Development of SERS tags for human diseases screening and detection

• Surface-enhanced Raman scattering (SERS) tags for human diseases diagnosis and treatment are reviewed. • Fabrication strategies SERS tags and their physical, chemical, and biological properties are discussed. • Advances in developing hybrid SERS tags and their biomedical applications are outlined. • The future challenges associated with clinical translational of SERS tags are discussed. Recent advances in surface-enhanced Raman scattering (SERS) have offered great promise for the early-stage diagnosis of life-threatening diseases by in vivo sensing and imaging techniques as well as a treatment and evaluation of its efficacy. The SERS technique makes use of specially designed tags made up of a metallic nanoparticle, a Raman reporter molecule, a biocompatible protection layer, and a sensing layer, realizing the signal amplification by the electromagnetic enhancement (EE) originating from the plasmon excitation of metal nanostructures and chemical enhancement (CE) owing to chemical interactions and photon-induced charge transfer between the metal and target molecule. These SERS tags have been proven to be a promising candidate for medical applications compared to other conventional techniques because of their high sensitivity, low detection limit, good selectivity, high photostability, low interferences from biological matrices, and multiplexing capabilities. As a result, there has been a surge in the reports for developing SERS tags for molecular diagnostics, immunoassays, biomarker detection, and drug screening applications. Here, we review the recent progress made in the development of SERS tags, including the preparation strategies and properties of SERS tags. The multiple uses of SERS tags in the detection of biomarkers, proteins, cancer and stem cells, cell labeling drug delivery, photothermal therapy, and multimodal imaging techniques have also been reviewed and discussed. Finally, we provide a forward look at how SERS tags may overcome their limitations to guide future SERS tags design with clinical outcomes.