NIRNANOBIOSENS · Developement of robust and quantitative biosensors based on near-infrared two-dyed silicate nanoparticles

The aim of this project is to develop quantitative biological sensors based on fluorescent spherical silicate nanoparticles (amorphous silica, zeolite beta) in controlled sizes in the range of 50 to 200 nanometers in diameter. The quantification of the analyte is based on a ratiometric detection of fluorescence from two dyes. The dyes are chosen such that the fluorescence of one dye is a function of an analyte (ion, biomolecule) concentration (sensing dye) whereas the fluorescence of the other dye is independent of variations in the medium (reference dye). Both dyes have the near-infrared light absorption property which lead to significant improvements for the detection in biological samples. The first step consists in confining a dye in the inorganic network yielding highly brilliant and photostable objects. Thus this fluorescent hybrid core can be used as the reference dye. Afterwards the ability of such material to undergo further chemical modification through the surface silanol functions and the use of coupling agents allows the immobilization of the sensing dye (commercially available or developed in the host structure). This is considered through various strategies e.g. direct immobilization or embedded polymeric shell.