Welcome to the pages of the Hybrid Nanostructures group. In our research we combine different methods from DNA nanotechnology, optical spectroscopy and scanning probe microscopy in order to study physico-chemical processes at the single-molecule level. Apart from methods development we investigate specific questions such as the nucleotide sequence dependence of DNA radiation damage and the mode of action of radiosensitizers that are applied in tumor radiation therapy.
Our recent work:
DNA origami technology allows for the precise nanoscale assembly of chemical entities that give rise to sophisticated functional materials. We have created a versatile DNA origami nanofork antenna (DONA) by assembling Au or Ag nanoparticle dimers with different gap sizes down to 1.17 nm, enabling signal enhancements in surface-enhanced Raman scattering (SERS) of up to 1011. This allows for single-molecule SERS measurements, which can even be performed with larger gap sizes to accommodate differently sized molecules, at various excitation wavelengths. A general scheme is presented to place single analyte molecules into the SERS hot spots using the DNA origami structure exploiting covalent and noncovalent coupling schemes. By using Au and Ag dimers, single-molecule SERS measurements of three dyes and cytochrome c and horseradish peroxidase proteins are demonstrated even under nonresonant excitation conditions, thus providing long photostability during time-series measurement and enabling optical monitoring of single molecules.
A Versatile DNA Origami-Based Plasmonic Nanoantenna for Label-Free Single-Molecule Surface-Enhanced Raman Spectroscopy; K. Tapio, A. Mostafa, Y. Kanehira, A. Suma, A. Dutta and I. Bald; ACS Nano 2021, 15, 7065-7077