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Surface Plasmon Resonance (SPR) based optical biosensors are recently the most attractive sensing devices that can detect minor changes in refractive index. Multiple methods have been developed to design SPR based biosensors with high-performance and ease of fabrication. This research is about a grating based biosensor that utilizes Silver (Ag) and Titanium (Ti) to produce the SP resonance state. The structure has a resonance wavelength, which displays sensitivity to changes in the surrounding medium of the refractive index. The study has been conducted using numerical simulations, utilizing the finite-difference-time-domain (FDTD) method.The simulation results shows a sharp resonance peaks in the wavelength range of 450-700 nm with a remarkable sensitivity of 172 nm/RIU (for mode 1 at SPR peak 465 nm) and 515 nm/RIU (for mode 2 at SPR peak 585 nm), which is superior to other on-chip device. The investigation involves a comparative analysis of sensing performance, focusing on parameters like transmission, reflection, FWHM and Quality factor to measure the detection accuracy of the proposed material combination. Later, we employed this miniature biosensor device to detect hemoglobin concentrations in the blood. Our findings indicate that this developed structure has great potential for detecting any biomolecule, such as proteins, glucose, fructose, nucleic acids, and cells.

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Zinc oxide nanoparticles (ZnO NPs) are metal oxide nanomaterials, which are important for several applications: antibacterial, anthelmintic, antiprotozoal and antitumoral, among others. These applications are mainly related to the ability to spontaneously produce and induce the production of reactive oxygen species that are important components for the destruction of pathogens and tumor cells. While trying to potentiate ZnO NPs, studies have associated these NPs with silver oxide (AgO) or silver (Ag) NPs. It has already been reported that this combination (Ag-ZnO/AgO NPs) is able to enhance the microbicidal potential. Although possessing much potential for several purposes, it is important to evaluate whether this association also poses the risk of toxicity to cells and experimental models. Therefore, this work aimed to evaluate the toxicity of various Ag-ZnO/AgO NP nanocomposites, in vitro and in vivo. Accordingly, ZnO nanocrystals and nanocomposites with various concentrations of AgO (ZnO:5Ag, ZnO:9Ag or ZnO:11Ag) were used in different cytotoxicity models: Galleria mellonella (G. mellonella), cell lines (VERO and RAW 264.7) and C57BL/6 mice. In the G. mellonella model, four concentrations were used in a single dose, with subsequent evaluation of mortality. In the case of cells, serial concentrations starting at 125 µg/mL were used, with subsequent cytotoxicity assessment. Based on the safe doses obtained in G. mellonella and cell models, the best doses were used in mice, with subsequent evaluations of weight, biochemistry as also renal and liver histopathology. It was observed that the toxicity, although low, of the nanocomposites was dependent upon the concentration of AgO used in association with ZnO NPs, both in vitro and in vivo.

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This study demonstrated a silver (Ag) and samarium-doped ceria (SDC) mixed ceramic and metal composite (i.e., cermet) as a cathode for low-temperature solid oxide fuel cells (LT-SOFCs). Introducing the Ag-SDC cermet cathode for LT-SOFCs revealed that the ratio between Ag and SDC, which is a crucial factor for catalytic reactions, can be tuned by the co-sputtering process, resulting in enhanced triple phase boundary (TPB) density in the nanostructure. Ag-SDC cermet not only successfully performed as a cathode to increase the performance of LT-SOFCs by decreasing polarization resistance but also exceeded the catalytic activity of platinum (Pt) due to the improved oxygen reduction reaction (ORR). It was also found that less than half of Ag content was effective to increase TPB density, preventing oxidation of the Ag surface as well.

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When creating titanium-containing bone implants, the bioactive coatings that promote their rapid engraftment are important. The engraftment rate of titanium implants with bone tissue depends significantly on the modification of the implant surface. It is achieved by changing either the relief or the chemical composition of the surface layer, as well as a combination of these two factors. In this work, we studied the creation of composite coatings with a two-level (the micro- and nanolevel) hierarchy of the surface relief, which have bioactive and bactericidal properties, which are promising for bone implantation. Using the developed non-lithographic template electrochemical synthesis, a composite coating on titanium with a controlled surface structure was created based on an island-type TiO2 film, silver and hydroxyapatite (HAp). This TiO2/Ag/HAp composite coating has a developed surface relief at the micro- and nanolevels and has a significant cytological response and the ability to accelerate osteosynthesis, and also has an antibacterial effect. Thus, the developed biomaterial is suitable for production of dental and orthopedic implants with improved biomedical properties.

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In this paper, we propose a simple two-step method for the synthesis of Ag, Au, and Pt-doped ZnO nanoparticles. The method is based on the fabrication of targets using the pulsed laser deposition (PLD) technique where thin layers of metals (Ag, Pt, Au) have been deposited on a metal-oxide bulk substrate (ZnO). Such formed structures were used as a target for the production of doped nanoparticles (ZnO: Ag, ZnO: Au, and ZnO: Pt) by laser ablation in water. The influence of Ag, Au, and Pt doping on the optical properties, structure and composition, sizing, and morphology was studied using UV-Visible (UV-Vis) and photoluminescence (PL) spectroscopies, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), respectively. The band-gap energy decreased to 3.06, 3.08, and 3.15 for silver, gold, and platinum-doped ZnO compared to the pure ZnO (3.2 eV). PL spectra showed a decrease in the recombination rate of the electrons and holes in the case of doped ZnO. SEM, TEM, and AFM images showed spherical-shaped nanoparticles with a relatively smooth surface. The XRD patterns confirm that Ag, Au, and Pt were well incorporated inside the ZnO lattice and maintained a hexagonal wurtzite structure. This work could provide a new way for synthesizing various doped materials.

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A single silver (Ag) nanoparticle (NP) collision was observed and analyzed in an alkaline solution using the electrocatalytic amplification (EA) method. Previously, the observation of a single Ag NP collision was only possible through limited methods based on a self-oxidation of Ag NPs or a blocking strategy. However, it is difficult to characterize the electrocatalytic activity of Ag NPs at a single NP level using a method based on the self-oxidation of Ag NPs. When using a blocking strategy, size analysis is difficult owing to the edge effect in the current signal. The fast oxidative dissolution of Ag NPs has been a problem for observing the staircase response of a single Ag NP collision signal using the EA method. In alkaline electrolyte conditions, Ag oxides are stable, and the oxidative dissolution of Ag NPs is sluggish. Therefore, in this study, the enhanced magnitude and frequency of the current response for single Ag NP collisions were obtained using the EA method in an alkaline electrolyte solution. The peak height and frequency of single Ag NP collisions were analyzed and compared with the theoretical estimation.

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In this review, the most recent advances in the field of magnetic composite photocatalysts with integrated plasmonic silver (Ag) is presented, with an overview of their synthesis techniques, properties and photocatalytic pollutant removal applications. Magnetic attributes combined with plasmonic properties in these composites result in enhancements for light absorption, charge-pair generation-separation-transfer and photocatalytic efficiency with the additional advantage of their facile magnetic separation from water solutions after treatment, neutralizing the issue of silver's inherent toxicity. A detailed overview of the currently utilized synthesis methods and techniques for the preparation of magnetic silver-integrated composites is presented. Furthermore, an extended critical review of the most recent pollutant removal applications of these composites via green photocatalysis technology is presented. From this survey, the potential of magnetic composites integrated with plasmonic metals is highlighted for light-induced water treatment and purification. Highlights: (1) Perspective of magnetic properties combined with plasmon metal attributes; (2) Overview of recent methods for magnetic silver-integrated composite synthesis; (3) Critical view of recent applications for photocatalytic pollutant removal.

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Recent developments in studies of the uptake and toxicity of both gold (Au) and silver (Ag) nanostructures (NS) in drug delivery systems have shown that physicochemical properties play an important role. Physicochemical properties of engineered NS such as size, shape, coordination chemistry, surface charge, and surface chemistry generally manifest in reactivity, surface energetics and electronic properties of the nanomaterials. This review discusses the computational and experimental studies conducted to study the effects of physicochemical properties on cellular uptake and nanostructure toxicity. The studies show that properties like coordination chemistry have often been overlooked when studying the high surface energy of NS.

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Nowadays, treatment to the infected wounds caused by bacterial even multi-resistant bacterial strains and subsequently complete skin regeneration remain a critical clinical challenge. Herein, a novel multi-functional platform (Alg/1.0Ag@CMC-PAMAM/PRP) was prepared as wound dressings by mixing platelet rich plasma (PRP) with the sodium alginate (Alg) based dressing containing nano silver (Ag)-doped carboxymethyl chitosan grafted polyamideamine (Ag@CMC-PAMAM) cationic polymers. The present dressings exhibited high swelling, suitable water vapor transmission rate (WVTR), and good mechanical properties and degradability, as well as sustained release of PRP. Besides, the component of Ag@CMC-PAMAM nanoparticles endow them with excellent antibacterial performance, while the incorporation of PRP promotes the effect of anti-inflammatory and angiogenesis by up-regulating relative activity factor expression of TGF-ß1, CD31 and α-SMA and down-regulating the inflammatory-relative genes including TNF-α, IL-6 and IL-1ß, all of which promote the closure of wound and produce a superior healing effect to the commercial Aquacel Ag group. This work indicates that the prepared Alg/1.0Ag@CMC-PAMAM/PRP wound dressing is a promising biomaterial with synergistic effect of antibacterial property and wound healing.

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In this study, an industrially scalable method is reported for the fabrication of polylactic acid (PLA)/silver nanoparticle (AgNP) nanocomposite filaments by an in-situ reduction reactive melt mixing method. The PLA/AgNP nanocomposite filaments have been produced initially reducing silver ions (Ag+) arising from silver nitrate (AgNO3) precursor mixed in the polymer melt to elemental silver (Ag0) nanoparticles, utilizing polyethylene glycol (PEG) or polyvinyl pyrrolidone (PVP), respectively, as macromolecular blend compound reducing agents. PEG and PVP were added at various concentrations, to the PLA matrix. The PLA/AgNP filaments have been used to manufacture 3D printed antimicrobial (AM) parts by Fused Filament Fabrication (FFF). The 3D printed PLA/AgNP parts exhibited significant AM properties examined by the reduction in Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria viability (%) experiments at 30, 60, and 120 min duration of contact (p < 0.05; p-value (p): probability). It could be envisaged that the 3D printed parts manufactured and tested herein mimic nature's mechanism against bacteria and in terms of antimicrobial properties, contact angle for their anti-adhesive behavior and mechanical properties could create new avenues for the next generation of low-cost and on-demand additive manufacturing produced personal protective equipment (PPE) as well as healthcare and nosocomial antimicrobial equipment.

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The rapid increase in the use of silver (Ag) and gold (Au) nanoparticles (NPs) can be a potential risk to humans. Ag and Au NPs may enter the blood, accumulate in organs and be cleared from the body. It is therefore necessary to develop detection and quantification methods for Ag and Au NPs in human matrices. To this end, the inductively coupled plasma mass spectrometry was used as single particle detector (SP-ICP-MS) and coupled on-line with asymmetric flow field flow fractionation (AF4-FFF-ICP-MS), multi-angle scattering (MALS) and UV. Both methods enabled the qualitative and quantitative measurement of mixtures of Ag NPs (20, 60 and 100 nm) and Au NPs (5, 20, 40 and 60 nm) in human urine, blood and serum. Methods were validated by estimating linearity, limit of detection, resolution, repeatability, recovery and stability of Ag and Au NPs measurements in fluids. The SP-ICP-MS showed concentration limits for Ag and Au NPs lower than AF4-FFF-ICP-MS (pg/mL vs. ng/mL, respectively), while AF4-FFF-ICP-MS could detect smaller sized NPs (2-5 nm vs. 7-14 nm for SP-ICP-MS) with good resolution between monodispersed NPs fractions. In addition, MALS detector was more promising respect to higher sizes of Ag and Au NPs (>40 nm), while UV for lower sized particle (<20 nm). The observed performances will allow to use ICP-MS-based methods, also coupled to other detectors, to carry out human biomonitoring campaigns dedicated to the analysis of metallic NPs in the general population and in exposed subjects.

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Gold (Au) and silver (Ag) nanostructures have widespread utilization from biomedicine to materials science. Therefore, their synthesis with control of their morphology and surface chemistry have been among the hot topics over the last decades. Here, we introduce a new approach relying on sugar derivatives that work as reducing, stabilizing, and capping agents in the synthesis of Au and Ag nanostructures. These sugar derivatives are utilized alone and as mixture, resulting in spherical, spheroid, trigonal, polygonic, and star-like morphologies. The synthesis approach was further tested in the presence of acetate and dimethylamine as size- and shape-directing agents. With the use of transmission electron microscopy (TEM), selected area electron diffraction (SAED), x-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) absorption spectroscopy techniques, the particle size, shape, assembly, aggregation, and film formation characteristics were evaluated. NPs' attributes were shown to be tunable by manipulating the sugar ligand selection and sugar ligand/metal-ion ratio. For instance, with an imine side group and changing the sugar moiety from cellobiose to lactose, the morphology of the Ag nanoparticles (NPs) transformed from well dispersed cubic to rough and aggregated. The introduction of acetate and dimethylamine further extended the growth pattern and morphological properties of these NPs. As examples, L5 AS, G5AS, and S5AS ligands formed spherical or sheet-like structures when used alone, which upon the use of these additives transformed into larger multicore and rough NPs, revealing their significant effect on the NP morphology. Selected samples were tested for their stability against protein corona formation and ionic strength, where a high chemical stability and resistance to protein coating were observed. The findings show a promising, benign approach for the synthesis of shape- and size-directed Au and Ag nanostructures, along with a selection of the chemistry of carbohydrate-derivatives that can open new windows for their applications.

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A versatile method is reported for the manufacturing of antimicrobial (AM) surgery equipment utilising fused deposition modelling (FDM), three-dimensional (3D) printing and sonochemistry thin-film deposition technology. A surgical retractor was replicated from a commercial polylactic acid (PLA) thermoplastic filament, while a thin layer of silver (Ag) nanoparticles (NPs) was developed via a simple and scalable sonochemical deposition method. The PLA retractor covered with Ag NPs (PLA@Ag) exhibited vigorous AM properties examined by a reduction in Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli) bacteria viability (%) experiments at 30, 60 and 120 min duration of contact (p < 0.05). Scanning electron microscopy (SEM) showed the surface morphology of bare PLA and PLA@Ag retractor, revealing a homogeneous and full surface coverage of Ag NPs. X-Ray diffraction (XRD) analysis indicated the crystallinity of Ag nanocoating. Ultraviolent-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM) highlighted the AgNP plasmonic optical responses and average particle size of 31.08 ± 6.68 nm. TEM images of the PLA@Ag crossection demonstrated the thickness of the deposited Ag nanolayer, as well as an observed tendency of AgNPs to penetrate though the outer surface of PLA. The combination of 3D printing and sonochemistry technology could open new avenues in the manufacturing of low-cost and on-demand antimicrobial surgery equipment.

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Ag-based plasmonic nanostructures were manufactured by thermal annealing of thin metallic films. Structure and morphology were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). SEM images show that the formation of nanostructures is influenced by the initial layer thickness as well as the temperature and the time of annealing. The Ag 3d and Ag 4d XPS spectra are characteristic of nanostructures. The quality of the nanostructures, in terms of their use as plasmonic platforms, is reflected in the UV-vis absorption spectra. The absorption spectrum is dominated by a maximum in the range of 450-500 nm associated with the plasmon resonance. As the initial layer thickness increases, an additional peak appears around 350 nm, which probably corresponds to the quadrupole resonance. For calculations leading to a better illustration of absorption, scattering and overall absorption of light in Ag nanoparticles, the Mie theory is employed. Absorbance and the distribution of the electromagnetic field around the nanostructures are calculated by finite-difference time-domain (FDTD) simulations. For calculations a novel approach based on modelling the whole sample with a realistic shape of the nanoparticles, instead of full spheres, was used. This led to a very good agreement with the experiment.

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There is increasing interest in the environmental fate and effects of engineered nanomaterials due to their ubiquitous use in consumer products. In particular, given the mounting evidence that dramatic transformations can occur to a nanomaterial throughout its product lifecycle, the appropriateness of using pristine nanomaterials in environmental testing is being questioned. Using a combination of transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma-mass spectrometry (ICP-MS), this work examines the morphological and compositional effects of conditions mimicking a typical lifecycle of a nano-enabled product, from the production of the silver nanoparticle (AgNP)-laden textiles, through its use, laundering, and then finally, its leaching and incubation in the wastewater collection system. These simulated weathering conditions showed evidence for the transformation of AgNPs into AgCl and Ag2S. Incubation in raw wastewater had the most dramatic effect on the AgNPs in terms of transformation, no matter what initial weathering was applied to the NPs prior to incubation. However, despite extensive transformation noted, AgNPs were still present within all the samples after the use scenarios.

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Pseudomonas aeruginosa has been detected in the lungs of ∼50% of patients with cystic fibrosis (CF), including 20% of adult CF patients. The majority of these adult patients harbor multi-drug resistant (MDR) strains, limiting the available treatment options. Silver has long been used as a broad-spectrum antimicrobial agent with a low incidence of resistance. Despite low toxicity, poor availability of silver cations mandates a high dosage to effectively eradicate infections. To address this shortcoming of silver, nanoparticles have been used as delivery devices to improve treatment outcomes. Furthermore, studies have demonstrated that synergistic combinations with careful dose calibrations and efficient delivery systems result in superior antimicrobial activity while avoiding potential side effects of both therapeutics. Here 4-epi-minocycline, a metabolite of minocycline, was identified as an active antimicrobial against P. aeruginosa using a high-throughput screen. The antimicrobial activities of 4-epi-minocycline, minocycline, and silver acetate against clinical isolates of P. aeruginosa obtained from CF patients were evaluated in vitro. Next, the synergistic activity of the silver/minocycline combination against P. aeruginosa isolates was investigated using checkerboard assays and identified with end-point colony forming unit determination assays. Finally, nanoparticles coloaded with minocycline and silver were evaluated in vitro for antimicrobial activity. The results demonstrated that both silver and minocycline are potent antimicrobials alone and that the combination allows a reduced dosage of both therapeutics to achieve the same antimicrobial effect. Furthermore, the proposed synergistic silver/minocycline combination can be coloaded into nanoparticles as a next-generation antibiotic to combat the threats presented by MDR pathogens.

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Bioglass nanoparticles (BGs) are of outmost importance in the biomedical field, because their unique characteristics, namely osteoconductivity and osteoinductivity, and also in certain conditions, angiogenic and bactericidal properties. In this work, novel bioglass nanoparticles containing silver (AgBGs) were synthesized by a sol-gel method, adopting different thermal treatments to obtain new nanoparticles with bioactive and antibacterial features. This is the first systematic study of the effect of the thermal treatment on the properties of AgBGs. The effect of the studied thermal treatments on the properties of synthesized nanoparticles was analyzed by several characterization techniques: FT-IR, XRD, S-TEM, SEM-EDS and Zeta potential. FT-IR allowed the identification of the characteristic peaks of the nanoparticles and XRD revealed the presence of the characteristic peaks of an apatite-like phase. By S-TEM analysis it was found that the produced nanoparticles are dense and have a diameter <200 nm. The SEM micrographs showed their surface morphology and Zeta potential measurements were performed to study their suspension stability. Additionally, in vitro bioactivity tests confirmed their bioactive potential and the microbiological tests evidenced their bactericidal effect. These promising AgBGs could be incorporated either in 2D or 3D structures for several biomedical applications, namely in the orthopedic and dental fields.

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Due to their relatively low cost, large surface area and good chemical and physical properties, carbon nanofibers (CNFs) are attractive for the fabrication of electrodes for supercapacitors (SCs). However, their relatively low electrical conductivity has impeded their practical application. To this end, a novel active-screen plasma activation and deposition technology has been developed to deposit silver, platinum and palladium nanoparticles on activated CNFs surfaces to increase their specific surface area and electrical conductivity, thus improving the specific capacitance. The functionalised CNFs were fully characterised using scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) and their electrochemical properties were evaluated using cyclic voltammetry and electrochemical impedance spectroscopy. The results showed a significant improvement in specific capacitance, as well as electrochemical impedance over the untreated CNFs. The functionalisation of CNFs via environmental-friendly active-screen plasma technology provides a promising future for cost-effective supercapacitors with high power and energy density.

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The use of membrane-based technologies has been applied for water treatment applications; however, the limitations of conventional polymeric membranes have led to the addition of inorganic fillers to enhance their performance. In recent years, nanocomposite membranes have greatly attracted the attention of scientists for water treatment applications such as wastewater treatment, water purification, removal of microorganisms, chemical compounds, heavy metals, etc. The incorporation of different nanofillers, such as carbon nanotubes, zinc oxide, graphene oxide, silver and copper nanoparticles, titanium dioxide, 2D materials, and some other novel nano-scale materials into polymeric membranes have provided great advances, e.g., enhancing on hydrophilicity, suppressing the accumulation of pollutants and foulants, enhancing rejection efficiencies and improving mechanical properties and thermal stabilities. Thereby, the aim of this work is to provide up-to-date information related to those novel nanocomposite membranes and their contribution for water treatment applications.

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Silver, such as silver nanoparticles (AgNPs), has been widely used in commercial products and may be released into the environment. The interaction between Ag deposition and biological systems is raising serious concerns because of one health consideration. Cetaceans, as the top predators of the oceans, may be exposed to Ag/Ag compounds and suffer negative health impacts from the deposition of these compounds in their bodies. In the present study, we utilized autometallography (AMG) to localize the Ag in the liver and kidney tissues of cetaceans and developed a model called the cetacean histological Ag assay (CHAA) to estimate the Ag concentrations in the liver and kidney tissues of cetaceans. Our results revealed that Ag was mainly located in hepatocytes, Kupffer cells and the epithelial cells of some proximal renal tubules. The tissue pattern of Ag/Ag compounds deposition in cetaceans was different from those in previous studies conducted on laboratory rats. This difference may suggest that cetaceans have a different metabolic profile of Ag, so a presumptive metabolic pathway of Ag in cetaceans is advanced. Furthermore, our results suggest that the Ag contamination in cetaceans living in the North-western Pacific Ocean is more severe than that in cetaceans living in other marine regions of the world. The level of Ag deposition in cetaceans living in the former area may have caused negative impacts on their health condition. Further investigations are warranted to study the systemic Ag distribution, the cause of death/stranding, and the infectious diseases in stranded cetaceans with different Ag concentrations for comprehensively evaluating the negative health effects caused by Ag in cetaceans.

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