Real-time detection of bacterial contamination in dynamic aqueous environments using optical sensors

Here we describe on-line, real-time detection of waterborne bacteria using an optical sensor based on a starburst dendrimer film containing a lipophilic fluorophore. The sensor is constructed via covalent coupling between amine-terminated polyamidoamine dendrimer and silanized glass through an amide bond. The reporter molecule is embedded in the dendrimer layer through host-guest interaction. Real-time automated detection and quantitation of the bacteria are realized by using a charge-coupled detector camera and customized imaging and analysis software. The sensor responds to bacteria introduced to an aqueous flow system within 1 min. The limit of detection is approximately 10(4)cells/mL. The operational lifetime is more than 64 h, and the storage lifetime of the sensor is at least 7 months.