Abstract: Photoresponsive devices, including a photoresponsive electrode, are provided and methods for their use to measure changes in environment at a site at or about the surface of the photoresponsive device. By employing a source of light for irradiating a site on the surface and means for biasing the photoresponsive electrode in relation to a counterelectrode, a variation in electrical signal can be related to a change in a medium in photoresponsive modulation relationship to the photoresponsive electrode surface.

Abstract: A device useful in diagnostics in which a biochemical species is attached to the surface of a sensor, especially to the gate of a field effect transistor. In such a "BIOCHEMFET" it has been a problem to attach two or more biochemical species to the surface of the sensor, especially to the gates of a multi-gated FET. It has now been found possible to bond a group having a photoactivatable function covalently to the sensor surface, photo-expose the resultant modified surface selectively, e.g. through a mask, and bond the biochemical species, e.g. a hapten, antigen, antibody, lectin or enzyme, to the photoactivated function. In this way the biochemical species becomes attached in selected areas only. In view of the success of this technique realized under conditions of miniaturization, the invention makes possible "printed circuits for proteins".

Abstract: Separation of all clinically relevant isoamylase bands including P.sub.1 P.sub.1b, P.sub.2, P.sub.3, P.sub.4, S.sub.1, S.sub.2, S.sub.3, S.sub.4 and S.sub.5 is achieved in a test in which a biological sample is electrophoresed on an agarose gel supporting a tris-sodium barbital-barbital buffer at a pH of between 8.4 and 9.2. The barbital anion concentration is between about 0.03 and about 0.08 M, the tris cation concentration is between about 0.03 M and about 0.07 M; and the sodium cation concentration is between about 0.03 M and about 0.07 M. Agarose is present in the gel at concentrations of between about 0.4 and about 1.5 weight percent.

Abstract: Method and apparatus for use in accurately measuring the binding reactions occurring between a predetermined class of components in a liquid specimen and their corresponding binding conjugates coated on separate test regions of a carrier. The carrier further includes a reference region that is uncoated, and the carrier is adapted for simultaneous contact of all of its regions with the liquid specimen. Any resulting binding reaction on each test region indicates both specific binding to the coated component as well as non-specific binding, and any resulting binding reaction on the reference region indicates merely non-specific binding. The measurements for the test regions are all reduced by an amount determined in accordance with the measurement for the reference region, to reduce the effects of non-specific binding on those measurements and thereby provide accurate measurements of the specific binding on each coated component.

Abstract: A method, sensor and semiconductor device for determining the concentration of an analyte in a medium. The device features an element constructed of semiconductive organic polymer associated with a binding substance having specific affinity for the analyte.

Abstract: A test-tube assembly and method for carrying out immunoassays. The apparatus features two independent components, the first having a series of test-tubes fixed to a support and equidistantly dependent therefrom, and the second having a base including magnets permanently fixed therein, the two components being releasably couplable to hold the lower ends of the test-tubes adjacent the magnets in the base.

Abstract: Electrochemically generated chromophores are measured by passing a beam of electromagnetic radiation parallel and close to the surface of the electrode at which they are being generated, and collecting the diffracted radiation. The response is so rapid (.about.0.025 sec.) that modulation is practicable and the path length, which is set by the thickness of the electrode, is much greater than in optically transparent electrodes, thus rendering the method very sensitive to weak chromophores or low concentrations.

Abstract: An air pollutant and/or fire combustion sensing apparatus includes a capacitive sensor having spaced sensing electrodes producing a free space mounted within an environment subject to possible fire or the like. One of the sensing electrodes has an outer dielectric layer for absorbing contaminating gaseous products. The electrodes are connected to a high voltage power source for producing a charged capacitor with a high intensity static electric field of substantially 5.times.10.sup.5 V/M up to the dielectric breakdown of air in the free space or gap. The electric field reacts upon the contaminating gaseous products of combustion and environmental pollution and produces an opposing electric field with a net change in the electric field and the summated voltage appearing across the electrodes. A high input impedance detecting circuit with good electrometer characteristics responds to the change in the field.