Effects of solid substrate on the SERS‐based immunoassay: a comparative study

Abstract

A comparative study of the solid substrates used in surface-enhanced Raman scattering (SERS) based immunoassay is made in this paper. Five different substrates were prepared and divided into two groups with and without SERS activity. They are (1) a poly-L-lysine slide, (2) a glutaraldehyde (GA)-aminosilane slide, (3) a substrate assembled with silver nanoparticles, (4) a substrate assembled with silver nanoparticles and functionalized with GA-aminosilane and (5) a substrate assembled with gold nanoparticles, of which the first two are substrates are without SERS activity and the latter three are with SERS activity because of the existence of the metallic nanoparticles. The SERS experimental results show that the immunoassay performed on an SERS-active substrate is more effective than that employing the inactive substrate. Among the inactive substrates, the GA-aminosilane slide with a better ability for antibody immobilization leads to a more sensitive immunoassay than the poly-L-lysine slide. Moreover, for SERS-based immunoassay, the substrate with assembled silver nanoparticles has an advantage of higher SERS enhancement capacity over the substrate assembled with gold nanoparticles. This work indicates that SERS-active substrates play important and positive roles in sensitive SERS-based immunoassay.

SERS-based Immunoassay in a Microfluidic System for the Multiplexed Recognition of Interleukins from Blood Plasma: Towards Picogram Detection

“…S5c ). Similar results have been observed and detected by the ATR/FTIR technique 23 . Additionally, according to the literature 24 the broadening and the shift to longer wavelength may also indicate aggregation.…”

Surface-Enhanced Raman Scattering-Based Immunoassay Technologies for Detection of Disease Biomarkers

“…A lot of effort has been put towards choosing and optimizing various types of different surfaces in recent years. It has been reported that the SERS effect can be attenuated by various substrates [44]. Thus far, assays have been made using many different solid substrates including glass slides, microtiter plate wells, and filter supports.…”

Bioanalytical application of surface‐ and tip‐enhanced Raman spectroscopy

“…In a typical SERS‐based immunoassay, capture biomolecules or proteins such as antigens are immobilized on a solid substrate. Labeled target molecules bind to their specific capture molecule and the interaction is detected by recording an SERS fingerprint spectrum of the label . Recently, a label‐free in situ detection of microorganisms, for example bacteria, is presented.…”

“…Here, the SERS signal was generated by the target protein and not from a Raman marker molecule. Various substrates were prepared and it was shown that SERS substrates with assembled silver nanoparticles were the most effective ones for the detection of 4‐mercaptobenzoic acid when excited at 633 nm .…”