Raman spectroscopy in biomedicine: new advances in SERRS cancer imaging

Raman spectroscopic technologies have proven to be valuable biomedical tools providing true biochemical fingerprints. For example, they have been used to identify and differentiate several pathogenic microorganisms found in bloodstream infections in intensive care unit patients (1). Raman spectroscopy can also discriminate healthy tissue from diseased tissue, due to the chemical changes resulting from a disease. For instance Huang et al. (2) used near infrared Raman spectroscopy to distinguish healthy bronchial tissue from tumor tissue, characterized by higher percentages of nucleic acids and lower percentages of phospholipids compared with healthy tissue. Haka et al. (3) demonstrated the potential of Raman spectroscopy to diagnose breast cancer lesions ex vivo with 94% sensitivity and 96% specificity. Although very informative and accurate, the Raman signal is intrinsically weak, which limits its applications for early diagnosis. SERS, or Surface Enhanced Raman Spectroscopy, represents a very exciting possibility to amplify and use this sharp and specific Raman signal. In turn, this enables much better limits of detection, even enabling single-molecule detection levels (4).