Porous silicon based biosensor for bacteria detection

Details

Supervisors

Francis, Laurent

Faculty

Ecole polytechnique de Louvain

Degree label

Master de spécialisation en nanotechnologie

Abstract

A label-free optical biosensor based on an oxidized porous silicon layer is designed for rapid detection of S.epidermidis bacteria. A mesoporous silicon layer, which displays well-resolved Fabry-Pérot fringes pattern in its reflect spectrum was used as the optical transducer element of the biosensor. Applying a fast Fourier transform (FFT) to reflective spectrum yields a single peak which indicates the effective optical thickness (EOT) and intensity. The PSi was fabricated by electrochemical etching and then oxidized. The sensor was placed in a custom-made flow cell, and then bacteria suspension with different concentration 106-108 CFU/mL were flown onto the sensor surface followed by the injection of lysostaphin solution. The refractive spectra are recorded during the whole process. The bacteria cells on the sensor surface, which can diffract light, cause an intensity decrease, while the lysate produced by the lysostaphin, which can penetrate into the pores, cause an EOT increase. We demonstrate that the sensor can detect selectively S.epidermidis in 165 min.