Surface‐Enhanced R aman Spectroscopy: Protein Application

Abstract This article outlines the recent progress in surface‐enhanced Raman spectroscopy (SERS)‐based biological applications, especially in the study of proteins. SERS is a specific Raman spectroscopic technique that provides enhanced Raman signals (several orders of magnitude greater than normal) for numerous Raman active analyte molecules adsorbed onto rough metal surfaces. SERS is a sensitive, selective, and versatile technique, and it lends itself readily to fast data acquisition. Therefore, SERS has undergone rapid development due to numerous technical advances in both instrumentation and methods of data analysis as well as to a vast proliferation and combination of basic techniques for its multiple biological applications. This article highlights several representative areas in biology where SERS could be employed. Some of the biological applications of SERS are more developed, whereas others are in their initial stages of development (in laboratories). This article discusses the recent developments in SERS‐based quantitative analysis: (i) directly with different substrates (e.g. biomolecules on electrodes, colloidal particles, and periodic pattern structure, semiconductor‐based substrates, and tip‐based substrates), and (ii) indirectly with different types of sensors (e.g. immunogold‐, enzymatic‐, reagent‐, and Raman active nanomaterial‐based sensors). Furthermore, SERS‐based techniques are advantageous for obtaining valuable information on protein–protein, protein–ligand and protein–drug recognition via spectral differences among molecular bridges. More importantly, SERS was employed to determination of disease‐related proteins which the structure and/or the content changes in the tissue fluid. SERS‐based techniques show considerable promise for qualitative and/or quantitative analysis and early diagnosis of disease for life body.