Highly sensitive detection of estradiol by a SERS sensor based on TiO2 covered with gold nanoparticles

We propose the use of gold nanoparticles grown on the surface of nanoporous TiO 2 films as Surface Enhanced Raman Scattering (SERS) sensors for the detection of 17β-estradiol. Gold deposition on top of TiO 2 surfaces leads to the formation of nanoparticles, which plasmonic properties fit the requirements of a SERS sensor well. The morphological and optical properties of this surface were investigated. Specifically, we demonstrated that the TiO 2 background pressure during pulsed laser deposition and annealing conditions enabled the formation of a variety of Au nanoparticles with controlled size, shape and distribution thus resulting in a versatile sensor. We have exploited this surface for the detection of 17β-estradiol, an emerging contaminant in environmental waters. We have found a limit of detection of 10 nM with a sensitivity allowing dynamic range of five orders of magnitude (up to 100 µM).