SERS-based ultrasensitive sensing platform: An insight into design and practical applications

Ultrasensitive detection of chemicals and biological analytes in trace or single molecular level is highly desirable in both scientific and technological fields, e.g., analytical chemistry, life science, materials science, biomedical diagnostics, and forensic science, etc. With high sensitivity, high specificity, narrow line-widths, and multiplexed non-destructive testing capabilities, surface enhanced Raman scattering (SERS)-based sensing is the most promising approach to monitor targeted analytes in the vicinity of nanostructured surface. An insight into the recent advances of SERS-based ultrasensitive sensing platform can provide an effective reference guideline to develop an optimal detection approach for arising real-world applications. Many SERS-based review articles mainly focus on the fundamental theory of SERS, nanostructured plasmonic SERS sensors, and single molecule SERS detection. However, no comprehensive review article targeting SERS-based ultrasensitive detection strategies, their working mechanisms and illustrative practical applications has been reported yet. Hence, it is important to project the latest SERS-based ultrasensitive detection research in a review, which will present a reference guideline to develop an optimal detection approach for specific detection or monitoring of analytes in highly diluted solutions. We present a systematic classification and discussion on the recent multiple strategies to achieve ultra-high SERS detection sensitivity. We also outline a detailed analysis on the up-to-date applications in vitro and in vivo. Finally, we also discuss a new trend in SERS-based ultrasensitive sensing applications.