Abstract: Resonant sensors, preferably having floating bilayer symmetry, and their methods of use is determining the presence, amount or binding kinetics of an analyte of interest in a test sample are disclosed. The test sample may be a liquid or gas.

Abstract: Extremely minute amounts of live pathogens are rapidly detected using a piezoelectric cantilever sensor. A single pathogen is detectable in about 30 minutes. Pathogen-specific antibodies are immobilized on the sensor surface. The sensor is exposed to a medium that potentially contains the target pathogen. When target pathogens are contained in the medium, both dead and live pathogen cells bind to the immobilized antibody on the sensor surface. The attached target pathogen cells are exposed to a pathogen discriminator capable of discriminating between live cells and dead cells by increasing the mass of live cells. Example pathogens include Escherichia coli, Listeri monocytogene, and Salmonella enteritidis. Example antibodies include those that bind to the pathogenic bacteria designated as ATCC 43251, ATCC 700375, and ATCC 31194. Example pathogen discriminators include intracellular pH indicating molecules.

Abstract: Detection of miniscule amounts of an analyte is accomplished via multiple bindings of specific materials on a sensor configured to sense mass. The sensor is prepared by immobilizing an antibody to a surface of the sensor, wherein the antibody is known to bind to the analyte. The prepared sensor is exposed to the analyte. The analyte binds to the antibody. The sensor then is exposed to additional antibody, which binds to the analyte. The sensor then can be sequentially exposed to additional antibodies that are known to bind to previously bound antibodies. Each additional binding further increases the effective mass of accumulated material on the sensor. The total effective mass is greater than the mass of the accumulated analyte, thus providing means for detecting extremely minute amounts of analyte. Applications include detection of pathogens and DNA.