Described herein are DNA-nanostructures that can be used in an assay to detect and/or quantify an analyte of interest. Aspects of the DNA-nanostructure can include a single DNA molecule composed of hairpin structural motifs, an anchor recognition moiety, and a signal moiety, where the anchor recognition moiety and the signal moiety are in effective proximity to each other such that the tethered diffusion of the signal molecule can be altered based upon binding status of the anchor recognition moiety. Also described herein are methods of making and using the DNA-nanostructures.

Described herein are DNA-nanostructures that can be used in an assay to detect and/or quantify an analyte of interest. Aspects of the DNA-nanostructure can include a single DNA molecule composed of hairpin structural motifs, an anchor recognition moiety, and a signal moiety, where the anchor recognition moiety and the signal moiety are in effective proximity to each other such that the tethered diffusion of the signal molecule can be altered based upon binding status of the anchor recognition moiety. Also described herein are methods of making and using the DNA-nanostructures.

Apparatuses, systems, and methods are disclosed for target detection based on collateral cleavage of a reporter by an enzyme. A biologically gated transistor may include a channel and a reporter moiety immobilized to the channel. The state of the reporter moiety may affect one or more output signals from the biologically gated transistor when excitation conditions are applied to the biologically gated transistor and a sample fluid is applied in contact with the channel. A sample fluid may include an enzyme configured to activate in response to a target nucleic acid to cleave the reporter moiety. Excitation circuitry may apply the excitation conditions, and measurement circuitry may measure output signals from the biologically gated transistor. An analysis module may determine a parameter relating to presence of the target nucleic acid, based on the one or more measurements.

Apparatuses, systems, and methods are disclosed for target detection based on collateral cleavage of a reporter by an enzyme. A biologically gated transistor may include a channel and a reporter moiety immobilized to the channel. The state of the reporter moiety may affect one or more output signals from the biologically gated transistor when excitation conditions are applied to the biologically gated transistor and a sample fluid is applied in contact with the channel. A sample fluid may include an enzyme configured to activate in response to a target nucleic acid to cleave the reporter moiety. Excitation circuitry may apply the excitation conditions, and measurement circuitry may measure output signals from the biologically gated transistor. An analysis module may determine a parameter relating to presence of the target nucleic acid, based on the one or more measurements.

A detection apparatus that includes (a) an array of responsive pads on a substrate surface; (b) an array of pixels, wherein each pixel in the array has a detection zone on the surface that includes a subset of at least two of the pads; and (c) an activation circuit to apply a force at a first and second pad in the subset, wherein the activation circuit is configured to apply a different force at the first pad compared to the second pad, and wherein the activation circuit has a switch to selectively alter the force at the first pad and the second pad.

A detection apparatus that includes (a) an array of responsive pads on a substrate surface; (b) an array of pixels, wherein each pixel in the array has a detection zone on the surface that includes a subset of at least two of the pads; and (c) an activation circuit to apply a force at a first and second pad in the subset, wherein the activation circuit is configured to apply a different force at the first pad compared to the second pad, and wherein the activation circuit has a switch to selectively alter the force at the first pad and the second pad.

A CRISPR electrochemical biosensing system (E-CRISPR) for detection of analytes includes a disposable, micro-fabricated three-electrode sensor that includes a working electrode, a counter electrode, a reference electrode, and a nonspecific ssDNA reporter with an electrochemical tag for signal transduction tethered to a surface of the working electrode; and a Cas12a-crRNA duplex that is designed to specifically recognize and cleave target nucleic acid strand based on the protospacer adjacent motif (PAM) sequence of the target and crRNA sequence, wherein the PAM recognition depends on specific 5′ TTTN nucleic acid sequence located at an opposite strand of a recognition strand, and wherein only upon the recognition of the PAM sequence by the Cas protein, the Cas protein, acting as a DNA helicase, unwinds the target DNA.

A CRISPR electrochemical biosensing system (E-CRISPR) for detection of analytes includes a disposable, micro-fabricated three-electrode sensor that includes a working electrode, a counter electrode, a reference electrode, and a nonspecific ssDNA reporter with an electrochemical tag for signal transduction tethered to a surface of the working electrode; and a Cas12a-crRNA duplex that is designed to specifically recognize and cleave target nucleic acid strand based on the protospacer adjacent motif (PAM) sequence of the target and crRNA sequence, wherein the PAM recognition depends on specific 5′ TTTN nucleic acid sequence located at an opposite strand of a recognition strand, and wherein only upon the recognition of the PAM sequence by the Cas protein, the Cas protein, acting as a DNA helicase, unwinds the target DNA.

The present disclosure provides methods and systems for performing single-molecule detection using fabricated integrated on-chip devices. In an aspect, the present disclosure provides a method for on-chip detection of an array of biological, chemical, or physical entities, comprising: (a) providing an array of light sensing devices; (b) immobilizing the array of biological, chemical, or physical entities on a substrate of the array of light sensing devices; (c) exposing the array of biological, chemical, or physical entities to electromagnetic radiation sufficient to excite the array of biological, chemical, or physical entities, thereby producing an emission signal of the array of biological, chemical, or physical entities; (d) using the array of light sensing devices, acquiring pixel information of the emission signal of the array of biological, chemical, or physical entities without scanning the array of light sensing devices across the array of biological, chemical, or physical entities; and (d) detecting the array of biological, chemical, or physical entities based at least in part on the acquired pixel information.

The present disclosure provides methods and systems for performing single-molecule detection using fabricated integrated on-chip devices. In an aspect, the present disclosure provides a method for on-chip detection of an array of biological, chemical, or physical entities, comprising: (a) providing an array of light sensing devices; (b) immobilizing the array of biological, chemical, or physical entities on a substrate of the array of light sensing devices; (c) exposing the array of biological, chemical, or physical entities to electromagnetic radiation sufficient to excite the array of biological, chemical, or physical entities, thereby producing an emission signal of the array of biological, chemical, or physical entities; (d) using the array of light sensing devices, acquiring pixel information of the emission signal of the array of biological, chemical, or physical entities without scanning the array of light sensing devices across the array of biological, chemical, or physical entities; and (d) detecting the array of biological, chemical, or physical entities based at least in part on the acquired pixel information.