Raman Activity of HS-(CH2 ) –NH-Coumarin Molecule Adsorbed on the Surface of Gold Nanostructures with various Morphologies

Synthesis of gold nanowires with an average diameter of 10 nm and length of up to 20 µm was achieved through a three-step heterogeneous nucleation process. Gold nanowires were formed through coalescence of spherical nanocrystals leading to grain growth and subsequently uneven nanowires. Furthermore, the uneven gold nanowires experienced thinning driven by thermodynamics to form relatively even nanowires with smaller diameters. Gold nanowires showed enhanced Raman activity in respect to enhancement factor than respective spherical gold nanoparticles with average particle sizes of 14 nm, 30 nm and 40 nm. The better Raman activity of gold nanowires with respect to spherical morphology was attributed to how they adsorb Raman active molecules, which are surface adsorption and network entanglement.

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PEGylated Gold Nanoparticles with Interesting Plasmonic Properties Synthesized Using an Original, Rapid, and Easy-to-Implement Procedure

Journal of Nanomaterials ◽

10.1155/2018/5954028 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 4

Author(s):

Ștefan Nițică ◽

Alin Iulian Moldovan ◽

Valentin Toma ◽

Cristian Silviu Moldovan ◽

Ioana Berindan-Neagoe ◽

...

Keyword(s):

Gold Nanoparticles ◽

Synthesis Method ◽

Average Diameter ◽

Liquid Droplets ◽

Sers Substrates ◽

New Class ◽

One Step ◽

Short Synthesis ◽

Spherical Gold Nanoparticles ◽

Synthesis Procedure

In this letter, we report a new, one-step, rapid, and easy-to-implement method for the synthesis of PEGylated gold nanoparticles (PEG-AuNPs) having a narrow size distribution and very interesting plasmonic properties. Unmodified polyethylene glycol molecules with a molecular weight of 1000 g/mole (PEG1000) have been employed as reducing and capping agents for the synthesis of spherical gold nanoparticles having an average diameter of 35 nm, within a few minutes. The novelty of the herein proposed synthesis method consists in the fact that the synthesis takes place inside of a sealed bottle flask containing aqueous solutions of PEG1000, tetrachloroauric(III) acid (HAuCl4), and NaOH, placed in the center of a microwave oven, capable to provide a very uniform temperature environment. It turned out that, during the very short synthesis procedure (2 minutes), PEG 1000 suffers an oxidative transformation in such a manner that its terminal alcohol groups (-CH2-OH) are transformed in carboxylate ones (-COO−). The as-synthesized PEG-AuNPs possess very interesting plasmonic properties allowing the detection of different molecules by means of SER spectroscopy performed either in liquid droplets or on solid spots. As a consequence of their unique plasmonic properties, the SER spectra acquired using this new class of nanoparticles on different molecules of interest (methylene blue, rhodamine 6G, doxorubicin, and 5-fluorouracil) are highly reproducible, making them ideal candidates for further use as SERS substrates.

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Advantages of Highly Spherical Gold Nanoparticles as Labels for Lateral Flow Immunoassay

Sensors ◽

10.3390/s20123608 ◽

2020 ◽

Vol 20 (12) ◽

pp. 3608

Author(s):

Nadezhda A. Byzova ◽

Anatoly V. Zherdev ◽

Boris N. Khlebtsov ◽

Andrey M. Burov ◽

Nikolai G. Khlebtsov ◽

...

Keyword(s):

Gold Nanoparticles ◽

Au Nanoparticles ◽

Troponin I ◽

Limit Of Detection ◽

Average Diameter ◽

Covalent Immobilization ◽

Lateral Flow ◽

Antibody Immobilization ◽

Site Testing ◽

Spherical Gold Nanoparticles

The use of lateral flow immunoassays (LFIAs) for rapid on-site testing is restricted by their relatively high limit of detection (LoD). One possible way to decrease the LoD is to optimize nanoparticle properties that are used as labels. We compare two types of Au nanoparticles: usual quasispherical gold nanoparticles (C-GNPs), obtained by the Turkevich–Frens method, and superspherical gold nanoparticles (S-GNPs), obtained by a progressive overgrowth technique. Average diameters were 18.6–47.5 nm for C-GNPs and 20.2–90.4 nm for S-GNPs. Cardiomarker troponin I was considered as the target analyte. Adsorption and covalent conjugation with antibodies were tested for both GNP types. For C-GNPs, the minimal LoD was obtained with 33.7 nm nanoparticles, reaching 12.7 ng/mL for covalent immobilization and 9.9 ng/mL for adsorption. The average diameter of S-GNPs varied from 20.2 to 64.5 nm, which resulted in a decrease in LoD for an LFIA of troponin I from 3.4 to 1.2 ng/mL for covalent immobilization and from 2.9 to 2.0 ng/mL for adsorption. Thus, we obtained an 8-fold decrease in LoD (9.9 to 1.2 ng/mL) by using S-GNPs. This effect can be related to more effective antibody immobilization and improved S-GNP optical properties. The obtained results can improve LFIAs for various practically significant analytes.

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DNA-Templated Assembly of Conducting Gold Nanowires

MRS Proceedings ◽

10.1557/proc-0921-t01-09 ◽

2006 ◽

Vol 921 ◽

Author(s):

Amro Satti ◽

Damian Aherne ◽

Claire Barrett ◽

Liam Floyd ◽

Aidan Quinn ◽

...

Keyword(s):

Gold Nanoparticles ◽

Aqueous Dispersion ◽

Average Diameter ◽

Gold Nanowires ◽

Current Voltage ◽

Calf Thymus ◽

Wafer Substrate ◽

Single Nanowires ◽

Positively Charged Gold Nanoparticles ◽

Dna Template

AbstractThe use of DNA to template the assembly of gold nanowires from gold nanoparticles is reported. Double-stranded calf thymus DNA, was deposited on a polystyrene-coated silicon wafer substrate. The substrate was then exposed to an aqueous dispersion of positively charged gold nanoparticles (~ 4 nm diameter), which adsorbed at the negatively charged DNA template. The adsorbed nanoparticles were then enlarged and enjoined by electroless deposition leading to formation of continuous nanowires of 85 nm average diameter. Gold electrodes were then overlaid on individual nanowires using conventional lithographic techniques. Two-terminal current-voltage measurements were employed to characterize the electrical characteristics of single nanowires. The nanowires exhibit resistivity values < 6 × 10-7 Ωm. These and related findings have implications for the design and assembly of next generation electronic devices.

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In SituSynthesis and Deposition of Gold Nanoparticles with Different Morphologies on Glass and ITO Substrate by Ultrasonic Spray Pyrolysis

Advances in Materials Science and Engineering ◽

10.1155/2013/916908 ◽

2013 ◽

Vol 2013 ◽

pp. 1-5 ◽

Cited By ~ 8

Author(s):

María de la Garza ◽

Israel López ◽

Idalia Gómez

Keyword(s):

Gold Nanoparticles ◽

Spray Pyrolysis ◽

Indium Tin Oxide ◽

Average Particle Size ◽

Ultrasonic Spray Pyrolysis ◽

Average Particle ◽

Particle Sizes ◽

Ultrasonic Spray ◽

Ito Film

Gold nanoparticles were synthesized and depositedin situby ultrasonic spray pyrolysis on glass and indium tin oxide (ITO) substrates. This technique led to the formation of gold nanoparticles with different morphologies without the use of any capping agent. The gold nanoparticles deposited on glass substrate were obtained as nanospheres with an average particle size of 30 nm with some agglomerates; however, the nanoparticles deposited on ITO substrate were obtained with different morphologies, such as triangular nanoprisms, nanorods, nanocubes, and nanorhombus, with particle sizes between 40 and 100 nm. The ITO substrate influenced the morphology of the gold nanoparticles obtained due to changes in the deposition temperature, which also change the crystalline structure of the ITO film on the substrate.

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Ultrathin Gold Nanowires to Enhance Radiation Therapy

10.21203/rs.2.23426/v2 ◽

2020 ◽

Author(s):

Lin Bai ◽

Fangchao Jiang ◽

Renjie Wang ◽

Chaebin Lee ◽

Hui Wang ◽

...

Keyword(s):

Oxidative Stress ◽

Gold Nanoparticles ◽

Radiation Therapy ◽

Xenograft Model ◽

Gold Nanowires ◽

Gold Nanospheres ◽

Radical Production ◽

Spherical Gold Nanoparticles

Abstract Background: Radiation therapy is a main treatment option for cancer. Due to normal tissue toxicity, radiosensitizers are commonly used to enhance RT. In particular, heavy metal or high-Z materials, such as gold nanoparticles, have been investigated as radiosensitizers. So far, however, the related studies have been focused on spherical gold nanoparticles. In this study, we assessed the potential of ultra-thin gold nanowires as a radiosensitizer, which is the first time. Methods: Gold nanowires were synthesized by the reduction of HAuCl4 in hexane. The as-synthesized gold nanowires were then coated with a layer of PEGylated phospholipid to be rendered soluble in water. Spherical gold nanoparticles coated with the same phospholipid were also synthesized as a comparison. Gold nanowires and gold nanospheres were first tested in solutions for their ability to enhance radical production under irradiation. They were then incubated with 4T1 cells to assess whether they could elevate cell oxidative stress under irradiation. Lastly, gold nanowires and gold nanoparticles were intratumorally injected into a 4T1 xenograft model, followed by irradiation applied to tumors (3 Gy/per day for three days). Tumor growth was monitored and compared. Results: Our studies showed that gold nanowires are superior to gold nanospheres in enhancing radical production under X-ray radiation. In vitro analysis found that the presence of gold nanowires caused elevated lipid peroxidation and intracellular oxidative stress under radiation. When tested in vivo, gold nanowires plus irradiation led to better tumor suppression than gold nanospheres plus radiation. Moreover, gold nanowires were found to be gradually reduced to shorter nanowires by glutathione, which may benefit fractionated radiation. Conclusion: Our studies suggest that gold nanowires are a promising type of radiosensitizer that can be safely injected into tumors to enhance radiotherapy. While the current study was conducted in a breast cancer model, the approach can be extended to the treatment of other cancer types.

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Decoration of Carbon Nanotubes with Gold Nanoparticles for Catalytic Applications

MRS Proceedings ◽

10.1557/proc-820-o3.10 ◽

2004 ◽

Vol 820 ◽

Cited By ~ 1

Author(s):

Wei Lü ◽

Xicheng Ma ◽

Ning Lun ◽

Shulin Wen

Keyword(s):

Electron Microscopy ◽

Carbon Nanotubes ◽

Transmission Electron Microscopy ◽

Gold Nanoparticles ◽

High Resolution ◽

Electroless Plating ◽

Particle Sizes ◽

Transmission Electron ◽

Spherical Gold Nanoparticles ◽

Catalytic Applications

AbstractGold nanoparticles supported on carbon nanotubes (CNTs) were prepared by using electroless plating technique. High-resolution transmission electron microscopy (HRTEM) has shown that spherical gold nanoparticles were homogeneously dispersed on the surfaces of the carbon nanotubes with a distribution of particle sizes sharply at around 3-4 nm in diameter. The results presented in this work will probably provide new catalysts with better performances.

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Ultrathin gold nanowires to enhance radiation therapy

Journal of Nanobiotechnology ◽

10.1186/s12951-020-00678-3 ◽

2020 ◽

Vol 18 (1) ◽

Author(s):

Lin Bai ◽

Fangchao Jiang ◽

Renjie Wang ◽

Chaebin Lee ◽

Hui Wang ◽

...

Keyword(s):

Oxidative Stress ◽

Gold Nanoparticles ◽

Radiation Therapy ◽

Xenograft Model ◽

Gold Nanowires ◽

Gold Nanospheres ◽

Radical Production ◽

Spherical Gold Nanoparticles

Abstract Background Radiation therapy is a main treatment option for cancer. Due to normal tissue toxicity, radiosensitizers are commonly used to enhance RT. In particular, heavy metal or high-Z materials, such as gold nanoparticles, have been investigated as radiosensitizers. So far, however, the related studies have been focused on spherical gold nanoparticles. In this study, we assessed the potential of ultra-thin gold nanowires as a radiosensitizer, which is the first time. Methods Gold nanowires were synthesized by the reduction of HAuCl4 in hexane. The as-synthesized gold nanowires were then coated with a layer of PEGylated phospholipid to be rendered soluble in water. Spherical gold nanoparticles coated with the same phospholipid were also synthesized as a comparison. Gold nanowires and gold nanospheres were first tested in solutions for their ability to enhance radical production under irradiation. They were then incubated with 4T1 cells to assess whether they could elevate cell oxidative stress under irradiation. Lastly, gold nanowires and gold nanoparticles were intratumorally injected into a 4T1 xenograft model, followed by irradiation applied to tumors (3 Gy/per day for three days). Tumor growth was monitored and compared. Results Our studies showed that gold nanowires are superior to gold nanospheres in enhancing radical production under X-ray radiation. In vitro analysis found that the presence of gold nanowires caused elevated lipid peroxidation and intracellular oxidative stress under radiation. When tested in vivo, gold nanowires plus irradiation led to better tumor suppression than gold nanospheres plus radiation. Moreover, gold nanowires were found to be gradually reduced to shorter nanowires by glutathione, which may benefit fractionated radiation. Conclusion Our studies suggest that gold nanowires are a promising type of radiosensitizer that can be safely injected into tumors to enhance radiotherapy. While the current study was conducted in a breast cancer model, the approach can be extended to the treatment of other cancer types.

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Varied-shaped gold nanoparticles with nanogram killing efficiency as potential antimicrobial surface coatings for the medical devices

Scientific Reports ◽

10.1038/s41598-021-91847-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ewelina Piktel ◽

Łukasz Suprewicz ◽

Joanna Depciuch ◽

Sylwia Chmielewska ◽

Karol Skłodowski ◽

...

Keyword(s):

Gold Nanoparticles ◽

Medical Devices ◽

Multidrug Resistant ◽

Resistance Mechanisms ◽

Antimicrobial Spectrum ◽

Antimicrobial Coatings ◽

Low Toxicity ◽

Spherical Gold Nanoparticles ◽

Cost Efficient ◽

Bactericidal Efficiency

AbstractMedical device-associated infections are a serious medical threat, particularly for patients with impaired mobility and/or advanced age. Despite a variety of antimicrobial coatings for medical devices being explored to date, only a limited number have been introduced for clinical use. Research into new bactericidal agents with the ability to eradicate pathogens, limit biofilm formation, and exhibit satisfactory biocompatibility, is therefore necessary and urgent. In this study, a series of varied-morphology gold nanoparticles in shapes of rods, peanuts, stars and spherical-like, porous ones with potent antibacterial activity were synthesized and thoroughly tested against spectrum of Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus clinical strains, as well as spectrum of uropathogenic Escherichia coli isolates. The optimization of gold nanoparticles synthesis allowed to develop nanomaterials, which are proved to be significantly more potent against tested microbes compared with the gold nanoformulations reported to date. Notably, their antimicrobial spectrum includes strains with different drug resistance mechanisms. Facile and cost-efficient synthesis of gold nanoparticles, remarkable bactericidal efficiency at nanogram doses, and low toxicity, underline their potential for development as a new coatings, as indicated by the example of urological catheters. The presented research fills a gap in microbial studies of non-spherical gold nanoparticles for the development of antimicrobial coatings targeting multidrug-resistant pathogens responsible for device-associated nosocomial infections.

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Facile Green, Room-Temperature Synthesis of Gold Nanoparticles Using Combretum erythrophyllum Leaf Extract: Antibacterial and Cell Viability Studies against Normal and Cancerous Cells

Antibiotics ◽

10.3390/antibiotics10080893 ◽

2021 ◽

Vol 10 (8) ◽

pp. 893

Author(s):

Olufunto T. Fanoro ◽

Sundararajan Parani ◽

Rodney Maluleke ◽

Thabang C. Lebepe ◽

Jose R. Varghese ◽

...

Keyword(s):

Gold Nanoparticles ◽

Cell Viability ◽

Leaf Extract ◽

Room Temperature ◽

Klebsiella Oxytoca ◽

Cost Effective ◽

Average Diameter ◽

Antibacterial Activities ◽

Inhibition Concentration ◽

First Time

We herein report a facile, green, cost-effective, plant-mediated synthesis of gold nanoparticles (AuNPs) for the first time using Combretum erythrophyllum (CE) plant leaves. The synthesis was conducted at room temperature using CE leaf extract serving as a reducing and capping agent. The as-synthesized AuNPs were found to be crystalline, well dispersed, and spherical in shape with an average diameter of 13.20 nm and an excellent stability of over 60 days. The AuNPs showed broad-spectrum antibacterial activities against both pathogenic Gram-positive (Staphylococcus epidermidis (ATCC14990), Staphylococcus aureus (ATCC 25923), Mycobacterium smegmatis (MC 215)) and Gram-negative bacteria (Proteus mirabilis (ATCC 7002), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 13822), Klebsiella oxytoca (ATCC 8724)), with a minimum inhibition concentration of 62.5 µg/mL. In addition, the as-synthesized AuNPs were highly stable with exceptional cell viability towards normal cells (BHK- 21) and cancerous cancer cell lines (cervical and lung cancer).

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Intracellular mineralization of gold nanoparticles using gold ion-binding peptides with cell-penetrating ability

Chemical Communications ◽

10.1039/d0cc06117d ◽

2021 ◽

Author(s):

Makoto Ozaki ◽

Shuhei Yoshida ◽

Takaaki Tsuruoka ◽

Kenji Usui

Keyword(s):

Gold Nanoparticles ◽

Gold Nanostructures ◽

Ion Binding ◽

Cell Penetrating ◽

Binding Peptides ◽

Conventional Methods ◽

Gold Ion

Our method can produce uniquely shaped gold nanostructures in lower HAuCl4 concentration than conventional methods by intracellular functions using peptide assembled structures as a template.

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