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In this paper, a highly connected chain-like Au/Ag nanoconfiguration which is synthesized by pulsed laser ablation pathway was investigated as an efficient SERS nanophotonics sensor. Very low SERS detection limit LOD for Thiram is about 10−8 M (0.024 ppm) that is lower than the allowed limit in the world of about 240 times. The results showed that the sensor performance (sensitivity) provides an excellent linear relationship between the Thiram concentrations and the SERS intestines, so the lower Thiram residence can efficiently monitor. The main reason behind this efficient performance is significantly related to the high specific surface area and the high density of the Au/Ag nanoconfiguration over the apple's surface. [ABSTRACT FROM AUTHOR]

This paper provides an efficient approach for making effectual and active substrates utilized for the detection of the Pyrromethene 580 (PM 580) molecule through the improvement of surface-enhanced Raman scattering (SERS). Those substrates have been fabricated with the use of the Au/Ag nanoparticles-coated porous silicon (PS). Au/Ag NPs have been prepared through laser ablation technique. This investigation is comparing Au/Ag NPs characteristics that have been generated by nanosecond laser ablation in PolyVinyl Alcohol (PVA) at 532 nm and 1064 nm laser wave-lengths. Then, Au/AgNPs were ablated in PVA colloidal solution to form (AuNPs:AgNPs)/PS plasmonic nano-structures. These plasmonic nanostructures on the SERS activities were studied utilizing PM 580 dye as examination molecule. Results have shown that the roughness and spots on nanostructures surfaces have resulted in causing increased absorbance spectra intensities and SERS signals. After effectual substrates have been excited by (λex. = 532 nm) laser source, the enhancement factor (EF) of SERS signals of PM 580 (0.01 M) attained 13.7 × 107 and 5.6 × 107 of the characteristic peaks at wavenumber 1657 cm−1 for the Au:AgNPs-532 nm/PS and Au:AgNPs-1064 nm/PS effectual substrates, respectively. The present research had shown that the nanostructure-coated PS substrates have repeatable and high signal frequency, inexpensive technique, stability in storage, and simplicity of use. [ABSTRACT FROM AUTHOR]

Chitosan is embedded by different ratios of Au/Ag NPs. Au/Ag NPs have been synthesised by laser ablation. The electrical conductivity and antibacterial behaviour of the synthesized films were obtained. In x-ray diffraction (XRD), a new pattern appeared at 2θ = 38.3° and 44.0° which correspond to face-centered cubic Ag, and a new pattern appeared at 38.5°, 45.0°, and 66.1° which corresponds to face-centered cubic Au. Fourier transform infrared (FTIR) data confirmed the interaction and miscibility between chitosan chains and Ag/Au NPs. Chitosan embedded with a 2/3 ratio of Au/Ag NPs reacted properly. Ultraviolet-visible (UV-Vis) spectroscopy results show a peak at 410 nm, corresponding to Ag NPs, and a very weak peak at 528 nm, corresponding to Au NPs, which shows evidence of the complexation between chitosan and Au/Ag NPs. The values of the ε' and loss ε̎ were increased after being embedded by pure Ag NPs until they reached a high value for sample S3 (2/3) (Au/Ag), then began to decrease by increasing the content of Au NPs and decreasing the ratio of Ag NPs. By decreasing the concentration of Ag NPs from S1 (0/5) to S6 (5/0) in the ration of Au/Ag NPs, there are decreases in the inhibition zone for both of the gram-negative bacterial strains tested, and the two gram-positive strains, using the zone of inhibition. The obtained results suggest that chitosan embedded with 2/3 Au/Ag possesses possible antibacterial action against the given bacteria. The given results suggest that the 2/3 Au/Ag-doped chitosan is the proper ratio used for both electrical and biomedical applications. [ABSTRACT FROM AUTHOR]