Optical sensors for detection of bacteria. 1. General concepts and initial development.

The concept of using immobilized nucleic acid stains as detection chemistry to fabricate optical bacterial sensors is first demonstrated. SYTO 13 (a green fluorescent cell stain) is used as the molecular recognition element and fluorescent reporter in the sensor. The sensor responds to aqueous and aerosolized bacterial samples in 15 and 30 min, respectively. In addition, the sensor can discriminate a change in Pseudomonas aeruginosa (Pa) cell concentration 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 monitoring the growth of a Pa cell culture over a period of 50 h.