Porous Silicon Used for the Determination of Bacteria Concentration Based on its Metabolic Activity

Optic spectroscopic based detection methods are always preferable for target detection under the urgent demand to develop easy to use and portable sensors in practical applications, due to their high sensitivity to changes in the platform surface and the simplicity of understanding their results. In this work, a sensitive platform of fluorescent porous silicon layer was used. Porous silicon (PS) is well known for its high reactivity due to its highly effective surface. PS was used to detect bacteria based on its metabolic activity. The detection process was based on oxygen production when it is put in contact with hydrogen peroxide. Fourier-transform infrared spectroscopy shows the oxidation of the PS surface associated with the concentration of bacteria. Photoluminescent spectra show a loss in intensity of the main luminescent emission associated with PS. Raman spectroscopy showed a reduction in the intensity of the wavenumber and a shift to lower wavenumbers, which can be related to the quantity of bacteria analyzed. This work reports an easy and in situ method to detect the metabolic activity of the bacteria.