Abstract: Catalytic colloidal metal particles bound to a biomolecule such as an antibody, avidin, or streptavidin are useful for detecting the presence of the biomolecule in an assay such as an immunoassay.

Abstract: A sensor for ultra-low concentration chemical recognition comprises a force transducer, a tip coupled to this force transducer, and a substrate positioned for force interaction with the force transducer tip, where the substrate and tip are chemically modified with antigens, antibodies, nucleic acids, or chelating agents so that there is a specific force interaction between the tip and the substrate in the presence of the target species, and a measurably different force interaction in the absence of the target species.

Abstract: A microassay card includes an upper layer containing wells for receiving a liquid sample. A second layer of the card, beneath the first layer, includes a supporting surface bound to a reactive species. A third layer includes a superabsorbent support impregnated with an indicator. Typically, the indicator is a substrate for an enzyme, such as a reduced dye precursor and a source of hydrogen peroxide necessary for the action of the enzyme upon the substrate to cause a spectral change in the absorbent layer. By selecting the structure of the first and second layers, the card can be formatted for a displacement assay or a competitive assay. The microassay card of the present invention is particularly useful for drug testing.

Abstract: A target polynucleic acid strand may be detected within a sample. A sensing strand of complementary polynucleic acid is labelled, at at least two internucleotide phosphate groups, with labels which vary their electronically interaction with each other, and thus their emission or absorption spectra, depending upon whether the sensing strand is bound to target polynucleic acid in the sample.

Abstract: A substance having binding sites for at least two molecules may be detected within a sample. A molecule which can be recognized by the substance is labelled such that when at least two of the labelled molecules are bound the binding sites on the substance, the labels on the molecules electronically interact with each other and vary the wavelength dependance of their spectra. This variation in the spectra of the label can be detected. If the sample is suspected of containing the unlabelled form of a molecule, such as biotin or cocaine, a known amount of the above substance, along with a known amount of the corresponding labelled biotin or cocaine is added to the sample. In this instance, the amount of the suspect molecule in the sample is then determined by the extent to which the variation in the spectra of the label has been reduced. Alternatively, the present invention can be used to determine the binding characteristics of the substance within the sample.

Abstract: A microassay card for a includes an upper layer containing wells for receiving a liquid sample. A second layer of the card, beneath the first layer, includes a supporting surface bound to a reactive species. A third layer includes a superabsorbent support impregnated with an indicator. Typically, the indicator is a substrate for an enzyme, such as a reduced dye precursor and a source of hydrogen peroxide necessary for the action of the enzyme upon the substrate to cause a spectral change in the absorbent layer. By selecting the structure of the first and second layers, the card can be formatted for a displacement assay or a competitive assay. The microassay card of the present invention is particularly useful for drug testing.

Abstract: An apparatus for conducting a highly sensitive assay is provided wherein the level of a specific material is detected using a reaction which produces a detectable substance such as a colored dye or a fluorescent material in proportion to the concentration of the material being detected and which is carried out on an absorbent detecting layer comprising a superabsorbent polymeric material. The use of the superabsorbent polymeric materials greatly increases the sensitivity of the assay in a manner not achieved in the prior art because these polymeric materials are an excellent medium for the detection of the color changes caused by the reactants in the assays. These superabsorbent polymers offer increased sensitivity of up to about ten times greater than that which was possible using conventional backing materials as the absorbent layer in assays. The present invention comprises a quick, inexpensive, and accurate means for testing materials such as alcohol with a sensitivity that approaches 0.001% (w/v).

Abstract: A method of analyzing a sample for selected molecules which consists of reacting the molecule with a reagent that produces a charged derivative which can be desorbed and analyzed using Secondary Ion Mass Spectrometry (SIMS).