TY - JOUR A1 - Heck, Christian A1 - Prinz, Julia A1 - Dathe, Andre A1 - Merk, Virginia A1 - Stranik, Ondrej A1 - Fritzsche, Wolfgang A1 - Kneipp, Janina A1 - Bald, Ilko T1 - Gold Nanolenses Self-Assembled by DNA Origami JF - ACS Photonics N2 - Nanolenses are self-similar chains of metal nanoparticles, which can theoretically provide extremely high field enhancements. Yet, the complex structure renders their synthesis challenging and has hampered closer analyses so far. Here, DNA origami is used to self-assemble 10, 20, and 60 nm gold nanoparticles as plasmonic gold nanolenses (AuNLs) in solution and in billions of copies. Three different geometrical arrangements are assembled, and for each of the three designs, surface-enhanced Raman scattering (SERS) capabilities of single AuNLs are assessed. For the design which shows the best properties, SERS signals from the two different internal gaps are compared by selectively placing probe dyes. The highest Raman enhancement is found for the gap between the small and medium nanoparticle, which is indicative of a cascaded field enhancement. KW - plasmonics KW - DNA origami KW - SERS KW - nanolenses KW - gold nanoparticles Y1 - 2017 U6 - https://doi.org/10.1021/acsphotonics.6b00946 SN - 2330-4022 VL - 4 SP - 1123 EP - 1130 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Matkovic, Aleksandar A1 - Vasic, Borislav A1 - Pesic, Jelena A1 - Prinz, Julia A1 - Bald, Ilko A1 - Milosavljevic, Aleksandar R. A1 - Gajic, Rados T1 - Enhanced structural stability of DNA origami nanostructures by graphene encapsulation JF - NEW JOURNAL OF PHYSICS N2 - We demonstrate that a single-layer graphene replicates the shape of DNA origami nanostructures very well. It can be employed as a protective layer for the enhancement of structural stability of DNA origami nanostructures. Using the AFM based manipulation, we show that the normal force required to damage graphene encapsulated DNA origami nanostructures is over an order of magnitude greater than for the unprotected ones. In addition, we show that graphene encapsulation offers protection to the DNA origami nanostructures against prolonged exposure to deionized water, and multiple immersions. Through these results we demonstrate that graphene encapsulated DNA origami nanostructures are strong enough to sustain various solution phase processing, lithography and transfer steps, thus extending the limits of DNA-mediated bottom-up fabrication. KW - graphene KW - DNA origami nanostructures KW - atomic force microscopy Y1 - 2016 U6 - https://doi.org/10.1088/1367-2630/18/2/025016 SN - 1367-2630 VL - 18 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Oertel, Jana A1 - Keller, Adrian A1 - Prinz, Julia A1 - Schreiber, Benjamin A1 - Huebner, Rene A1 - Kerbusch, Jochen A1 - Bald, Ilko A1 - Fahmy, Karim T1 - Anisotropic metal growth on phospholipid nanodiscs via lipid bilayer expansion JF - Scientific reports N2 - Self-assembling biomolecules provide attractive templates for the preparation of metallic nanostructures. However, the intuitive transfer of the "outer shape" of the assembled macromolecules to the final metallic particle depends on the intermolecular forces among the biomolecules which compete with interactions between template molecules and the metal during metallization. The shape of the bio-template may thus be more dynamic than generally assumed. Here, we have studied the metallization of phospholipid nanodiscs which are discoidal particles of similar to 10 nm diameter containing a lipid bilayer similar to 5 nm thick. Using negatively charged lipids, electrostatic adsorption of amine-coated Au nanoparticles was achieved and followed by electroless gold deposition. Whereas Au nanoparticle adsorption preserves the shape of the bio-template, metallization proceeds via invasion of Au into the hydrophobic core of the nanodisc. Thereby, the lipidic phase induces a lateral growth that increases the diameter but not the original thickness of the template. Infrared spectroscopy reveals lipid expansion and suggests the existence of internal gaps in the metallized nanodiscs, which is confirmed by surface-enhanced Raman scattering from the encapsulated lipids. Interference of metallic growth with non-covalent interactions can thus become itself a shape-determining factor in the metallization of particularly soft and structurally anisotropic biomaterials. Y1 - 2016 U6 - https://doi.org/10.1038/srep26718 SN - 2045-2322 VL - 6 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Prinz, Julia A1 - Heck, Christian A1 - Ellerik, Lisa A1 - Merk, Virginia A1 - Bald, Ilko T1 - DNA origami based Au-Ag-core-shell nanoparticle dimers with single-molecule SERS sensitivity JF - Nanoscale N2 - DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 10(10), which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled. Y1 - 2016 U6 - https://doi.org/10.1039/c5nr08674d SN - 2040-3364 SN - 2040-3372 VL - 8 SP - 5612 EP - 5620 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Prinz, Julia A1 - Heck, Christian A1 - Ellerik, Lisa A1 - Merk, Virginia A1 - Bald, Ilko T1 - DNA origami based Au–Ag-core–shell nanoparticle dimers with single-molecule SERS sensitivity JF - Nanoscale N2 - DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 1010, which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled. Y1 - 2016 U6 - https://doi.org/10.1039/C5NR08674D IS - 8 SP - 5612 EP - 5620 PB - RSC Publishing CY - Cambridge ER - TY - JOUR A1 - Prinz, Julia A1 - Matkovic, Aleksandar A1 - Pesic, Jelena A1 - Gajic, Rados A1 - Bald, Ilko T1 - Hybrid Structures for Surface-Enhanced Raman Scattering: DNA Origami/Gold Nanoparticle Dimer/Graphene JF - Small N2 - A combination of three innovative materials within one hybrid structure to explore the synergistic interaction of their individual properties is presented. The unique electronic, mechanical, and thermal properties of graphene are combined with the plasmonic properties of gold nanoparticle (AuNP) dimers, which are assembled using DNA origami nanostructures. This novel hybrid structure is characterized by means of correlated atomic force microscopy and surface-enhanced Raman scattering (SERS). It is demonstrated that strong interactions between graphene and AuNPs result in superior SERS performance of the hybrid structure compared to their individual components. This is particularly evident in efficient fluorescence quenching, reduced background, and a decrease of the photobleaching rate up to one order of magnitude. The versatility of DNA origami structures to serve as interface for complex and precise arrangements of nanoparticles and other functional entities provides the basis to further exploit the potential of the here presented DNA origami-AuNP dimer-graphene hybrid structures. Y1 - 2016 U6 - https://doi.org/10.1002/smll.201601908 SN - 1613-6810 SN - 1613-6829 VL - 12 SP - 5458 EP - 5467 PB - Wiley-VCH CY - Weinheim 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 - TY - JOUR A1 - Vogel, Stefanie A1 - Rackwitz, Jenny A1 - Schuerman, Robin A1 - Prinz, Julia A1 - Milosavljevic, Aleksandar R. A1 - Refregiers, Matthieu A1 - Giuliani, Alexandre A1 - Bald, Ilko T1 - Using DNA origami nanostructures to determine absolute cross sections for UV photon-induced DNA strand breakage JF - The journal of physical chemistry letters N2 - We have characterized ultraviolet (UV) photon-induced DNA strand break processes by determination of absolute cross sections for photoabsorption and for sequence-specific DNA single strand breakage induced by photons in an energy range from 6.50 to 8.94 eV. These represent the lowest-energy photons able to induce DNA strand breaks. Oligonudeotide targets are immobilized on a UV transparent substrate in controlled quantities through attachment to DNA origami templates. Photon-induced dissociation of single DNA strands is visualized and quantified using atomic force microscopy. The obtained quantum yields for strand breakage vary between 0.06 and 0.5, indicating highly efficient DNA strand breakage by UV photons, which is clearly dependent on the photon energy. Above the ionization threshold strand breakage becomes clearly the dominant form of DNA radiation damage, which is then also dependent on the nucleotide sequence. Y1 - 2015 U6 - https://doi.org/10.1021/acs.jpclett.5b02238 SN - 1948-7185 VL - 6 IS - 22 SP - 4589 EP - 4593 PB - American Chemical Society CY - Washington ER -