The present investigation reports the first-time successful synthesis of AuNPs using a new precursor salt of Au(III) acetate through USP. An aqueous solution of this salt was prepared with very ...limited solubility with H
2
O. HCl and HNO
3
were then added separately to increase the solubility, resulting in a clear, yellowish solution. This enabled the successful formation of AuNPs with USP. In order to improve AuNPs synthesis, NaOH and Na
2
CO
3
were added into the precursor to increase its pH (6–7). With such approach, it was possible to perform USP synthesis using varying concentrations of Au in the precursor. Evaporation and reaction temperatures (100 and 300 °C) of USP were chosen based on detected decomposition temperatures of Au(III) acetate with TGA-DT. TEM confirmed the presence of circular shaped, unagglomerated AuNPs having an Fm-3m space group with diameter range of 15–30 and circularity value range of 0.89–0.92. The UV–Vis spectroscopy showed absorbance peaks at 528 and 532 nm. ICP-MS indicated the highest concentration of AuNPs, 79 ppm, by the precursor with the lower initial concentration of Au. This could be due to the smallest sedimentation and turbulent losses of larger AuNPs in transport tubes and reaction USP zones.
The article presents the problem of rapid antigen tests when they become mass waste after use. Based on this, the hypothesis was made that rapid antigen tests can be recycled. Rapid antigen tests, ...which were used in the Covid-19 epidemic to quickly detect infections in the population or to confirm the presence of the Sars-Cov 2 virus in patients, were intended to limit the spread of the epidemic. To confirm the hypothesis of recycling for rapid antigen tests, the LFIA-REC ATP 150 project was prepared, which was selected for co-financing by the Norwegian Fund. Rapid antigen tests consist of a sample and conjugate pad, detectable or nitrocellulose membranes and absorbent pads and a plastic case. The function of the sample pad is to evenly absorb the sample (mucus, blood) and lead it to the conjugate pad with a steady flow. Gold nanoparticles (labels) are deposited on the conjugate pad. The key is that the gold nanoparticles are conjugated with capture molecules capable of binding to potentially present antibodies or virus in the sample. The scope of the research problem thus required the inclusion of various characterization techniques that must be applied to the individual material in the rapid antigen test to subsequently develop an efficient recycling process for the rapid antigen tests. The result of the research presented in this paper represents a newly developed algorithm of characterization techniques, which includes a recommended description of the preparation of samples of key materials from rapid antigen tests. This algorithm successfully achieved the characterization of gold nanoparticles from rapid antigen tests. Based on the developed algorithm, the final part of the project will validate the recycling process of rapid antigen tests, so that they can be recycled, i.e. gold nanoparticles or plastic used in new products. The paper presents the algorithm of characterization techniques with a description of the preparation of material samples from rapid antigen tests.
The surface plasmon resonance of gold nanoparticles causes visible light absorption and scattering effects that may be used in optical coatings for eliminating blue light emission from display ...monitors, for blocking UV light, and for decorative applications. This study examines the achievement of functional properties provided by gold nanoparticles in a commercially established C60 fullerene-coated eyewear product. The gold nanoparticles used were sourced from recycling rapid lateral flow tests (LFIA), which use gold nanoparticles as test markers. After the gold’s recovery, Ultrasonic Spray Pyrolysis (USP) with freeze-drying was used for the synthesis of new gold nanoparticles, to be used in optical coatings. The gold nanoparticles were examined with SEM, TEM, DLS, zeta potential, BET, and Vis-NIR for characterising their shapes and sizes, as is required for determination of the surface plasmon resonance effect. After applying the newly produced gold nanoparticles with fullerene C60 in a combined coating for eyewear lenses, the absorption and transmission of the lenses were determined for establishing changes in the coating’s functionality. The results show that enhancing the fullerene C60 coating with gold nanoparticles improves light absorption and reflectance for blue and UV light further, which may be evaluated as beneficial for the eyewear user, as the reduction in eye strain is increased due to the coating.
Herein, we report for the first time the successful preparation of a gold(III) nitrate Au(NO3)3 water‐based precursor for use in a bottom‐up ultrasonic spray pyrolysis (USP) process. Due to its ...limited solubility in water, the precursor was prepared under reflux conditions with nitric acid (HNO3) as the solvent and ammonium hydroxide (NH4OH) as a neutralizer. This precursor enabled the USP synthesis of gold nanoparticles (AuNPs) and the in situ formation of low concentrations of NO2− and NO3− ions, which were caught directly in deionized water in a collection system. These ions were proven to act as stabilizers for the AuNPs. Investigations showed that the AuNPs were monodispersed and spherically shaped with a size distribution over three groups: the first contained 5.3 % AuNPs with diameters (2 r) <15 nm, the second contained 82.5 % AuNPs with 2 r between 15 and 200 nm, and the third contained 12.2 % AuNPs with 2 r>200 nm. UV/Vis spectroscopy revealed the maximum absorbance band of the AuNPs at λ=528 nm. Additionally, scanning transmission electron microscopy (STEM) observations of the smallest AuNPs (2 r<5 nm) revealed atomically resolved coalescence phenomena induced by interaction with the electron beam. Four stages of the particle‐growth process were distinguished: 1) movement and rotation of the AuNPs; 2) necking mechanism; 3) orientated attachment at matching facets; 4) reshaping of the AuNPs by surface diffusion. This provided important insight into the formation/synthesis process of the AuNPs.
Solving Au(NO3)3: In‐depth investigations are performed for the unique preparation of soluble and stable Au(NO3)3 as a precursor for the synthesis of gold nanoparticles (AuNPs) through ultrasonic spray pyrolysis. Interaction of the AuNPs with the electron beam is explored to provide new insight into their formation process.
Nanomaterials are becoming an integral part of high-performance products and services. As technology advances, the possibilities for engineering components with nanomaterials are more numerous, ...taking advantage of the benefits that these materials have the potential to provide. Nanostructured materials have bulk dimensions with a structure that includes nanoscale features, and have been around for quite some time, hidden in everyday items. More recently, they have been made possible to be analysed and manipulated with increasingly sophisticated instruments and processes. This ability has made them more accessible, however, challenges still remain in the more widespread adoption of these materials for exploiting their advantages. The present paper outlines the position and emergence of nanostructured materials in the broader context of nanomaterials, examining their mechanical properties, production methods and applications.
Ultrasonic Spray Pyrolysis (USP) possesses a great potential for production of higher quantities of gold nanoparticles (AuNPs), thus overcoming the problem of batch-to-batch variations in their ...properties. Recently, we demonstrated that USP with an additional evaporation chamber (modular USP) led to a better size control of AuNPs. However, their morphology, stability, toxicity, and immunomodulatory properties have not been investigated completely. Here, two types of spherical AuNPs were produced by using different USP parameters, followed by their stabilization in Na-citrate solution. No significant changes in their size, agglomeration, and z-potential occurred 3 months after their initial production in citrate solution. However, the conditioning of AuNPs in serum-containing cell culture media for 24 h induced an increase in the AuNPs’ hydrodynamic size and a red shift in their Surface Plasmon Resonance, pointing to their instability in biological media. Cytocompatibility tests showed that the produced AuNPs were internalized by L929 cells and primary human monocytes and were not cytotoxic at the concentrations lower than 200 μg/mL, but they exhibited antiproliferative and anti-inflammatory effects, respectively. AuNPs reduced the percentage of CD14+CD16+ but not CD14lowCD16+ monocytes in vitro and reduced the expression of CD86, HLA-DR, TNF-α, and IL-12/IL-23 by these cells. These results indicate that the anti-inflammatory effects of citrate-capped AuNPs produced by modular USP could be beneficial for their application in the treatment of inflammatory conditions.
This article studies the synthesis of bimetallic Fe/Au submicron particles with Ultrasonic Spray Pyrolysis (USP). The combination of Fe oxide particles’ ferromagnetism with Au nanoparticles’ (AuNPs) ...surface plasmon resonance has gained high interest in biomedical and various other applications. Initial investigations for producing Fe/Au particles with USP were carried out in order to study the particle formation mechanisms. Firstly, three precursor salt solutions (Fe acetate, Fe nitrate and Fe chloride) were used to produce Fe oxide particles and to study their effect on particle morphology through characterization by Scanning and Transmission Electron Microscopy (SEM and TEM) with Energy Dispersive X-ray spectroscopy (EDX). These precursor salts produce three types of submicron particles, a mesh of primary nanoparticles, spherical particles and irregular particles, respectively. Next, different solution combinations of precursor salts of Fe and Au were used with the USP. The obtained particles were characterized, and similarities were then examined in the particle formation of pure Fe oxide and Fe/Au particles. The effects of using different salts were analyzed for the formation of favorable morphologies of Fe/Au particles. The combinations of Fe chloride/Au chloride and Fe chloride/Au nitrate in the precursor solution indicate potential in synthesizing bimetallic Fe/Au submicron particles with the USP process.
The analysis of the behaviour of new materials in the natural environment is important for their application and commercial use. In order to explore the application of Shape Memory Alloys in the ...Maritime industry, this research focuses on the corrosive behaviour of the NiTi rod that was produced by means of a continuous casting process. The experiment included three samples of NiTi rods that were exposed to the marine environment for 6, 12 and 18 months at a depth of 3 metres below the surface. The morphological and chemical changes were analysed separately during the experiment. Ultrasonic thickness equipment and the Scanning Electron Microscope (SEM) technique were used for the tests that determined the corrosion rates and detected pitting. The changes in the chemical composition of the NiTi rod were investigated by means of an Energy Dispersive X-ray (EDX) analysis, in order to define the pitting behaviour of the rod`s surfaces during its exposure to seawater. The obtained research results prove that the rate of pitting corrosion follows a progressive curve – the minimum value of corrosion rate equalled 0.04 mm/month, while the maximum value was 0.12 mm/month.
The article presents a study of the possible use of materials with Shape Memory Effect (SME) in shipbuilding, which have two special abilities of transformation and changing shape with changing of ...temperature or deformation. Among the most well-known SME materials, our study focuses on Ni-Ti and Cu- based alloys. An example of the existing fabrication presents casting of Ni-Ti in the form of a disk, and a new approach – continuous casting of Ni-Ti and CuAlNi alloys in the form of rods. In the article some results are shown of characterisation of microstructure and the basic properties. This was done in accordance with the fact that such scientific approach could define the starting point for further identification of the functional characteristics of these alloys by knowing the their chemical content and microstructure. Numerous studies are being carried out today in order to find the optimal functional characteristics of SME alloys. All of this is aimed at optimising the fabrication of these alloys, with the achievement of suitable properties for application in shipbuilding.
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