SERS as an advanced tool for investigating chloroethyl nitrosourea derivatives complexation with DNA

We report surface-enhanced Raman spectroscopic (SERS) studies on free calf thymus DNA and its complexes with anti-tumor chloroethyl nitrosourea derivatives; semustine and nimustine. Since, first incident of SERS in 1974, it has rapidly established into an analytical tool, which can be used for the trace detection and characterization of analytes. Here, we depict yet another application of SERS in the field of drug-DNA interaction and thereby, its promising role in rational designing of new chemotherapeutic agents. Vibrational spectral analysis has been performed in an attempt to delineate the anti-cancer action mechanism of above mentioned nitrosourea derivatives. Strong SERS bands associated with the complexation of DNA with semustine and nimustine have been observed, which reveal binding of nitrosourea derivatives with heterocyclic nitrogenous base pair of DNA duplex. Formation of dG-dC interstrand cross-link in DNA double helices is also suggested by the SERS spectral outcomes of CENUs-DNA adduct. Results, demonstrated here, reflect recent progress in the newly developing field of drug-DNA interaction analysis via SERS.