Thermal and electron induced damage to DNA on laser illuminated
plasmonic nanoparticles
Robin Schürmann, Ilko Bald
Department of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam,
Germany,
BAM Federal Institute for Materials Research and Testing Richard-Willstätter-Str. 11, 12489 Berlin,
Germany
In cancer photothermal therapy (PTT) the plasmonic heating of laser illuminated gold nanoparticles
(GNPs) is exploited to destroy tumorous tissue [1]. The irradiation of GNPs with ns-laser pulses induces
a fragmentation of DNA nucleobases into its smallest subunits in close proximity to the particle most
likely caused by the extremely high temperatures on the GNP surface [2]. Furthermore, low energy
electrons (LEEs), which are strongly reactive towards the halogenated nucleobases 5-bromouracil or 8bromoadenine (8BrA), are generated by thermionic emission from the GNP at high laser fluences. Due
to the attachment of a LEE such nucleobase analogues form transient negative ions that subsequently
dissociate, favorably by cleavage of the C-Br bond, forming radicals that might act as a precursor for
DNA single strand breaks (SSB). 8BrA containing DNA strands show an enhanced SSB cross section
towards LEEs compared to its native counterparts. Using surface enhanced Raman scattering (SERS)
the decomposition products of DNA nucleobase analogues on laser illuminated GNPs can be
monitored [3]. Even under illumination with low intensity continuous wave lasers in a typical SERS
setup 8BrA rapidly dissociates into adenine mediated by a dissociative electron transfer from the
plasmonic nanoparticles [4]. Beside the potential applications for PTT, such reactions need to be taken
into account in the interpretation of SERS spectra of electrophilic molecules.
Figure 1: Illustration of the fragmentation of 8BrA on pulsed laser illuminated GNP and the
determination of the decomposition kinetics with UV-Vis-Spectroscopy. Image adapted from source
[2]
[1]
[2]
[3]
[4]
N. S. Abadeer and C. J. Murphy, J. Phys. Chem. C, 2016, 120 (9), pp 4691–4716
R. Schürmann and I. Bald, PCCP, accepted DOI: 10.1039/C6CP08433H
R. Schürmann and I. Bald, J. Phys. Chem. C, 2016 120 (5), pp 3001–3009
R. Schürmann and I. Bald, Nanoscale, 2017,9, 1951-1955
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