133 © Springer Nature Singapore Pte Ltd. 2021 B.-H. Jun (ed.), Nanotechnology for Bioapplications, Advances in Experimental Medicine and Biology 1309, https://doi.org/10.1007/978-981-33-6158-4_6 Plasmonic Nanoparticles: Basics to Applications (I) Hyejin Chang, Won-Yeop Rho, Byung Sung Son, Jaehi Kim, Sang Hun Lee, Dae Hong Jeong, and Bong-Hyun Jun Abstract This review presents the main characteristics of metal nanoparticles (NPs), especially con- sisting of noble metal such as Au and Ag, and brief information on their synthesis meth- ods. The physical and chemical properties of the metal NPs are described, with a particular focus on the optically variable properties (sur- face plasmon resonance based properties) and surface-enhanced Raman scattering of plas- monic materials. In addition, this chapter cov- ers ways to achieve advances by utilizing their properties in the biological studies and medi- cal felds (such as imaging, diagnostics, and therapeutics). These descriptions will help researchers new to nanomaterials for biomedi- cal diagnosis to understand easily the related knowledge and also will help researchers involved in the biomedical feld to learn about the latest research trends. Keywords Surface plasmon resonance (SPR) · Surface- enhanced fuorescence (SEF) · Surface- enhanced Raman scattering (SERS) · Plasmon resonance energy transfer (PRET) 6.1 Introduction Nanoparticles (NPs) are considered to be the most valuable and important functional materials in the feld of material science. Noble metal NPs comprise one of the most actively studied felds in nanotechnology, with carbon materials, mag- netic materials, and quantum dots. The interest- ing ability of metal NPs to interact effectively with electromagnetic radiation makes them suit- able for many biomedical applications, including H. Chang Division of Science Education, Kangwon National University, Chuncheon, Republic of Korea W.-Y. Rho School of International Engineering and Science, Jeonbuk National University, Jeonju, Republic of Korea B. S. Son · J. Kim · B.-H. Jun (*) Department of Bioscience and Biotechnology, Konkuk University, Seoul, South Korea e-mail: bjun@konkuk.ac.kr S. H. Lee Department of Chemical and Biological Engineering, Hanbat National University, Daejeon, Republic of Korea D. H. Jeong Department of Chemistry Education, Seoul National University, Seoul, Republic of Korea 6 Hyejin Chang and Won-Yeop Rho contributed equally to this work.