Surface functionalization of heterogeneous gold/silica substrates for the selective anchoring of biomolecules and colloids onto LSPR biosensors

Resumen

Orthogonal surface chemical functionalization is an efficient method for the selective trapping of different targets (biomolecules or nano-objects) onto predefined regions of a patterned substrate. This is specially interesting in the field of localized surface plasmon resonance (LSPR) biosensors, where transduction only occurs on metallic nanostructures. The aim is thus to ensure that the target molecules can be selectively anchored onto these nanostructres and not adsorbed on the surrounding dielectric surface. Thus, we have developped during this PhD different orthogonal functionalizations of micro and nanopatterned gold on silica surfaces with thiols and silanes. In regards to the state of the art in this topic, we have proposed a single-step protocol and demonstrated the good orthogonality of such functionalizations by extensive surface chemical characterization including PM-IRRAS, XPS and ToF-SIMS analysis. Furthermore, these functionalizations have been used for the selective anchoring of different latex nanoparticles onto micro and nanopatterns of gold surrounded by silica, as shown by SEM. At the moment, this methodology is being applied in two different photonic devices where we expect on the one hand a coupling between fluorescent nanobeads and plasmonic nano-antennas and, on the other hand, the increase in sensitivity of an LSPR biosensor for detecting different biomolecules.