The subject invention provides materials and methods for single-step fluorescence and electrochemical detection of small molecules, e.g., fentanyl and its analogs, in a sample. The subjection invention provides nucleic acids materials, e.g., aptamers (nucleic acid oligonucleotides) that can bind to fentanyl and its analogs with nanomolar affinity and high specificity against illicit drugs, adulterants, and cutting agents commonly existing in seized samples. The method for detecting fentanyl and/or its analogs in a sample comprises contacting the sample with an aptamer-based sensor selective for fentanyl and its analogs, and sensitively, specifically, and rapidly detecting fentanyl and/or its analogs in the sample.

Described herein are nucleic acid-based electrochemical proximity assays (ECPAs) for sample quantification. The invention may also include a biosensor with a sensing mechanism that uses a pair of aptamers or antibodies that bind the target of interest. More specifically, the invention relates to an electrochemical-based read out of a sensing mechanism that uses a nucleic acid-based proximity assay in conjunction with a pair of aptamers or antibodies for sample quantification. The biosensor or a set of biosensors can be used either as a standalone measurement system for a single analyte target or as a component of a multiplexed cartridge for multiple analytes.

Described herein is an immobilization-free, electrochemical method of detecting a target DNA sequence in a sample. The method includes: incubating the sample with a detection mixture, applying an electric field including an alternating current electric field and a direct current offset to the detection mixture to concentrate nucleic acids in the sample and the nucleic acid probe on a positively charged working electrode, wherein a Class 2 Cas protein trans-cleaved electroactive probe is released from the nucleic acid probe when the target DNA is present in the sample and diffuses toward a negatively charged electrode; and measuring the current as potential is applied, wherein detection of a current in the detection mixture indicates the presence of the target DNA sequence in the sample.

Various aspects of the present disclosure provide methods, apparatus and systems for single-molecule biosensors having nanowire or nanoribbon bridges between electrodes for sequencing and information storage and reading. In various embodiments, the present disclosure provides nanofabrication of biomolecular sensing devices beginning with parallel arrangements of transferable nanowires or nanoribbons, and provides in general methods of manufacturing biosensor devices for sequencing DNA or RNA and analyzing biomolecules.

The present invention relates to methods for creating conductive nanojunctions using metalized or conductive polymer joined to a DNA nanowire in a nanodevice for chemosensing and biosensing.

Methods, apparatus, systems, and methods are described that relate to microneedle-assisted aptamer-based electrochemical sensing for label-free, continuous real-time monitoring of biomarkers in a biofluid. One example device for electrochemical monitoring of one or more analytes in a biofluid includes a substrate and at least two microneedles coupled to the substrate. Each microneedle in the at least two microneedles includes a protruded needle structure and an electrode probe structure. The electrode probe structure of a first microneedle in the at least two microneedles includes an aptamer sequence which is specific for a first analyte and the electrode probe structure of the first microneedle is operable as a working electrode for detection of the first analyte using a first electrochemical detection technique.

The presence of analytes can be detected in the bodily fluid using Electrochemical Impedance Spectroscopy (EIS) or Electrochemical Capacitance Spectroscopy (ECS) in devices, such as handheld point-of-care devices. The devices, as well as systems and methods, utilize using Electrochemical Impedance Spectroscopy (EIS) or Electrochemical Capacitance Spectroscopy (EIS) in combination with an antibody or other target-capturing molecule on a working electrode. Imaginary impedance or phase shift, as well as background subtraction, also may be utilized.

A device, liquid handling cartridge and related method for detecting the presence or absence of a chemical or biological target within a sample. The method includes the steps of: providing an electrochemical cell with a first electrode module and a second electrode; providing an electronic component between the first electrode module and the second electrode; introducing the sample into the electrochemical cell; measuring the potential difference between the first electrode module and second electrode; and confirming the presence of the chemical or biological target if the measured potential difference exceeds a predetermined threshold value.

A biomolecule is more easily and reliably reciprocated in a nanopore. An adapter molecule that directly or indirectly binds to a biomolecule to be analyzed comprises a three-dimensional structure formation domain consisting of a single-stranded nucleotide.

Disclosed in the embodiments of the present application are a microelectrode of a gene sequencing chip, a manufacturing method therefor, and a gene sequencing chip. The microelectrode comprises a substrate, a current collector layer formed on the substrate, and an electrode layer formed on the current collector layer; the current collector layer comprises a transition metal thin film or a nitride thin film thereof or a composite thin film of a transition metal and nitride thereof, and the electrode layer comprises a nitrogen oxide thin film of the transition metal, which is formed on the transition metal thin film or the nitride thin film thereof or the composite thin film of the transition metal and nitride thereof The embodiments of the present application improve the per unit area voltage driving capabilities of a microelectrode in a gene sequencing chip, can meet requirements for an ultra-high number of cycles, and improve the throughput and stability of a gene sequencing chip.