Abstract: A method for detecting a target molecule in a test mixture suspected of containing said target molecule is described. The nucleic acid ligand capable of binding to the target molecule has a first sequence A and a second sequence B, which are partially complementary sequences that form an imperfect intramolecular duplex, which unwinds upon the binding of the target to the nucleic acid ligand. Sequences A and B are able to participate in extramolecular hybridization reactions only when the duplex is unwound. Three different cascade nucleic acids contain a first sequence and a second sequence, which are partially complementary sequences. At least one sequence is exactly complementary to A or B. The second sequence may be complementary to A or B, or may be a third sequence C, or its complement.

Abstract: A Nucleic acid ligand “Biochip” is disclosed, consisting of a solid support to which one or more specific Nucleic acid ligands is attached in a spatially defined manner. Each Nucleic acid ligand binds specifically and avidly to a particular Target molecule contained within a Test mixture, such as a Bodily fluid The Target molecules include, but are not limited to, proteins (cellular, viral, bacterial, etc.) hormones, sugars, metabolic byproducts, cofactor, and intermediates, drugs, and toxins. Contacting the Test mixture with the Biochip leads to the binding of a Target molecule to its cognate Nucleic acid ligand. Binding of Target to the Nucleic acid ligand results in a detectable change at each specific location on the Biochip. The detectable change can include, but is not limited to, a change in fluorescence, or a change in a physical parameter, such as electrical conductance or refractive index, at each location on the Biochip.

Abstract: This invention discloses high-affinity oligonucleotide ligands to the thermostable Taq polymerase, Tth polymerase and TZ05 polymerase. Specifically, this invention discloses DNA ligands having the ability to bind to the Taq, Tth and TZ05 polymerases and the methods for obtaining such ligands. The ligands are capable of inhibiting polymerases at any predetermined temperature.

Abstract: The presence of a target in a test mixture or the concentration of such target can be determined by a method relying on fluorescence emission measurement. Such method utilizes a nucleic acid ligand to the target and a ligand beacon comprising: i) a nucleic acid sequence complimentary to at least a portion of said nucleic acid ligand, ii) a fluorescent group, and iii) a fluorescence-modifying group. The emission profile of the ligand beacon is altered based on the presence and/or concentration change of the target in the test mixture.

Abstract: Methods are described for the identification and preparation of high-affinity nucleic acid ligands to cytokines. Included in the invention are specific nucleic acid ligands to IFN-gamma, IL-4, IL-10, TNF-alpha, and RANTES.

Abstract: This invention pertains to methods of determining the presence and/or quantity of homocysteine in a sample containing other thiol-containing compounds. The methods of this invention involve modifying the homocysteine to facilitate the separation of homocysteine from cysteine. An assay protocol comprises adjusting the conditions of the sample suspected of containing homocysteine so that homocysteine forms homocysteine thiolactone, separating the homocysteine thiolactone from free thiol-containing compounds present in the sample, including cysteine, reconverting the homocysteine thiolactone to homocysteine, and determining the presence and/or quantity of homocysteine in the sample by conventional means.

Abstract: The presence of a target in a test mixture or the concentration of such target can be determined by a method relying on fluorescence emission measurement. Such method utilizes a nucleic acid ligand to the target and a ligand beacon comprising: i) a nucleic acid sequence complimentary to at least a portion of said nucleic acid ligand, ii) a fluorescent group, and iii) a fluorescence-modifying group. The emission profile of the ligand beacon is altered based on the presence and/or concentration change of the target in the test mixture.

Abstract: Methods are described for the identification and preparation of high-affinity nucleic acid ligands to cytokines. Included in the invention are specific nucleic acid ligands to IFN-gamma, IL-4, IL-10, TNF-alpha, and RANTES.

Abstract: Methods are described for the identification and preparation of high-affinity nucleic acid ligands to CD4. Included in the invention are specific 2'F RNA ligands to CD4 identified by the SELEX method.

Abstract: This invention discloses the use of high-affinity oligonucleotide ligands in flow cytometry diagnostic applications. Specifically, DNA ligands having one or more fluorophore molecules attached are disclosed which are useful in flow cytometry.