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Specialized iNANO lecture by Ilko Bald, University of Potsdam, Germany

DNA origami based plasmonic nanoantennas for surface-enhanced Raman scattering and plasmonic chemistry

Info about event

Time

Thursday 19 December 2024,  at 15:15 - 16:00

Location

iNANO meeting room 1590-213

Organizer

Associate Professor Victoria Birkedal (vicb@inano.au.dk)

Ilko Bald, Institute of Chemistry, Hybrid Nanostructures, University of Potsdam, Potsdam, Germany

 

DNA origami based plasmonic nanoantennas for surface-enhanced Raman scattering and plasmonic chemistry

One of the most intriguing applications of plasmonic nanoparticles is based on their ability to transform the energy of light into chemical energy. A broad range of chemical transformations have been demonstrated already to be triggered directly by excitation of the nanoparticle’s surface plasmon resonance. It is still debated whether hot electrons or heat are driving the plasmon-induced chemical reactions, but the details depend on the respective chemical systems and the nanoparticle species. We have recently established the plasmon-induced transformation of 8-bromoadenine into adenine as a model system, in which the carbon-bromine bond is cleaved by an irreversible transfer of a hot electron from the light-excited nanoparticle to the 8-bromoadenine molecule.1,2 We have characterized the kinetics of the plasmon-induced dissociation of 8-bromoadenine by surface-enhanced Raman scattering (SERS) on Au and Ag nanoparticles, and with 8-bromoadenine incorporated into DNA. 1,2

Furthermore, we are interested to study chemical transformations in general at a single-molecular level by SERS. DNA origami nanostructures are ideally suited to arrange both plasmonic nanoparticles as well as receptors for analyte molecules with nanometer precision. In this way they can provide optimized substrates for SERS, where the strongest signal enhancement is localized in nanometric hot spots and where the DNA origami can be used to precisely position the molecules of interest. In recent years we have demonstrated the few- and single-molecule SERS detection in different nanoparticle arrangements.3 We have created a dedicated DNA origami nanoantenna,4 which was also used to study chemical changes in hemin,5 and to detect single proteins.4,6,7 Very recently, we have further optimized the plasmonic nanoantennas by comparing the SERS performance of dimers of different nanoparticle species from spherical Au and Ag nanoparticles to anisotropic gold nanoflowers and combinations thereof.8 We could show that a combination of Au nanoflower and Ag nanosphere allows for a broadband SERS excitation and improved single-molecule detection.

References
1. Dutta et al. ACS Catal., 11, 8370-8381, 2021.
2. S. Kogikoski Jr. et al., ACS Nano, 15, 20562, 2021.
3. Kogikoski Jr. et al., Chem. Commun., 59, 4726, 2023.
4. Tapio et al., ACS Nano, 15, 7065, 2021.
5. Dutta et al., Nanoscale, 14, 16467, 2021.
6. Mostafa et al., Nano Lett., 24, 6916, 2024.
7. Kanehira et al., ACS Nano, 18, 20191, 2024.
8. Kanehira et al., ACS Nano, 17, 21227, 2023.