Abstract: Bacteria in fluid systems are identified by using a fluorescently labeled virus as a molecular recognition element for bacteria. The virus, or bacteriophage, are optically encoded with fluorescent reporter molecules to allow detection and quantitation of the phage and the host/phage complex. Biosensors are provided in which the molecular recognition element is immobilized on a substrate.

Abstract: Bacteria in fluid systems are identified by using a fluorescently labeled virus as a molecular recognition element for bacteria. The virus, or bacteriophage, are optically encoded with fluorescent reporter molecules to allow detection and quantitation of the phage and the host/phage complex. Biosensors are provided in which the molecular recognition element is immobilized on a substrate.

Abstract: Bacterial spores can be rapidly and sensitively detected and quantified based upon molecular recognition of unique chemicals in the spore coat. Spores can be detected and assayed based upon the calcium concentration in bacterial spore coats using the calcium which is unique to the bacterial spores. Since spores contain a high concentration of calcium relative to other biological materials, fluorescent calcium-sensitive indicators are used to detect Ca+2 displaced from the spore case or free in solution or from the aerosol phase. Visibly excitable fluorescent dyes provide a sensitive and selective means to monitor changes in spore concentration and avoid difficulties associated with laser or UV-excitation.

Abstract: Sensors for detecting microorganisms in gases, liquids, and aerosols are provided which include molecular receptors to interact with the microorganisms, polymeric membranes containing luminescent reagents, optional non-drying membrane additives, an optical substrate as a sensor support, an optional conformable optical substrate or rotating film to refresh the sensor chemistry, and means for detecting the signal from the sensor. Optical sign can be enhanced by immobilizing biocidal compounds in the sensing membrane, immobilizing metal colloids in the sensing membrane, or immobilizing sol-gel coated colloidal particles in the sensing membrane.

Abstract: A robust fiber optic sensor and sensing method for reliable, long-term measurement of analytes is disclosed. The sensor comprises an optical interrogation region comprising an indicator dye confined at a distal end of an optical fiber and an analyte permeable membrane enclosing the interrogation region at the distal fiber end. In a preferred embodiment, a reservoir member is provided with excess dye for continuous replenishment of the interrogation region with dye over the lifetime of the sensor. In another preferred embodiment, the reservoir member comprises an indicator support for containment of excess dye. In one preferred embodiment, a ratiometric dye is used for monitoring optical signal-to-noise and signal drift caused by sensor aging. The sensor may be configured with a variety of alternative indicator dyes and membrane materials as a specific ion sensor for analyzing dissolved analytes such as gases, cations, and anions.