Jerome Wenger NanoBioPhotonics

Plasmonic antennas enable monitoring biochemical reactions in nanometer-sized volumes with high fluorescence brightness. Among the antenna designs, the double nanohole (DNH) is attracting much interest thanks to its distinctive advantages of narrow gaps, high enhancement and efficient background screening.

In a Scientific Reports paper “Nanoscale volume confinement and fluorescence enhancement with double nanohole aperture”, we completely characterize the fluorescence emission in a DNH antenna, and realize a volume reduction of 7000-fold as compared to diffraction-limited confocal microscopes together with single molecule fluorescence enhancement up to 100-fold and 30-fold LDOS enhancement.

The DNH is an efficient design to reach nanometer confinement of light, with comparatively simpler nanofabrication as compared to other designs. The high optical performance and the robust design open promising perspectives to study complex biochemical dynamics at micromolar physiological concentrations.

Custom design for PHOCCS ERC project. Made @ Fresnel.

Stephanie Vial joins the team to work on the ERC Proof of Concept grant and develop the chemical synthesis and functionalisation for our new biosensing platform.

Youri Berrahal joins the team to work on the ERC Proof of Concept grant and develop the optical reader prototype for our new biosensing platform.

Pamina Winkler has started her PhD at ICFO in the Single Molecule Biophotonics group of Prof. Maria Garcia Parajo. She is currently visiting the institute for special FCS training on nanoantennas.

Confining light at a spatial scale comparable to the molecular size opens unexplored opportunities to enhance Förster resonance energy transfer (FRET), which is a ubiquitous phenomenon governing the energy exchange at the nanoscale. In a recent Nano Letters article, we present a resonant nanogap antenna tailored for single molecule FRET enhancement.

Significance:

- We demonstrate up to 5x enhanced energy transfer in a resonant antenna by confining the electromagnetic energy into nanoscale dimensions, comparable in size to the FRET pair distances.

- We describe design rules to enhance the FRET rate with nanoantennas that pave the way towards the nanophotonic enhancement of FRET applications in photovoltaics, organic lighting sources and biosensing.

Plasmonic antennas have a strong potential to enable monitoring biochemical reactions in nanometer-sized volumes with high sensitivity. However, the difficulty to realize nanometer gap sizes with lithography has restricted the broad use of plasmonic antennas in biochemical applications.

We solve this issue in a recent ACS photonics article where we demonstrate the effectiveness of self-assembled gold nanoparticle antennas with 6nm gap to enhance single molecule fluorescence detection at high concentrations over 10 µM.

This work reports a simple approach towards the realization of efficient dimer gap antennas, that any chemical laboratory can easily reproduce. We also provide the first quantitative measurements of the near-field detection volumes and the fluorescence enhancement factors for a large set of self-assembled nanoantenna designs.