pH-ChemFET-based analysis devices for the bacterial activity monitoring

Silicon and polymer microtechnologies have been developed in order to integrate pH-metry techniques in the frame of medical diagnosis. Thus, a fluidic analysis device has been designed and realised in order to monitor pH-related bacterial activities. It includes a SiO₂/Si₃N₄ pH-sensitive chemical field effect transistor (pH-ChemFET), its titanium/gold pseudo-reference gate electrode and a poly-dimethylsiloxane (PDMS) integrated flow-cell (total volume: ≤2 mm³). The whole analysis device has been used to detect the biological activities of the Lactobacillus crispatus bacteria and to estimate its sensitivity to antibiotics. Results demonstrate the detection of pH-related bacterial metabolisms in microvolumes, enabling to reduce significantly the analysis response time with regards to standard procedures and to the development of pH-ChemFET-metry for medical analysis.