(Invited) Bacterial Identification by Using Photogate-Type Optical Sensor

This work describes the recent researches on bacterial sensing through fluorescence detection by a photogate-type optical sensor. The fluorescence behavior of Legionella pneumophila (L. pneumophila) and Legionella dumoffii (L. dumoffii) trapped in a bio-MEMS microfluidic chip were first studied, showing the former emit blue fluorescence as a stress response to ultraviolet (UV) light irradiation and the latter also emits blue fluorescence in the decay process of fluorescent material. The UV-photoirradiation time dependences of fluorescent spectra were further compared between L. dumoffii emitting blue fluorescence and Legionella erythra (L. erythra) emitting red fluorescence. Finally, photogate-type optical sensor was examined for observing the behavior of fluorescence from L. dumoffii and L. erythra in comparison with spectrometer measurement. The photocurrent generated by the fluorescence from L. dumoffii and L. erythra were successfully observed, indicating that the photogate-type optical sensor can identify the kind of bacteria those emit fluorescence.