This lecture covers the use of plasmonic nanoparticles as robust biomarkers in various applications, such as sensing and microscopy. The instructor discusses the advantages of plasmonic biomarkers over fluorescent ones, including their stability and chemical properties. Examples are provided on how different metals can be mixed to create a wide range of markers, known as nano-codbars. Additionally, the lecture explores the use of plasmonic nanoparticles in alternative microscopy techniques, showcasing their effectiveness in visualizing individual receptors on cell surfaces.