Surface Enhanced Raman Spectroscopy-Based Bio-molecular Detectors Sovan Kumar Panda Abstract This chapter aims to describe multifarious schemes of detecting bio- molecules by using surface enhanced Raman spectroscopy (SERS)-substrates. At first, current state of knowledge concerning the mechanism of SERS, SERS-active materials and various parameters that influence SERS have been discussed. Classifi- cation of SERS substrates, depending on their physical structures, has been reported in the following section. Finally, fabrication methods and recent applications of SERS including sensing, single molecule SERS, and real-world applications for bio-molecular probing have been highlighted. Keywords Surface enhanced Raman scattering (SERS) · Electromagnetic hotspot · SERS substrate · Nobel metal nanoparticles · Bio-molecular detector 1 Introduction Surface enhanced Raman spectroscopy or surface enhanced Raman scattering (SERS) is a surface-sensitive technique that amplifies Raman scattering by a fac- tor of ~10 10 to 10 14 , overcoming the traditional drawback of Raman scattering—its inherent weakness (at most 10 -7 of the total scattering) [1–3]. It is a localized sur- face plasmon (LSP) based powerful vibrational spectroscopy technique which has attracted tremendous interest for the detection of wide range of analyte because of its ultrahigh sensitivity down to the single molecule detection limit and amenability to molecular finger printing. Therefore, SERS is being used in medical, chemical, biological, environmental and forensic sciences for the highly sensitive structural detection of low concentration analytes. More precisely, SERS has been used for the quantitative detection of DNA, pesticides, nicotin, components of milk, glucose in blood, viruses, contents of human urine etc. [4–12]. SERS spectroscopy provides same information as the normal non-surface enhanced Raman spectroscopy but signal intensity is much enhanced in SERS as compared to traditional Raman signal and hence the sensitivity. Therefore, use of S. K. Panda (B ) Department of Electronics, Bidhan Chandra College, Rishra, Hooghly 712248, West Bengal, India e-mail: sovan.panda@gmail.com © Springer Nature Switzerland AG 2019 C. D. Geddes (ed.), Reviews in Plasmonics 2017, Reviews in Plasmonics 2017, https://doi.org/10.1007/978-3-030-18834-4_9 229