Our article “Multi-focus parallel detection of fluorescent molecules at picomolar concentration with photonic nanojets arrays” has just been released in Applied Physics Letters. We replace the complex microscope objective commonly used in fluorescence sensing by an array of latex microspheres. This realizes a novel regime where several focal spots are illuminated to detect the possible presence of a fluorescent molecule in one of them. A detailed theoretical description of the phenomen is provided along with experimental demonstration.
This work describes an efficient disposable lens element that enables single molecule sensitivity at low picomolar concentration. The simplicity of the design makes it perfect for integration in portable microfluidic readers.
Deep Punj is giving a talk at the 13th international conference of Near-field Optics and Nanophotonics NFO13 on nanoantennas for enhanced single molecule fluorescence detection at high concentrations. Our group will also have two posters:
- Plasmonic enhanced fluorescence energy transfer
- Enhanced fluorescence from resonant DNA assembled plasmonic nanoantennas loaded with single dye molecules
Energy transfer between molecules is promoted when they are set in an environment that confines light
The energy transfer between molecules is an essential phenomenon for photosynthesis, photovoltaics and biotechnology. Now, thanks to the work of the Institut Fresnel Institute, energy transfer between molecules can be controlled and enhanced with optical structures etched at the nanoscale.
Researchers prepared pairs of energy donor and acceptor molecules linked by rigid double stranded DNA. These pairs were then inserted into apertures milled in a gold film with nanoscale dimensions. By accurately measuring the radiation properties of pairs of molecules, the researchers were able to demonstrate that the rate of energy transfer between molecules is 6 times greater when placed in a nanoaperture.
These promising results are clearing a new path to improve the energy transfer process widely used in life sciences and biotechnology. Optical nanostructures open up many potential applications for biosensors, light sources or photovoltaics.
This work has been supported by the European Research Council under ERC Grant 278242.