Publications

Optical Spectroscopy and Chemical Imaging (OSCI)
Decomposition of DNA nucleobases by laser
Decomposition of DNA nucleobases by laser irradiation of gold nanoparticles monitored by surface-enhanced Raman scattering
2016
R. Schürmann, I. Bald
Different approaches have been proposed to treat cancer cells using gold nanoparticles (AuNPs) in combination with radiation ranging from infrared lasers to high-energy ion beams. Here we study the decomposition of the DNA/RNA nucleobases thymine (T) and uracil (U) and the well-known radiosensitizer 5-bromouracil (BrU) in close vicinity to AuNPs, which are irradiated with a nanosecond pulsed laser (532 nm) matching the surface plasmon resonance of the AuNPs. The induced damage of nucleobases is analyzed by UV–vis absorption spectroscopy and surface-enhanced Raman scattering (SERS). A clear DNA damage is observed upon laser irradiation. SERS spectra indicate the fragmentation of the aromatic ring system of T and U as the dominant form of damage, whereas with BrU mainly the cleavage of the Br–C bond and formation of Br–ions is observed. This is accompanied by a partial transformation of BrU into U. The observed damage is at least partly ascribed to the intermediate formation of low-energy electrons from the laser-excited AuNPs and subsequent dissociative electron attachment to T, U, and BrU. These reactions represent basic DNA damage pathways occurring on the one hand in plasmon-assisted cancer therapy and on the other hand in conventional cancer radiation therapy using AuNPs as sensitizing agents.

Details

Journal Article
The Journal of Physical Chemistry
120
5
3001–3009
10.1021/acs.jpcc.5b10564

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