TY  - JOUR
A1  - Marques, Telma S.
A1  - Smialek, Malgorzata A.
A1  - Schürmann, Robin
A1  - Bald, Ilko
A1  - Raposo, Maria
A1  - Eden, Sam
A1  - Mason, Nigel J.
T1  - Decomposition of halogenated nucleobases by surface plasmon resonance excitation of gold nanoparticles
JF  - The European physical journal : D, Atomic, molecular, optical and plasma physics
N2  - Halogenated uracil derivatives are of great interest in modern cancer therapy, either as chemotherapeutics or radiosensitisers depending on their halogen atom. This work applies UV-Vis spectroscopy to study the radiation damage of uracil, 5-bromouracil and 5-fluorouracil dissolved in water in the presence of gold nanoparticles upon irradiation with an Nd:YAG ns-pulsed laser operating at 532 nm at different fluences. Gold nanoparticles absorb light efficiently by their surface plasmon resonance and can significantly damage DNA in their vicinity by an increase of temperature and the generation of reactive secondary species, notably radical fragments and low energy electrons. A recent study using the same experimental approach characterized the efficient laser-induced decomposition of the pyrimidine ring structure of 5-bromouracil mediated by the surface plasmon resonance of gold nanoparticles. The present results show that the presence of irradiated gold nanoparticles decomposes the ring structure of uracil and its halogenated derivatives with similar efficiency. In addition to the fragmentation of the pyrimidine ring, for 5-bromouracil the cleavage of the carbon-halogen bond could be observed, whereas for 5-fluorouracil this reaction channel was inhibited. Locally-released halogen atoms can react with molecular groups within DNA, hence this result indicates a specific mechanism by which doping with 5-bromouracil can enhance DNA damage in the proximity of laser irradiated gold nanoparticles.
Y1  - 2020
U6  - https://doi.org/10.1140/epjd/e2020-10208-3
SN  - 1434-6060
SN  - 1434-6079
VL  - 74
IS  - 11
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Ribar, Anita
A1  - Huber, Stefan E.
A1  - Smialek, Malgorzata A.
A1  - Tanzer, Katrin
A1  - Neustetter, Michael
A1  - Schürmann, Robin
A1  - Bald, Ilko
A1  - Denifl, Stephan
T1  - Hydroperoxyl radical and formic acid formation from common DNA stabilizers upon low energy electron attachment
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - 2-Amino-2-(hydroxymethyl)-1,3-propanediol (TRIS) and ethylenediaminetetraacetic acid ( EDTA) are key components of biological buffers and are frequently used as DNA stabilizers in irradiation studies. Such surface or liquid phase studies are done with the aim to understand the fundamental mechanisms of DNA radiation damage and to improve cancer radiotherapy. When ionizing radiation is used, abundant secondary electrons are formed during the irradiation process, which are able to attach to the molecular compounds present on the surface. In the present study we experimentally investigate low energy electron attachment to TRIS and methyliminodiacetic acid ( MIDA), an analogue of EDTA, supported by quantum chemical calculations. The most prominent dissociation channel for TRIS is through hydroperoxyl radical formation, whereas the dissociation of MIDA results in the formation of formic and acetic acid. These compounds are well-known to cause DNA modifications, like strand breaks. The present results indicate that buffer compounds may not have an exclusive protecting effect on DNA as suggested previously.
Y1  - 2018
U6  - https://doi.org/10.1039/c7cp07697e
SN  - 1463-9076
SN  - 1463-9084
VL  - 20
IS  - 8
SP  - 5578
EP  - 5585
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -