Retracted: Zeptomolar detection of 4-aminothiophenol by SERS using silver nanodendrites decorated with gold nanoparticles

Abstract

In the present work we report a simple, fast, reproducible and cheap methodology for SERS substrate fabrication of silver dendritic nanostructures (prepared by electrodeposition) decorated with gold nanospheres by electrophoretic deposition. This is the first report where a metal dendritic nanostructure has been decorated with another type of metal nanoparticles by this technique. The decorated nanostructures were used directly as SERS substrate using 4-aminothiophenol (4-ATP) as analyte. The objective of the decoration is to create more hot-spots in order to detect the analyte in a lower concentration. Decorated nanodendrites had a detection limit one million times lower than bare silver nanodendrites and all the substrates showed an increase in the Raman intensity at concentrations below 1 nM; because this concentration corresponds to the threshold for the formation of a monolayer resulting in a triple mechanism of intensity increase, namely electric field, chemical factor and hot-spots. 4-ATP was detected in zeptomolar concentration, which is below 1 ppq, corresponding to an analytical enhancement factor (AEF) in the order of 1015.

SERS/EC Dual-Mode Sensing System for the Assay of SARS-CoV-2 RNA by Using Single Gold Nanowires as a Platform

“…The Raman peaks at 1014 and 1186 cm –1 are attributed to C–C bending vibration and C–H bending, respectively. The Raman peaks at 1500 cm –1 correspond to a combination of C–C stretching and C–H bending vibration . Finally, we chose a wavelength of 532 nm for the subsequent SERS tests.…”

“…The Raman peaks at 1500 cm −1 correspond to a combination of C−C stretching and C−H bending vibration. 50 Finally, we chose a wavelength of 532 nm for the subsequent SERS tests. By comparison (Figure 1F), two dominant Raman peaks were observed at 1080 and 1591 cm −1 for Au/4-ATP, Au@Ag/4-ATP, and the nanoprobe compared to bare Au@Ag NPs, which are considered as characteristic peaks for 4-ATP.…”

Silicon Nanostructures for Molecular Sensing: A Review

“…231−234 Yin et al have demonstrated the fabrication of Ag@Au core−shell dendrite structure on Si by synergetic hydrothermal corrosion and chemical reduction processes. 235,236 The fabricated structure illustrated the mean diameters of trunks, branches, and sub-branches of Ag@Au For example, Osminkina and co-workers have reported flowerlike gold NSs (AuNFs) on pSi/SiO 2 surface by one-spot synthesis for superior SERS detection. 238 The as-prepared AuNFs contained coral-like petals with 50−150 nm length, and the diameter was estimated to be ∼500 nm.…”

“…Apart from AgNDs, highly branched gold NSs have drawn increasing attention to the area of sensing due to their promising optoelectronic properties for biomedical investigations. − Yin et al have demonstrated the fabrication of Ag@Au core–shell dendrite structure on Si by synergetic hydrothermal corrosion and chemical reduction processes. , The fabricated structure illustrated the mean diameters of trunks, branches, and sub-branches of Ag@Au were about 120, 80, and 40 nm, respectively, with an average spacing of adjacent sub-branches of about ∼20 nm. The group tested SERS with widespread analytes like R6G, CV, methylene orange (MO), p -aminothiophenol (PATP), and DNA.…”