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The adoption of green chemistry protocols in nanoparticle (NP) synthesis has exhibited substantial potential and is presently a central focus in research for generating versatile NPs applicable across a broad spectrum of applications. In this scientific contribution, we, for the first time, examined the ability of Aconitum Laeve (A. Laeve) crude extract to synthesize silver and gold nanoparticles (AgNPs@AL; AuNP@AL) and explored their potential applications in biological activities and the catalytic degradation of environmental pollutants. The synthesized NPs exhibited a distinctive surface plasmon resonance pattern, a spherical morphology with approximate sizes of 5–10 nm (TEM imaging), a crystalline architecture (XRD analysis), and potential functional groups identified by FTIR spectroscopy. The antibacterial activity was demonstrated by inhibition zones that measured 16 and 14 mm for the AgNPs@AL and AuNP@AL at a concentration of 80 µg/mL against Staphylococcus aureus and 14 and 12 mm against Escherichia coli, respectively. The antioxidant potential of the synthesized NPs was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-Oxide (PTIO), and 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. Our findings suggest that the AuNP@AL effectively countered the tested radicals considerably, displaying IC50 values of 115.9, 103.54, and 180.85 µg/mL against DPPH, PTIO, and ABTS, respectively. In contrast, the AgNPs@AL showed IC50 values of 144.9, 116.36, and 95.39 µg/mL against the respective radicals. In addition, both the NPs presented significant effectiveness in the photocatalytic degradation of methylene blue and rhodamine B. The overall observations indicate that A. Laeve possesses a robust capability to synthesize spherical nanoparticles, exhibiting excellent dispersion and showcasing potential applications in both biological activities and environmental remediation. [ABSTRACT FROM AUTHOR]

This paper presents the syntheses of SiO2 particles immobilized with Ag nanoparticles and their composite with Au. Ag nanoparticles are present on the surfaces of the SiO2 particles, and Ag+ ions are galvanically replaced with Au3+ ions. Finally, a method for maintaining the color durability and dispersibility of the Ag nanoparticles is demonstrated. The particles are primarily synthesized in three steps: In the first step, Sn2+ ions are adsorbed on the surfaces of the SiO2 particles; in the second step, Ag+ ions are added, which are reduced and simultaneously adsorbed on the surface while Sn2+ is oxidized to Sn4+; in the third step, Au3+ ions are reduced by galvanic replacement and deposited on the Ag surface. Extensive characterization using transmission electron microscopy, scanning transmission electron microscopy, ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy reveals that the Ag–Au composite nanoparticles (17.2 ± 4.1 nm) are immobilized on the surface of the SiO2 particles (<1 µm). The morphology and coloration of the SiO2 particles with the immobilized Ag–Au composite nanoparticles remain preserved in nitric acid. This preservation is more pronounced than that observed in SiO2 particles with immobilized Ag nanoparticles. This enhanced durability can be attributed to the formation of stable bonds between Ag and Au. [ABSTRACT FROM AUTHOR]

Pesticides play an important role in conventional agriculture. Yet, their harmful effects on the environment are becoming increasingly apparent. The occurrence of pesticides is hence being monitored worldwide. For fast, easy, yet sensitive identification, surface-enhanced Raman spectroscopy (SERS) is a powerful tool. In this study, a method is introduced that may be amended to in-field detection of pesticides. Gold and silver nanoparticles were synthesized, size-tailored, and characterized. The herbicide paraquat and the fungicide thiram served as model compounds. The preparation yielded reproducible SERS spectra. Using quantum chemical computation, Raman and SERS spectra were calculated and analyzed. The interpretation of vibrational modes in combination with SERS enhancement and attenuation allowed us to identify compound-specific bands. The assignment was interpreted in terms of the orientation of paraquat and thiram on the gold and silver nanoparticle surfaces. Paraquat preferred a co-planar arrangement parallel to the gold nanoparticle surface and a head-on orientation on the silver nanoparticle. For thiram, breaking of the disulfide bond was recognized, such that interaction with the surface occurred via the sulfur atoms. Successful detection of the pesticides after recollection from vegetable leaves demonstrated the method's applicability for pesticide identification. [ABSTRACT FROM AUTHOR]

The review article emphasizes the silver nanoparticles (AgNPs)/gold nanoparticles (AuNPs) decorated graphene oxide (GO)/functionalized carbon nanotubes (f-CNTs) hybrid nanofillers reinforced polyaniline (PANI) ternary nanocomposites due to their extraordinary properties and multifunctional applications as compare to the individual components. Conducting polymer nanocomposites are used in various applications due to the synergic effect that enhances various properties of the individual components. Owing to the elevated thermal, optical, sensing, and dielectric properties of the nanocomposites that revealed as an effective material, which can be employed for the application in energy storage devices like solar cells, batteries, supercapacitors, sensing of heavy metal ions, etc. [ABSTRACT FROM AUTHOR]

AbstractThe green synthesis of metal nanoparticles with curcumin which is a compound with antibiotic effects, was considered for the synthesis of metal nanoparticles. Gold and silver nanoparticles were synthesized with an average diameter of 19.8 ± 6.2 nm and 29.8 ± 6.4 nm respectively. Both particles represent stability in the physiological environment and after a series of washing procedures to remove unreacted precursors. The antimicrobial efficacy of the synthesized nanoparticles was investigated in different techniques such as disk diffusion, agar well diffusion, minimum inhibitory concentration, and minimum bactericidal concentration tests. The results of both curcumin-coated metal nanoparticles in the disk diffusion test were negative. However, in the agar dilution and MIC tests of antibacterial effect of both nanoparticles on the tested bacteria was observed. The silver nanoparticles had an inhibitory effect on all selected bacteria in the agar dilution (8-256 µg/ml). However, gold nanoparticles had a lower inhibitory effect on the growth of some of the selected bacteria (64-512 µg/ml). In conclusion, silver nanoparticles were more effective than gold nanoparticles in most of the investigated methods. [ABSTRACT FROM AUTHOR]

This work presents a novel multielectrode array (MEA) to quantitatively assess the dose enhancement factor (DEF) produced in a medium by embedded nanoparticles. The MEA has 16 nanocrystalline diamond electrodes (in a cell-culture well), and a single-crystal diamond divided into four quadrants for X-ray dosimetry. DEF was assessed in water solutions with up to a 1000 µg/mL concentration of silver, platinum, and gold nanoparticles. The X-ray detectors showed a linear response to radiation dose (r2 ≥ 0.9999). Overall, platinum and gold nanoparticles produced a dose enhancement in the medium (maximum of 1.9 and 3.1, respectively), while silver nanoparticles produced a shielding effect (maximum of 37%), lowering the dose in the medium. This work shows that the novel MEA can be a useful tool in the quantitative assessment of radiation dose enhancement due to nanoparticles. Together with its suitability for cells' exocytosis studies, it proves to be a highly versatile device for several applications. [ABSTRACT FROM AUTHOR]

Early detection of diseases can increase the chances of successful treatment and survival. Therefore, it is necessary to develop a method for detecting or sensing biomolecules that cause trouble in living organisms. Disease sensors should possess specific properties, such as selectivity, reproducibility, stability, sensitivity, and morphology, for their routine application in medical diagnosis and treatment. This work focuses on biosensors in the form of surface-functionalized gold (AuNPs) and silver nanoparticles (AgNPs) prepared using a less-time-consuming, inexpensive, and efficient synthesis route. This allows for the production of highly pure and stable (non-aggregating without stabilizers) nanoparticles with a well-defined spherical shape, a desired diameter, and a monodisperse distribution in an aqueous environment, as confirmed by transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM-EDS), X-ray diffraction (XRD), photoelectron spectroscopy (XPS), ultraviolet-visible (UV-VIS) spectroscopy, and dynamic light scattering (DLS). Thus, these nanoparticles can be used routinely as biomarker sensors and drug-delivery platforms for precision medicine treatment. The NPs' surface was coated with phosphonate dipeptides of L-leucine (Leu; l-Leu–C(R1)(R2)PO3H2), and their adsorption was monitored using SERS. Reproducible spectra were analyzed to determine the orientation of the dipeptides (coating layers) on the nanoparticles' surface. The appropriate R2 side chain of the dipeptide can be selected to control the arrangement of these dipeptides. This allows for the proper formation of a layer covering the nanoparticles while also simultaneously interacting with the surrounding biological environment, such as cells, tissues, and biological fluids. [ABSTRACT FROM AUTHOR]

The study aims at synthesizing a simple, cost-effective, selective, and sensitive colorimetric sensor based on chlorophyll-coated silver nanoparticles (Chl-AgNPs) using microwave-assisted method for the determination of Cr(VI) ions in an aqueous medium. The characterization reveals that synthesized nanoparticles are 20–30 nm in size and spherical in shape. The presence of methyl, carboxyl, aldehyde, and ketone groups on the surface of Chl-AgNPs results in the formation of size controlled, well dispersed, and stable silver nanoparticles. The prepared nano-colloidal solution has been used for selective and sensitive determination of Cr(VI) in water samples. The addition of single drop of Chl-AgNPs solution immediately changes the color of water samples containing Cr(VI) to red displaying good sensitivity from 10 to 100 µM and high selectivity even in the presence of other metal ions. The ultraviolet–visible spectra show that in the presence of Cr(VI), the localized surface plasmon resonance (LSPR) band of Chl-AgNPs at 410 nm shifts to 470 nm with a new peak at 357 nm. Furthermore, the absorbance of the LSPR band decreases and the absorbance at 357 nm increases linearly with the concentration of Cr(VI). The functional groups on the surface of nanoparticles bind Cr(VI) on the surface leading to agglomeration and alterations in interparticle distance that are observed as changes in the color and LSPR profile. The limits of detection and quantification for Cr(VI) ions were determined to be 0.62 µM and 1.88 µM, respectively. [ABSTRACT FROM AUTHOR]

For the first time in this study, silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) were green synthesized by the cost-effective and eco-friendly procedure using Cotton seed meal and Fodder yeast extracts. The biosynthesized NPs were characterized by UV–Vis spectroscopy, dynamic light scattering analysis (DLS), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and fourier-transform infrared (FTIR) spectroscopy. Furthermore, the biosynthesized NPs were tested in vitro against biofilm formation by some pathogenic negative bacteria (Escherichia coli, Proteus mirabilis, Klebsiella sp., Salmonella sp., and Pseudomonas aeruginosa) and negative bacteria (staphylococcus aureus) as well as against human denovirus serotype 5 (HAdV-5) and anticancer activity using HepG2 hepatocarcinoma cells. UV–Vis absorption spectra of reaction mixture of AgNPs and AuNPs exhibited maximum absorbance at 440 nm and 540 nm, respectively. This finding was confirmed by DLS measurements that the highest intensity of the AgNPs and AuNPs were 84 nm and 73.9 nm, respectively. FTIR measurements identified some functional groups detected in Cotton seed meal and Fodder yeast extracts that could be responsible for reduction of silver and gold ions to metallic silver and gold. The morphologies and particle size of AgNPs and AuNPs were confirmed by the TEM and SAED pattern analysis. Biosynthesized AgNPs and AuNPs showed good inhibitory effects against biofilms produced by Escherichia coli, Proteus mirabilis, Klebsiella sp., Salmonella sp., Pseudomonas aeruginosa, and Staphylococcus aureus. In addition, they showed anticancer activities against hepatocellular carcinoma (HepG-2) and antiviral activity against human adenovirus serotype 5 infection in vitro. Finally, the results of this study is expected to be extremely helpful to nano-biotechnology, pharmaceutical, and food packing applications through developing antimicrobial and/or an anticancer drugs from ecofriendly and inexpensive nanoparticles with multi-potentiality. [ABSTRACT FROM AUTHOR]

Polymer nanocomposite materials with catalytic activity were designed via modification of MF-4SK ion-exchange membranes with Au and Ag nanoparticles obtained according to various synthetic methods in reverse micellar solutions. A sufficient transparency of the films allowed us to detect nanoparticles in the films using UV–Vis spectrophotometry, monitoring changes in the content of metal nanoparticles in the reverse micellar solution. A different mechanism of interaction of Au and Ag nanoparticles obtained by the same synthetic method with the MF-4SK film upon their contact with its surface was discovered, the destruction of nanoparticles was observed, and the influence of mechanism of primary acts in the formation of metal nanoparticles in reverse micellar solutions on their adsorption properties was confirmed. The highest concentration of gold nanoparticles was found in films immersed in reverse micellar solutions at the time of their exposure to ionizing radiation. [ABSTRACT FROM AUTHOR]

Gold and silver nanoparticles have witnessed increased scientific interest due to their colourful colloidal solutions and exceptional applications. Comparing the localized surface plasmon resonance (LSPR) of gold and silver nanoparticles is crucial for understanding and optimizing their optical properties. This comparison informs the design of highly sensitive plasmonic sensors, aids in selecting the most suitable nanoparticles for applications like surface-enhanced infrared spectroscopy (SEIRA) and biomedical imaging, and guides the choice between gold and silver nanoparticles based on their catalytic and photothermal properties. Ultimately, the study of LSPR facilitates the tailored use of these nanoparticles in diverse scientific and technological applications. Two SEIRA methods combined with partial least squares regression (PLSR) chemometric tools were developed. This development is based on the synthesis of homogeneous, high-dense deposited metal nanoparticle islands over the surface of glass substrates to be used as lab-on-chip SEIRA sensors for the determination of bisacodyl (BIS) and its active metabolite in plasma. SEM micrographs revealed the formation of metallic islands of colloidal citrate-capped gold and silver nanoparticles of average sizes of 29.7 and 15 nm, respectively. BIS and its active metabolite were placed on the nanoparticles' coated substrates to be directly measured, then PLSR chemometric modelling was used for the quantitative determinations. Plasmonic citrate-capped gold nanoparticle substrates showed better performance than those prepared using citrate-capped silver nanoparticles in terms of preparation time, enhancement factor, PLSR model prediction, and quantitative results. This study offers a way to determine BIS and its active metabolite in the concentration range 15–240 ng/mL in human plasma using inexpensive disposable glass-coated substrates that can be prepared in 1 h to get results in seconds with good recovery between 98.77 and 100.64%. The sensors provided fast, simple, selective, molecular-specific and inexpensive procedures to determine molecules in their pure form and biological fluid. [ABSTRACT FROM AUTHOR]

Silver and gold nanoparticles have found extensive biomedical applications due to their strong localized surface plasmon resonance (LSPR) and intriguing plasmonic properties. This review article focuses on the correlation among particle geometry, plasmon properties and biomedical applications. It discusses how particle shape and size are tailored via controllable synthetic approaches, and how plasmonic properties are tuned by particle shape and size, which are embodied by nanospheres, nanorods, nanocubes, nanocages, nanostars and core–shell composites. This article summarizes the design strategies for the use of silver and gold nanoparticles in plasmon-enhanced fluorescence, surface-enhanced Raman scattering (SERS), electroluminescence, and photoelectrochemistry. It especially discusses how to use plasmonic nanoparticles to construct optical probes including colorimetric, SERS and plasmonic fluorescence probes (labels/reporters). It also demonstrates the employment of Ag and Au nanoparticles in polymer- and paper-based microfluidic devices for point-of-care testing (POCT). In addition, this article highlights how to utilize plasmonic nanoparticles for in vitro and in vivo bio-imaging based on SERS, fluorescence, photoacoustic and dark-field models. Finally, this article shows perspectives in plasmon-enhanced photothermal and photodynamic therapy. [ABSTRACT FROM AUTHOR]

• Eco-friendly synthesis of gold and silver nanoparticles using Solanum nigrum root extract, characterized using various techniques (XRD, UV–Vis, FTIR, TEM, SAED and EDAX). • Dose-dependent lung cancer activity is evaluated. • Environmental remediation against methylene blue and methylene orange dyes. • Antibacterial assessment targeting Salmonella typhi and Staphylococcus aureus. In this study, we utilized the natural reducing and stabilizing properties of Solanum nigrum root (SNR) to create nanoscale gold and silver particles, and explored their potential for anticancer, antibacterial, and photocatalytic applications. Natural source-based nanoparticle preparation was achieved by combining root extract with aqueous solutions of chloroauric acid and silver nitrate. The produced nanoparticles were recognized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible spectroscopy (UV–VIS), Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), and Energy-Dispersive X-ray spectroscopy (EDAX). Resulting nanoscale particles had diameters of 22.35 nm and 11.85 nm for gold and silver nanoparticles synthesized using a 5 ml SNR extract. While 16.06 nm and 8.72 nm sized gold and silver nanoparticles were synthesized using a 10 ml SNR extract. Their antibacterial properties were tested against Salmonella typhi and Staphylococcus aureus. Staphylococcus aureus showed the highest inhibitory activity. To evaluate the effectiveness of NPs in treating lung cancer, in vitro experiments were performed utilising the A549 cell line. The remarkable performance of gold and silver nanoparticles in the photocatalytic degradation of methylene blue and methylene orange was demonstrated. This research contributes to Solanum nigrum -derived metal nanoparticles and their multifunctional capabilities, paving the way for new prospects in cancer therapeutics, antibacterial agents, and environmental remediation strategies. [ABSTRACT FROM AUTHOR]

This work has focused on the development of a new analytical alternative based on the laser-induced breakdown spectroscopy (LIBS) technique for the fast, reliable, and economical determination of the gold and silver nanoparticle content in a low linear concentration range between 2.9 and 0.058 μg mL−1 and 2.9–0.116 μg mL−1, respectively, without requiring complicated sample pretreatment procedures or advanced separation techniques. Metallic nanoparticles are currently essential materials for the development of new technologies in different scientific and technical areas. However, numerous studies have pointed out these nanomaterials' toxic and polluting potential and the various health implications for humans, animals, and the ecosystem. The current reality reflects the lack of analytical techniques with low economic, environmental, and health impacts and the capacity to quantify the total metallic nanoparticle content. For this purpose, a novel and simple method for the selective capture of gold and silver nanoparticles, consisting of a chemically functionalized glass surface, has been custom-developed for subsequent analysis with LIBS. The results show that the proposed method, employing a functionalized sample glass support, presents a suitable analytical performance characterized by increased sensitivity, specifically 4.7% and 329.2% for Au-NPs and Ag-NPs, and proportionally decreased error in the slope and intercept of the calibration curves, 68% for Au-NPs and 87% for Ag-NPs, respectively. [ABSTRACT FROM AUTHOR]

The global increase in multidrug-resistant bacteria poses a challenge to public health and requires the development of new antibacterial materials. In this study, we examined the bactericidal properties of mesoporous silica-coated silver nanoparticles, varying the core sizes (ca. 28 nm and 51 nm). We also investigated gold nanoparticles (ca. 26 nm) coated with mesoporous silica as possible inert metal cores. To investigate the modification of antimicrobial activity after the surface charge change, we used silver nanoparticles with a silver core of 28 nm coated with a mesoporous shell (ca. 16 nm) and functionalized with a terminal amine group. Furthermore, we developed a facile method to create mesoporous silica-coated silver nanoparticles (Ag@mSiO2) doped films using polyurethane (IROGRAN®) as a polymer matrix via solution casting. The antibacterial effects of silver nanoparticles with different core sizes were analyzed against Gram-negative and Gram-positive bacteria relevant to the healthcare and food industry. The results demonstrated that gold nanoparticles were inert, while silver nanoparticles exhibited antibacterial effects against Gram-negative (Escherichia coli and Salmonella enterica subsp. enterica serovar Choleraesuis) and Gram-positive (Bacillus cereus) strains. In particular, the larger Ag@mSiO2 nanoparticles showed a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) of 18 µg/mL in the Salmonella strain. Furthermore, upon terminal amine functionalization, reversing the surface charge to positive values, there was a significant increase in the antibacterial activity of the NPs compared to their negative counterparts. Finally, the antimicrobial properties of the nanoparticle-doped polyurethane films revealed a substantial improvement in antibacterial efficacy. This study provides valuable information on the potential of mesoporous silica-coated silver nanoparticles and their applications in fighting multidrug-resistant bacteria, especially in the healthcare and food industries. [ABSTRACT FROM AUTHOR]

Globally, cardiovascular diseases (CVDs) are the leading cause of death and disability. While there are many therapeutic alternatives available for the management of CVDs, the majority of classic therapeutic strategies were found to be ineffective at stopping or significantly/additionally slowing the progression of these diseases, or they had unfavorable side effects. Numerous metal-based nanoparticles (NPs) have been created to overcome these limitations, demonstrating encouraging possibilities in the treatment of CVDs due to advancements in nanotechnology. Metallic nanomaterials, including gold, silver, and iron, come in various shapes, sizes, and geometries. Metallic NPs are generally smaller and have more specialized physical, chemical, and biological properties. Metal-based NPs may come in various forms, such as nanoshells, nanorods, and nanospheres, and they have been studied the most. Massive potential applications for these metal nanomaterial structures include supporting molecular imaging, serving as drug delivery systems, enhancing radiation-based anticancer therapy, supplying photothermal transforming effects for thermal therapy, and being compounds with bactericidal, fungicidal, and antiviral qualities that may be helpful for cardiovascular diseases. In this context, the present paper aims to review the applications of relevant metal and metal oxide nanoparticles in CVDs, creating an up-to-date framework that aids researchers in developing more efficient treatment strategies. [ABSTRACT FROM AUTHOR]

In this study, p(CTP‐co‐MMCA) microparticles, a novel cyclomatrix polyphosphazene, were synthesized. Among the p(CTP‐co‐MMCA) polymeric structures, p(CTP‐co‐MMCA) (1 : 3) with a high surface amine group was found to be in the form of microparticles after detailed structural and morphological characterization. These microparticles were modified with Au0 and Ag0 nanoparticles using two different green reductants. The antimicrobial activities of p(CTP‐co‐MMCA) microparticles and their Au0 and Ag0 composites against P.Aeruginosa ATCC 27853, S.Aureus ATCC 6538 and C.Albicans were investigated. Metal composites were found to have better antimicrobial activity. Cyclomatrix p(CTP‐co‐MMCA) microparticles with antimicrobial properties and their Au0 and Ag0 composites were also used for the release of Ceftriaxone sodium and RNA. Cyclomatrix p(CTP‐co‐MMCA) microparticles and its Au0 and Ag0 composites retained 48.21±5.34 mg/g, 49.36±6.95 mg/g and 23.95±6.45 mg/g ceftriaxone sodium, respectively, while they retained 79.15±6.85 mg/g, 47.49±6.24 mg/g and 57.47±9.48 mg/g RNA, respectively. Release studies revealed that the presence of Au0 and Ag0 nanoparticles imparted a slower release behavior to p(CTP‐co‐MMCA) microparticles. The release studies revealed that the presence of Au0 and Ag0 nanoparticles imparted a slower release behavior to the p(CTP‐co‐MMCA) microparticles. [ABSTRACT FROM AUTHOR]

Through plasmon resonance, silver and gold nanoparticles can selectively backscatter light within different regions of the visible electromagnetic spectrum. We engineered a plasmonic film technology that utilizes gold and silver nanoparticles to enhance light at the necessary wavelengths for microalgal photosynthetic activities. Nanoparticles were embedded in a polymeric matrix to fabricate millimeter-thin plasmonic films that can be used as light filters in microalgal photobioreactors. Experiments conducted with microalga Chlamydomonas reinhardtii proved that microalgal growth and photosynthetic pigment production can be increased by up to 50% and 78%, respectively, by using these plasmonic film light filters. This work provides a scalable strategy for the efficient production of specialty chemicals and biofuels from microalgae through irradiation control with plasmonic nanoparticles. [ABSTRACT FROM AUTHOR]

Metal nanoparticle formation using laser ablation of targets in water by picosecond pulses is a well-developed process. Here we demonstrate how the salt and sugar being dissolved in water differently affect the spectral characteristics of the absorbance of the suspensions produced during ablation of silver and gold targets. We demonstrate the disappearance of the surface plasmon resonances of Ag and Au nanoparticles in the salt-containing solutions. The presence of salt does not allow for maintaining the synthesis of nanoparticles during ablation of metals contrary to the sugar-containing solution. Our nonlinear optical studies show that the saturable absorption observed in the nanoparticles-containing suspensions produced during laser ablation of silver and gold in distilled water and sugar-containing water entirely disappears in the case of the suspension produced during the ablation of these metals in salt-containing solution. [ABSTRACT FROM AUTHOR]

The colorimetric method is a common detection method in biosensing, which has received much attention because of its high sensitivity and specificity. Among them, multicolor colorimetric method based on multicolor probes has become a hot research topic in recent years. Its sensitivity is significantly higher than that of monochromatic colorimetric method, and it has higher resolution which can be visualized for semiquantitative detection by naked eye recognition, quickly quantified by calculating color ratios or based on smartphone image processing software. Based on three different color development mechanisms： organic small molecule fluorescence, nanomaterial color development and enzymatic reaction color development, the detection mechanisms of multicolor fluorescent small molecule probes, multicolor nanomaterial colorimetric probes and multicolor enzymatic reaction colorimetric probes are reviewed and their applications in practical sample detection are discussed. The challenges and future development opportunities are also discussed. [ABSTRACT FROM AUTHOR]

Plasmonic nanoparticles are an emerging tool for developing label-free multicolorimetric sensors for biosensing and chemosensing applications. The color absorbed by nanoparticles from visible light is influenced by their size, shape, orientation, and interparticle distance. Differently sized and shaped gold and silver nanoparticles exhibit a wide range of colors, aiding in the development of label-free sensors. Etching is the process of oxidizing nanoparticles, which alters their aspect ratio, shape, plasmonic peak, and outward appearance. It is typically used to create sensitive sensing platforms. Through etching, analytes could be detected in a simple, sensitive, and selective manner. The multicolor readout of nanoparticle etching-based multicolorimetric sensors can overcome the limitations of conventional colorimetric assays and improve the accuracy of visual inspection. This review discusses different approaches for target sensing using nanoparticle etching strategies like direct etching, enzyme-mediated etching, chemical reaction-driven etching, and anti-etching-based sensors and their mechanisms. In the future, etching strategies could be modified into portable sensing devices to detect a variety of analytes, which will aid in the development of on-time, in situ, and point-of-care sensing systems. [ABSTRACT FROM AUTHOR]

Nanometals constitute a rapidly growing area of research within nanotechnology. Nanosilver and nanogold exhibit significant antimicrobial, antifungal, antiviral, anti-inflammatory, anti-angiogenic, and anticancer properties. The size and shape of nanoparticles are critical for determining their antimicrobial activity. In this study, silver and gold nanoparticles were synthesized within a hyaluronic acid matrix utilizing distilled water and distilled water treated with low-pressure, low-temperature glow plasma in an environment of air and argon. Electron microscopy, UV-Vis and FTIR spectra, water, and mechanical measurements were conducted to investigate the properties of nanometallic composites. This study also examined their microbiological properties. This study demonstrated that the properties of the composites differed depending on the preparation conditions, encompassing physicochemical and microbiological properties. The application of plasma-treated water under both air and argon had a significant effect on the size and distribution of nanometals. Silver nanoparticles were obtained between the range of 5 to 25 nm, while gold nanoparticles varied between 10 to 35 nm. The results indicate that the conditions under which silver and gold nanoparticles are produced have a significant effect on their mechanical and antibacterial properties. [ABSTRACT FROM AUTHOR]

Poly(tartaric acid) is a relatively recently described polymer that can be easily synthesized and scaled up from a readily available renewable material (tartaric acid). This article demonstrates its use in a green synthesis of gold nanoparticles, silver nanoparticles, copper particles, and magnetite nanoparticles. In this case poly(tartaric acid) acts both as a reductant and as a coating agent. To our knowledge this is the first green synthesis of several different types of nanoparticles using only one reagent (polytartrate) as both reductant and coating. The resulting particles were analyzed by XRD, TEM/SEM, EDX, FTIR, DLS, zeta-potential, XPS, and UV/VIS spectroscopy. Preliminary studies of the thermal behavior of mixtures of different types of particles with poly(tartaric acid) were also conducted. The obtained particles show different sizes depending on the material, and the coating allows for better dispersibility as well as potential further functionalization, making them potentially useful also for other applications, besides the inclusion in polymer composites. [ABSTRACT FROM AUTHOR]

Endophytes are organism dwelling totally dynamic and novel biotopes this makes them able to produce novel biochemicals that may become assets to the future. This study aims at understanding the biochemical components of the endophytic fungus Phlebia sp. synthesis of gold and silver nanoparticles from it, and the antimicrobial as well as antioxidant ability of these green synthesised nanoparticles. Aqueous fungal extract was subjected for HRLCMS analysis which revealed 34 biochemicals within the extract. Silver and gold nanoparticles were also produced from the fungal extract. UV–vis analysis revealed a peak at 450 nm for silver nanoparticle and 550 nm for gold nanoparticles. FESEM analysis confirmed the presence of these nanoparticles with its spherical shape. Both of these nanoparticles were able to produce a conspicuous zone of inhibition in the antimicrobial tests against Escherichia coli, Salmonella paratyphi. For both of the organisms under study, a concentration-dependent expansion of the zone of inhibition was discovered in the nanoparticles. However, with silver nanoparticles, a relatively high zone of inhibition and vulnerability of the organism was discovered. Four in vitro free radical scavenging assays, including the DPPH, Hydroxyl, Superoxide, and Nitric oxide radical scavenging assays, were used for antioxidant analysis. The results of every test demonstrated that green synthesised silver nanoparticles had higher activity than gold nanoparticles. All of the tests showed that silver nanoparticles were more active than gold nanoparticles with the maximum value of 86.254 ± 0.296% being discovered at the greatest concentration of superoxide radical scavenging assay. [ABSTRACT FROM AUTHOR]

The design and development of silver and gold nanoparticles incorporated into silk fibroin and gelatin composite nanofibers were prepared using the electrospun method. The functional group, chemical composition, and thermal stability of composite nanofibrous scaffolds were investigated using different characterization techniques. The confirmation of SF/GL/Ag-Au composite nanofibers was achieved through FE-SEM and AFM images, which proved to be highly beneficial for assessing surface morphology, thickness, and roughness area (Ra) with dimensions of 777 nm and 292.71 nm, respectively. Furthermore, HR-TEM images were used to elucidate the morphological structure and size of metal nanoparticles in SF/GL/Ag-Au composite nanofibers, revealing an average diameter length of 220.85 ± 82.65 nm for Ag and Au nanoparticles sizes noted at 6.25 nm and 11.56 nm. In addition, flow cytometry analysis of SF/GL/Ag-Au composite nanofibers was conducted to assess the viability of L929 cells and detect the apoptosis levels. Furthermore, invivo wound healing studies were performed on Sprague-Dawley rat animals. The results demonstrated that SF/GL/Ag-Au composite nanofiber scaffolds significantly accelerated wound closure, achieving a remarkable 99.58 % wound healing rate in the 21 days compared to control groups. In conclusion, our findings highlight that SF/GL/Ag-Au composite nanofiber scaffolds are highly suitable for wound dressing applications. [Display omitted] • The SF/GL/Ag-Au composite nanofiber was prepared through the electrospinning method. • Silk fibroin and gelatin act as reducing and stabilizing agents for metal nanoparticles. • The average diameter length of SF/GL/Ag-Au composite nanofibers is 220.85 ± 82.65 nm. • Flow cytometry analysis is more beneficial for detecting apoptosis and cell viability. • SF/GL/Ag-Au composite nanofiber is the most effective material for wound dressing applications. [ABSTRACT FROM AUTHOR]

Green synthesized silver/gold nanoparticles (Ag/Au NPs) with an average size of 19 nm have been added to polyethylene glycol/sodium alginate (PEG/NaAlg) by the casting technique. The PEG/NaAlg blend's semicrystalline structure was revealed by the XRD, which also showed peaks that indicated the existence of silver and gold nanoparticles. Diffraction peak intensities change when Ag/Au NPs are added to the blend, indicating that some PEG/NaAlg composite domains are broken by the blend-Ag/Au NP interactions. A change in peak position and intensity is observed in the FT-IR absorption spectrum after adding Ag/Au nanoparticles. The optical characteristics were studied by analyzing the UV–Vis absorbance spectrum. Incorporating Ag/Au NPs reduced band-gap values, confirming that Ag/Au NPs can be used in many applications as band-gap-regulated optical materials. The Optical band gap values decrease in the presence of Ag/Au NPs due to the correlation between defect levels and localized state density. All of the samples follow Jonscher's power law in their AC conductivity spectra. Maximum values of ε′′ at lower frequencies were associated with an increase in energy loss in the fabricated composites, while maximum values of ε′ at lower frequencies were associated with the influence of the interfacial polarization generated by charge accumulation. A semicircle arc can be seen on the Cole–Cole plot because of the relaxation process and grain boundary. The prepared films become polarized and have a greater capacity to store electrical energy when exposed to an electric field. These composite materials can be utilized in flexible capacitors. [ABSTRACT FROM AUTHOR]

The discrete sources method is adapted to the study of surface quantum effects based on mesoscopic boundary conditions with Feibelman parameters. A comparative analysis of the influence of bulk nonlocal effects and surface effects on optical characteristics of gold and silver nanoparticles is carried out using the generalized nonlocal optical response model. It is established that allowance for the nonlocal effect in the noble metals always leads to a reduced amplitude of the surface plasmon resonance (SPR) and its blue shift, while the surface effect depends substantially on the geometry of the particles. To a large degree, the mesoscopic boundary conditions recover the SPR amplitude as compared with the bulk nonlocal effect. This difference is especially noticeable in the field enhancement factor on the surface of the particles. Additionally, substantial differences in the SPR behavior for gold and silver particles are found in the case of mesoscopic boundary conditions. [ABSTRACT FROM AUTHOR]

The biomedical applications of the noble metal nanoparticles have been the field of interest, especially in cancer therapy. In this paper, the synthesis of spherical silver and gold nanoparticles and their apoptotic activity against breast cancer cells is reported. The chemicals reduction method is used to synthesize nanoparticles. Two different types of surfactants i.e., citrate and polyvinylpyrrolidone were used as a reducing and capping agent. The synthesized nanoparticles have been characterized using X-ray diffraction, ultraviolet-visible absorption spectroscopy, dynamic light scattering, zeta potential and transmission electron microscopy. The synthesized nanoparticles have crystalline phase with average size in the range of 25-30 nm and possess negative surface charge. In vitro studies of nanoparticles against breast cancer cells (MCF-7), were performed. The results show the significant cytotoxicity of nanoparticles against the cancer cell line and found to be mediated by DNA damage. [ABSTRACT FROM AUTHOR]

The therapeutic success of nanomedicines requires nanomaterials to either adhere to the surface or internalize within the cytoplasm. The endocytosis phenomenon is controlled by the nanomaterial's shape, size, composition, charge, and capping molecules. The membrane potential‐based non‐specific internalization of therapeutic nanomedicines offers limited benefits than receptor‐based specific delivery. Glut receptor‐based internalization of glucose molecules is a well‐known process in cancerous cells, which is one of the most exploited strategies to target cancer cells using nanoparticles. However, the internalization process of other structurally similar monosaccharides (D‐Galactose, Mannose, and D‐Fructose) conjugated nanoparticles remains to be unexplored. Herein, D‐Glucose, D‐Galactose, Mannose, and D‐Fructose‐coated AuNPs and AgNPs have been synthesized and studied the role of Glut receptors in their internalization in liver cancer cells, and compared them with non‐cancerous cells. Results revealed that almost all monosaccharide‐coated NPs exhibited high uptake in liver cancer cells than non‐cancerous cells. Glut‐1 receptor is observed to play a key role in the uptake and inhibition of Glut‐1 receptors by genistein lead to a significant decrease in nanoparticle uptake. In conclusion, monosaccharide‐conjugated nanoparticles can be used to direct the selective internalization of AuNPs and AgNPs in hepatic cancer cells to realize therapeutic and imaging applications. [ABSTRACT FROM AUTHOR]

Monodispersed and spherical gold nanoparticles and over nanoparticles with average is about 50 nm and 45 nm respectively, were synthesized by chemical reduction method using gearing as the protective agents, chioroauric aid SOUSE and over nitrate as metal source, hydrant hydrate as riding agents. UV-vis spectrum (UV-vis), X-ray powder diffraction ( XRD), flourier transform mortared spectrometer (FT-IR)and scorning electron microscope (SEM)were used to check the as-prepared gold and over nanoparticles. Some influencing factors nan the process of preparation of gold and over nanoparticles are briefly discussed. The results show that the prepared gold and over nanopaerieles are small Nan is with narrow distriburion. The amounts of precursor soon, reducing agent and gelatin solution play important roles in the size and morphologies of gold and silver nanoparticles. As the amount of precursor solution, reducing agents and gelatin solution increased, the particles size showed a trend of first decreasing and then increasing. The optimized processing parameters nan this research for preparation of gold and silver nanoparticles can be obtained when the consumption of gelatin solution, precursor solution, and redoing agent is 5,2 and 2 mL,respectively. [ABSTRACT FROM AUTHOR]

This paper presents a simple, fast, and inexpensive method for the large-scale fabrication of polymer-based humidity sensors on glass substrates. The nanoparticles were synthesized using laser ablation, this is an environmentally friendly method for fabricating metal nanoparticles and provides a unique tool for nanofabrication. In this work, humidity sensing material, poly(3,4 ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) along with different kinds of nanoparticles, Au and Ag, are employed to enhance the stability and sensitivity to humidity sensing. Based on the experimental results, the TEM images show the crystallinity of the nanoparticles, indicating alloying of the nanoparticles. Based on XRD, this result indicates that the amorphous structure of PEDOT:PSS is only slightly affected by mixing with nanoparticles. According to FE-SEM analysis, the formation of interconnected crystallites facilitates the charge transport mechanism in the polymer chains due to improved conduction paths. Has been Characterization of humidity sensors Using (LCR), study the effect of humidity on capacitance at different frequencies (100 Hz, 1 kHz, 10 kHz, and 100 kHz), and the response and recovery time characteristics. The results show excellent linear and active behavior of the capacitive humidity response. Ag, PEDOT, and Au NPs have a synergistic effect, exhibiting a more extended sensing range and better stability. This work shows a high-sensitivity and low-cost sensing material for different humidity sensor applications. [ABSTRACT FROM AUTHOR]

Metal nanoparticles (NPs) have garnered considerable attention, due to their unique physicochemical properties, that render them promising candidates for various applications in medicine and industry. This article offers a comprehensive overview of the most recent advancements in the manufacturing, characterization, and biomedical utilization of metal NPs, with a primary focus on silver and gold NPs. Their potential as effective anticancer, anti-inflammatory, and antimicrobial agents, drug delivery systems, and imaging agents in the diagnosis and treatment of a variety of disorders is reviewed. Moreover, their translation to therapeutic settings, and the issue of their inclusion in clinical trials, are assessed in light of over 30 clinical investigations that concentrate on administering either silver or gold NPs in conditions ranging from nosocomial infections to different types of cancers. This paper aims not only to examine the biocompatibility of nanomaterials but also to emphasize potential challenges that may limit their safe integration into healthcare practices. More than 100 nanomedicines are currently on the market, which justifies ongoing study into the use of nanomaterials in medicine. Overall, the present review aims to highlight the potential of silver and gold NPs as innovative and effective therapeutics in the field of biomedicine, citing some of their most relevant current applications. [ABSTRACT FROM AUTHOR]

This study reports the successful fabrication of complex 3D metal nanoparticle–polymer nanocomposites using two‐photon polymerization (2PP). Three complementary strategies are detailed: in situ formation of metal nanoparticles (MeNPs) through a single‐step photoreduction process, integration of pre‐formed MeNPs into 2PP resin, and site‐selective MeNPs decoration of 3D 2PP structures. In the in situ formation strategy, a phase‐transfer method is applied to transfer silver and copper ions from an aqueous phase into a toluene solvent to disperse them in photoreactive monomers.The addition of a photosensitive dye, coumarin 30, facilitated the reduction of silver ions and improved the distribution of silver nanoparticles (AgNPs). This strategy is successfully used to produce other MeNPs, such as Cu and Au. The integration of pre‐formed MeNPs enabled highly controlled NP size distribution within the 2PP 3D structures with high‐fidelity To enable selective decoration of 2PP 3D surfaces with MeNPs, a multimaterial strategy is developed, with one of the resins designed for thiol‐ene reaction, which demonstrated selective binding to AuNPs. The successful development of complementary strategies for integration of MeNPs into 2PP resins offers exciting opportunities for fabrication of MeNP composites with sub‐micron resolution for applications from photonics to metamaterials and drug delivery. [ABSTRACT FROM AUTHOR]

Nanoparticle-based electrochemical immunosensors demonstrate high sensitivity toward biomarker detection due to the large surface area of the nanoparticles and their ability to amplify the signal of the target molecule. Additionally, they have a fast response time, relatively lower cost, and can be easily miniaturized for point-of-care applications. Among noble metals, silver nanoparticles (AgNPs) have been extensively used in electrochemical sensors due to their unique properties, such as catalytic activity and excellent electrical conductivity. This Feature Article describes six approaches for incorporating AgNPs in electrochemical platforms, featuring the most recent developments in the silver–gold galvanic exchange-based detection strategy. With a few exceptions, many of these detection methods use AgNP oxidation into Ag+ ions, followed by electrodeposition of Ag+ ions onto the working electrode as zero-valent Ag metal and a final stripping step using a voltammetric technique. Combining these steps provides desirable low detection limits and good sensitivity for various biomarkers. A few other methods involved the reduction of Ag+ ions and depositing them as Ag metal onto the electrode using a reagent mixture so that the striping analysis could be performed. Typically, this reagent mixture includes Ag+ ions, a reducing agent, or an enzyme substrate. Besides, AgNPs have also been directly used to modify the surface of electrodes to facilitate kinetically favored redox-mediated electrochemical reactions. In addition to Ag detection methods, this report will also provide recent examples to illustrate how the size and shape of AgNPs impact the detection limits and sensitivity of an electrochemical assay. Finally, we discuss recent developments in lab-on-a-chip type immunosensors designed explicitly for Ag-based metalloimmunoassay detection, and we envision that this article will provide a comprehensive summary of the operational principles and new insights into such immunoassay systems. [ABSTRACT FROM AUTHOR]

This paper explores the photochemical synthesis of noble metal nanoparticles, specifically gold (Au) and silver (Ag) nanoparticles, using a one-component photoinitiator system. The synthesis process involves visible light irradiation at a wavelength of 419 nm and an intensity of 250 mW/cm2. The radical-generating capabilities of the photoinitiators were evaluated using electron spin resonance (ESR) spectroscopy. The main objective of this study was to investigate how the concentration of metal salts influences the size and distribution of the nanoparticles. Proposed mechanisms for the photochemical formation of nanoparticles through photoinitiated radicals were validated using cyclic voltammetry. The results showed that the concentration of AgNO3 significantly impacted the size of silver nanoparticles, with diameters ranging from 1 to 5 nm at 1 wt% and 3 wt% concentrations, while increasing the concentration to 5 wt% led to an increase in the diameter of silver nanoparticles to 16 nm. When HAuCl4 was used instead of AgNO3, it was found that the average diameters of gold nanoparticles synthesized using both photoinitiators at different concentrations ranged between 1 and 4 nm. The findings suggest that variations in HAuCl4 concentration have minimal impact on the size of gold nanoparticles. The photoproduction of AuNPs was shown to be thermodynamically favorable, with the reduction of HAuCl4 to Au0 having ∆G values of approximately −3.51 and −2.96 eV for photoinitiators A and B, respectively. Furthermore, the photoreduction of Ag+1 to Ag0 was demonstrated to be thermodynamically feasible, with ∆G values of approximately −3.459 and −2.91 eV for photoinitiators A and B, respectively, confirming the effectiveness of the new photoinitiators on the production of nanoparticles. The synthesis of nanoparticles was monitored using UV-vis absorption spectroscopy, and their sizes were determined through particle size analysis of transmission electron microscopy (TEM) images. [ABSTRACT FROM AUTHOR]

Exposure to metal nanoparticles is potentially harmful, particularly when occurring during embryogenesis. In this study, we tested the effects of commercial AuNPs and AgNPs, widely used in many fields for their features, on the early development of Xenopus laevis, an anuran amphibian key model species in toxicity testing. Through the Frog Embryo Teratogenesis Assay—Xenopus test (FETAX), we ascertained that both nanoparticles did not influence the survival rate but induced morphological anomalies like modifications of head and branchial arch cartilages, depigmentation of the dorsal area, damage to the intestinal brush border, and heart rate alteration. The expression of genes involved in the early pathways of embryo development was also modified. This study suggests that both types of nanoparticles are toxic though nonlethal, thus indicating that their use requires attention and further study to better clarify their activity in animals and, more importantly, in humans. [ABSTRACT FROM AUTHOR]

Facile synthesis of metal nanoparticles with controlled physicochemical properties using environment-friendly reagents can open new avenues in biomedical applications. Nanomaterials with controlled physicochemical properties have opened new prospects for a variety of applications. In the present study, we report a single-step photochemical synthesis of ~5 nm-sized silver (Ag) and gold (Au) nanoparticles (NPs), and Ag–Au alloy nanoparticles using L-tyrosine. The physicochemical and surface properties of both monometallic and bimetallic NPs were investigated by analytical, spectroscopic, and microscopic techniques. Our results also displayed an interaction between L-tyrosine and surface atoms that leads to the formation of AgAu NPs by preventing the growth and aggregation of the NPs. This method efficiently produced monodispersed NPs, with a narrow-sized distribution and good stability in an aqueous solution. The cytotoxicity assessment performed on breast cancer cell lines (MCF-7) revealed that the biofriendly L-tyrosine-capped AgNPs, AuNPs, and bimetallic AgAu NPs were biocompatible. Interestingly, AgAu NPs have also unveiled controlled cytotoxicity, cell viability, and in vitro peroxidase nanozyme activity reliant on metal composition and surface coating. [ABSTRACT FROM AUTHOR]

Cancer is still a leading cause of deaths worldwide, especially due to those cases diagnosed at late stages with metastases that are still considered untreatable and are managed in such a way that a lengthy chronic state is achieved. Nanotechnology has been acknowledged as one possible solution to improve existing cancer treatments, but also as an innovative approach to developing new therapeutic solutions that will lower systemic toxicity and increase targeted action on tumors and metastatic tumor cells. In particular, the nanoparticles studied in the context of cancer treatment include organic and inorganic particles whose role may often be expanded into diagnostic applications. Some of the best studied nanoparticles include metallic gold and silver nanoparticles, quantum dots, polymeric nanoparticles, carbon nanotubes and graphene, with diverse mechanisms of action such as, for example, the increased induction of reactive oxygen species, increased cellular uptake and functionalization properties for improved targeted delivery. Recently, novel nanoparticles for improved cancer cell targeting also include nanobubbles, which have already demonstrated increased localization of anticancer molecules in tumor tissues. In this review, we will accordingly present and discuss state-of-the-art nanoparticles and nano-formulations for cancer treatment and limitations for their application in a clinical setting. [ABSTRACT FROM AUTHOR]

The present investigation is relevant to the multiphase flow of non-Newtonian fluid passing through the steep channel. Third-grade fluid is taken as the base liquid, while two different types of metallic particles are considered to form nano-suspensions. Two different plane flows are devised based on the development of rigid walls of the inclined channels. A comprehensive apprehension regarding the nonlinear flow dynamics is carried out with the help of a regular perturbation method, which is effectively less time-consuming and more analogous to analytic. Moreover, a comparative analysis depicts complete harmony with the existing literature. In addition, the current study reduces back to the customary nanofluid problem for the limiting case. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) has been used for trace detection at the single-molecule level. The low-cost preparation of high-performance test strips has enabled the development of SERS techniques. In this study, oil-dispersible metal or alloy nanoparticles prepared by the Brust-Schiffrin method were used as "inks" in a ballpoint pen to handwrite SERS test strips on polytetrafluoroethylene (PTFE) membranes. Because of the good PTFE lipophilicity, the flexible substrates had good uniformity. The large laser damage threshold of the PTFE membrane also enabled increased laser powers for SERS testing. The Au and Ag alloy nanoparticle inks exhibited increased performance with larger proportions of Ag. The Au1Ag8 nanoparticles had the best properties, and those strips could detect 10-11-M Rhodamine 6G dyes in a 10-µL volume with an enhancement factor of 5.4×108. The SERS strips were used to demonstrate detection of malachite green, the use of which is prohibited in aquaculture and fish tanks. [ABSTRACT FROM AUTHOR]

A simple, affordable and green method for synthesis gold (Au) and sliver (Ag) nanoparticles (NPs) has been adopted using Thyme plant (Thymus kotschyanus) extract. The plant extract, being rich in polyphenolic compounds, act as natural green reducing agent to generate noble metal NPs in situ from their corresponding ions. The structural and physical characteristics of the synthesized nanoparticles were ascertained over Ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Transmission electron microscopy (TEM) analysis. Both of the NPs displayed Surface Resonance Plasmon (SPR) excitation. The Synthesized Ag/Thyme NPs and Au/Thyme NPs catalytically explored in the reduction of 4-nitrophenol in presence of sodium borohydride as hydrogen donor. While used in different concentrations (100 µg/mL, 200 µg/mL and 300 µg/mL) as catalyst, it was seen that the activity gradually increased with higher catalyst load. The kinetic study of the reactions was also performed using the UV–Vis analysis data. All the reactions were of pseudo first order kinetics. The catalysts were isolated by centrifuge and recycled 6 successive times without any significant loss of its catalytic activity. As a result, at the same conditions, the reaction in the presence of Au NPs is faster than the reaction in the presence of Ag NPs. In summary, the noble gold and silver nanoparticles were synthesized over Thyme plant extract in a bio-inspired pathway. [ABSTRACT FROM AUTHOR]

Novel methods for high-performance detection of Hg2+ in seafood are critical for ensuring food safety and human health. Herein, Ag nanoparticles (Ag NPs) were successfully deposited on carbon microspheres (CMs) to form Ag NPs-CMs nanocomplex. The proposed Ag NPs-CMs could oxidize colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidation state TMB (oxTMB) in the presence of hydrogen peroxide (H2O2) and had a significant UV–vis absorption peak at 652 nm. The excellent peroxidase-like activity was attributed to the increased electrostatic attraction of CMs and the catalytic synergistic effect. After adding Hg2+, the catalytic activity of Ag NPs-CMs was specifically enhanced and the Michaelis–Menten constant (Km) decreased from 0.067 to 0.052 mmol/L due to the formation of Ag-Hg amalgam which produced more superoxide anions (O2•−) and hydroxyl radicals (•OH). The linear response ranges for Hg2+ were 2~833 nmol/L and 2.5~40 μmol/L, with the low detection limit of 1.10 nmol/L. This method was applied to detect Hg2+ in seafood with satisfactory recoveries of 95.65~106.56%. A hydrogel kit was designed for portable detection of Hg2+, and the response range was 0.5~5 μmol/L. This work provides a reliable method for visual Hg2+ detection in seafood as well as a feasible strategy for the design of high-performance nanozymes. [ABSTRACT FROM AUTHOR]

Percolative memristive networks based on self-organized ensembles of silver and gold nanoparticles are synthesized and investigated. Using cyclic voltammetry, pulse and step voltage excitations, we study switching between memristive and capacitive states below the percolation threshold. The resulting systems demonstrate scale-free (self-similar) temporal dynamics, long-term correlations, and synaptic plasticity. The observed plasticity can be manipulated in a controlled manner. The simplified stochastic model of resistance dynamics in memristive networks is testified. A phase field model based on the Cahn–Hilliard and Ginzburg–Landau equations is proposed to describe the dynamics of a self-organized network during the dissolution of filaments. [ABSTRACT FROM AUTHOR]

A lot of innovative methods to synthesize various kinds of nanoparticles having specific shape and size are being explored for targeting immense applications through nanotechnology. In this work, simple, eco-friendly and cost-effective method has been adopted for the synthesis of silver (Ag), gold (Au) and palladium (Pd) nanoparticles using tannic acid. The morphology and size of nanoparticles were determined by TEM study, which revealed that nanoparticles are spherical in shape and exhibit an average diameter of about 6.66 nm, 12.24 nm and 19.65 nm for tannic acid mediated silver, gold and palladium nanoparticles (TA-AgNPs, TA-AuNPs and TA-PdNPs), respectively. The application of these nanoparticles was then explored as catalyst for the degradation of methylene blue and congo red dyes. The presence of these dyes was found to be detrimental for the aquatic life, as these dyes can seep into the ecosystem from the industrial waste. The catalytic activity of nanoparticles was compared by determining rate constant values. For, both the dyes, the value of rate constant followed the order- kAg ˃ kPd ˃ kAu. The dye degradation potential of TA-AgNPs was higher than TA-Au and TA-PdNPs. This difference in catalytic activity was attributed to lower work function value of AgNPs as compared to AuNPs and PdNPs. Present study provides an environmentally benign pathway for synthesizing metallic nanoparticles and their utilization as catalyst for degradation of harmful dyes. Such kinetic studies of comparative catalytic analysis may be useful in selection of nanoparticles, which may be best suited for a specific purpose. [ABSTRACT FROM AUTHOR]

Uropathogenic Escherichia coli (UPEC) is a nosocomial pathogen associated with urinary tract infections and biofilm formation, which contributes to antibiotic resistance. Discovering potent antibacterial agents is crucial. This study aimed to assess the antibacterial and antibiofilm effects of gold and silver nanoparticles on UPEC using Scanning Electron Microscopy (SEM). UPEC biofilms were cultivated on nitrocellulose membranes for 48 hours at 37°C, then treated with gold nanoparticles (50 ppm and 100 ppm) and silver nanoparticles (50 ppm and 100 ppm) for another 48 hours. Antibacterial and antibiofilm activities were evaluated through cell density and SEM analysis. SEM revealed lower cell density, reduced biofilm formation, and altered cell morphology with rough, wrinkled surfaces after nanoparticle treatment. In conclusion, gold and silver nanoparticles exhibit antibacterial and antibiofilm properties, as observed in SEM analysis. SEM is a valuable tool for studying the antimicrobial effects of nano gold and silver on bacterial cell morphology and biofilm populations. [ABSTRACT FROM AUTHOR]

Silver nanoparticles modified with 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (AgNPs-AHMT) have been developed as colorimetric sensors for cortisol detection as a stroke biomarker. This method's principle was based on AgNPs-AHMT aggregation with cortisol due to the hydrogen bonding interaction between the surfaces of AHMT and cortisol. This process caused the color change that can be seen with the naked eye. Then, it is confirmed by ultraviolet-visible (UV-Vis) spectroscopy, particle size analyzer (PSA), Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). The color of colloidal AgNPs-AHMT changed from yellow to brownish orange, giving a red shift in the localized surface plasmon resonance (LSPR) peak. The quantitative monitor for cortisol determination had good linearity in the range of cortisol concentrations of 1.0-50.0 nM, with a limit of detection (LOD) and a limit of quantification (LOQ) of 0.719 nM and 2.37 nM, respectively. The relative standard deviations (RSD%) for intra-day and inter-day were <3.2% and <2.26%, respectively. Moreover, this method was applied for cortisol detection in a saliva sample. So, the simple, rapid, and real-time strategy exhibited a promising potential for cortisol detection in a saliva sample. [ABSTRACT FROM AUTHOR]

The transformation of high-molecular DNA from a random swollen coil in a solution to a discrete nanosized particle with the ordered packaging of a rigid and highly charged double-stranded molecule is one of the amazing phenomena of polymer physics. DNA condensation is a well-known phenomenon in biological systems, yet its molecular mechanism is not clear. Understanding the processes occurring in vivo is necessary for the usage of DNA in the fabrication of new biologically significant nanostructures. Entropy plays a very important role in DNA condensation. DNA conjugates with metal nanoparticles are useful in various fields of nanotechnology. In particular, they can serve as a basis for creating multicomponent nanoplatforms for theranostics. DNA must be in a compact state in such constructions. In this paper, we tested the methods of DNA integration with silver, gold and palladium nanoparticles and analyzed the properties of DNA conjugates with metal nanoparticles using the methods of atomic force microscopy, spectroscopy, viscometry and dynamic light scattering. DNA size, stability and rigidity (persistence length), as well as plasmon resonance peaks in the absorption spectra of systems were studied. The methods for DNA condensation with metal nanoparticles were analyzed. [ABSTRACT FROM AUTHOR]

Zinc nanoparticles (ZnNPs) are showing promising medical applications. However, their cytotoxicity is relatively high. This study aims to use a green synthesis technique based on the natural propolis (honeybees glue) and produce three counterparts of Zinc nanoparticles (ZnO-NPs, AuNPs@ZnO and AgNPs@ZnO). Then, the three would be analyzed for their potential antibacterial activity and cytotoxicity. The study compares the antibacterial activity and cytotoxicity of ZnO-NPs alone to its combination with gold and silver (AuNPs@ZnO and AgNPs@ZnO). The results showed that AgNPs@ZnO had contributed significantly to antibacterial activity against Gram-positive and Gram-negative bacteria. Moreover, AuNPs@ZnO and AgNPs@ZnO showed similar cytotoxicity to ZnO-NPs with higher safety. Furthermore, the Scanning and Transmission Electron Microscopes' micrographs (SEM and TEM) displayed the biosynthesized ZnNPs that have a spherical shape with sizes ranging from 17 to 70 nm, from 45 to 75 nm, and from 22 to 73 nm for ZnONPs, ZnO-AgNPs, free AgNPs, and ZnO-AuNPs, respectively. In addition, zeta potential values for ZnONPs were 11.4 mV, while ZnO-AgNPs and ZnO-AuNPs have a higher overall charge of 13.6 mV and 23.9 mV, respectively. Furthermore, ZnNPs exhibited antibacterial activity, yet AgNPs@ZnO demonstrated the highest antibacterial action against Gram-negative and Gram-positive bacteria. In addition, cytotoxicity analyses of biosynthesized ZnNPs on three cell lines; breast cancer cell (MCF-7), liver cancer cell (HepG-2) and Human skin fibroblast (HSF) revealed that Zn-NPs in a combination could function as an anticancer agent. Therefore, there are promising medical applications for the biosynthesized ZnNPs in combinations with other metals, such as ZnO-AgNPs, as safe antibacterial and anticancer medicines. [ABSTRACT FROM AUTHOR]

Silver and gold nanoparticles were produced using the pinhole discharge generated by dc non-pulsing high voltage directly in a precursor solution. Silver nitrate solution was used as the precursor for silver nanoparticles, and chloroauric acid was used as the precursor for gold nanoparticles. Effects of discharge time, precursor concentration, and additives such as reduction agent (ethylene glycol) and capping agent (polyethylene glycol and sucrose) were studied. Nanoparticles were mainly analyzed by UV-VIS spectrometry. The size of prepared nanoparticles was determined by the dynamic light scattering with backscattering detection. To determine the stability of nanoparticles, the zeta potential was measured by the electrophoretic light scattering. It was found that the absorption maximum of nanoparticles increases with the time of the discharge treatment and concentration of the precursor. The size of silver nanoparticles ranged from 10 to 1000 nm and the final solution had higher polydispersity. The size of Au nanoparticles ranged from 10 to 100 nm, depending on the precursor concentration. The most stable particles were prepared from the pure precursor solution without any additives. The addition of ethylene glycol stimulated the reduction process of nanoparticles from the solution but it decreased their zeta potential. Final particles were less stable, which started to form larger structures that tended to sediment. Added capping agent decreased the input of power needed for the stable discharge operation. The formation of silver and gold nanoparticles was confirmed by scanning electron microscopy with the energy dispersion spectrometer. Both silver and gold particles had spherical shapes. [ABSTRACT FROM AUTHOR]

In conventional time-resolved laser-induced incandescence (TiRe-LII) measurements, a laser pulse heats the nanoparticles within a probe volume of aerosol, and the particle size distribution and other characteristics are inferred from the observed incandescence decay rate, which is connected to the change in sensible energy through a spectroscopic model. There is strong evidence, however, that for some aerosol systems, the incandescence signal is contaminated with other non-incandescent emission sources. Recent TiRe-LII measurements on polydisperse aerosolized silver and gold nanoparticles energized with a 1064 nm laser pulse exhibit broadband emission that is temporally aligned with the temporal profile of the laser pulse, suggesting that the signal is due to non-thermal emission. One candidate for this emission phenomenon is multiphoton-induced upconversion luminescence, in which the conduction-band electron gas is heated up to an effective lattice temperature, resulting in luminescence due to high-energy intraband transitions. [ABSTRACT FROM AUTHOR]