scholarly journals Hydrogen-Free Diamond Like Carbon Films with Embedded Cu Nanoparticles: Structure, Composition and Reverse Saturable Absorption Effect

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 760
Author(s):  
Meškinis ◽  
Vasiliauskas ◽  
Viskontas ◽  
Andrulevičius ◽  
Guobienė ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Carbon Films ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Diamond Like Carbon ◽  
Optical Absorbance ◽  
Wide Range ◽  
Absorbance Spectra

In the present research, hydrogen-free diamond like carbon films with embedded copper nanoparticles (DLC:Cu) were grown by simultaneous DC magnetron sputtering of the graphite and copper targets. X-ray photoelectron spectroscopy was used to define the composition of the samples. Atomic force microscopy studies of diamond, like carbon films containing different amount of copper, revealed wide range of the surface morphologies as well as sizes and shapes of the embedded copper nanoclusters. Raman scattering spectra of all the DLC:Cu films investigated were typical for diamond-like carbon (including samples containing more than 60 at.% of copper). sp3/sp2 carbon bond ratio in the films decreased with the increase of the Cu amount in the films. According to the optical absorbance measurements, the surface plasmon resonance related absorption peak of DLC:Cu films was only detected in the films containing 28.45 at.% Cu. For the diamond like carbon films containing more than 40 at.% Cu, a further increase of Cu amount in the nanocomposite resulted in minor changes of the absorbance spectra. Some correlation between the changes of the samples surface morphology as well as phase structure and optical absorbance spectra of the films was found. In all cases, reverse-saturable absorption of the DLC:Cu films was observed. For some DLC:Cu films damage of the sample occurred at higher light fluences that can be related to the heating that is caused by the surface plasmon resonance effect.

scholarly journals Surface Plasmon Resonance Dependent Third-Order Optical Nonlinearities of Silver Nanoplates

Photonics ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 299
Author(s):  
Marcello Condorelli ◽  
Vittorio Scardaci ◽  
Mario Pulvirenti ◽  
Luisa D’Urso ◽  
Fortunato Neri ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Optical Limiting ◽  
Pulse Generation ◽  
Saturable Absorption ◽  
Nanosecond Laser ◽  
Reverse Saturable Absorption ◽  
Optical Nonlinearities ◽  
Third Order

A systematic study of the surface plasmon resonance (SPR)-dependent nonlinear optical response of Ag nanoplates is presented and discussed. The Ag nanoplates were synthesized using the well-known seed-mediated growth method. By performing the z-scan method with a nanosecond laser (532 nm, 5 ns), the optical nonlinearities of the Ag nanoplates, prepared tuning the SPR contribution in the 400–1000 nm range, were determined. The results showed a SPR-related competition between the saturable absorption and reverse saturable absorption mechanisms, while the nonlinear refraction changed from self-defocusing to self-focusing. Furthermore, the scattering effects contribute to determine the nature of the optical limiting response. The observed SPR-tunable third order optical nonlinearities make Ag nanoplates a suitable candidate to be used in different fields, i.e., laser pulse generation, optical limiting, or bio-imaging applications.

scholarly journals Determination of Vitamin B12 in Fortified Bovine Milk- Based Infant Formula Powder, Fortified Soya-Based Infant Formula Powder, Vitamin Premix, and Dietary Supplements by Surface Plasmon Resonance: Collaborative Study

2011 ◽  
Vol 94 (4) ◽  
pp. 1217-1226 ◽  
Author(s):  
Pathik Vyas ◽  
Anthony A O'kane ◽  
E Ager ◽  
S Crooks ◽  
C Elliott ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Protein Binding ◽  
Vitamin B12 ◽  
Infant Formula ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Binding Protein ◽  
Collaborative Study ◽  
Wide Range

Abstract A collaborative study was conducted on an inhibition-based protein-binding assay using the Biacore Q™ biosensor instrument and the Biacore Qflex™ Kit Vitamin B12 PI. The samples studied included infant formula, cereals, premixes, vitamin tablets, dietary supplements, and baby food. The collaborative study, which involved 11 laboratories, demonstrated that the assay showed an RSDr of 1.59–27.8 and HorRat values for reproducibility of 0.34–1.89 in samples with levels ranging from ppm to ppb. The assay studied is a label-free protein binding-based assay that uses the principle of surface plasmon resonance (SPR) to measure the interaction between vitamin B12 and a specifc binding protein. A Biacore Q biosensor uses this principle to detect binding directly at the surface of a sensor chip with a hydrophilic gold-dextran surface. The instrument passes a mixture of prepared sample extract and binding protein solution across a covalently immobilized vitamin B12 chip surface, and the response is given as free-binding protein as the mixture binds to the immobilized surface. This technique uses the specifcity and robustness of the protein-ligand interaction to allow minimal sample preparation and a wide range of matrixes to be analyzed rapidly. The reagents and accessories needed to perform this assay are provided as the ready-to-use format “Qflex Kit Vitamin B12 PI.” The method is intended for routine use in the quantitative determination of vitamin B12 (as cyanocobalamin) in a wide range of food products, dietary vitamin supplements, and multivitamin premixes.

Rapid surface plasmon resonance immunoassays for the determination of mycotoxins in cereals and cereal-based food products

2014 ◽  
Vol 7 (4) ◽  
pp. 491-505 ◽  
Author(s):  
J.P. Meneely ◽  
C.T. Elliott
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Cost Effective ◽  
Food Products ◽  
Future Research ◽  
Portable Devices ◽  
Wide Range ◽  
Food And Feed ◽  
Robust Sensing

In recent times surface plasmon resonance has demonstrated its applicability to the detection of a wide range of contaminants in food and feed including mycotoxins in cereals and cereal-based food products. Commercially available, laboratory-based systems have exploited high affinity polyclonal, monoclonal and recombinant antibodies and robust sensing surfaces to provide rapid, accurate and sensitive means of determining these toxins. In addition many custom-built, prototype devices have shown a great deal of potential for this particular application and have included the combination of surface plasmon resonance with enzyme-derivatised sensors, molecularly imprinted polymers, fluorescence spectroscopy and the use of gold nanoparticles for signal enhancement. Of note is the lack of available devices that allow the detection of multiple mycotoxins simultaneously and portable devices that could be used in the field, therefore future research and development should focus on these areas to deliver cost-effective miniaturised devices with multiplexing capabilities.

scholarly journals Colloidal Metal Oxide Nanoparticles Prepared by Laser Ablation Technique and Their Antibacterial Test

2019 ◽  
Vol 3 (1) ◽  
pp. 25 ◽  
Author(s):  
Johan Duque ◽  
Brayan Madrigal ◽  
Henry Riascos ◽  
Yenny Avila
Keyword(s):  
Surface Plasmon Resonance ◽  
Laser Ablation ◽  
Metal Oxide ◽  
Band Gap ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Ablation Technique ◽  
532 Nm ◽  
Absorbance Spectra ◽  
Laser Ablation Technique

In this article we report the production of metal oxide (TiFe2O4, ZnFe2O4) nanoparticles by pulsed laser ablation technique in a liquid environment. We used nanosecond Nd: YAG laser systems working at 532 nm and 1064 nm of wavelength and the energy of the laser beam was kept constant at 80 mJ. Absorbance spectra, surface plasmon resonance, optical band-gap, and nanoparticle morphology were investigated using ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Changing the wavelength of the laser for growth, nanoparticles showed shift between the absorbance and surface plasmon resonance peaks in their UV-Vis spectra, which implies that the optical properties of the colloid nanoparticles depend on laser parameters. This was confirmed with the variation of the band gap energy. Furthermore, redshift for the absorbance peak was observed for samples as-grown at 532 nm around 150 nm as a function of time preparation. Conversely, for the samples as-grown at 1064 nm there was no shift in the absorbance spectra, which could be due to agglomeration and formation of larger particles. The characterization results showed appropriate plasmonic photo-catalysts properties of the particles, hence the photoactivation of the nanoparticles was examined on antibacterial effect using colonies of Staphylococcus aureus and Escherichia coli.

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