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 TiO2 films as Surface Enhanced Raman Scattering (SERS) sensors for the detection of 17-estradiol. Gold deposition on top of TiO2 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 TiO2 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 17-estradiol, an emerging contaminant in environmental waters. We have found a limit of detection of 1 nM with a sensitivity allowing dynamic range of five orders of magnitude (up to 100 µM).