A Piezoelectric Crystal Immunosensor for E.coli 972423
Two oscillator circuits capable of oscillating an AT cut piezoelectric crystal in contact with liquid were built and tested. E.coli concentrations in the range of 700 cells/ml can be detected using the total immersion techniques. Scanning electron microscope images revealed that ‘under-liquid’ biosensors might offer lower detection limits than the dip-and-dry method. The effect of water temperature on the crystal frequency was found to be linear in the range of 18 - 45 °C. A linear decrease in crystal frequency was noticed as the relative viscosity increased from 1 to 3. These oscillator circuits were duplicated and integrated to result in a Computer Automated Biosensor Array (CABA), which was designed to overcome the antibody selectivity problems. This system utilizes a commercially available pattern recognition tool to fingerprint a particular antigen. The proposed technology will enhance abilities in fingerprinting of antigens and alleviate some of the problems associated with cross reactivity.