Methods and apparatus relating to very large scale FET arrays for analyte measurements. ChemFET (e.g., ISFET) arrays may be fabricated using conventional CMOS processing techniques based on improved FET pixel and array designs that increase measurement sensitivity and accuracy, and at the same time facilitate significantly small pixel sizes and dense arrays. Improved array control techniques provide for rapid data acquisition from large and dense arrays. Such arrays may be employed to detect a presence and/or concentration changes of various analyte types in a wide variety of chemical and/or biological processes. In one example, chemFET arrays facilitate DNA sequencing techniques based on monitoring changes in hydrogen ion concentration (pH), changes in other analyte concentration, and/or binding events associated with chemical processes relating to DNA synthesis.

A system for nucleic acid sequencing includes a machine-readable memory and a processor configured to execute machine-readable instructions. The instructions, when executed by the processor, cause the system to expose template polynucleotide strands in a plurality of defined spaces of a sensor array to a series of flows of nucleotide species, the series comprising a sequence of random flows; and obtain, for each of the series of flows of nucleotide species, a signal indicative of how many nucleotide incorporations occurred for that particular flow to determine a predicted sequence of nucleotides corresponding to the template polynucleotide strands.

A system for nucleic acid sequencing includes a machine-readable memory and a processor configured to execute machine-readable instructions. The instructions, when executed by the processor, cause the system to expose template polynucleotide strands in a plurality of defined spaces of a sensor array to a series of flows of nucleotide species, the series comprising a sequence of random flows; and obtain, for each of the series of flows of nucleotide species, a signal indicative of how many nucleotide incorporations occurred for that particular flow to determine a predicted sequence of nucleotides corresponding to the template polynucleotide strands.

The present disclosure relates to methods and compositions involving HCR reactions that involve initiators that are split into two or more parts. Effective HCR is dependent upon two or more of these split initiators being brought into proximity (e.g., via binding events mediated by a target) such that a full initiator is formed that is capable of triggering HCR signal amplification.

The present disclosure relates to methods and compositions involving HCR reactions that involve initiators that are split into two or more parts. Effective HCR is dependent upon two or more of these split initiators being brought into proximity (e.g., via binding events mediated by a target) such that a full initiator is formed that is capable of triggering HCR signal amplification.

Real time electronic sequencing devices, chips, and systems are described. Arrays of nanoFET devices are used to provide sequence information about a template nucleic acid in a polymerase-template complex bound to the nanoFET. The nanoFET devices typically have a source, a drain and a gate comprising a nanowire. A single polymerase enzyme complex comprising a polymerase enzyme complexed with the template nucleic acid is bound to the gate. The polymerase is bound to the gate non-covalently through a polymeric binding agent that has two strands, each strand interacting with the nanowire such that the polymerase is in a central location between the strands with the polymeric binding agent extending away from the polymerase complex along the nanowire in both directions.

Real time electronic sequencing devices, chips, and systems are described. Arrays of nanoFET devices are used to provide sequence information about a template nucleic acid in a polymerase-template complex bound to the nanoFET. The nanoFET devices typically have a source, a drain and a gate comprising a nanowire. A single polymerase enzyme complex comprising a polymerase enzyme complexed with the template nucleic acid is bound to the gate. The polymerase is bound to the gate non-covalently through a polymeric binding agent that has two strands, each strand interacting with the nanowire such that the polymerase is in a central location between the strands with the polymeric binding agent extending away from the polymerase complex along the nanowire in both directions.

Minimal-copy-ratio of templates is a problem in detecting early stage cancer where minimal copies of somatic cancer-specific mutations are targeted in the presence of large copies of wildtype genome DNA, commonly a 1/10,000 or even less minimal-copy-ratio between the mutant target and wildtype control templates. To overcome this problem, delayed pyrophosphorolysis activated polymerization (delayed-PAP) was developed which can delay product accumulation of the wildtype control to a much later time or cycle by up to 15 cycles or by 30,000 folds. In the multiplex format, delayed-PAP is particularly useful to amplify not only the wildtype control but also mutant target templates accurately and consistently in the minimal-copy-ratio situation.

Minimal-copy-ratio of templates is a problem in detecting early stage cancer where minimal copies of somatic cancer-specific mutations are targeted in the presence of large copies of wildtype genome DNA, commonly a 1/10,000 or even less minimal-copy-ratio between the mutant target and wildtype control templates. To overcome this problem, delayed pyrophosphorolysis activated polymerization (delayed-PAP) was developed which can delay product accumulation of the wildtype control to a much later time or cycle by up to 15 cycles or by 30,000 folds. In the multiplex format, delayed-PAP is particularly useful to amplify not only the wildtype control but also mutant target templates accurately and consistently in the minimal-copy-ratio situation.

Real time electronic sequencing devices, chips, and systems are described. Arrays of nanoFET devices are used to provide sequence information about a template nucleic acid in a polymerase-template complex bound to the nanoFET. The nanoFET devices typically have a source, a drain and a gate comprising a nanowire. A single polymerase enzyme complex comprising a polymerase enzyme complexed with the template nucleic acid is bound to the gate. The polymerase is bound to the gate non-covalently through a polymeric binding agent that has two strands, each strand interacting with the nanowire such that the polymerase is in a central location between the strands with the polymeric binding agent extending away from the polymerase complex along the nanowire in both directions.