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.

Super-resolution microscopy techniques such as PALM/STORM/STED are revolutionizing optical imaging. While diffraction is no longer a limit, another technical barrier arises driven by the need to compensate for mechanical and thermal drifts at the nanoscale. In a recent article published in Nature Communications, we introduce a novel approach to enhance the image quality in dSTORM microscopy by 3D super-localization of nanoparticles with unprecedented nanometer accuracy.

Significance:

- We show how to exploit the phase response of nanoparticles to recover their 3D position with sub-nanometer accuracy, two orders of magnitude below the diffraction limit, even with large and unknown drifts of several microns.

- The platform uses a commercial wavefront sensing camera to realize highly efficient 3D stabilization and resolution improvement for super-resolution microscopes.

This work provides a leap towards the design of optical super-resolution microscopes with nanometer resolutions, reaching the dream of biological imaging at the molecular scale.

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