uv-vis), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), X-ray diffractometer (XRD) and dynamic light scattering (DLS). The effects of pH, temperature, time and material ratio on the synthesis of GO-AgNPs were investigated experimentally. The results showed that ideal GO-AgNPs could be prepared under the conditions of pH = 9, 45°C, 2 h and the 2:1 of molar ratio of AgNO3 to GA. The AgNPs within GO-AgNPs are highly crystalline spherical particles with moderate density on the surface of GO, and the size of AgNPs is relatively uniform and determined to be about 8.19 ± 4.21 nm. The research results will provide new ideas and references for the green synthesis of metal nanoparticles and their complexes using plant-derived natural products as the reducing agent and stabilizer.

Nanocomposites of Graphene Oxide-Silver Nanoparticles for Enhanced Antibacterial Activity: Mechanism of Action and Medical Textiles Coating.

The resistance of microorganisms to antibiotics is a crucial problem for which the application of nanomaterials is among a growing number of solutions. The aim of the study was to create a nanocomposite (composed of graphene oxide and silver nanoparticles) with a precise mode of antibacterial action: what enables textiles to be coated in order to exhibit antibacterial properties. A characterization of nanomaterials (silver nanoparticles and graphene oxide) by size distribution, zeta potential measurements, TEM visualization and FT-IR was performed. The biological studies of the nanocomposite and its components included the toxicity effect toward two pathogenic bacteria species, namely Pseudomonas aeruginosa and Staphylococcus aureus, interaction of nanomaterials with the outer layer of microorganisms, and the generation of reactive oxygen species and lipid peroxidation. Afterwards, antibacterial studies of the nanocomposite’s coated textiles (cotton, interlining fabric, polypropylene and silk) as well as studies of the general toxicity towards a chicken embryo chorioallantoic membrane model were conducted. The toxicity of the nanocomposite used was higher than its components applied separately (zones of growth inhibition for P. aeruginosa for the final selected concentrations were as follows: silver nanoparticles 21 ± 0.7 mm, graphene oxide 14 ± 1.9 mm and nanocomposite 23 ± 1.6 mm; and for S. aureus were: silver nanoparticles 27 ± 3.8 mm, graphene oxide 14 ± 2.1 mm, and nanocomposite 28 ± 0.4 mm. The viability of P. aeruginosa and S. aureus after treatment with selected GO-Ag decreased to 27% and 31%, respectively, compared to AgNPs, when the viability of both species was 31% and 34%, accordingly). The coated textiles showed encouraging antibacterial features without general toxicity towards the chicken embryo chorioallantoic membrane model. We demonstrated that graphene oxide might constitute a functional platform for silver nanoparticles, improving the antibacterial properties of bare silver. Due to the application of the nanocomposite, the textiles showed promising antibacterial features with a low general toxicity, thereby creating a wide possibility for them to be used in practice.

Surface Modification of Commercial Cotton Yarn as Electrode for Construction of Flexible Fiber-Shaped Supercapacitor

In this study, we report on the rational design and facile preparation of a cotton-reduced graphene oxide-silver nanoparticle (cotton-RGO-AgNP) hybrid fiber as an electrode for the building of a flexible fiber-shaped supercapacitor (FSSC). It was adequately characterized and found to possess a well-defined core−shell structure with cotton yarn as a core and a porous RGO-AgNP coating as a shell. Thanks to the unique morphological features and low electrical resistance (only 2.3 Ω·cm−1), it displayed attractive supercapacitive properties. When evaluated in a three-electrode setup, this FSSC electrode delivered the highest linear and volumetric specific capacitance of up to ca. 12.09 mF·cm−1 and ca. 9.67 F·cm−3 with a satisfactory rate capability as well as a decent cycling stability. On the other hand, an individual parallel symmetric FSSC cell constructed by this composite fiber fulfilled the largest linear and volumetric specific capacitance of ca. 1.67 mF·cm−1 and ca. 0.67 F·cm−3 and offered the maximum energy density, as high as ca. 93.1 μWh·cm−3, which outperformed a great number of graphene- and textile yarn-based FSSCs. Impressively, bending deformation brought about quite a limited effect on its electrochemical behaviors and almost no capacitance degradation took place during the consecutive charge/discharge test for over 10,000 cycles. Consequently, these remarkable performances suggest that the currently developed cotton-RGO-AgNP fiber has considerable application potential in flexible, portable and wearable electronics.

Colorimetric and “turn-on” fluorescence detection of saccharin using silver nanoparticles-graphene oxide composite

Saccharin (SAC) is a synthetic sweetener used in soft drinks and candies. Consumption of excess SAC leads to several health problems. Therefore, developing a simple method to detect its concentration in food stuffs and soft drinks is very important. The present study describes a simple colorimetric method for SAC determination using graphene oxide-silver nanoparticles (GO-AgNPs) composite solution. The yellow color GO-AgNPs was changed to reddish brown while adding 600 μM SAC and the emission of GO was “turn off” after the formation of AgNPs. However, the emission was “turn on” after the addition of SAC. This was ascribed to the strong interaction between sulfonamide groups of SAC with AgNPs, resulting the leaching of AgNPs from GO surface. The emission intensity increases linearly when SAC concentration increases from 500 nM to 1 mM with R2 = 0.9971 and the limit of detection was 0.7 mg L−1 (S/N = 3). The present GO-AgNPs composite was also used to selectively determine SAC containing 1400-fold higher concentration of interferents. Finally, the real sample analysis was carried out by determining SAC in candies and soft drinks by using GO-AgNPs.

A novel electrochemical immunosensor for the sensitive detection of tiamulin based on staphylococcal protein A and silver nanoparticle-graphene oxide nanocomposites

Tiamulin (TML) is a pleuromutilin antibiotic and mainly used to treat pulmonary and gastrointestinal infections. However, excessive use of TML can bring health threats to consumers. In this work, a label-free electrochemical immunosensor was proposed for sensitive detection of TML in pork and pork liver. Silver nanoparticles (AgNPs) were synthesized in situ on graphene oxide (GO), in which GO acted as a carrier for loading more AgNPs and AgNPs exhibited both strong conductivity and good redox property. In addition, staphylococcal protein A (SPA) was applied to oriented immobilization of fragment crystallizable (Fc) region of the TML monoclonal antibody. Under the optimal condition, the developed electrochemical immunosensor exhibited a good linear response with a concentration of TML ranging from 0.05 ng mL−1 to 100 ng mL−1 and the limit of detection (LOD) was 0.04 ng mL−1. Furthermore, the designed immunosensor was applied to detect TML in real samples with a good accuracy. Therefore, the label-free electrochemical immunosensor could be used as a potential method to detect TML and other antibiotic residues in animal derived foods.

Silver-Graphene Oxide Nanohybrids for Highly Sensitive, Stable SERS Platforms.

Graphene oxide–silver nanoparticle nanohybrids were synthesized by simple reduction of the silver nitrate and graphene oxide (GO) mixture in water using the mild reducing agent ascorbic acid. The concentration of ascorbic acid was varied to verify the possible influence of the GO surface composition on the efficiency of the hybrid material as substrates for surface enhanced Raman spectroscopy (SERS). Furthermore, the composites were conditioned in ammonia solution or in potassium hydroxide diluted solution. For comparison, the graphene oxide–silver nanoparticle composite has been synthesized using the ammonia-treated GO. All materials were characterized using spectroscopic and microscopic methods including UV–Vis, infrared, and Raman spectroscopy and scanning electron microscopy. The SERS efficiency of the nanohybrids was tested using 4-aminothiophenol (PATP). The optimal synthesis conditions were found. Ammonia and potassium peroxide drop-casted on the composite changed the SERS properties. The sample treated with KOH showed the best SERS enhancement. The variation of the SERS enhancement was correlated with the shape of the UV–Vis characteristics and the surface structure of the composites.

Graphene Oxide-Silver Nanoparticle Nanocomposites Induce Oxidative Stress and Aberrant Methylation in Caprine Fetal Fibroblast Cells.

Graphene oxide–silver nanoparticle (GO-AgNPs) nanocomposites have drawn much attention for their potential in biomedical uses. However, the potential toxicity of GO-AgNPs in animals and humans remains unknown, particularly in the developing fetus. Here, we reported the GO-AgNP-mediated cytotoxicity and epigenetic alteration status in caprine fetal fibroblast cells (CFFCs). In brief, the proliferation and apoptosis rate of GO-AgNP-treated CFFCs (4 and 8 µg/mL of GO-AgNPs) were measured using the cell-counting kit (CCK-8) assay and the annexin V/propidium iodide (PI) assay, respectively. In addition, the oxidative stress induced by GO-AgNPs and detailed mechanisms were studied by evaluating the generation of reactive oxygen species (ROS), superoxide dismutase (SOD), lactate dehydrogenase (LDH), malondialdehyde (MDA), and caspase-3 and abnormal methylation. The expression of pro- and anti-apoptotic genes and DNA methyltransferases was measured using reverse transcription followed by RT-qPCR. Our data indicated that GO-AgNPs cause cytotoxicity in a dose-dependent manner. GO-AgNPs induced significant cytotoxicity by the loss of cell viability, production of ROS, increasing leakage of LDH and level of MDA, increasing expression of pro-apoptotic genes, and decreasing expression of anti-apoptotic genes. GO-AgNPs incited DNA hypomethylation and the decreased expression of DNMT3A. Taken together, this study showed that GO-AgNPs increase the generation of ROS and cause apoptosis and DNA hypomethylation in CFFCs. Therefore, the potential applications of GO-AgNPs in biomedicine should be re-evaluated.

The interaction of graphene oxide-silver nanoparticles with trypsin: Insights from adsorption behaviors, conformational structure and enzymatic activity investigations

In this work, we synthesized graphene oxide-silver nanoparticles (GO-AgNPs) hybrids by one-pot method. Since there are relatively few reports on whether GO-AgNPs bind and change the structure and function of trypsin, A variety of methods were employed to systematically characterize the molecular interaction between GO-AgNPs and trypsin. Results exhibited that GO-AgNPs bound with trypsin to form a ground state complex. GO-AgNPs had higher adsorption capacity for trypsin compared with single GO. Langmuir-Blodgett assembly method was used to confirm that AgNPs did not interfere with the adsorption of trypsin by GO. The secondary structure and the microenvironment of amino acid residues of trypsin were altered after interacting with GO-AgNPs. In addition, GO-AgNPs can enhance the activity of trypsin and promote the hydrolysis of bovine serum protein (BSA) by trypsin. These findings provide important support for the application of GO-based nanocomposites in the efficient immobilization of enzymes.

Enhanced Optical and Electrical Properties of Graphene Oxide-Silver Nanoparticles Nanocomposite Film by Thermal Annealing in the Air

Enhanced Optical and Electrical Properties of Graphene Oxide-Silver Nanoparticles Nanocomposite Film by Thermal Annealing in the Air

Preparation and properties of conductive bacterial cellulose-based graphene oxide-silver nanoparticles antibacterial dressing

It is difficult to obtain stable multifunctional silver-containing materials that are suitable for use as wound dressings. To solve this problem, we added graphene oxide (GO) to an acetobacter culture medium and used a biological blending self-growth method to fix GO onto the bacterial cellulose to form a mixed-growth film. We then used polydopamine to fix AgNPs to obtain a novel silver-based cellulose wound dressing. This composite material was characterized by infrared spectroscopy, electron microscopy, and X-ray diffractometry, and the results showed that silver nanoparticles uniformly covered the material surface, while graphene was wrapped in a layer of bacterial cellulose. This composite film was conductive and produced a weak current, and it generated heat when a voltage was applied. This allowed it to accelerate wound cell migration and promote wound healing. In addition, AgNPs immobilized on the surface released Ag+, which generated a large number of oxidizing free radicals that killed and bacteria. The in vitro cytotoxicity tests showed that the Ag-pDA/BC (rGO) composite film has excellent biocompatibility, giving it good application prospects for wound dressings.

Facile sonochemical synthesis of silver nanoparticle and graphene oxide deposition on bismuth doped manganese oxide nanotube composites for electro-catalytic sensor and oxygen reduction reaction (ORR) applications

Pristine silver nanoparticles and silver-graphene oxide nanoparticles have incorporated in Bismuth doped manganese oxide (Bi-MnOx) nanotubes by an ultra-sonication deposition method. Pristine Bismuth doped porous MnO2 has prepared by a non-ionic surfactant (Triton-X-100) assisted co-precipitation and heat treatment process. In the second stage, the biogenic method prepared very fine Ag nanoparticles with a quantum dot size of particles (below 10 nm). They have further deposited on the dried powder of Bi-MnOx by ultra-sonication fabricate the composite material for electrode application. The pure nanotube formation obtained for silver nanoparticle deposited Bi-MnOx (Ag-BiMnOx) and silver/GO nanoparticle(Ag-BiMnOx/GO) nanocomposites have clearly confirmed by high resolution transmission electron micrographs (HR-TEM). The nanotube diameter obtained in the range of 10–25 nm and length of nanotube obtained in the rage of 40–50 nm. Enhanced thermal stability has achieved for Ag-BiMnOx and Ag-BiMnOx/GO composite compared to pristine manganese oxide. Band gap values of prepared compoiste is calculated from Diffuse reflectance spectral data provide the bandgap values of Ag–Bi-MnOx/GO (1.93 eV) and Bi-MnOx (2.47 eV). As prepared graphene oxide modified Bi-MnOx composite modified electrode have further analyzed for hydrogen peroxide sensor and Oxygen reduction reactions (ORR). Silver nanoparticle-graphene oxide modified Bi-MnOx composite shows an enhanced electrochemical capacitance activity of 2.61 mF and improved electrochemical surface area of 65.25 cm2 towards clean energy technology application.

Graphene oxide-silver nanoparticle hybrid material: an integrated nanosafety study in zebrafish embryos

This work reports an integrated nanosafety study including the synthesis and characterization of the graphene oxide-silver nanoparticle hybrid material (GO-AgNPs) and its nano-ecotoxicity evaluation in the zebrafish embryo model. The influences of natural organic matter (NOM) and a chorion embryo membrane were considered in this study, looking towards more environmentally realistic scenarios and standardized nanotoxicity testing. The nanohybrid was successfully synthesized using the NaBH4 aqueous method, and AgNPs (~ 5.8 nm) were evenly distributed over the GO surface. GO-AgNPs showed a dose-response acute toxicity: the LC50 was 1.5 mg L-1 for chorionated embryos. The removal of chorion, however, increased this toxic effect by 50%. Furthermore, the presence of NOM mitigated mortality, and LC50 for GO-AgNPs changed respectively from 2.3 to 1.2 mg L-1 for chorionated and de-chorionated embryos. Raman spectroscopy confirmed the ingestion of GO by embryos; but without displaying acute toxicity up to 100 mg L-1, indicating that the silver drove toxicity down. Additionally, it was observed that silver nanoparticle dissolution has a minimal effect on these observed toxicity results. Finally, understanding the influence of chorion membranes and NOM is a critical step towards the standardization of testing for zebrafish embryo toxicity in safety assessments and regulatory issues.

Modification of polyvinylidene fluoride membrane by silver nanoparticles-graphene oxide hybrid nanosheet for effective membrane biofouling mitigation

Membrane biofouling poses severe impacts on the membrane lifespan and performance. In this study, a silver nanoparticles-graphene oxide hybrid nanosheet (AgNPs-GO) was synthesized as a bactericidal agent for effective membrane biofouling mitigation. The surface polymerization between polyvinyl alcohol (PVA) and AgNPs-GO nanosheet improved the stability of inorganic biocidal materials on the membrane surface and had a significant effect on the permeability and rejection performance of membranes. The PVA/AgNPs-GO modified hydrophilic polyvinylidene fluoride (H-PVDF) membrane exhibited an excellent anti-microbial activity in both static contact and filtration modes; nearly 100% inactivation of Pseudomonas aeruginosa in solution and 91% reduction in the membrane surface adhesion were found. The composite membrane with good stability and anti-microbial ability may offer an alternative to alleviate membrane biofouling problem.

Eco-friendly synthesis of graphene oxide–silver nanoparticles hybrids: The effect of amine derivatization

We addressed the deposition of silver nanoparticles (Ag NPs) onto graphene oxide (GO) in the form of powder and paper (GOP), functionalized with amines and non-functionalized, for comparison. The functionalized supports were fabricated by means of solvent-free treatment with two aliphatic amines: 1-octadecylamine (ODA) and 1,8-diaminooctane (DAO). Ag NPs were generated in situ by using silver nitrate as a precursor and citric acid as a non-toxic and eco-friendly reducing agent. Characterization of chemical composition of GO-Ag hybrids was done by Fourier-transform infrared, X-ray photoelectron and energy dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetric and differential thermal analysis. The morphology was studied by scanning and transmission electron microscopy. In addition, we compared electrical conductivity of GOP before and after functionalization with amines and decoration with Ag particles. While considerable particle agglomeration was observed on pristine GOP and GO powder, the prior amine functionalization gave rise to more controlled formation of Ag NPs in terms of size and distribution, with the best results obtained on 1,8-diaminooctane-functionalized supports. According to the results of DFT calculations, Ag NP binding is the strongest on pristine GO, followed by ODA and finally DAO-functionalized material, which correlates with the size and distribution of Ag nanoparticles observed experimentally.

An ultra-sensitive and selective AChE based colorimetric detection of malathion using silver nanoparticle-graphene oxide (Ag-GO) nanocomposite

Herein, we propose rapid, precise acetylcholinesterase (AChE) inhibition-based sensing strategy for malathion detection in the presence of Ag-GO and acetylthiocholine (ATCh). The biosensing method was developed with a nanocomposite of citrate stabilized AgNPs anchored on the GO sheets (Ag-GO). The physical and chemical properties of the prepared Ag-GO composite were analyzed with various characterization techniques, including XRD, FT-IR, XPS, UV–Visible spectroscopy, and HR-TEM. The positively charged thiocholine (TCh) produced by enzyme hydrolysis triggers the AgNPs aggregation on GO sheets, which ultimately decreases the intensity of the corresponding SPR absorption peak. While the addition of malathion into the sensing system hindered the AChE activity and limited the TCh production, and thus inhibits the decrease in the SPR band intensity. The designed sensing system displayed linearity in the broad range of malathion concentrations (0.01 pM–1000 pM) with a limit of detection and the limit of quantification values of 0.01 pM, and 0.035 pM, respectively. The application of the designed biosensing system was extended to determine the malathion in actual samples namely, tap water, agricultural runoff water, lake water, and grape extract, which resulted in almost 100% recovery rates in all the spiked samples.

A novel ionic liquid based electrochemical sensor for detection of pyrazinamide

In this work, we report electrochemical detection of pyrazinamide at the surface of a glassy carbon electrode fabricated with a sensing nanocomposite comprising silver nanoparticles, 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim][BF4]) ionic liquid, and reduced graphene oxide. The electrochemical reaction of the pyrazinamide at the fabricated electrode was measured using cyclic and differential pulse voltammetric methods. Ionic liquid-reduced graphene oxide-silver nanoparticles were successfully synthesized and characterized by transmission electron microscope and Fourier transform infrared spectroscopy, respectively. The synthesized silver nanoparticles were spherical in shape with an average size of ~ 30 nm. The fabricated electrode exhibits excellent electrocatalytic utility with favourable electrochemical parameters for the reduction of pyrazinamide in acidic media, with optimized pH of 6.0 at an operational potential of − 0.82 V (vs. SCE). The transmission electron microscopy results for the fabricated surfaces demonstrated the formation of nanoscale structures, representing successful electrodeposition and electro-polymerization processes to modify the glassy carbon electrode surface. Moreover, these results showed a linear electrochemical response to pyrazinamide within the concentration in the interval ranging from 3 to 24 µM, with the detection limit and limit of quantification of 0.0102 µM and 0.3658 µM. The fabricated sensor proved high selectivity and sensitivity for pyrazinamide, which made it possible to determine pyrazinamide in pharmaceutical formulations. Schematic illustration of the steps involved in the preparation of ionic liquid-reduced graphene oxide-silver nanoparticles-glassy carbon electrode for the electrochemical detection of pyrazinamide.

Reduced Graphene Oxide-Silver Nanoparticles for Optical Pulse Generation in Ytterbium- and Erbium-Doped Fiber Lasers

This work has demonstrated the potential of a reduced graphene oxide silver/polyvinyl alcohol (rGO-Ag/PVA) film as a saturable absorber (SA) in ytterbium and erbium based Q-switched optical fiber lasers. The facile hydrothermal method was used to synthesize the nanocomposite between rGO and Ag nanoparticles. This was followed by a simple solution method to form the rGO-Ag film using PVA as the host polymer. From nonlinear absorption characterization, the rGO-Ag/PVA SA was determined to have a modulation depth of 30%, a nonsaturable loss of 70%, and a saturable intensity of 0.63 kW/cm2. Stable self-starting Q-switched pulses were obtained at the threshold pump power of 72.76 mW and 18.63 mW in the ytterbium-doped (YDFL) and erbium-doped fiber laser (EDFL) cavities respectively. The center operating wavelengths were observed at 1044.4 nm and 1560 nm for the two cavities. The shortest pulse width and maximum repetition rate of the YDFL and EDFL were 1.10 µs and 62.10 kHz and 1.38 µs and 76.63 kHz respectively. This work has demonstrated that the rGO-Ag/PVA film is suitable as an SA for pulse generation in the 1.0 and 1.5 μm regions and would have many potential photonics applications.

Synthesis, Physical, Mechanical and Antibacterial Properties of Nanocomposites Based on Poly(vinyl alcohol)/Graphene Oxide-Silver Nanoparticles.

The design of new materials with antimicrobial properties has emerged in response to the need for preventing and controlling the growth of pathogenic microorganisms without the use of antibiotics. In this study, partially reduced graphene oxide decorated with silver nanoparticles (GO–AgNPs) was incorporated as a reinforcing filler with antibacterial properties to poly(vinyl alcohol) (PVA) for preparation of poly(vinyl alcohol)/graphene oxide-silver nanoparticles nanocomposites (PVA/GO–AgNPs). AgNPs, spherical in shape and with an average size of 3.1 nm, were uniformly anchored on the partially reduced GO surface. PVA/GO–AgNPs nanocomposites showed exfoliated structures with improved thermal stability, tensile properties and water resistance compared to neat PVA. The glass transition and crystallization temperatures of the polymer matrix increased with the incorporation of the hybrid. The nanocomposites displayed antibacterial activity against Staphylococcus aureus and Escherichia coli in a filler content- and time-dependent manner. S. aureus showed higher susceptibility to PVA/GO–AgNPs films than E. coli. Inhibitory activity was higher when bacterial cells were in contact with nanocomposite films than when in contact with leachates coming out of the films. GO–AgNPs based PVA nanocomposites could find application as wound dressings for wound healing and infection prevention.

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.