Silver Nanocomposites Research Articles

Synthesis approach-dependent antiviral properties of silver nanoparticles and nanocomposites.

Numerous viral infections are common among humans, and some can lead to death. Even though conventional antiviral agents are beneficial in eliminating viral infections, they may lead to side effects or physiological toxicity. Silver nanoparticles and nanocomposites have been demonstrated to possess inhibitory properties against several pathogenic microbes, including archaea, bacteria, fungi, algae, and viruses. Its pronounced antimicrobial activity against various microbe-mediated diseases potentiates its use in combating viral infections. Notably, the appropriated selection of the synthesis method to fabricate silver nanoparticles is a major factor for consideration as it directly impacts antiviral efficacy, level of toxicity, scalability, and environmental sustainability. Thus, this article presents and discusses various synthesis approaches to produce silver nanoparticles and nanocomposites, providing technological insights into selecting approaches to generate antiviral silver-based nanoparticles. The antiviral mechanism of various formulations of silver nanoparticles and the evaluation of its propensity to combat specific viral infections as a potential antiviral agent are also discussed.Graphical abstract

Silver-titanium polymeric nanocomposite non ecotoxic with bactericide activity.

In view of the intense interest in applications of silver nanoparticles in products for the medical field and in food preservation packaging due to their antimicrobial properties, the ecotoxicology of silver nanocomposites was evaluated in films. Test with the sea urchin Echinometra lucunter, to evaluate embryonic development and contamination by the action of silver and titanium nanoparticles in polyethylene nanocomposite films presents new results. The silver nanoparticle’s stability in polymeric materials can be enhanced by adding carriers, such as titanium dioxide and montmorillonite clay (MMT) without to producing one unfriendly material. For this research, low-density polyethylene (LDPE)/linear low-density polyethylene (LLDPE) were used processed in a twin-screw extruder, followed by gamma irradiation with 25 kGy and characterized by ecotoxicology assays, field emission scanning electron microscopy (FESEM), scanning electron microscopy and energy dispersive spectroscopy (SEM–EDX), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), Raman spectroscopy (SERS) and mechanical properties. The antibacterial properties of the LDPE films were investigated against Escherichia coli and Staphylococcus aureus. The gamma irradiation had an important effect in the synthesis of silver nanoparticles resulting in bactericidal activity and the death of 100% of the tested bacteria. The evaluation of the environment was considered with the ecotoxicological investigation carried out. The results indicated that the polymeric films with silver nanoparticles and TiO2 do not contaminate the environment and neither interfere with the larval development of Echinometra lucunter. The obtained materials can be used in various applications with antimicrobial properties.Graphical

Antibacterial and in vivo studies of poly(ɛ-caprolactone)-silver electrospun nanofibers: effect of preparation methods on the properties

Poly(ɛ-caprolactone)-silver nanocomposite were prepared by two main methods of metal-polymer nanocomposite preparation approaches, in situ and ex situ methods, by electrospinning. Effective parameters on electrospun nanofibers were optimized by Design Expert, CCD method. Using in situ and ex situ methods, effect of incorporating silver nanoparticle into Poly(ɛ-caprolactone) on conductivity, average fiber diameter, morphology of nanofiber mats and antibacterial properties were investigated. According to Field Emission Scanning Electron Microscopy (FESEM) and Energy-Dispersive X-ray Spectroscopy (EDX) analysis, average fibers diameters decreased by increasing incorporated Ag nanoparticles. Conductivity results confirmed the higher content of silver nanoparticles in in situ samples. Antibacterial test was performed against two bacteria types: Staphylococcus-aureus and Escherichia-coli. Due to higher content and smaller size of Ag nanoparticles incorporated in nanofibers, silver-loaded PCL electrospun nanofibers obtained by in situ method showed higher antibacterial efficiency in comparison to the ex situ samples. Moreover, Ag particles had more effects on Staphylococcus aureus due to sensitive membrane of this type of bacteria. In vivo study has proved that in situ samples improved the wounds on Wistar rat lateral part of body skin. Antibacterial and in vivo results showed that PCL-Ag nanofiber mats obtained by in situ method are suitable for medical applications.

3D Modeling of Silver Doped ZrO2 Coupled Graphene-Based Mesoporous Silica Quaternary Nanocomposite for a Nonenzymatic Glucose Sensing Effects.

We described the novel nanocomposite of silver doped ZrO2 combined graphene-based mesoporous silica (ZrO2-Ag-G-SiO2,) in bases of low-cost and self-assembly strategy. Synthesized ZrO2-Ag-G-SiO2 were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, Nitrogen adsorption-desorption isotherms, X-ray photoelectron spectroscopy (XPS), and Diffuse Reflectance Spectroscopy (DRS). The ZrO2-Ag-G-SiO2 as an enzyme-free glucose sensor active material toward coordinate electro-oxidation of glucose was considered through cyclic voltammetry in significant electrolytes, such as phosphate buffer (PBS) at pH 7.4 and commercial urine. Utilizing ZrO2-Ag-G-SiO2, glucose detecting may well be finished with effective electrocatalytic performance toward organically important concentrations with the current reaction of 9.0 × 10−3 mAcm−2 and 0.05 mmol/L at the lowest potential of +0.2 V, thus fulfilling the elemental prerequisites for glucose detecting within the urine. Likewise, the ZrO2-Ag-G-SiO2 electrode can be worked for glucose detecting within the interferometer substances (e.g., ascorbic corrosive, lactose, fructose, and starch) in urine at proper pH conditions. Our results highlight the potential usages for qualitative and quantitative electrochemical investigation of glucose through the ZrO2-Ag-G-SiO2 sensor for glucose detecting within the urine concentration.

Non‐Enzymatic Electrochemical Biosensing of Glucose Using Nanocomposites of Polyaniline Nanofibers and Silver

AbstractIn this study silver nanoparticles were dispersed over polyaniline nanofibers (nPANI) by simple chemical reduction of silver nitrate in the presence of nPANI, and the prepared nPANI/Ag nanocomposite was employed for sensitive and cost‐effective non‐enzymatic detection of glucose using a modified carbon paste electrode. Detailed structural, crystallographic and morphological characterization of nPANI/Ag was carried out by means of Fourier‐transform infrared spectroscopy, X‐ray diffractometry and scanning electron microscopy. The enhancement of charge transfer of nPANI upon incorporation of Ag nanoparticles was confirmed by electrochemical impedance spectroscopy, and the electrocatalytic efficacy of the nPANI/Ag nanocomposite towards oxidation of glucose in alkaline medium was proven by cyclic voltammetry. Crucially, chronoamperometry demonstrated a linear response of the nPANI/Ag‐based glucose sensor over a wide range of glucose concentrations from 100 μM to 10 mM with a lowest detection limit of 1,3 μM. The sensor had a good selectivity for glucose in the presence of common interfering biomolecules. The sensor also had a shelf‐life of several days and the response was repeatable for up to nine individual measurements.

НАНОКОМПОЗИТИ СРІБЛА НА ОСНОВІ СИНТЕТИЧНИХ ГУМІНОВИХ РЕЧОВИН ЯК ВИСОКОЕФЕКТИВНІ СТИМУЛЯТОРИ РОСТУ РОСЛИ

Introduction. Nanotechnology have positive impact in improving many sectors of economy including agriculture. Silver nanoparticles (AgNPs) have been implicated nowadays to enhance seed germination, plant growth, improvement of photosynthetic quantum efficiency and as antimicrobial agents to manage plant diseases.Despite the known growth-stimulating activity of preparations of humic substances and silver nanoparticles, there is currently no information on the effect on growth processes of composites containing silver nanoparticles encapsulated in macromolecules from synthetic humic substances. It is expected that such combined nanopreparations have enhanced and complementary properties of a metal core and a shell of humic synthetic substances.Purpose. The aim of this study was to investigate the growth-stimulating activity of silver nanocomposites based on synthetic humic substances derived from quercetin, and to determine the range of active concentrations in the process of germination of wheat seeds.Methods. The received silver nanoparticles are characterized by UV–visible spectroscopy, X-ray diffraction (XRD), FT-IR spectroscopy and transmission electron microscopy (TEM). To study the growth-stimulating activity of synthetic humic substances and silver nanocomposites, a series of solutions was prepared on their basis by dilution with a logarithmic decrease in concentration from 1·10–1 to 4·10-16%.Result. Nanobiocomposites containing silver nanoparticles and synthetic humic substances were synthesized in the reaction of reduction of silver ions with synthetic humic substances obtained in laboratory conditions from quercetin.Preference of synthetic humic substances over natural humic substances is determined by a standardization problem resolution due to the strict control of conditions of the HS formation that expands the areas of application of the silver nanoparticles made on their basis. The high crystallinity of nanobiocomposites with fcc phase is evident from XRD patterns. The TEM results show that the silver nanoparticles are spherical in shape with average size about 9.6 nm. The FTIR spectroscopic study confirmed that the synthetic humic substances have ability to perform dual functions of reduction and stabilization of silver nanoparticles.The growth-promoting activity of synthetic humic substances and silver nanocomposites based on them was studied on the example of germination of wheat seeds of the variety "Zolotokosa" according to standard procedures. It is established that aqueous solutions of synthetic humic substances and silver 54 Серія «Біологічні науки», 202 2nanocomposites based on them in a wide range of concentrations have a complex effect on the growth and development of wheat seeds. It is shown that seed germination increases (by 2–40%) and the length of the main root (by 9–100%) of wheat germ increases. It should be noted that synthetic humic substances and silver nanocomposites based on them to a greater extent stimulate root growth, which is important for agriculture in arid areas. The ranges of effective concentrations of solutions of the studied drugs show the maximum total stimulating activity (by the number of germinated seeds and the length of the main root compared to the control) during germination of wheat seeds for synthetic humic substances and for silver nanocomposite - 10-10-10-4%. Stimulation of root growth by silver nanocomposites based on synthetic humic substances in most concentrations exceeds the effect of the original humic substances.Originality. The established activity of synthetic humic substances and silver nanocomposites based on them is a prerequisite for the further development of highly effective growth-stimulating preparations of a new generation.Conclusion. It has been established that silver nanocomposites based on synthetic humic substances exhibit highly effective growth-stimulating activity. The ranges of active concentrations of the studied preparations demonstrate the optimal stimulating activity for synthetic humic substances and silver nanocomposite based on them by the number of germinated seeds 1·10–10–1·10–4 %, by the length of the main roots compared to the control - 1· 10-12-1· 10-4%. The established activity of synthetic humic substances and silver nanocomposites based on them is a prerequisite for the further development of highly effective growth-stimulating preparations of a new generation.Key words: synthetic humic substances; silver nanocomposites; growth-promoting activity; wheat

Microwave-promoted continuous flow synthesis of thermoplastic polyurethane–silver nanocomposites and their antimicrobial performance

The present study reports a reducing agent-free continuous manufacturing of ∼5 nm silver nanoparticles in a thermoplastic polyurethane matrix using a microwave-promoted fluidic system.

Bifunctional manganese oxide–silver nanocomposites anchored on graphitic mesoporous carbon to promote oxygen reduction and inhibit cathodic biofilm growth for long-term operation of microbial fuel cells fed with sewage

Manganese oxide–silver nanocomposites anchored on graphitic mesoporous carbon were synthesized for enhancing oxygen reduction and inhibiting cathodic biofilm growth for the long-term operation of microbial fuel cells.

The effects of metal concentration and annealing temperature on the optical properties of silver nanocomposite

The optical properties of silver-silica nanocomposites (NCs) are studied at various annealing temperatures for two different silver concentrations. The NC thin films are prepared using co-sputtering of silver and silica using an energetic neutralized Ar beam, which are further annealed at various temperatures upto 900 °C under flowing Ar gas. Rutherford Backscattering Spectrometry is carried out to estimate the thickness of films and relative concentration of silver in the silica matrix. The Transmission Electron Microscope (TEM) images of the NC thin films show the presence of nano-particles (NP) in the as deposited thin films, which grow in size when annealed at 400 °C. The selected area diffraction (SAED) pattern and spacing between the lattice fringes confirm the presence of Ag NPs inside silica matrix. UV–Visible absorption spectroscopy is performed to investigate the optical absorption due to Localized Surface Plasmon Resonance of these Ag NP surrounded by silica matrix. The results indicate that the resonance peak position redshifts and the width of the peaks decreases with increasing annealing temperature for both concentrations. These results attribute to the growth of NPs due to diffusion-based growth and Ostwald ripening in different annealing regimes. The role of metal concentration in NC on the growth of NPs upon various annealing temperatures is discussed based on optical absorption results.

A highly sensitive colorimetric sensing platform based on silver nanocomposites for alkaline phosphatase.

Alkaline phosphatase (ALP) plays significant roles in regulating intracellular processes and is an important biomarker connected to several diseases. In this work, one facile and sensitive sensing platform based on CQD-silver nanocomposites (CQD-silver NPs) for colorimetric detection of alkaline phosphatase (ALP) was introduced. ALP triggers the removal of the phosphate group of ascorbic acid 2-phosphate (AA2P), which is then transformed into ascorbic acid (AA). The as-obtained AA can easily cause significant aggregation of monodispersed NPs and cause the system color to turn from bright yellow to gray. Based on the color change of the ratio of 490 nm/630 nm, ALP was sensitively and selectively detected. Under the optimum, the established method showed linearity for ALP in the range of 0.1-50 U L-1 and the detection limit was low at 0.035 U L-1, and it was subjected to ALP inhibitor screening from goji berry extract. These results indicated that the colorimetric system can be used as a simple tool for visual and fast evaluation of ALP activity as well as providing an alternative to screen ALP inhibitors.

Correction: Bifunctional manganese oxide–silver nanocomposites anchored on graphitic mesoporous carbon to promote oxygen reduction and inhibit cathodic biofilm growth for long-term operation of microbial fuel cells fed with sewage

Correction for ‘Bifunctional manganese oxide–silver nanocomposites anchored on graphitic mesoporous carbon to promote oxygen reduction and inhibit cathodic biofilm growth for long-term operation of microbial fuel cells fed with sewage’ by Dena Z. Khater et al., Sustainable Energy Fuels, 2022, DOI: 10.1039/d1se01479j.

Zirconium Oxide Supported Silver Nanocomposites: Synthesis, Characterization and in Vitro Evaluation of Anticancer, Antioxidant, Antibacterial Applications

Zirconium Oxide Supported Silver Nanocomposites: Synthesis, Characterization and in Vitro Evaluation of Anticancer, Antioxidant, Antibacterial Applications

Highly Efficient Catalytic Performances of Polyvinyl Alcohol/ Silver Nanocomposites Synthesized Through Gamma Irradiation for Nitro Aromatic Compound Reduction

Highly Efficient Catalytic Performances of Polyvinyl Alcohol/ Silver Nanocomposites Synthesized Through Gamma Irradiation for Nitro Aromatic Compound Reduction

Analysis of Chitosan‐Based Nanosilver Composites for the Repair of Umbilical Cord Wounds in Newborns

The study aim reports a new umbilical cord wound repair material based on modified chitosan‐based nanosilver (CS‐HDH/Ag NPs). The repair of umbilical cord wound has always been the focus of neonatal departments. The study method chitosan, which is famous for its “biological glue,” is used as a modifier to compound silver nanoparticles with strong coordination and adsorption capacity of chitosan. It is worth noting that CS‐HDH/Ag NPs has a significant inhibitory effect on common bacterial infection and reduces the incidence of umbilical cord wound inflammation. The study problem wound bleeding and stump shedding and other factors make the periumbilical cord vulnerable to bacterial infection. For study results, the porous and lamellar structure endows the repair material with breathable properties and excellent antiadhesion, which greatly reduces the number of dressing changes and effectively protects the skin of newborns. CS‐HDH/Ag NPs provides a new model for efficient neonatal health management.

Application of Carbon Nanocomposite Sensing and Functional Magnetic Nanomaterial in the Sports Industry and Its Biosecurity Research

Nanomaterial science is a particularly important research field in modern science and technology, which has attracted wide attention and research from all walks of life since its inception and has formed a relatively perfect category of science and technology. The purpose of this paper is to explore the application of carbon nanocomposite sensing and functional magnetic nanomaterial in the sports industry and their biosecurity research. This paper first discusses the research progress of nanocomposite in biosecurity and concludes that chemical modification can reduce the negative biological effects of nanomaterial, then puts forward the research methods on nanocomposite in the sports industry, and then selects nanosilver composites to explore and study the effects of different particle sizes and concentrations on the antibacterial properties of Aspergillus and test and characterize the properties of nanocomposite. The stability of nanocomposite modification electrodes is also explored. The results show that nanosilver has excellent bactericidal effects on both AF293 and Gra04. In particular, 8.08 × 10−5 mol/L and 4.03 × 10−5 mol/L nanosilver has a bacteriological rate of 100%, indicating that the growth of all fungal spores can be completely inhibited, and when the content of 10 wt% is found, the thermal conductivity of PHBE‐MWNT pressure‐sensitive composite materials is achieved 0.6975 W/(m‐K), 1.8 times the MWNT pressure‐sensitive glue, higher than the pure pressure‐sensitive glue about 255%.

Preparation of spherical silver and tin dioxide nanocomposites with the high photocatalytic performance by laser-induced deposition in liquid medium

Nanospheres were widely utilized as atomic clusters for the self-assembly and modification of functional nanomaterials. In this study, by using the laser-induced deposition in a liquid medium, the spherical Silver (Ag) and Tin dioxide (SnO2) nanocomposites were successfully prepared. The characteristics of the product, such as morphologies, components, structures and optical properties were obtained by STEM, EDS, ICP-OES, XPS, XRD, UV-Vis and PL instruments, respectively. During the laser-induced liquid deposition, the pristine Ag nanoparticles were melted to be spheres with the average particle size decreased and welded with the SnO2 nanomaterials under the laser heating and liquid quenching. The photocatalytic performance of the synthesized nanocomposites was evaluated by the degradation of methylene blue aqueous solution as a model organic pollutant. The results indicated that, for the spherical Ag and SnO2 nanocomposites, the reaction rate constant was enhanced 3.1 times than the pure-SnO2 nanomaterials and 13.3 times than the pure-Ag nanoparticles, respectively, with a high value of 0.08 min−1. Where 99.1% methylene blue can be removed in 60 min by using Ag and SnO2 nanocomposites as catalysts under ultraviolet lamp irradiation. This performance performed better than the previous reports in similar physical conditions. The possible enhanced mechanism was analyzed, where the spherical Ag anchoring on the surface of SnO2 induced the perturbation of SnO2 bandgap, the free electrons transfer of spherical Ag promoted the separation of photogenerated electron-hole pairs, increased the formation of superoxide and hydroxyl radicals for methylene blue effectively removal via a redox reaction.

One Pot-Synthesized Ag/Ag-Doped CeO2 Nanocomposite with Rich and Stable 3D Interfaces and Ce3+ for Efficient Carbon Dioxide Electroreduction.

Electrochemical CO2 reduction (ECR) technology is promising to produce value-added chemicals and alleviate the climate deterioration. Interface engineering is demonstrated to improve the ECR performance for metal and oxide composite catalysts. However, the approach to form a substantial interface is still limited. In this work, we report a facile one-pot coprecipitation method to synthetize novel silver and silver-doped ceria (Ag/CeO2) nanocomposites. This catalyst provides a rich 3D interface and high Ce3+ concentration (33.6%), both of which are beneficial for ECR to CO. As a result, Ag/CeO2 exhibits a 99% faradaic efficiency and 10.5 A g-1 mass activity to convert CO2 into CO at an overpotential of 0.83 V. The strong interfacial interaction between Ag and CeO2 may enable the presence of surface Ce3+ and guarantee the improved durability during the electrolysis. We also develop numerical simulation to understand the local pH effect on the ECR performance and propose that the superior ECR performance of Ag/CeO2 is mainly due to the accelerated CO formation rate rather than the suppressed hydrogen evolution reaction.

γ-Irradiated Chitosan Mediates Enhanced Synthesis and Antimicrobial Properties of Chitosan-Silver (Ag) Nanocomposites.

Chitosan (CSN) and its derivatives are being exploited for their potential role in agriculture in mitigating environmental stress factors. The present study was aimed to enhance the synthesis of chitosan (CSN)-based silver nanoparticles (Ag NPs) using γ-irradiated chitosan (IR-CSN) and to study the antimicrobial activity of IR-CSN–Ag NPs. The chitosan–silver nanocomposites (CSN–Ag NPs) were prepared by employing the green synthesis method using normal chitosan (high molecular weight (MW), NL-CSN) and oligochitosans (low MW, IR-CSN). The latter was derived by irradiation with γ rays (60Co) at 100 kGy dose to obtain a lower MW (approximately 25 kDa). NL-CSN and IR-CSN (0.0–2.5% w/v) were amalgamated with different concentrations of silver nitrate (0.0–2.5% w/v) and vice versa. The UV–visible spectra displayed a single peak in the range of 419–423 nm, which is the characteristic surface plasmon resonance (SPR) for Ag NPs. The physicochemical properties were assessed using different methods such as transmission electron microscopy (TEM), Fourier transform infrared (FTIR), zetasizer, elemental (CHNS) analysis, etc. The degree of Ag NP synthesis was more in IR-CSN than NL-CSN. The in vitro disc diffusion assay with IR-CSN–Ag NPs exhibited a significantly higher antimicrobial activity against Escherichia coli. Further evaluation of the antifungal activity of IR-CSN and Ag NPs showed a synergistic effect against chickpea wilt (Fusarium oxysporum f. sp. ciceris). The study has provided a novel approach for the improved synthesis of CSN–Ag nanoparticle composites using γ-irradiated chitosan. This study also opens up new options for the development and deployment of γ-irradiated chitosan–silver nanocomposites for the control of phytopathogens in sustainable agriculture.

Ag-doped FeCo2O4 nanoparticles and their composite with flat 2D reduced graphene oxide sheets for photocatalytic degradation of colored and colorless compounds

The present study is based on the fabrication of nanoparticles of iron cobalt oxide (FeCo2O4, FCO), silver doped iron cobalt oxide (Ag-FeCo2O4, AgFCO) by auto-moisturization approach. The nanocomposite of silver doped iron cobalt oxide with reduced graphene oxide (Ag-FeCo2O4@rGO, AgFCO@rGO) was fabricated by ultra-sonication approach for the degradation of the organic effluents photocatalytically. The rGO possesses immense surface area, excellent stability, and greater ability for the transfer of electrons during photocatalysis. The physiochemical characteristics of fabricated materials were investigated by X-ray diffraction technique (XRD), Fourier transform infrared spectroscopic technique (FT-IR), Scanning electron microscopy (SEM), and UV – Visible spectroscopy. The results of XRD showed that the crystallite size of FCO, AgFCO, and AgFCO@rGO nanocomposite was 14 nm, 12 nm, and 10 nm respectively. The results of SEM revealed quasi spherical morphology of synthesized materials and rGO sheets could be easily observed in the SEM image of AgFCO@rGO. The degradation of rhodamine B and benzimidazole was performed under solar light. The photocatalysis experiment exhibited 86 % degradation of rhodamine B and 54.46 % degradation of benzimidazole by using AgFCO@rGO under the same conditions. The photoactive species like hydroxyl radicals, holes and electrons were found to be main participants during photo-degradation of pollutants. In contrast to bare iron cobalt oxide and silver doped iron cobalt oxide, AgFCO@rGO showed greater photocatalytic degradation activity. The increased activity of AgFCO@rGO was due to its small crystallite size and increased surface area. The recombining rate of electron/hole pair decreased as the surface area of nanocatalysts increased and hence photocatalytic efficiency increased. It is investigated that the AgFCO@rGO has potential implementations in the photo degradation of organic effluents.

Sensitive determination of Cu (II) ions using different doped carbon dot and silver nanocomposites: comparative study

Sensitive determination of Cu (II) ions using different doped carbon dot and silver nanocomposites: comparative study