Fast synthesis of gold nanoparticles by cold atmospheric pressure plasma jet in the presence of Au^(+) ions and a capping agent

Homogeneous gold nanoparticles were synthesized under atmospheric pressure using a nonthermal helium plasma jet in a single-step process.A current power supply was used to generate the plasma discharge rich in diverse reactive species.These species induce rapid chemical reactions responsible for the reduction of the gold salts upon contact with the liquid solution.In this study,spherical and monodispersed gold nanoparticles were obtained within 5 min of plasma exposure using a solution containing gold(Ⅲ)chloride hydrate(HAuCl_(4))as a precursor and polyvinylpyrrolidone(PVP)as a capping agent to inhibit agglomerations.The formation of these metal nanoparticles was initially perceptible through a visible change in the sample's color,transitioning from light yellow to a red/pink color.This was subsequently corroborated by UVvis spectroscopy,which revealed an optical absorption in the 520-550 nm range for Au NPs,corresponding to the surface plasmon resonance(SPR)band.An investigation into the impact of various parameters,including plasma discharge duration,precursor and capping agent concentrations,was carried out to optimize conditions for the formation of well-separated,spherical gold nanoparticles.Dynamic light scattering(DLS)was used to measure the size of these nanoparticles,transmission electron microscopy(TEM)was used to observe their morphology and X-ray diffraction(XRD)was also employed to determine their crystallographic structure.The results confirm that homogeneous spherical gold nanoparticles with an average diameter of 13 nm can be easily synthesized through a rapid,straightforward,and environmentally friendly approach utilizing a helium atmospheric pressure plasma.

Biological Interaction and Imaging of Ultrasmall Gold Nanoparticles

Ultrasmall gold nanoparticles(AuNPs)typically includes atomically precise gold nanoclusters(AuNCs)and AuNPs with a core size below 3 nm.Serving as a bridge between small molecules and traditional inorganic nanoparticles,the ultrasmall AuNPs show the unique advantages of both small molecules(e.g.,rapid distribution,renal clearance,low non-specific organ accumulation)and nanoparticles(e.g.,long blood circulation and enhanced permeability and retention effect).The emergence of ultrasmall AuNPs creates significant opportunities to address many challenges in the health field including disease diagnosis,monitoring and treatment.Since the nano–bio interaction dictates the overall biological applications of the ultrasmall AuNPs,this review elucidates the recent advances in the biological interactions and imaging of ultrasmall AuNPs.We begin with the introduction of the factors that influence the cellular interactions of ultrasmall AuNPs.We then discuss the organ interactions,especially focus on the interactions of the liver and kidneys.We further present the recent advances in the tumor interactions of ultrasmall AuNPs.In addition,the imaging performance of the ultrasmall AuNPs is summarized and discussed.Finally,we summarize this review and provide some perspective on the future research direction of the ultrasmall AuNPs,aiming to accelerate their clinical translation.

Applications and safety of gold nanoparticles as therapeutic devices in clinical trials

Use of gold nanoparticles(GNPs)in medicine is an emerging field of translational research with vast clinical implications and exciting therapeutic potential.However,the safety of using GNPs in human subjects is an important question that remains unanswered.This study reviews over 20 clinical trials focused on GNP safety and aims to summarize all the clinical studies,completed and ongoing,to identify whether GNPs are safe to use in humans as a therapeutic platform.In these studies,GNPs were implemented as drug delivery devices,for photothermal therapy,and utilized for their intrinsic therapeutic effects by various routes of delivery.These studies revealed no major safety concerns with the use of GNPs;however,the number of trials and total patient number remains limited.Multi-dose,multicenter blinded trials are required to deepen our understanding of the use of GNPs in clinical settings to facilitate translation of this novel,multifaceted therapeutic device.Expanding clinical trials will require collaboration between clinicians,scientists,and biotechnology companies.

Theoretical investigation of F-P cavity mode manipulation by single gold nanoparticles

The ability to manipulate microlaser is highly desirable towards high-performance optoelectronic devices.Here we demonstrate feasible mode manipulation of Fabry-Perot type microlasers of a perovskite nanowire via incorporation of single gold nanoparticles.The influences of resonant wavelength,quality factor and emission directions are successively investigated using a two-dimensional finite-difference time-domain method.It is found that blueshift of resonant wavelength could be achieved together with either promoted or degraded quality factor of the microlaser via single Au NPs with varied sizes.Unidirectional emission could also be realized which is favorable for on-chip integration.Our results provide useful reference for feasible manipulation of light-matter interactions and mode selection.

Molecular fluorescence significantly enhanced by gold nanoparticles@zeolitic imidazolate framework-8

Noble metal nanoparticles exhibit unique surface plasmon resonance dependent optical properties.On this basis,gold nanoparticles(AuNPs)encapsulated in metal–organic frameworks(MOFs)can form AuNPs@MOFs composites to modulate the optical properties of fluorescent molecules,which is less reported.In this paper,based on the fluorescence enhancement effect of AuNPs on 2-(2-hydroxyphenyl)-1H-benzimidazole(HPBI)molecules,zeolitic imidazolate framework-8(ZIF-8)crystals with structural stability were introduced.AuNPs@ZIF-8 exhibited a significantly pronounced fluorescence enhancement of the HPBI molecules.In addition,by comparing the fluorescence characteristics of the HPBI molecules adsorbed on AuNPs@ZIF-8 and those captured in AuNPs@ZIF-8,we found that the ZIF-8 can act as a spacer layer with highly effective near-field enhancement.All our preliminary results shed light on future research on the composite structures of noble metal particles and MOFs for fluorescent probes and sensing applications.

Synthesis and Physicochemical Characterization of Biodegradable Star-Shaped Poly Lactide-Co-Glycolide-<i>β</i>-Cyclodextrin Copolymer Nanoparticles Containing Albumin

The purposes of this research were to synthesize and characterize star-shaped poly lactide-co-glycolide-β-cyclo-dextrin (PLGA-β-CD) copolymer by reacting L-lactide, glycolide and β-cyclodextrin in the presence of stannous octoate as a catalyst. The structure of PLGA-β-CD copolymer was confirmed with 1H-NMR, 13C-NMR and FT-IR spectra. Albumin as a model peptide drug was encapsulated within nanoparticles made of PLGA-β-CD with a modified double emulsion method. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) photomicrographs showed that the nanoparticles have the mean diameter within the range of 80 - 210 nm. Also they were almost spherical in shape. Effects of the experimental parameters, such as copolymer composition, copolymer concentration, and reaction temperature, on particular size and encapsulation efficiency were investigated.

Effect of Gold Nanoparticles on the Photocatalytic and Photoelectrochemical Performance of Au Modified BiVO_4

An efficient visible light driven photocatalyst, gold nanoparticles(NPs) modified Bi VO_4(Au/Bi VO_4), has been synthesized by deposition-precipitation with urea method. Au/Bi VO_4 exhibits enhanced photocatalytic activity for phenol degradation underλ>400 nm irradiation but negligible activity underλ>535 nm,indicating that the surface plasmon resonance(SPR) effect is too weak for organic photodegradation. According to the photoelectrochemical results of the porous powder electrodes of Bi VO_4 and Au/Bi VO_4, the SPR effect of Au NPs has been assessed. The role of Au NPs as electron sinks or sources, which is controllable by incident photon energy and applied potentials, has been discussed.

A Concise Review of Gold Nanoparticles-Based Photo-Responsive Liposomes for Controlled Drug Delivery

The focus of drug delivery is shifting toward smart drug carriers that release the cargo in response to a change in the microenvironment due to an internal or external trigger. As the most clinically successful nanosystem, liposomes naturally come under the spotlight of this trend. This review summarizes the latest development about the design and construction of photo-responsive liposomes with gold nanoparticles for the controlled drug release. Alongside, we overview the mechanism involved in this process and the representative applications.

Improving the performance of solid oxide electrolysis cell with gold nanoparticles-modified LSM-YSZ anode

Gold, as the common current collector in solid oxide electrolysis cell(SOEC), is traditionally considered to be inert for oxygen evolution reaction at the anode of SOEC. Herein, gold nanoparticles were loaded onto conventional strontium doped lanthanum manganite-yttria stabilized zirconia(LSM-YSZ) anode, which evidently improved the performance of oxygen evolution reaction at 800 °C. The current densities at 1.2 V and 1.4 V increased by 60.0% and 46.9%, respectively, after loading gold nanoparticles onto the LSM-YSZ anode. Physicochemical characterizations and electrochemical measurements suggested that the improved SOEC performance was attributed to the accelerated electron transfer of elementary process in anodic polarization reaction and the newly generated triple phase boundaries in gold nanoparticles-loaded LSMYSZ anode.

Fluorescence quenching method for the determination of catechol with gold nanoparticles and tyrosinase hybrid system

The determination method of catechol by fluorescence quenching was developed.The assay was based on the combination of the unique property of gold nanoparticles with tyrosinase enzymatic reaction.In the presence of tyrosinase,the fluorescence of gold nanoparticles was quenched by catechol which can be employed to detect catechol.Under the optimal conditions,a linear range 5.0×10^(-7)-1.0×10^(-3) mol L^(-1) and a detection limit 1.0×10^(-7) mol L^(-1) of catechol were obtained.o-Quinone intermediate produced...

Hesperetin conjugated PEGylated gold nanoparticles exploring the potential role in anti-inflammation and anti-proliferation during diethylnitrosamine-induced hepatocarcinogenesis in rats

Liver cancer is the fifth most common cancer and one of the leading causes of death in the world, and second most common cause of death in men. Natural products emerge as the most enduring approaches in the development of anticancer targeting drug. Hesperetin(HP), one of the abundant flavonoids found naturally in citrus fruits, has received considerable attention in anti-cancer promotion and progression. The present study was conducted to decipher the role of 0.5 ml hesperetin conjugated gold nanoparticles(Au-m PEG(5000)-S-HP NPs) during diethylnitrosamine(DEN)-induced hepatocarcinogenesis in male Wistar albino rats and shows the better antioxidant that possesses anti-inflammatory,anti-proliferation and anticarcinogenic properties and may modulate signaling pathways.The confirmation of polymer functionalized gold nanoparticles and drug loaded polymer gold nanoparticles were characterized by HR-TEM with EDAX, and DLS with Zeta potential techniques. The drug encapsulation efficiency and release properties were carried out in PBS at pH 7.4 for Au-mPEG(5000)-S-HP and compared with the control pure hesperetin(HP).Here, we review the role of mast cell counts, tumor necrosis factor alpha(TNF-α), transcription factor nuclear factor-κB(NF-κB), levels of glycoconjugates, proliferating cell nuclear antigen(PCNA) and argyrophilic nucleolar organizing regions, are the master regulator of inflammation and proliferation, in the development of hepatocellular injury, liver fibrosis and HCC. DEN-administered animals showed increased mast cell counts, tumor necrosis factor alpha, transcription factor nuclear factor-κB, glycoconjugates, proliferating cell nuclear antigen, and argyrophilic nucleolar organizing regions. Whereas Au-mPEG(5000)-S-HP NPs supplementation considerably suppressed all the above abnormalities. These results suggest that the Au-m PEG(5000)-S-HP NPs exhibited the better potential anticancer activity by inhibiting cell inflammation and proliferation in DEN-induced hepatocellular carcinogenesis.

Optical manipulation of gold nanoparticles using an optical nanofiber

Gold nanoparticles are gaining increasing attention due to their biological and medical applications.In this letter,we experimentally demonstrate the optical manipulation of 250-nm-diameter gold nanoparticles along an optical nanofiber（550 nm in diameter） injected by an 808-nm laser light.The nanoparticles situated in the evanescent optical field are trapped by optical gradient force and move along the direction of light propagation due to optical scattering force.The velocities reach as high as 132 μm/s at an optical power of 80 mW.

Efficacy of Gold Nanoparticles against Nephrotoxicity Induced by Schistosoma mansoni Infection in Mice

Objective In this study, the ameliorative effects of gold nanoparticles （gold NP） on the renal tissue damage in Schistosoma mansoni （S. mansoni）-infected mice was investigated. Methods High-resolution transmission electron microscopy was used for the characterization of NP. The gold NP at concentrations of 250, 500, and 1000 μg/kg body weight were inoculated into 5. mansoni-infected mice. Results The parasite caused alterations in the histological architecture. Furthermore, it induced a significant reduction in the renal glutathione levels; however, the levels of nitric oxide and malondialdehyde were significantly elevated. The parasite also managed to downregulate KIM-I, NGAL, MCP-1, and TGF-8 mRNA expression in infected animals. Notably, gold NP treatment in mice reduced the extent of histological impairment and renal oxidative damage. Gold NP were able to regulate gene expression impaired by 5. Mansoni infection. Conclusion The curative effect of gold NP against renal toxicity in 5. mansoni-infected mice is associated with their role as free radical scavengers.

Self-organization of Gold Nanoparticles Protected by 9-(5-Thiopentyl)-carbazole

Through the reduction of [AuCl4] by aqueous sodium borohydride in the presence of 9-(5-thiopentyl)-carbazole, the gold nanoparticles has been prepared and characterized.

Preparation of Gold Nanoparticles Protected with Polyelectrolyte

Gold nanoparticles were synthesized through the reduction of tetrachlorauric acid (HAuCl4) by NaBH4, with polyethyleneimine(PEI) as stabilizer. The nanoparticles were characterized by UV-vis spectroscopy and atomic force microscopy(AFM).

A Simple Approach to Control the Growth of Non-spherical Gold Nanoparticles

A simple method to prepare the non-spherical gold particles was developed. The result solution included trigonal, truncated trigonal, hexagonal layers, and a pseudo-pentagonal shaped gold nanocrystals. The key factor is to control the relative rates of nucleation and cluster growth in this method. These attributes make seeding growth method as a useful tool in the fabrication of colloidal metal materials. A longitudinal plasmon resonance of 866 nm was observed, which is in the near-IR spectral regions (600-1000 nm). The excellent optical properties as near-IR labels are used to develop highly sensitive analysis method.

Inhibition of retinal angiogenesis by gold nanoparticles via inducing autophagy

AIM： To investigate the effect of gold nanoparticles on retinal angiogenesis in vitro and in vivo, and to reveal the possible mechanism.METHODS： Seed growth method was used to synthesize gold nanoparticles（GNPs）. The size, zeta potential, absorption spectrum and morphology of GNPs were identified using Malvern Nano-ZS, multimode reader（Bio Tek synergy2） and transmission electron microscope. Cell viability was analyzed using cell counting kit-8 method and cell growth was assessed with EdU kit. Transwell chamber was used to investigate cell migration. Tube formation method was used to assess the angiogenic property in vitro. Oxygen induced retinopathy（OIR） model was used to investigate the effect of GNPs on retinal angiogenesis. Confocal microscope and Western blot were used to study the possible mechanism of GNPs inhibited angiogenesis.RESULTS： The GNPs synthesized were uniform and well dispersed. GNPs of 10 μg/mL and 20 μg/mL were able to inhibit human umbilical vein endothelial cells proliferation（50% and 72% separately, P〈0.001）, migration（54% and 83% separately, P〈0.001） and tube formation（52% and 90% separately, P〈0.001）. Further data showed that GNPs were able to improve the retinopathy in an OIR model. The possible mechanism might be that GNPs were able to induce autophagy significantly（P〈0.05）.CONCLUSION： The present study suggests that GNPs are able to inhibit retinal neovascularization in vitro and in vivo. GNPs might be a potential nanomedicine for the treatment of retinal angiogenesis.

Molecular recognition by gold, silver and copper nanoparticles

The intrinsic physical properties of the noble metal nanoparticles,which are highly sensitive to the nature of their local molecular environment,make such systems ideal for the detection of molecular recognition events.The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles.In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization.A brief discussion of the three common methods of functionalization:Electrostatic adsorption;Chemisorption;Affinity-based coordination is given.In the second section a discussion of the optical and electrical properties of nanoparticles is given to aid the reader in understanding the use of such properties in molecular recognition.In the main section the various types of capping agents for molecular recognition;nucleic acid coatings,protein coatings and molecules from the family of supramolecular chemistry are described along with their numerous applications.Emphasis for the nucleic acids is on complementary oligonucleotide and aptamer recognition.For the proteins the recognition properties of antibodies form the core of the section.With respect to the supramolecular systems the cyclodextrins,calix[n]arenes,dendrimers,crown ethers and the cucurbitales are treated in depth.Finally a short section deals with the possible toxicity of the nanoparticles,a concern in public health.

Fabrication of gold nanoparticles with different morphologies in HEPES buffer

Gold nanoparticles with different morphologies, such as spindle, octahedron, and decahedron were obtained by using different molar ratios of HAuCl4/HEPES in the presence and absence of surfactants at room temperature.These nanoparticles were characterized by X-ray diffraction（XRD）, transmission electron microscopy（TEM）, high-resolution transmission electron microscopy（HRTEM）, scanning electron microcopy（SEM）, energy-dispersive X-rays analysis（EDX）, and selected area electron diffraction（SAED）.The kinetics of the formation of gold nanoparticles in HEPES buffer was studied by UV-visible spectrophotometer.The formation of gold nanoparticles was strongly dependent on the concentration of HEPES and pH value.The surfactants play a crucial role in the size and shape controlled synthesis of gold nanoparticles.

The effect of pH on the sorption of gold nanoparticles on illite

Sorption between nanoparticles(NPs)and minerals may critically affect the migration of associated elements as well as the environmental impact of NPs.Since illite is widely present in soil,sediment,and water,we have experimentally investigated the sorption behavior of citrate-coated gold nanoparticles(AuNPs)as model NPs on illite under different pH and mineral mass conditions.We demonstrated that sorption of these negatively charged AuNPs strongly depended on the suspension pH.At pH above 8,which coincided with the apparent point of zero charge(pH 7.9)of our illite sample,only marginal sorption of AuNPs was observed.At pH 3-8,significant sorption of AuNPs on illite was found,with almost complete sorption occurring at more acidic conditions(pH 3-4).TEM observations revealed that sorption took place through the attachment AuNPs on illite edges.At pH 2,AuNPs mostly formed chain-like fused structures and precipitated out of the suspension.Based upon the above pH dependence,residual organic ligand content after sorption,and complementary sorption results with positively charged AuNPs,we conclude that the sorption process is mainly driven by the electrostatic attraction between negatively charged AuNPs and positively charged illite edges,with possible competitive involvement of citrate molecules.We expect that our findings will improve our understanding of NP-mineral interaction and the environmental fate of NPs.