Optical sensors for detection of bacteria. 1. General concepts and initialdevelopment

The concept of using immobilized nucleic acid stains as detection chemistry to fabricate optical bacterial sensors is first demonstrated. SYTO 13 (a g reen fluorescent cell stain) is used as the molecular recognition element a nd fluorescent reporter in the sensor. The sensor responds to aqueous and a erosolized bacterial samples in 15 and 30 min, respectively. In addition, t he sensor can discriminate a change in Pseudomonas aeruginosa (Pa) cell con centration of 1 order of magnitude or less and can detect down to 2.4 x 10( 5) cells/mL of Pa cells. The utility of the sensor is demonstrated by monit oring the growth of a Pa cell culture over a period of 50 h.