In order to develop an optical immunosensor based on Surface Plasmon
Resonance (SPR) and guided waves propagation, the sol-gel process has
been used to prepare thin films of amorphous silica, deposited by spin
coating on a gold-coated glass slide, and possessing chemically active
functional groups (SH, NH2...). After activation of the sol-gel film in
aqueous buffers by a bifunctional coupling agent, biological molecules
such as antibodies could be covalently bonded on or inside the sol-gel
film. Therefore, the behaviour of the functionalized silica thin films in
aqueous solutions has been analyzed by SPR and guided waves propagation.
The matrix hydrophilicity has been studied with different mixtures of
functionalized silicon precursors forming organic-inorganic hybrid films.
Immunoassays outline the possibility of obtaining covalent binding of
antibodies to the sol-gel matrix with optimal stability and biological
activity.