CONICET | Buscador de Institutos y Recursos Humanos

In the first part of this presentation we will show how the conjunction of the plasmonic properties of silver nanoparticle dimers together with the tool-kit (except the enzyme) used in the standard Enzime Linked Immunolinked Assay (ELISA) give rise to a novel enzyme free quantification assay able to detect ultra-low concentrations of antigens. The novel methodology developed by our group, denoted as IDILA (Intensity Depeltion Immunolinked Assay) is based on the controlled agglomeration of functionalized Ag nanospheres generated in the presence of a biotinylated immunoglobulin acting as linker between these nanoparticles and the inhibition of the agglomeration (dimer formation) in the presence of the specific antigen. This inhibition is translated in a change in the near field optical response (extinction spectra) that depends on the antigen concentration. The capabilities of this methodology to detect (sub)picomolar concentrations of antigens as well as the factors that controls the superior sensitivity of this technique will be demonstrated for the detection of biomarkers of interest in Medicine such as cytokines (implicated in the pathogenesis of Rheumatoid arthritis as well as in Food Science such as gliadin (the protein complex of gluten, responsible of the celiac desease ). In the second part we will discuss our recent research on the optical phenomena produced by the interaction between a plasmonic nanostructure such as noble metal (Ag, Au) sphere and a highly damped plasmonic nanosphere (Fe, Co, Ni). It will be shown, using electrodynamics simulations, the new modes generated as a result of this interaction and that a new hybrid mode denoted as ferroplasmon, give rise to a significant electric field enhancement at the gap between the two nanospheres.