Reusable SERS Substrates Based on Gold Nanoparticles for Peptide Detection

Abstract

Raman spectroscopy is a powerful analytical technique widely used for quantitative and qualitative analysis. However, the development of inexpensive, reproducible, and reusable enhancing substrates remains a challenge for material scientists and analytical chemists. In this study, we address this challenge by demonstrating the deposition of core–shell nanoparticles consisting of a gold core and a thin inert SiO2 shell within a confined space, resulting in the formation of a highly efficient Raman-enhancing structure. Nanoparticles were characterized by UV–vis spectroscopy, dynamic light scattering, and total reflectance X-ray fluorescence spectroscopy, whereas the prepared substrates were characterized by scanning electron microscopy and Raman spectroscopy with a model molecule, malachite green. The relationship between Raman intensity and the loading of malachite green dye exhibited linearity, indicating the uniform spatial distribution of hotspots across the substrate. The limit of detection was determined as 2.9 μM of malachite green when 10 uL was distributed over a ca. 25 mm2 surface area. Moreover, the same substrate, after thorough washing in ethanol, was successfully employed for the detection of bovine serum albumin at a concentration level of 55 μg mL−1, demonstrating its reusability and versatility. Our findings highlight the potential of these substrates for various applications in biomedical research, clinical diagnosis, and beyond.

Rapid Solution-Based SERS Detection of Pesticides Using Graphene Oxide-Coated Silver–Gold Nanostars

“…The LOD of TP was calculated to be 0.05 nM with a good signal-to-noise ratio (S/ N = 3.5). We further calculated the analytical enhancement factor (AEF) of the GO-SGNS by following the previously described method 66,67 as AEF = (I SERS /C SERS )/(I Raman /C Raman ), where I SERS and I Raman are the SERS intensity of TP at 1584 cm −1 in the presence and in the absence of GO-SGNS, respectively. C SERS and C Raman are the concentrations of TP in the SERS and normal Raman measurements, respectively.…”