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.
Highlights
High-performance detection technique of surface-enhanced Raman scattering (SERS) has been widely applied in chemical and biological sensing due to its high sensitivity, rapid response and nondestructive testing process[1,2,3]
Our analysis suggested that the Au/dragonfly wings (DW) substrate with the sputtering time of 45 min achieved the best enhancement and the limit of detection (LOD) for Rhodamine 6 G (R6G) was as low as [10−7] M
As we can see from the field emission scanning electron microscopy (FE-SEM) image in Fig. 2(A), a large number of multi-column nanopillars existed on the epicuticular layers of the dragonfly wings and they were randomly distributed
Summary
High-performance detection technique of surface-enhanced Raman scattering (SERS) has been widely applied in chemical and biological sensing due to its high sensitivity, rapid response and nondestructive testing process[1,2,3]. An increasing number of researchers have paid extensive attention to combining noble metal materials with super-hydrophobic biomaterials (e.g. plant leaves, insect wings) to fabricate SERS substrates These rough biomaterials show a high-performance enhancement as SERS substrates after decorated with noble metal nanoparticles. A SERS enhancement factor of 2.06 × 105 was obtained and the LOD for the malachite green was [10−11] M Mu and his co-workers developed a low-cost and green method to fabricate SERS substrates by in situ reducing gold nanoparticles in different butterfly wings and gained satisfactory results[25]. All the sputtering deposition processes were performed at room temperature
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