Applications of surface-enhanced Raman spectroscopy for the study of indicators of exposure to selected genotoxins

Surface-enhanced Raman scattering spectroscopy (SERS) was used to detect and analyze certain genotoxic chemicals, their metabolites, and selected deoxyribonucleic acid/ribonucleic acid (DNA/RNA) adducts that may be produced from exposure to specific toxins. Substances examined included nucleic acid (purine/pyrimidine) etheno adducts of adenine and cytosine and carcinogens benzo[a]pyrene and aflatoxins. SERS was shown to be an effective tool for sensitive, selective detection and analysis of these genotoxins and related substances. Detection was accomplished even at such low concentrations as might be present in biological systems, and in minute volumes of approximately one microliter per sample. Most substances were found to possess unique spectral signatures and could be distinguished from other chemicals in this study. The sample molecules were also analyzed in body fluids (e.g. plasma, serum, and urine) and adducted to DNA.

In this study SERS was demonstrated to open a new dimension in chemical analysis not previously available by utilizing other spectroscopies or methods of chemical detection. Special attention was given to the various factors affecting the quality and reproducibility of a SERS spectrum, emphasizing the importance of optimization of Raman cross-scattering enhancement. Methods for adapting SERS to deal with specific research problems and for expanding the capabilities of SERS to address the health effects from human exposure to toxic pollutants were addressed in the concluding remarks section of this manuscript.