Biological Sensor Based on Silicon Nanowires for Electrical Detection of Staphylococcus Aureus Bacteria

Biological sensor for bacteria (Staphylococcus aureus) detection was fabricated using silicon nanowires as sensitive units, with a two-level masking manufacturing process with conventional silicon microelectronics technologies. A chemical functionalization step was then used to attach the antibodies and bacteria. The sensor was made of two interdigited comb electrodes connected by silicon nanowires. The very large number of interlaced and functionalized silicon nanowires facilitated the attachment of biomolecules allowing an increased sensitivity to the detection of bacteria. This work used an approach that directly measured the electrical contribution of bacteria immobilised on the nanowires between two electrodes by a significant variation in current. The sensor showed a linear behaviour in the bacteria concentration 10
³
to 10
⁸
CFU/mL and a sensitivity of
$73\mu\mathrm{A}$
per decade of CFU/mL.