Universidad Autonoma de Madrid (UAM), Spain
Abstract / Thesis download
In the field of biosensors for cancer detection, nanomaterials are a very promising
candidate since they can enhance the performances in terms of sensitivity and detection limits.
In particular, porous silicon (PSi) is a versatile matrix with large adsorption surface and
tailorable surface reactivity, which allows processing a diversity of biofunctional structures.
Indeed, the biomedical applications of PSi often require a surface capping with organic
functionalities. In this thesis we report the visible light-induced modification of PSi by selfassembled
silane monolayers for its application as biosensing platform. Versatile
hydrophilic/hydrophobic surfaces were obtained and characterized by different and
complementary analytical techniques. In particular, a dynamic in-situ study of wetting of
functionalized PSi was conducted by obtaining adsorption isotherms from wet scanning
transmission electron microscopy (wetSTEM) images.
On the other hand, we demonstrated the significance of PSi combined with gold
nanoparticles (GNPs) for biosensing by developing two new dual sensing platforms providing
both plasmonic and nanomechanical or electrical transduction for the specific detection of
prostate specific antigen (PSA). Indeed, we transferred the fabrication of PSi to nanomechanical
and impedimetric platforms and a sandwich bioassay, in which the secondary antibody was
tethered to GNPs, was performed. In both cases, the GNPs act as an optoplasmonic label.
Moreover, they are also able to contribute to the mass of the nanomechanical device and to the
conductivity of the impedimetric one, magnifying therefore the sensitivity of the detection.