Under one aspect, a composition includes a substrate; a first polynucleotide coupled to the substrate; a second polynucleotide hybridized to the first polynucleotide; and a catalyst coupled to a first nucleotide of the second polynucleotide, the catalyst being operable to cause a chemiluminogenic molecule to emit a photon. Under another aspect, a method includes providing a catalyst operable to cause a first chemiluminogenic molecule to emit a photon; providing a substrate; providing a first polynucleotide coupled to the substrate; hybridizing a second polynucleotide to the first polynucleotide; coupling a first quencher to a first nucleotide of the second polynucleotide; and inhibiting, by the first quencher, photon emission by the first chemiluminogenic molecule.

Provided are methods, compositions and devices for high sensitivity detection of biomolecules such as nucleic acids in biological samples. The methods rely on target detection, nucleic acid amplification, and sensitive detection to provide a signal which can be conveniently measured in a lab assay or device, including with portable and point-of-care instrumentation.

Provided are methods, compositions and devices for high sensitivity detection of biomolecules such as nucleic acids in biological samples. The methods rely on target detection, nucleic acid amplification, and sensitive detection to provide a signal which can be conveniently measured in a lab assay or device, including with portable and point-of-care instrumentation.

The present application provides for systems and methods for detecting and estimating signals corresponding to one or more biomarkers in biological samples stained for the presence of protein and/or nucleic acid biomarkers. On particular aspect is directed to a method of estimating an amount of signal corresponding to at least one biomarker in an image of a biological sample. The method includes detecting isolated spots in a first image, deriving an optical density value of a representative isolated spot based on signal features from the detected isolated spots, estimating a number of predictive spots in signal aggregates in each of a plurality of sub-regions based on the derived optical density value of the representative isolated spot, and storing the estimated number of predictive spots and detected isolated spots in each of the plurality of generated sub-regions in a database.

The present application provides for systems and methods for detecting and estimating signals corresponding to one or more biomarkers in biological samples stained for the presence of protein and/or nucleic acid biomarkers. On particular aspect is directed to a method of estimating an amount of signal corresponding to at least one biomarker in an image of a biological sample. The method includes detecting isolated spots in a first image, deriving an optical density value of a representative isolated spot based on signal features from the detected isolated spots, estimating a number of predictive spots in signal aggregates in each of a plurality of sub-regions based on the derived optical density value of the representative isolated spot, and storing the estimated number of predictive spots and detected isolated spots in each of the plurality of generated sub-regions in a database.

An assay system is provided of great sensitivity and portability where the presence of a specific target in a sample, as well as its concentration (qualification and quantification) is detected by reason of a potential or voltage in a closed circuit, built up a redox reaction. The reaction is produced by binding a capture moiety to an enzymatic redox reaction partner, allowing the capture moiety to bind to any target in the sample, and washing any such bound target. The bound target, if not immobilized, may be immobilized through use of a second capture moiety. Substrate for the enzyme is then added. The action of the enzyme upon the substrate frees electrons, creating a potential across an anode and cathode which may be separated by a membrane.

An assay system is provided of great sensitivity and portability where the presence of a specific target in a sample, as well as its concentration (qualification and quantification) is detected by reason of a potential or voltage in a closed circuit, built up a redox reaction. The reaction is produced by binding a capture moiety to an enzymatic redox reaction partner, allowing the capture moiety to bind to any target in the sample, and washing any such bound target. The bound target, if not immobilized, may be immobilized through use of a second capture moiety. Substrate for the enzyme is then added. The action of the enzyme upon the substrate frees electrons, creating a potential across an anode and cathode which may be separated by a membrane.

A method for testing a sample for the presence of one or more targets comprises multiplexed catalyzed reporter deposition (CARD) is provided.

A method for testing a sample for the presence of one or more targets comprises multiplexed catalyzed reporter deposition (CARD) is provided.

A method for detecting a target nucleic acid includes: (a) a step of mixing a sample containing the target nucleic acid with a nucleic acid detection solution containing i) ssDNA-protease conjugate, ii) ssDNA-zymogen conjugate, and iii) a substrate specific for the zymogen; and (b) a step of detecting a signal generated by a proximity proteolysis reaction between the ssDNA-zymogen conjugate and the ssDNA-protease conjugate which are hybridized to the target nucleic acid.