Optical nanoantennas are known to focus freely propagating light and reversely to mediate the emission of a light source located at the nanoantenna hotspot. DNA origami technique can be used to build such antennas with colloidal gold nanoparticles (NPs). The research group of the PIs Dr. Guillermo Acuna and Prof. Philip Tinnefeld has developed dimer nanoantennas (DNs) which consist of two 100 nm colloidal gold NPs attached to the pillar-shaped DNA origami and a single fluorophore incorporated at the center of the inter-particle gap. The origami structure has a total height of 125 nm with the main shaft based on a 12 helix-bundle. Over the last 29 nm, where the NPs are incorporated, the shaft is narrowed to a 6 helix. The NPs are functionalized with a thiolated DNA oligos and bound to previously immobilized origami structures on a glass cover-slip leading to an overall interparticle distance between 12 and 17 nm depending on the extent of steric effects on particle binding.The combination of factors including proper design of DNA origami structure, small inter-particle distance, alignment of the incident electric field polarization to the dimer orientation and introducing a quenching agent to reduce the fluorophore's quantum yield makes DNA origami based self-assembled DNs be able to achieve fluorescence enhancement of 5468. It was also demonstrated that these antennas can be employed for the detection of a single molecule at a concentration of 25 µM. The robust design and the further improments indicate the potential of self-assembled nanoantennas for biosensing and emerging nanobiotechnological applications.
Publication
Puchkova A., Vietz C., Pibiri E., Wünsch B., Sanz Paz M., Acuna G.P., Tinnefeld P.
DNA Origami Nanoantennas with over 5000-fold Fluorescence Enhancement and Single-Molecule Detection at 25 μM
Nano Letters 11/2015
Contact
Dr. Guillermo Acuna and Prof. Philip Tinnefeld
Institute for Physical and Theoretical Chemistry and
Laboratory for Emerging Nanometrology
Technische Universität Braunschweig
Hans Sommer Str. 10
D-38106 Braunschweig