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An integrated, sensitive, and rapid system was developed for the detection of bacteria. The system combined an optical metal-clad leaky waveguide (MCLW) sensor with ultrasound standing waves (USW). The performance of a MCLW sensor for the detection of bacteria has been increased (> 100 fold) by using USWs to drive bacteria onto the sensor surface. By forming the USW nodes at or within the surface of the MCLW, the diffusion-limited capture rate has been replaced by fast movement. Immobilized anti-BG antibody on the MCLW sensor surface was used to capture Bacillus subtilis var. niger (BG) bacterial spores driven to the surface. This combination of sensor and attractor force combination has been tested by detecting the evanescent scattering from bacterial spores at the sensor surface. Application of ultrasound for 3 min gave a detection limit for BG bacterial spores of 1 x [10.sup.3] spores/mL.

An integrated optical metal clad leaky waveguide (MCLW) sensor device has been developed for the detection of bacteria. This is more sensitive than waveguide sensors currently in use. The MCLW device has been fabricated to extend the evanescent field to provide significant light intensity over the entire volume of the bacteria bound on the chip surface within this field. This in turn increases the interaction of the light with the entire volume of the bacteria. MCLW devices have been used for detecting refractive index changes, scattering, and fluorescence from bacterial spores captured on an immobilized antibody. The detection limit of Bacillus subtilis var. niger bacterial spores using refractive index detection was 8 x [10.sup.4] spores/mL. The scattering intensity of the BG spores was found to be three times greater than the scattering intensity generated using surface plasmon resonance. The extended light propagation along the direction of flow for a few millimeters provides an effective interrogation approach to increase the area of detection to detect low concentrations down to 1 x [10.sup.4] spores/mL. The sensor was then optimized by studying the key factors affecting sensor performance including changing the pH of the medium, type of antibody immobilization matrix, sensor surface regeneration approaches, and longevity of the sensor.

A microfluidic device with integrated spectrophotometric elements has been injection molded in poly(methyl methacrylate) (PMMA). The strategy for producing the device combined the direct photopatterning, replica molding techniques and a rapid cooled release mechanism in conjunction with material-material transfer to form a multilayer epoxy master on an injection mold insert. An injection-molded flow cell consisting of 1800 diffractive elements patterned on 25-[micro]m-high PMMA pillars was produced. The design incorporated a large cross sectional surround, simplifying the alignment and bonding procedure. The absorbance range of one of the devices was standardized against a commercially available visible spectrophotometer at 605 nm to increasing concentrations of Nile blue perchlorate A dye in aqueous solution. The detection limit for a new integrated device was 1.2 x [10.sup.-6] m/Lof the mentioned dye.

An integrated optical metal clad leaky waveguide (MCLW) sensor device has been developed for the detection of bacteria. This is more sensitive than waveguide sensors currently in use. The MCLW device has been fabricated to extend the evanescent field to provide significant light intensity over the entire volume of the bacteria bound on the chip surface within this field. This in turn increases the interaction of the light with the entire volume of the bacteria. MCLW devices have been used for detecting refractive index changes, scattering, and fluorescence from bacterial spores captured on an immobilized anti- body. The detection limit of Bacillus subtilis var. niger bacterial spores using refractive index detection was 8 × 104 spores/mL. The scattering intensity of the BG spores was found to be three limes greater than the scattering intensity generated using surface plasmon resonance. The extended light propagation along the direction of flow for a few millimeters provides an effective interrogation approach to increase the area of detection to detect low concentrations down to 1 × 104 spores/mL The sensor was then optimized by studying the key factors affecting sensor performance including changing the pH of the medium, type of antibody immobilization matrix, sensor surface regeneration approaches, and longevity of the sensor. [ABSTRACT FROM AUTHOR]