TY  - JOUR
A1  - Keller, Adrian
A1  - Kopyra, Janina
A1  - Gothelf, Kurt V.
A1  - Bald, Ilko
T1  - Electron-induced damage of biotin studied in the gas phase and in the condensed phase at a single-molecule level
JF  - New journal of physics : the open-access journal for physics
N2  - Biotin is an essential vitamin that is, on the one hand, relevant for the metabolism, gene expression and in the cellular response to DNA damage and, on the other hand, finds numerous applications in biotechnology. The functionality of biotin is due to two particular sub-structures, the ring structure and the side chain with carboxyl group. The heterocyclic ring structure results in the capability of biotin to form strong intermolecular hydrogen and van der Waals bonds with proteins such as streptavidin, whereas the carboxyl group can be employed to covalently bind biotin to other complex molecules. Dissociative electron attachment (DEA) to biotin results in a decomposition of the ring structure and the carboxyl group, respectively, within resonant features in the energy range 0-12 eV, thereby preventing the capability of biotin for intermolecular binding and covalent coupling to other molecules. Specifically, the fragment anions (M-H)(-), (M-O)(-), C3N2O-, CH2O2-, OCN-, CN-, OH- and O- are observed, and exemplarily the DEA cross section of OCN- formation is determined to be 3 x 10(-19) cm(2). To study the response of biotin to electrons within a complex condensed environment, we use the DNA origami technique and determine a dissociation yield of (1.1 +/- 0.2) x 10(-14) cm(2) at 18 eV electron energy, which represents the most relevant energy for biomolecular damage induced by secondary electrons. The present results thus have important implications for the use of biotin as a label in radiation experiments.
Y1  - 2013
U6  - https://doi.org/10.1088/1367-2630/15/8/083045
SN  - 1367-2630
VL  - 15
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Prinz, Julia
A1  - Schreiber, Benjamin
A1  - Olejko, Lydia
A1  - Oertel, Jana
A1  - Rackwitz, Jenny
A1  - Keller, Adrian
A1  - Bald, Ilko
T1  - DNA origami substrates for highly sensitive surface-enhanced raman scattering
JF  - The journal of physical chemistry letters
N2  - DNA nanotechnology holds great promise for the fabrication of novel plasmonic nanostructures and the potential to carry out single-molecule measurements using optical spectroscopy. Here, we demonstrate for the first time that DNA origami nanostructures can be exploited as substrates for surface-enhanced Raman scattering (SERS). Gold nanoparticles (AuNPs) have been arranged into dimers to create intense Raman scattering hot spots in the interparticle gaps. AuNPs (15 nm) covered with TAMRA-modified DNA have been placed at a nominal distance of 25 nm to demonstrate the formation of Raman hot spots. To control the plasmonic coupling between the nanoparticles and thus the field enhancement in the hot spot, the size of AuNPs has been varied from 5 to 28 nm by electroless Au deposition. By the precise positioning of a specific number of TAMRA molecules in these hot spots, SERS with the highest sensitivity down to the few-molecule level is obtained.
Y1  - 2013
U6  - https://doi.org/10.1021/jz402076b
SN  - 1948-7185
VL  - 4
IS  - 23
SP  - 4140
EP  - 4145
PB  - American Chemical Society
CY  - Washington
ER  -