TY - JOUR A1 - Prinz, J. A1 - Schreiber, B. A1 - Olejko, L. A1 - Oertel, J. A1 - Rackwitz, J. A1 - Keller, A. A1 - Bald, Ilko T1 - DNA origami substrates for highly sensitive surface-enhanced Raman scattering 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. KW - DANN Origami KW - Surface-enhanced Raman scattering KW - Nanoparticles KW - TAMRA PY - 2013 DO - https://doi.org/10.1021/jz402076b SN - 1948-7185 VL - 4 IS - 23 SP - 4140 EP - 4145 PB - ACS CY - Washington, DC AN - OPUS4-29907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Olejko, L. A1 - Cywinski, P.J. A1 - Bald, Ilko T1 - Ion-selective formation of a guanine quadruplex on DNA origami structures N2 - DNA origami nanostructures are a versatile tool that can be used to arrange functionalities with high local control to study molecular processes at a single-molecule level. Here, we demonstrate that DNA origami substrates can be used to suppress the formation of specific guanine (G) quadruplex structures from telomeric DNA. The folding of telomeres into G-quadruplex structures in the presence of monovalent cations (e.g. Na+ and K+) is currently used for the detection of K+ ions, however, with insufficient selectivity towards Na+. By means of FRET between two suitable dyes attached to the 3'- and 5'-ends of telomeric DNA we demonstrate that the formation of G-quadruplexes on DNA origami templates in the presence of sodium ions is suppressed due to steric hindrance. Hence, telomeric DNA attached to DNA origami structures represents a highly sensitive and selective detection tool for potassium ions even in the presence of high concentrations of sodium ions. KW - DNA nanotechnology KW - FRET KW - G-quadruplexes KW - Nanostructures KW - Self-assembly KW - DNA origami KW - Fluorescence spectroscopy KW - Sensing PY - 2014 UR - http://onlinelibrary.wiley.com/doi/10.1002/anie.201409278/full DO - https://doi.org/10.1002/anie.201409278 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 53 SP - 1 EP - 6 PB - Wiley-VCH CY - Weinheim AN - OPUS4-32196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Choi, Youungeun A1 - Kotthoff, Lisa A1 - Olejko, L. A1 - Resch-Genger, Ute A1 - Bald, Ilko T1 - DNA origami-based Förster resonance energy-transfer nanoarrays and their application as ratiometric sensors N2 - DNA origami nanostructures provide a platform where dye molecules can be arranged with nanoscale accuracy allowing to assemble multiple fluorophores without dye–dye aggregation. Aiming to develop a bright and sensitive ratiometric sensor system, we systematically studied the optical properties of nanoarrays of dyes built on DNA origami platforms using a DNA template that provides a high versatility of label choice at minimum cost. The dyes are arranged at distances, at which they efficiently interact by Förster resonance energy transfer (FRET). To optimize array brightness, the FRET efficiencies between the donor fluorescein (FAM) and the acceptor cyanine 3 were determined for different sizes of the array and for different arrangements of the dye molecules within the array. By utilizing nanoarrays providing optimum FRET efficiency and brightness, we subsequently designed a ratiometric pH nanosensor using coumarin 343 as a pH-inert FRET donor and FAM as a pH-responsive acceptor. Our results indicate that the sensitivity of a ratiometric sensor can be improved simply by arranging the dyes into a well-defined array. The dyes used here can be easily replaced by other analyte-responsive dyes, demonstrating the huge potential of DNA nanotechnology for light harvesting, signal enhancement, and sensing schemes in life sciences. KW - DNA origami KW - FRET KW - Sensing KW - Ratiometric sensing KW - Fluorescence PY - 2018 DO - https://doi.org/10.1021/acsami.8b03585 SN - 1944-8244 SN - 1944-8252 VL - 10 IS - 27 SP - 23295 EP - 23302 PB - ACS AN - OPUS4-46002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -