Detection of the Viral Infectious Diseases in Blood by Surface-Enhanced Raman Spectroscopy: Mini Review

Raman spectroscopy is an optical spectroscopic technique that is commonly used to identify the vibrational modes of a substance. However, the efficiency of exciting Raman scattering is very weak—approximately 1 out of 106 phonons are absorbed and emitted through Raman scattering. This weak efficiency dramatically limits the signal intensity of Raman spectroscopy. Studies have shown that metal nanoparticles can dramatically enhance Raman scattering via a nanoparticles-based localized plasmon resonance (LSPR). This enhancement of the Raman signal enables detection down to the single molecule level (~picomolar) [1,2]. Surface-enhanced Raman spectroscopy (SERS) is a technique which induces local surface plasmons at the vicinity of a metal or dielectric material by laser excitation to enhance the Raman signal. This surface-based detection technique can enhance the Raman signal up to 1010 by molecular adsorption on a rough metal surface and makes single biomolecular detection possible if the target molecule is near the metal surface [3,4]. When detecting viruses there are two conventional approaches to bringing the target virus close to the rough metal, one is through antibody-conjugated nanoparticles, and the other is through surface engineered metal nanostructures. In the following, we will focus on reviewing SERS based detection for different infectious diseases.