IMMUNOELECTROCHEMICAL ASSAYS FOR BACTERIA - USE OF EPIFLUORESCENCE MICROSCOPY AND RAPID-SCAN ELECTROCHEMICAL TECHNIQUES IN DEVELOPMENT OF AN ASSAY FOR SALMONELLA

Immunoelectrochemical sensors in which the sensor surface functions as both analyte capture phase and electrochemical detector have recently been developed for bacteria analysis. The speed and sensitivity of th ese devices make them very attractive for applications such as the det ection of pathogenic microorganisms in food and water. However, the de velopment and optimization of assays utilizing these sensors can be co mplicated by undesired interactions between the capture and detection functions. Modification of the sensor to achieve improvements in one f unction can have deleterious effects on the other function, and such e ffects can be difficult to diagnose and correct. In the course of inve stigations on immunoelectrochemical detection of Salmonella, we develo ped a rapid, nondestructive epifluorescence microscopy method to deter mine bacteria capture efficiency. This method enabled us to study capt ure and detection functions independently and efficiently identify per formance-limiting factors. Rapid-scan electrochemical methods were use d to optimize detection sensitivity and to provide diagnostic informat ion on detection performance.