SERS Tags: Novel Optical Nanoprobes for Bioanalysis

CONTENTS1. Introduction1.1. Fundamental Theory of Surface-Enhanced Raman Scattering1.2. Optical Properties of SERS Tags2. Synthesis of SERS Tags2.1. Noble Metal Nanosubstrates2.1.1. Single Particle-Based SERS Substrates2.1.2. Nanoparticle Cluster-Based Substrates2.2. Raman Reporter Molecules2.2.1. Selection Principles and Reporter Types2.2.2. Self-Assembled Monolayer Coverage Strategy2.3. Surface Coating for Protection2.3.1. Biomolecule Coating2.3.2. Polymer Coating2.3.3. Liposome Coating2.3.4. Silica Coating2.4. Attachment of Targeting Molecules3. Bioanalysis Applications3.1. Ionic and Molecular Detection3.2. Pathogen Detection3.3. Live-Cell Imaging3.3.1. Cancer Marker Detection3.3.2. Intercellular Microenvironment Sensing3.4. Tissue SERS Imaging3.5. In Vivo SERS Imaging4. Challenges and Perspectives4.1. Reproducible Signal of SERS Tags4.1.1. Precisely Controlled Hot Spots for Nanosubstrates4.1.2. Calibration of SERS Intensities and Enhancements4.2. Improving Multiplexing Capability4.3. Reduced Size for Subcellular Imaging4.4. Development of Multifunctional Nanoplatforms4.4.1. Magnetic SERS Dots4.4.2. Multimodal Imaging Dots4.4.3. SERS Tag-Based Therapeutic Systems4.5. Biocompatibility5. Conclusions and Remarks