One-pot Synthesis Of Gold Nanoparticles Research Articles

Gold nanoparticles-doped MXene heterostructure for ultrasensitive electrochemical detection of fumonisin B1 and ampicillin.

Early transition metal carbides (MXene) hybridized by precious metals open a door for innovative electrochemical biosensing device design. Herein, we present a facile one-pot synthesis of gold nanoparticles (AuNPs)-doped two-dimensional (2D) titanium carbide MXene nanoflakes (Ti3C2Tx/Au). Ti3C2Tx MXene exhibits high electrical conductivity and yields synergistic signal amplification in conjunction with AuNPs leading to excellent electrochemical performance. Thus Ti3C2Tx/Au hybrid nanostructure can be used as an electrode platform for the electrochemical analysis of various targets. We used screen-printed electrodes modified with the Ti3C2Tx/Au electrode and functionalized with different biorecognition elements to detect and quantify an antibiotic, ampicillin (AMP), and a mycotoxin, fumonisin B1 (FB1). The ultralow limits of detection of 2.284pM and 1.617pg.mL-1, which we achieved respectively for AMP and FB1 are far lower than their corresponding maximum residue limits of 2.8nM in milk and 2 to 4mgkg-1 in corn products for human consumption set by the United States Food and Drug Administration. Additionally, the linear range of detection and quantification of AMP and FB1 were, respectively, 10pM to 500nM and 10pgmL-1 to 1µgmL-1. The unique structure and excellent electrochemical performance of Ti3C2Tx/Au nanocomposite suggest that it is highly suitable for anchoring biorecognition entities such as antibodies and oligonucleotides for monitoring various deleterious contaminants in agri-food products.

Facile one-pot synthesis of gold nanoparticles using Lactobacillus acidophilus as a potential photocatalytic agent against multi-drug-resistant pathogens of public health importance

Facile one-pot synthesis of gold nanoparticles using Lactobacillus acidophilus as a potential photocatalytic agent against multi-drug-resistant pathogens of public health importance

One-pot generation of gold-polymer hybrid nanoparticles using a miniemulsion reactor system

We investigated one-pot synthesis of gold nanoparticles (AuNPs) and AuNPs-polymer hybrid nanoparticles in a water-in-oil (W/O) miniemulsion. Water nanodroplets were dispersed as a reactor in cyclohexane using dimethicone as a surfactant. First, we intended to generate AuNPs in water nanodroplets, which contained HAuCl4 with a mixture of 1-vinylpyrrolidone (VP) and N,N’-methylenebisacrylamide (MBAAm). Several AuNPs with the size of approximately 10–20 nm were generated in each nanodroplet via reduction of AuCl4- by dimethicone. On the other hand, AuNPs was scarcely generated in water nanodroplets containing HAuCl4 with 2-hydroxyethyl methacrylate (HEMA). Next, we carried out polymerization in water nanodroplets to encapsulate AuNPs into polymer nanoparticles. Several AuNPs were encapsulated within polymer particles by copolymerization of VP and MBAAm with an oil-soluble initiator (V-601), and some AuNPs were present in the oil phase. The encapsulation efficiency of AuNPs was 34%. The encapsulation efficiency of AuNPs was dramatically increased by increasing the concentration of the initiator. The same result was obtained by increasing the concentration of the crosslinker due to rapid gelation of nanodroplets. On the other hand, monodisperse particles could be obtained by polymerization of HEMA using a water-soluble initiator (V-65). After polymerization for 5 d at 65ºC, the color of the suspension changed from opaque blue to blue purple and the encapsulation efficiency of AuNPs (5–20 nm) increased to 99 wt%. The average number of AuNPs encapsulated in a PHEMA nanoparticle increased from 1.5 to 4.6 particle. Furthermore, the size of AuNPs could be tuned by increasing the HAuCl4 concentration, and the corresponding color of the suspensions such as blue, purple, and red could be observed. The number and location of AuNPs in polymer nanoparticles could also be tuned by additives such as L-histidine and polyvinylpyrrolidone. By drop-casting the obtained hybrid nanoparticles, we could obtain gold-polymer hybrid films where AuNPs were evenly distributed within a film. The films exhibited different colors corresponding to their LSPR of AuNPs.

Hyaluronic acid-coated gold nanoparticles as a controlled drug delivery system for poorly water-soluble drugs.

Hyaluronic acid (HA) is a natural linear polysaccharide which has been widely used in cosmetics and pharmaceuticals including drug delivery systems because of its excellent biocompatibility. In this study, we investigated the one-pot synthesis of HA-coated gold nanoparticles (AuNP-HA) as a drug delivery carrier. The HAs with different molecular weights were produced by e-beam irradiation and employed as coating materials for AuNPs. Sulfasalazine (SSZ), a poorly water-soluble drug, was used to demonstrate the efficiency of drug delivery and the controlled release behaviour of the AuNP-HA. As the molecular weight of the HA decreased, the drug encapsulation efficiency of the SSZ increased up to 94%, while drug loading capacity of the SSZ was maintained at the level of about 70%. The prepared AuNP-HA-SSZ exhibited slow release of the SSZ over a short time and excellent sensitivity to different pHs and physiological conditions. The SSZ release rate was the lowest in simulated gastric conditions and the highest in simulated intestinal conditions. In this case, the AuNP-HA protects the SSZ from release under the acidic pH conditions in the stomach; on the other hand, the drug release was facilitated in the basic environment of the small intestine and colon. The SSZ was released under simulated intestinal conditions through anomalous drug transport and followed the Korsmeyer-Peppas model. Therefore, this study suggests that AuNP-HA is a promising orally-administered and intestine-targeted drug delivery system with controlled release characteristics.

Bombesin Peptide Conjugated Water-Soluble Chitosan Gallate-A New Nanopharmaceutical Architecture for the Rapid One-Pot Synthesis of Prostate Tumor Targeted Gold Nanoparticles.

PurposeWe report herein bombesin peptide conjugated water-soluble chitosan gallate as a template for rapid one-pot synthesis of gold nanoparticles (AuNPs) with capabilities to target receptors on prostate cancer cells.MethodsWater-soluble chitosan (WCS), anchored with gallic acid (GA) and LyslLys3 (1,4,7,10-tetraazacyclo dodecane-1,4,7,10-tetraacetic acid) bombesin 1–14 (DBBN) peptide, provides a tumor targeting nanomedicine agent. WCS nanoplatforms provide attractive strategies with built-in capabilities to reduce gold (III) to gold nanoparticles with stabilizing and tumor-targeting capabilities. WCS-GA-DBBN encapsulation around gold nanoparticles affords optimum in vitro stability.ResultsThe DBBN content in the WCS-GA-DBBN sample was ~27%w/w. The antioxidant activities of WCS-GA and WCS-GA-DBBN nanocolloids were enhanced by 12 times as compared to the nascent WCS. AuNPs with a desirable hydrodynamic diameter range of 40–60 nm have been efficiently synthesized using WCS-GA and WCS-GA-DBBN platforms. The AuNPs were stable over 4 days after preparation and ~3 days after subjecting to all relevant biological fluids. The AuNPs capped with WCS-GA-DBBN peptide exhibited superior cellular internalization into prostate tumor (PC-3) cells with evidence of receptor mediated endocytosis.ConclusionThe AuNPs capped with WCS-GA-DBBN exhibited selective affinity toward prostate cancer cells. AuNPs conjugated with WCS-GA-DBBN serve as a new generation of theranostic agents for treating various neoplastic diseases, thus opening-up new applications in oncology.

Phyto-labelled Gold Nanoparticles Using Garcinia cambogia Capsules for Selective Detection of Cyanide Ions

Plant-based nutraceuticals have paved much attention as they are biocompatible as well as non-toxic. A similar trend has also been seen in the synthesis of nanomaterials. Phyto-assisted synthesis of gold nanoparticles and their potential applications are of great interest among the research community as they are biocompatible, non-toxic and eco-friendly. Herein we report the one-pot synthesis of gold nanoparticles using commercially available Garcinia cambogia (GC) capsules used for weight reduction. The aqueous suspension (GCA) of the formulation was prepared using a steam bath method and used for gold nano synthesis. The synthesis of gold nanoparticles was standardized and optimized with respect to the GCA concentration at room temperature by keeping the concentration of Gold chloride constant. The rapid formation of the GCA mediated gold nanoparticles was visually observed by the colour change from the brown colour of the extracts to violet, purple and pink depending on the concentration of GCA. The synthesized gold nanoparticles were characterized using UV-Visible spectroscopy, FT-IR spectroscopy, FE-SEM and EDS. The rapid bioreduction of Au3+ to Au0 is attributed to the phytoconstituents present in the GC formulations. The synthesized gold nanoparticles were screened for the selective detection of various chemicals commonly used in the food industry. Of the screened chemicals, the GCA mediated gold nanoparticles efficiently detect CN– ions, which shows the phytomediated gold nanoparticles' sensory activity

In Situ Gold Nanoparticle Synthesis Mediated by a Water-Soluble Leaning Pillar[6]arene for Self-Assembly, Detection, and Catalysis.

An anionic water-soluble leaning pillar[6]arene (AWLP6) has been synthesized and utilized as both the reductant and stabilizer for the one-pot synthesis of gold nanoparticles (AWLP6-AuNPs). Interestingly, AWLP6-AuNPs show not only optimal performance in self-assembly and label-free detection of methyl viologen, one of the most widely used herbicides, but also efficient catalytic activity for the hydrogenation of p-nitrophenol.

Green one-pot synthesis of gold nanoparticles using Sansevieria roxburghiana leaf extract for the catalytic degradation of toxic organic pollutants

Biogenic gold nanoparticles were synthesized using aqueous solution of Sansevieria roxburghiana leaf extract. Optimum synthesis of gold nanoparticles was observed at 2 mM concentration of chloroauric acid and the reaction was completed by 60 min at 40 °C. The biomolecules, proteins and polyphenols present in the leaf extract were involved in the bioreduction of chloroauric acid. The synthesized gold nanoparticles were characterized by UV–vis absorption spectroscopy, dynamic light scattering, X-ray diffraction, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy and transmission electron microscopy. The bioreduced gold nanoparticles exhibited shapes such as spherical, triangle, hexagonal, rod and decahedral. In the present investigation, for the first time, we report the biosynthesis of gold nanoparticles from S. roxburghiana and their catalytic potential in the degradation of organic pollutants such as 4-nitrophenol, acridine orange, congo red, bromothymol blue, phenol red and methylene blue.

Polyethyleneimine-assisted one-pot synthesis of quasi-fractal plasmonic gold nanocomposites as a photothermal theranostic agent.

Gold nanoparticles have been thoroughly used in designing thermal ablative therapies and in photoacoustic imaging in cancer treatment owing to their unique and tunable plasmonic properties. While the plasmonic properties highly depend on the size and structure, controllable aggregation of gold nanoparticles can trigger a plasmonic coupling of adjacent electronic clouds, henceforth leading to an increase of light absorption within the near-infrared (NIR) window. Polymer-engraftment of gold nanoparticles has been investigated to achieve the plasmonic coupling phenomenon, but complex chemical steps are often needed to accomplish a biomedically relevant product. An appealing and controllable manner of achieving polymer-based plasmon coupling is a template-assisted Au+3 reduction that ensures in situ gold reduction and coalescence. Among the polymers exploited as reducing agents are polyethyleneimines (PEI). In this study, we addressed the PEI-assisted synthesis of gold nanoparticles and their further aggregation to obtain fractal NIR-absorbent plasmonic nanoaggregates for photothermal therapy and photoacoustic imaging of colorectal cancer. PEI-assisted Au+3 reduction was followed up by UV-visible light absorption, small-angle X-ray scattering (SAXS), and photo-thermal conversion. The reaction kinetics, stability, and the photothermal plasmonic properties of the as-synthesized nanocomposites tightly depended on the PEI : Au ratio. We defined a PEI-Au ratio range (2.5-5) for the one-pot synthesis of gold nanoparticles that self-arrange into fractal nanoaggregates with demonstrated photo-thermal therapeutic and imaging efficiency both in vitro and in vivo in a colorectal carcinoma (CRC) animal model.

Rational screening of biomineralisation peptides for colour-selected one-pot gold nanoparticle syntheses.

Biomineralisation peptides that facilitate the one-pot synthesis of gold nanoparticles (AuNPs) with selected optical properties, were screened using a coherent peptide-spotted array consisting of a AuNP binding peptide library. As the biomineralised AuNPs were captured on each peptide spot, analysis of the images provided information on their collective optical properties.

One-pot synthesis of gold nanoparticles embedded in polysaccharide-based hydrogel: Physical-chemical characterization and feasibility for large-scale production

In this study, polysaccharide-based hydrogel wound dressings containing in situ synthesized gold nanoparticles (AuNPs) were prepared by using a simple, fast and green protocol. The prepared hydrogels were characterized with UV–vis and infrared spectroscopy (FT-IR), and dynamic light scattering (DLS). The rheological and swelling properties and the feasibility to scale-up the wound dressing production from the lamination of the prepared hydrogel on non-woven fabric were also investigated. UV–vis spectra confirmed the AuNPs synthesis and the DLS results exhibited an increase in the size of AuNPs with increasing the initial Au3+ concentration. The rheological analysis showed that the augmentation of the initial Au3+ concentration reduces the gel viscosity and gelling temperature. Besides, the FT-IR spectra revealed that the AuNPs hinder the intermolecular interactions between kappa-carrageenan (κCG) and locust bean gum (LBG). The feasibility of scale-up the wound dressing production from the prepared hydrogel was confirmed through the lamination tests.

Green Synthesis of Hydroxylatopillar[5]arene-Modified Gold Nanoparticles and Their Self-Assembly, Sensing, and Catalysis Applications

A novel, green, one-pot synthesis of gold nanoparticles (AuNPs) was obtained by the redox reaction between AuCl4– and hydroxylatopillar[5]arene (HP5) in aqueous solution with the aid of OH– at room temperature without the need of a traditional harsh reducing agent such as NaBH4, N2H4, etc. Monodisperse AuNPs with a uniform diameter of ∼5.0 nm are fabricated via the proposed one-step colloidal synthesis route by using HP5 as both reducing agent and stabilizer, while AuNPs cannot be effectively protected by noncyclic monomers of HP5. The FTIR, 13C NMR, and XPS studies demonstrated that the hydroxy groups in HP5 reduce Au3+ into Au0, which leads to nucleation, growth, and formation of AuNPs, and the hydroxy groups themselves are oxidized to carboxyl groups. It is surprising that the HP5 functionalized AuNPs can self-assemble and form multiple well-defined architectures, including vesicles, like nanotubes, and one-/two-dimensional (1D/2D) nanostructures without the need of a guest mediator. The self-assembly ...

Multifaceted peptide assisted one-pot synthesis of gold nanoparticles for plectin-1 targeted gemcitabine delivery in pancreatic cancer

An astute modification of the plectin-1-targeting peptide KTLLPTP by introducing a C-terminal cysteine preceded by a tyrosine residue imparted a reducing property to the peptide. This novel property is then exploited to fabricate gold nanoparticles (GNP) via an in situ reduction of gold(iii) chloride in a one-pot, green synthesis. The modified peptide KTLLPTPYC also acts as a template to generate highly monodispersed, spherical GNPs with a narrow size distribution and improved stability. Plectin-1 is known to be aberrantly expressed in the surface of pancreatic ductal adenocarcinoma (PDAC) cells while showing cytoplasmic expression in normal cells. The synthesized GNPs are thus in situ surface modified with the peptides via the cysteine residue leaving the N-terminal KTLLPTP sequence free for targeting plectin-1. The visual molecular dynamics based simulations support the experimental observations like particle size, gemcitabine conjugation and architecture of the peptide-grafted nanoassembly. Additionally, GNPs conjugated to gemcitabine demonstrate significantly higher cytotoxicity in vitro in two established PDAC cell lines (AsPC-1 and PANC-1) and an admirable in vivo antitumor efficacy in a PANC-1 orthotopic xenograft model through selective uptake in PDAC tumor tissues. Altogether, this strategy represents a unique method for the fabrication of a GNP based targeted drug delivery platform using a multifaceted peptide that acts as reducing agent, template for GNP synthesis and targeting agent to display remarkable selectivity towards PDAC.

Effect of Temperature on the Direct Synthesis of Gold Nanoparticles Mediated by Poly(dimethylaminoethyl methacrylate) Homopolymer

The one-pot synthesis of gold nanoparticles (AuNPs) mediated by poly(dimethylaminoethyl methacrylate) homopolymer, without the use of a reducing agent, has been studied under different temperatures. The obtained results show that the higher is the temperature, during nanoparticle synthesis, the faster is nanoparticle creation and the more uniform are the produced nanoparticles. The kinetic studies on the nanoparticles synthesis were performed mainly by light scattering techniques. The obtained results indicate that at elevated temperatures the synthesis takes place in three steps, while at lower temperatures the followed synthetic pathways are more complex. Finally, the development of gold nanoparticles was also followed by UV–vis absorption measurements, indicating a good agreement between the two techniques.

A novel gold nanoparticle stabilization and its muon chemistry

We report a novel one-pot synthesis of gold nanoparticles (AuNPs) non-covalently stabilized by ionic liquid benzyldimethyltetradecylammonium chloride (Bac-14). Bac-14 demonstrates unprecedented long-term stabilization for its class of long-chain alkylated quaternary ammonium halides; the AuNP size remained constant for months. The mechanism of stabilization of similar surfactants has not been thoroughly explored in the literature. We elucidate the conformational mechanism of Bac-14 stabilization of the AuNP. Our proposed conformation suggests that these AuNPs are promising catalytic oxidization agents. This is suggestive of their ultra-fast electron capture behavior investigated by muon chemistry, which pioneers the field of muon chemistry of nanostructures.

One-pot synthesis of gold nanoparticles by using 4-aminoantipyrine as a novel reducing and capping agent for simultaneous colorimetric sensing of four triptan-family drugs

We prepared Au NPs using 4-aminoantipyrine as a novel reagent and the Au NPs aggregation was induced by triptan-family drugs independently, resulting a color change from pink to blue.

One-pot synthesis of gold nanoparticles embedded in silica for cyclohexane oxidation

Highly-dispersed gold nanoparticles embedded in amorphous silica (Au/M-SiO2) were prepared by a facile one-pot process utilizing thioether functional groups to anchor AuCl4−. A surprisingly high TOF up to 21 097 h−1 was obtained over the 0.2% Au/M-SiO2 catalyst, and the 1.5% Au/M-SiO2 catalyst exhibited a high catalytic activity of 22.7% for cyclohexane conversion and 80.6% selectivity to cyclohexanol and cyclohexanone under dipolar non hydrogen bond donor (HBD) acetone solvent at 423 K and 1.5 MPa O2 for 3 h.

One-pot synthesis of gold nanoparticles densely coated with nitroxide spins

We describe a new and simple method for one-pot synthesis of gold nanoparticles of spherical shape densely coated with unpaired electrons. The gold nanoparticles have a narrow size distribution (1.90±0.54nm) and even coverage of nitroxide spins per particle and are soluble both in non-polar and polar organic solvents. The one-pot synthesis consists of direct grafting of nanoparticles by ligand substitution with an in situ generated bisnitroxide radical-containing thiol nucleophile. The obtained nanoparticles are stabilized by two types of ligands: covalently attached nitroxide radicals and tetraoctylammonium bromide ions pairs weakly bound to the gold surface. The average number of ligands per core was derived from X-ray photoelectron spectroscopy (XPS) as well as from thermogravimetric and bromine concentration analyses. The proposed procedure can be a powerful tool for the preparation of spin-labeled gold nanoparticles soluble in non-polar and polar organic solvents which should be useful for applications in various fields including biochemistry, catalysis and electrochemistry.

Facile one-pot synthesis of gold nanoparticles using tannic acid and its application in catalysis

The paper reports a simple and efficient method for the synthesis of stable, nearly spherical gold nanoparticles using tannic acid as both the reducing and stabilizing agent. The nanoparticles are characterized by UV–visible spectroscopy, transmission electron microscopy (TEM), EDX and X-ray diffraction (XRD) analysis. The influence of tannic acid on the control of size and shape of gold nanoparticles is reported. Upon an increase in the concentration of tannic acid, there is a shift in the shape of nanoparticles as evidenced by the change in bandwidth and peak position of the surface plasmon resonance (SPR) band. Also, it is found that tannic acid ceases to act as a reducing agent beyond the limit of 10mL (6×10−3M) for 30mL of HAuCl4 (1.3×10−3M). On increasing the quantity of tannic acid, nucleation is favored in the initial stages and thereafter growth supersedes nucleation. The stable colloids obtained by this method are found to consist of nanoparticles with average size 8 and 12nm. The crystallinity of the sample with fcc phase is observed from TEM, SAED and XRD pattern. Involvement of carboxylic acid group in capping of gold nanoparticles is evident from the FTIR spectrum. The application of the synthesized nanoparticles as catalyst in the reduction of 4-Nitrophenol to 4-Aminophenol is also reported.

Functionalized gold nanoparticles and films stabilized by in situ formed polyeugenol

Eugenol (2-methoxy-4-allyl-phenol) was used as a reducing agent for one-pot synthesis of gold nanoparticles in a mild alkaline aqueous/organic solution at room temperature. In this reaction, eugenol acts also as a stabilizing agent, since it undergoes polymerization upon oxidation. As a result, stable colloids of polyeugenol (PE)-capped gold nanoparticles are formed during the reaction with the average particle size of 44 nm. Moreover, conducting supports, such as ITO glass, are covered by Au/PE composite film when immersed in the reaction medium. The modified ITO shows redox activity assignable to residual quinone moieties of PE with redox couples at a potential range of −0.2 to 0.4 V (vs. Ag/AgCl at pH 7.4). Redox properties of Au/PE nanoparticulate films can be exploited for the electrocatalytic oxidation of NADH with over 0.5 V reduction of the reaction overpotential vs. unmodified ITO. Nanoparticulate composite films were characterized by UV–vis spectroscopy, XPS and FT-IR spectroscopy. The characterization revealed structural similarity of the formed PE to lignin.