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The coupled processes of coprecipitation and ultrasonic spray pyrolysis (USP) were used to synthesize Fe3O4-Au hybrid nanostructures. The first coprecipitation method enabled the synthesis of Fe3O4 nanoparticles by mixing iron salts' ions (Fe2+ and Fe3+) and ammonia as the base, and USP was used as the coating process of the Fe3O4 nanoparticles with Au. The formatted hybrid nanostructures consist of Fe3O4 nanoparticles that have Au on their surface in the form of gold nanoparticles (AuNPs). AuNPs have a crystalline structure and range in size from 10 to 200 nm. Additional characterization techniques, including ICP-OES, TEM, SEM, EDS, DLS, zeta potential, and room temperature magnetic hysteresis loops, were used to determine the chemical, physical, and magnetic properties of the Fe3O4 nanoparticles and hybrid nanostructures. It was found that USP produces separate AuNPs too (not just on the Fe3O4 surface), suggesting a bimodal formation of AuNPs. The zeta potential of the Fe3O4 nanoparticles showed poor stability (−15 mV), indicating a high tendency to aggregate, and the zeta potential of the hybrid nanostructures was also very low (≅0), which, comparatively means even worse stability. The saturation magnetization of the Fe3O4 nanoparticles was 35 emu/g, which is relatively lower than that of bulk Fe3O4, while the saturation magnetization of the hybrid nanostructures was significantly lower (0.1 emu/g) compared to the Fe3O4 nanoparticles. [ABSTRACT FROM AUTHOR]

The present study was designed to explore the effect of gold nanoparticles on the hmgA gene expression and pyomelanin pigment production from local Pseudomonas aeruginosa isolates. Out of 162 patients suffering from ear infections, urinary tract infections, burns, wounds, cerebrospinal fluid (CSF), respiratory tract infections (RTI), and blood infection (sepsis), eight isolates identified to produce pyomelanin pigment (8.42%). All isolates were characterized using microscopical, morphological, and biochemical methods, VITEK-2 compact systems, and 16SrRNA gene, which showed that all these isolates belong to P. aeruginosa. Screening producing pyomelanin pigment was carried out by using a specific media to promote the production of pyomelanin pigment. The extracted pyomelanin pigment was purified using simple acid sedimentation followed by centrifugation to extract the crude product and purify it with HPLC. The purified pigment was positive for all major physical and chemical tests that characterize pyomelanin pigment, including UV-visible spectroscopy and Fourier transform infrared spectroscopy (FT-IR). The study also covered the preparation of gold nanoparticles using the green chemistry method, which used black tea-leaf extract. The resulting nanoparticles were positive for all significant qualitative tests used to characterize them, including UV-visible spectroscopy (FT-IR), X-ray diffraction (XRD), and SEM. The results of the SEM image showed spherical particles with a size of approximately 19nm nanoparticles. In conclusion, the effect of the prepared gold nanoparticles on the gene expression of the hmgA gene was studied at different concentrations compared to the control sample using a real-time one-step polymerization reaction, also the gene expression results showed that the gold nanoparticles significantly increased the gene expression of the hmgA gene. [ABSTRACT FROM AUTHOR]

Self-assembled nanoparticles are an area of great research prospect as they offer switchable element for designing and creating micro-scale constructs. Self-assembly of nano-hybrids through some noncovalent interactions such as electrostatic, π-π and van der Waal interactions in different classes of composite materials provide a great prospect of utilization of these functional properties in tailor-made device applications. In this work gold nanoparticle functionalized with coumarin based fused-ring heterocyclic thiol exhibiting self-assembly is reported. The present work has been designed giving prior to pi-stacking mediated self-aggregation of nanoparticles resulting formation of larger superstructures. The work reports the coumarin-based heterocyclic fused ring having a thiol anchoring group grafted to the gold nanoparticle surface for easier electron flow between the metal nanoparticle and the aromatic ligand and study their self-assembly nature. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nigella sativa seed extract as an gold nanoparticles (AuNPs) surface coating material. • Nigella sativa seed extract efficiently produced the AuNPs. • Synthesized AuNPs showed high antioxidant and antidiabetic activity. • Greener synthesis of AuNPs has high anti-diabatic property. In the present investigation, gold NPs (Au-NPs) were synthesized via seed decoction of Nigella sativa , in which, the aqueous seed extract of Nigella sativa acted as a reducing agent as well as coated on Au-NPs surface. Herein, an attempt was made to develop a rapid and biocompatible method to synthesize gold NPs by phytofabrication for anti-diabetic applications. The Nigella sativa seed extract and the Au-NPs synthesized using Nigella sativa exhibited a good antioxidant property, which was determined by the 2, 2- Diphenylpicrylhydrazyl (DPPH) scavenging activity assay. These Au-NPs exhibited 78 % of anti- diabetic property, which was confirmed by α- amylase method. The synthesized nanoparticle Au-NPs size was confirmed by using SEM and TEM. The functional groups (thymoqninone) present in the seed extract as well as Au-NPs were analysed by FTIR. The major functional group i.e. thymoquinone was confirmed by the anthraquinone test and it is responsible for the antioxidant, anti-diabetic, and anticancer properties of the Au-NPs. The phytochemical based nanoparticle prepared in this work showed efficient anti-diabetic activities and it can be considered for the medical applications. In addition, phytochemical based nanoparticle synthesis is safe, eco-friendly, biocompatible, and cost effective. [ABSTRACT FROM AUTHOR]

Nanotechnology play vital role in the science and technology form the fabrication or synthesis, design and analysis of nano material. Nanoparticles in the desired range of nanoscale in µm and nm which are important in various fields. Amongst all nanoparticles Silver and Gold Nanoparticles were synthesized by various methods like sol-gel, precipitation, mechano-chemical. Over the all-green synthesis is the newer and better environment friendly. The present review is based on only greener or biogenic way for the synthesis of nanoparticles. Biological material like different plant parts, tea, coffee, polyphenols present in plant materials biomolecules as proteins, enzymes. Bacteria, yeast, algae and viruses were used as reducing agents and capping agents to reduce the size to prepare the NPs by ecofriendly approach. The synthesized Nanoparticles were characterized by X-ray diffraction, SEM, TEM, FTIR and UV-Vis spectroscopic methods, and data obtained for further interpretation of results. A major aim to recognize the material for nano conversion and their antimicrobial activity. Many researchers used biological materials for sizing outs. In this regard to try to critically analyze the literature of Au and Ag metals and biological material searches. The scope of paper only silver and gold metal Nanoparticles and biomolecules from natural sources by investigators. [ABSTRACT FROM AUTHOR]

In this work, the encapsulated-Au nanoparticles (NPs) into the silica hollow NPs were synthesized by microwave-assisted preparation of PEG-coated Au NPs, coating them with a layer of organically modified silica and removing the PEG around the Au NPs. The structure of these encapsulated NPs was characterized by TEM, SEM, XRD, FTIR, EDX, TGA, and ICP-OES. These NPs have shown excellent activities in the aerobic oxidation of benzyl alcohol derivatives and tandem oxidative A3 coupling reactions as a catalyst and reactor in the water at room temperature. Synthesis of a new silica/gold nanoparticles as catalytic nano-reactor for carrying out A3-coupling reaction in the water at ambient temperature [ABSTRACT FROM AUTHOR]

This study aimed to prepare, optimise, and characterise the novel hybrid hydrogel scaffold containing atorvastatin lipid nanocapsules (LNCs) and gold nanoparticles (NPs) to improve cardiomyoblasts proliferation and regeneration of myocardium. A thermo‐responsive aminated guaran (AGG) hydrogel was prepared to encompass extracellular matrix (ECM) fetched from human adipose tissue. Emulsion phase‐inversion technique was used to obtain LNCs. Biocompatibility, tensile strength, conductivity, and proliferation of human myocardial cells of the optimised formulation were studied. The LNCs have a spherical shape, and the optimised formulation showed a mean particle size of 18.79 nm, the zeta potential of − 11.4 mV, drug loading of 99.99%, and release efficiency percent over 72 h was 18.73%. The injectable thermo‐sensitive hydrogel prepared using 1 w/v% of AGG, 35 w/w% of ECM, ∼0.5 mg/ml of gold NPs and atorvastatin loaded LNCs showed the best physical characteristics. The hybrid scaffold loaded with atorvastatin and gold NPs improved the proliferation of cardiomyoblasts more than sevenfold with enhanced cell attachment to the scaffold. The tensile strength and the conductivity of the scaffold were 300 kPa and 0.14 S/m, respectively. Injectable hybrid adipose tissue prepared by ECM and AGG hydrogel loaded with atorvastatin and gold NPs showed promising physical characteristics for myocardial tissue engineering. [ABSTRACT FROM AUTHOR]

In this study, bio-ultrasound-assisted synthesized gold nanoparticles using Gracilaria canaliculata algae have been immobilized on a polymeric support and used as a glassy probe chemosensor for detection and rapid removal of Hg 2+ ions. The function of the suggested chemosensor has been explained based on gold-amalgam formation and its catalytic role on the reaction of sodium borohydride and rhodamine B (RhB) with fluorescent and colorimetric sensing function. The catalyzed reduction of RhB by the gold amalgam led to a distinguished color change from red and yellow florescence to colorless by converting the amount of Hg 2+ deposited on Au-NPs. The detection limit of the colorimetric and fluorescence assays for Hg 2+ was 2.21 nM and 1.10 nM respectively. By exposing the mentioned colorless solution to air for at least 2 h, unexpectedly it was observed that the color and fluorescence of RhB were restored. Have the benefit of the above phenomenon a recyclable and portable glass-based sensor has been provided by immobilizing the Au-NPs and RB on the glass slide using electrospinning. Moreover, the introduced combinatorial membrane has facilitated the detection and removal of Hg 2+ ions in various Hg (II)-contaminated real water samples with efficiency of up to 99%. [ABSTRACT FROM AUTHOR]

The purpose of the present work was to design a colorimetric method for the determination of 6-mercaptopurine (6-MP). 6-MP is a useful drug for the treatment of leukemia. Gold nanoparticles (NPs) are known to undergo a change in colour upon aggregation. Hence, in the present work phenylalanine-capped gold NPs were used as a colorimetric probe for the determination of 6-MP. Transmission electron microscopy (TEM) measurements revealed that the phenylalanine-capped gold NPs ranged from 6 to 9 nm in size. The UV–vis spectrophotometric measurements showed that the surface plasmon resonance (SPR) band of the metallic NPs was positioned at 516 nm. The effect of 6-MP addition on the SPR band of the gold NPs was investigated at pH 8 and 5. At pH 8, only a slight change in the position and intensity of the SPR band was observed. However, at pH 5, the SPR band of the gold NPs was broadened as well as red shifted in the presence of 6-MP. The colour of the gold NPs changed from red to dark purple. The ratio of the absorbance of the gold NPs at 600 and 516 nm versus the concentration of 6-MP was found to be linear in the range 0.2–1.8 μM. The limit of detection (LOD) of the colorimetric method for the determination of 6-MP was calculated to be 0.647 μM. [ABSTRACT FROM AUTHOR]

In the present study, we carried out a chemical synthesis and characterization of Fe3O4@PEG-Au as a core/shell nanocomposite in an aqueous solution by the chemical co-precipitation of Fe3+ and Fe2+ ions and encapsulated it by polyethylene glycol (PEG) in order to enhance hydrophilicity and biocompatibility of gold ions and immobilize them in the presence of NaBH4 as a reducing agent. The nanostructures were characterized with FT-IR, FESEM, EDS, WDX, VSM, ICP-MS, and TEM. The antimicrobial activities of the nanostructures were tested against pathogenic microorganisms, including Staphylococcus aureus, Escherichia coli, and Candida albicans by broth microdilution method according to the methods of the Clinical Laboratory Standard Institute (CLSI). The toxicity of the nanostructures was tested against animal cell line based on MTT assay. The synthesized core/shell nanostructures had a good activity against the representative microorganisms of public health concern and revealed an insignificant toxicity against animal cell line. [ABSTRACT FROM AUTHOR]

Mesoporous silica nanoparticles-gold nanoparticles (MSNPs/AuNPs) nanocomposite was prepared using mono-dispersed mesoporous silica as a template for gold nanoparticles without any functional group on the silica surface. The growth of gold layer over the surface of mesoporous silica nanoparticles (MSNPs) was demonstrated via scanning electron microscopies (SEM), Fourier transform infrared (FTIR) spectra, high-resolution transmission electron microscopy (HRTEM), and ultraviolet-visible (UV) adsorption spectrum. The presence of gold on the mesoporous nanoparticles gave an absorption band at 520 nm, also X-ray diffraction (XRD) indicated the crystal structure of gold NPs which has a cubic shape. Raman spectra proofed the high ability of MSNPs/AuNPs nanocomposite for removing methacrifos from water which was also confirmed by using high-performance liquid chromatography (HPLC) at room temperature where the removal rate exceeded 98 %. MSNPs/AuNPs nanocomposite has high capacity as an adsorbent which could be considered as a new eco-friendly strategy for pesticide removal and appears to be the new promising material in water treatment application. [ABSTRACT FROM AUTHOR]

Enhancing the optical response of rare earth doped glasses for miscellaneous optical applications is challenging in materials science and technology. Influences of heat treatments in modifying the spectral features of melt-quench synthesized gold nanoparticles embedded Er 3 + -doped lead–tellurite glasses are investigated. Time of heat treatment is varied from 1 to 24 h. Modifications in physical, optical and structural parameters are ascribed to the alteration of non-bridging oxygen due to heat treatments. X-ray Diffraction patterns of all glass samples confirm their amorphous nature in the presence of crystalline peak at 28.66°. Transmission Electron Microscopic images reveal the nucleation of gold nanoparticles having average diameter in the range 1.24–8.40 nm for the heat-treated samples. The ultraviolet–visible-near-infrared spectra exhibit seven absorption bands centered at 490, 526, 551, 652, 800, 979 and 1520 nm corresponding to 4f–4f transitions of Er 3 + ions. The up-conversion emissions peaks centered at 520, 550 and 660 nm are assigned to 2 H 11/2 – 4 I 15/2 , 4 S 3/2 – 4 I 15/2 and 4 F 9/2 – 4 I 15/2 transitions, respectively. Intensity enhancement displayed by heat treated glass samples is attributed to the local field effect of gold NPs. The intensity parameters related to the radiative transitions within 4f n configuration of Er 3 + ion are determined and analyzed using Judd–Ofelt theory. [ABSTRACT FROM AUTHOR]

Abstract: Tuning the enhanced optical properties of rare earth (RE) doped inorganic glasses mediated via surface plasmon resonance (SPR) by embedding metallic nanoparticles (NPs) with controlled sizes is ever-demanding in photonics. Erbium (Er3+) doped zinc–sodium tellurite glasses containing gold NPs are prepared and spectroscopic characterization are made. The heat treatment temperature dependent variations in refractive index, density, molar volume, molar refraction and polarizability are ascribed to the alteration in bonding of non-bridging oxygen (NBO) ions originates from annealing processes between 325 and 400°C. X-ray diffraction pattern confirms the amorphous nature of the glass samples. TEM micrograph reveals the nucleation of heat treated Au0 NPs and SAED manifest their growth along the (111) crystallographic planes having average diameter in the range 7.4–10.3nm. The UV–vis spectra exhibit seven absorption bands corresponding to 4f–4f transitions of Er3+ ions. The SPR bands evidenced in the range 629–631nm validate the growth of gold NPs in the glass matrix. The glass annealed at 350°C displays maximum enhancement in the up-conversion (UC) emission intensity by a factor of 4.86 and 3.40 for green bands (2H11/2→4I15/2 and 4S3/2→4I15/2) and a strong enhancement by a factor of 4.91 for red band (4F9/2→4I15/2). The enhancement is primarily attributed to the local field effect of non-spherical NPs assisted SPR effects and the energy transfer processes between Er3+ ions and NPs. The excellent luminescence efficiency of proposed glasses nominates them potential for photonic devices and solid state lasers. [Copyright &y& Elsevier]

[Display omitted] • Facile synthesis of Au NPs on zirconia NPs by laser ablation in liquid (LAL) protocol. • A high-performance strategy for NaBH 4 -mediated degradation of MO and MB in water. • Characterization of ZrO 2 -Au nanocomposite via XRD, FTIR, SEM, EDS, XPS, BET, and MAP analyses. • The ZrO 2 -Au nanocomposite can be reused several times with almost no loss in activity. The continuous development of industrial activities and also changing climate of worldwide lead to increase water pollutants and the eradication of safe water sources. Hence, remediation of wastewater and reduction of water pollutants notably organic dyes have become a serious environmental challenge. Reducing organic pollutants by heterogeneous nanocatalysts can be employed as an efficacious manner to overcome this problem. Accordingly, a nanocomposite catalyst consisting of zirconium oxide or zirconia nanoparticles (ZrO 2 NPs) and gold (Au) NPs were made by means of a straightforward and green route. Au NPs were firstly prepared via laser ablation in liquid (LAL) method and then deposited on the ZrO 2 NPs with the size of 53–88 nm using the magnetic stirring approach. The characterization methods indicated that the ZrO 2 -Au nanocomposite was successfully fabricated. The catalytic performance of ZrO 2 -Au catalyst for the degradation of methylene orange (MO) and methylene blue (MB) was investigated. [ABSTRACT FROM AUTHOR]

Despite recent progress in localized surface plasmon resonance (LSPR) based bio-sensing, it remains challenging to achieve sensitive and high throughput LSPR detection with facilities available in common laboratories. Here we developed a wall-less LSPR array chip for facile, label-free and high throughput detection of biomolecules using a normal microplate reader. The wall-less LSPR array chip was fabricated by immobilizing plasmonic nanoparticles (NPs) on a hydrophilic–hydrophobic patterned glass slide, enabling high throughput detection. The wall-less configuration simplifies chip fabrication and sample processing, and enables miniaturization to significantly reduce sample and reagent consumption. A double-gold NPs enhanced system comprising of 13-nm-gold NPs conjugated to aptamer modified 39-nm-gold NPs on glass substrate was adopted to constitute competitive replacement assay for signal amplification in small molecule (i.e. ATP) detection. Upon enhancement, the detection sensitivity of ATP was augmented by 5 orders of magnitude from 0.01µM to 100µM measured by the laboratory microplate reader. The wall-less LSPR sensor chip can be widely applied for miniaturized and high throughput detection of a variety of targets in biomedical applications and environmental monitoring using facilities available in common laboratories. [ABSTRACT FROM AUTHOR]

A series of glass with appropriate chemical compositions (48-x) B 2 O 3 –30P 2 O 5 –20ZnO–2Nd 2 O 3 -xAu, (0 = x ≤ 2.5 mol%) were prepared by using the melt quenching technique. The glass phase structure was confirmed with the aid of the X-ray diffraction (XRD) technique. The thermal characteristics of the prepared glass were approved by using the differential thermal analysis (DTA) technique. The highest thermal stability 196.8 °C were detected for the BPZNA4 sample, the glass tendency explained by calculating the Hruby's parameter (H), the maximum value of H parameter was detected for sample BPZNA4 with 1.984, this clearly shows the highest ability to form a glass. The optical properties were studied by using ultraviolet visible near infrared (UV–Vis–NIR) spectroscopy and the emission transitions studied by using photoluminescence spectroscopy (PL). The absorption spectra for the samples doped with Nd3+ ions show nine transitions, the photoluminescence spectra exhibited two emission transitions for green and red light emission due to tetrahedral symmetry and octahedral symmetry, respectively. The decay curves of Nd3+ ions were calculated for all the glass samples. It was shown that the lifetimes dependent on the concentration of Au NPs and the glass composition. • Nd3+-doped zinc borophosphate glasses were investigated and characterized. • Highest thermal stability value is found to be 196.8 oC for the Au NPs content 1.5 mol%. • The optimum relative radiative parameters are obtained for 2P3/2→4F9/2 of BPZNA2. • Higher quantum efficiency (81.6%) has been noticed for the present glasses. • Results are improving the ability using this composition for the illumination applications. [ABSTRACT FROM AUTHOR]

Gold NPs were biosynthesized using the extracellular cell free filtrate of fungus Glomus aureum and were used for their anti-bacterial potential and photocatalytic degradation of methyl orange dye. Different types of analytical techniques were employed for determination of purity, composition and morphology of the biosynthesized gold NPs. The functional groups and elemental contents of the biosynthesized gold NPs were determined through FTIR and EDX, respectively. The biosynthesized gold NPs exhibited significant antibacterial activity with zones of inhibition of 20 and 19 mm against Acinetobacter baumannii and Proteus mirabilis , respectively. The minimum inhibitory concentration (MICs) values of the biosynthesized gold NPs against A. baumannii and P. mirabilis were 32 and 28 μg/mL, respectively. The increased leakage of the intracellular constituents from the bacterial cells suggested that the biosynthesized gold NPs probably acted upon the cell membrane by interaction with the membrane lipid and protein. The biosynthesized gold NPs could be used as a photo catalyst for the degradation of methyl orange dye under solar light illumination showing excellent photocatalytic activity of 45% for methyl orange dye in 6 h. These findings suggested that biosynthesized gold NPs could be used as a promising candidate for the clinical development of treatment of bacterial pathogenesis and as an efficient photo catalyst for the removal of toxic water pollutants. Image 1 • Cell free filtrate of Glomus aureum has greater ability to biosynthesized AuNPs. • Biosynthesized AuNPs have outstanding antibacterial potential. • The MIC values of the biosynthesized AuNPs were also very significant. • Bactericidal action of AuNPs was due to damaging the bacterial membrane. • Biosynthesized AuNPs have ability to degrade methyl orange under solar illumination. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) with unique physicochemical properties have received a great deal of interest in the field of biological, chemical and biomedical implementations. Despite the widespread use of AuNPs in chemical and biological sensing, catalysis, imaging and diagnosis, and more recently in therapy, no comprehensive summary has been provided to explain how AuNPs could aid in developing improved sensing and catalysts systems as well as medical settings. The chemistry of Au-based nanosystems was followed by reviewing different applications of Au nanomaterials in biological and chemical sensing, catalysis, imaging and diagnosis by a number of approaches, and finally synergistic combination therapy of different cancers. Afterwards, the clinical impacts of AuNPs, future application of AuNPs, and opportunities and challenges of AuNPs application were also discussed. AuNPs show exclusive colloidal stability and are considered as ideal candidates for colorimetric detection, catalysis, imaging, and photothermal transducers, because their physicochemical properties can be tuned by adjusting their structural dimensions achieved by the different manufacturing methods. This review provides some details about using AuNPs in sensing and catalysis applications as well as promising theranostic nanoplatforms for cancer imaging and diagnosis, and sensitive, non-invasive, and synergistic methods for cancer treatment in an almost comprehensive manner. • We listed different applications of AuNPs as biological and chemical sensing, catalysis, imaging and diagnosis by various techniques. • Moreover, we tried to cover all aspects of Au nanosystems (AuNPs, AuNRs, AuNC, and Au nanoshells) in cancer therapeutics. • Finally, the clinical impact of AuNPs, future application of AuNPs, and opportunities and challenges of AuNPs application were also discussed. [ABSTRACT FROM AUTHOR]

A facile bottom-up "green" synthetic route of gold nanoparticles (Au NPs) is described, using a leaf extract of the Malvaceae plant Corchorus olitorius as a reducing and stabilizing agent. The size and shape of the obtained nanoparticles were modulated by varying the amounts of the metal salt and the broth extract in the reaction medium. Only one hour was required for the complete conversion to Au NPs, suggesting that the reaction rate was higher or comparable to those of nanoparticles synthesized by chemical methods. The obtained nanoparticles were characterized by UV–visible spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and thermal gravimetric analysis (TGA). While infrared spectroscopy was employed to characterize the various functional groups in the organic layer that stabilized the particles, TEM images were used to optimize the conditions for NPs growth. A low concentration of the C. olitorius extract yielded mixed triangular and hexagonal shapes; in contrast, quasi-spherical shapes of Au NPs with an average size of 37–50 nm were obtained at a higher extract broth concentration. The Au NPs displayed Surface Plasmon Resonance (SPR) bands at 535 nm. An in vitro cytotoxic assay of the biocompatible Au NPs revealed a strong cytotoxic activity in three human cancer cell lines, namely, colon carcinoma HCT-116, hepatocellular carcinoma HepG-2, and breast adenocarcinoma MCF-7. In-silico bioactivity, drug-likeness, and ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) predictions were conducted in order to examine the pharmacokinetic behavior of the compounds present in the C. olitorius extract. [ABSTRACT FROM AUTHOR]