University of Utah Research Foundation

Vladimir Hlady

Joseph D Andrade

Philip M Triolo

Andras Pungor

Robert J Scheer

Chung-Yih Wang

Eric W Stroup

A method and associated apparatus for measuring chemical concentration in a liquid sample based on spatial separation and resolution of light is disclosed. The method is preferably applied to sensitive, quantitative, luminescence-based biosensors which reads the analyte concentration via spatial distribution of the emitted light. The detection of light is used to assess the spatial position, rather than the intensity or wavelength, of emitted light. A bioluminescent or chemiluminescent reaction requiring, for example, ATP, NADPH or NADH as a specific, and sensitive co-factor is used. ATP or NADH concentration is modulated, &ldquo;tuned,&rdquo; and/or regulated via, for example, an enzyme which consumes (&ldquo;consumase&rdquo;) ATP, NADPH, or NADH, thereby producing a spatial distribution of ATP or NADH and a spatial distribution in the emitted light. By appropriate control of the consumase or &ldquo;synthase&rdquo; activity and kinetics, a sensitive, specific, and easily readable luminescent pattern is produced, permitting detection.

Method of measuring chemical concentration based on spatial separation and resolution of luminescence

The method for mapping a mechanical property of a surface of a sample with a scanning force microscope comprises the steps of (a) scanning a fine tip in contact with the surface of the sample within a predetermined scan area, the fine tip being supported on an end of a cantilever beam, (b) applying a loading force on the surface of the sample by the fine tip, (c) using a constant frequency sine wave to oscillate the cantilever beam relative to the surface of the sample, (d) measuring a detector response of the fine tip at the end of the cantilever beam, (e) determining an amplitude of the detector response and a change in phase angle of the detector response relative to the sine wave used to oscillate the cantilever beam, and (f) relating the amplitude and the change in phase angle to a property of the surface of the sample. A feedback system is utilized which regulates the total force imposed by the fine tip onto the surface of the sample so that the amplitude of the detector response is maintained constant. Because the force does not depend on the topography of the sample, the average cantilever deflection is directly related to the mechanical property of the surface of the sample and is not affected by any topographical feature present on the surface of the sample.

Method for mapping mechanical property of a material using a scanning

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Salt Lake City, UT, United States of America

Vladimir Hlady