Surface Enhanced Raman Spectroscopy for Single Molecule Protein Detection

Abstract

A two-step process of protein detection at a single molecule level using SERS was developed as a proof-of-concept platform for medical diagnostics. First, a protein molecule was bound to a linker in the bulk solution and then this adduct was chemically reacted with the SERS substrate. Traut’s Reagent (TR) was used to thiolate Bovine serum albumin (BSA) in solution followed by chemical cross linking to a gold surface through a sulfhydryl group. A Glycine-TR adduct was used as a control sample to identify the protein contribution to the SER spectra. Gold SERS substrates were manufactured by electrochemical deposition. Solutions at an ultralow concentration were used for attaching the TR adducts to the SERS substrate. Samples showed the typical behavior of a single molecule SERS including spectral fluctuations, blinking and Raman signal being generated from only selected points on the substrate. The fluctuating SER spectra were examined using Principle Component Analysis. This unsupervised statistics allowed for the selecting of spectral contribution from protein moiety indicating that the method was capable of detecting a single protein molecule. Thus we have demonstrated, that the developed two-step methodology has the potential as a new platform for medical diagnostics.

SERS Activity of Silver Nanosphere, Triangular Nanoplates, Hexagonal Nanoplates and Quasi-Spherical Nanoparticles: Effect of Shape and Morphology

“…Nevertheless, the Raman scattering is not very high, and this limitation prevents its use for the detection of low analyte concentrations [1]. For this reason, Surface Enhanced Raman Scattering (SERS) is a powerful vibrational spectroscopic technique that can extend the sensitivity of conventional Raman spectroscopy to the single molecule level [2][3][4]. The power of SERS can be exploited for its versatility and feasibility in a wide variety of fields including polymers, materials science, biochemistry and bio-sensing, catalyst, electrochemistry, pesticides, and food additives [5][6][7][8][9].…”

Multilayer Gold-Silver Bimetallic Nanostructures to Enhance SERS Detection of Drugs

“…Surface-enhanced Raman scattering (SERS) is a non-destructive and ultra-sensitive analytical technique, which allows rapid molecular-specific detection of a wide range of targets [1,2]. Since its discovery in 1974, SERS has been applied for the analytical sensing of many molecules of biological interest ranging from small organic molecules [3][4][5], pesticides [6,7] and drugs [8,9] to larger structures such as proteins, nucleic acids and cells [10][11][12][13]. Due to its promptness, high sensitivity and molecular specificity, SERS is particularly useful for drug detection.…”

Fabrication of Bioprobe Self-Assembled on Au–Te Nanoworm Structure for SERS Biosensor

“…It has been reported that frequency shifting in SERS-based immunoassays may be due to structural modifications that occur during antibody–antigen conjugation [ 46 , 47 ]. In addition, there have been no reports of the extinction of the Raman signal in the immunoassay method, but there are reports of the extinction of the Raman signal at the single-molecule level [ 48 ]. As a result, antigen antibody conjugation without labels could be confirmed by SERS.…”