Dragonfly wing decorated by gold nanoislands as flexible and stable substrates for surface-enhanced Raman scattering (SERS)

Abstract

A flexible and stable biomimetic SERS substrate was successfully fabricated by depositing gold (Au) nanoislands on the dragonfly wings (DW) via a simple DC magnetron sputtering system. Characterizations of the Au/DW nanostructure indicated that the optimum Au/DW-45 (sputtering time was 45 min) substrate owns high sensitivity, good stability and outstanding reproducibility. The limit of detection (LOD) for Rhodamine 6 G (R6G) was as low as 10−7 M and enhancement factor (EF) was calculated to be 2.8 × 106. 70-day-duration stability tests showed that Raman intensity of R6G reduced only by 12.9% after aging for 70 days. The maximum relative standard deviations (RSD) of SERS intensities from 100 positions of Au/DW-45 substrate were less than 8.3%, revealing outstanding uniformity and reproducibility. Moreover, the flexible Au/DW-45 bioscaffold arrays were employed to solve the vital problem of pesticide residues. By directly sampling from tomato peels via a “press and peel off” approach, cypermethrin has been rapidly and reliably determined with a LOD centered at 10−3 ng/cm2 and a correlation coefficient (R2) of 0.987. The positive results demonstrated that the Au-based DW biomimetic arrays may offer an efficient SERS platform for the identification of various pesticide residues on real samples.

Irreversible accumulated SERS behavior of the molecule-linked silver and silver-doped titanium dioxide hybrid system

“…urface-enhanced Raman scattering (SERS) has been intensive studied since it was first observed by a roughened silver electrode decorated by pyridine 1 . Due to its high sensitivity and selectivity on the designated analyte adsorbed on the noble metal and/or semiconductor substrates, SERS has been used as a powerful and useful tool for fingerprint tracing of biological and chemical molecules, such as tumor markers 2 , extracellular metabolites 3 , and pesticide residues 4 , even explosives 5 . And it is widely accepted that the electromagnetic enhancement (EE) and the chemical enhancement (CE) are two main mechanisms to contribute the SERS 6,7 .…”

Surface-Enhanced Raman Spectroscopy for Molecule Characterization: HIM Investigation into Sources of SERS Activity of Silver-Coated Butterfly Scales

“…Top-down approaches are represented by electron beam lithography which is capable of generating metallic nanostructures of almost any arbitrary shape [ 26 , 27 ]. In addition to these bottom-up and top-down approaches, one recent approach exploits natural microscopic structures such as wings of cicadas, dragonflies, and butterflies [ 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. Wings of cicadas and dragonflies are characterized by sharp protrusions which, when decorated by nanostructured noble metal, function as a SERS platform.…”

SERS background imaging – A versatile tool towards more reliable SERS analytics

“…Spectral acquisition delivers average spectra of the diffraction-limited areas. The uniformity of the signal enhancement on a SERS substrate is most often checked by pointwise [22][23][24] or linewise 25 Raman mapping or by randomly selecting different measurement spots on the substrate 15,26,27 . However, the long spectral acquisition times hinder the imaging of large areas in high resolution in short time, for example to study the distribution of hot spots.…”