A mutant cytochrome protein originated from a cytochrome protein having three heme-binding domains, which mutant cytochrome protein lacks the first heme-binding domain and the second heme-binding domain as counted from the N-terminus, is provided. The mutant cytochrome protein may lack a region(s) containing the first and second heme-binding domains.

Methods, devices, and systems for analyte analysis using a nanopore are disclosed. The methods, devices, and systems utilize a first and a second binding member that each specifically bind to an analyte in a biological sample. The method further includes detecting and/or counting a cleavable tag attached to the second binding member and correlating the presence and/or the number of tags to presence and/or concentration of the analyte. Certain aspects of the methods do not involve a tag, rather the second binding member may be directly detected/quantitated. The detecting and/or counting may be performed by translocating the tag/second binding member through a nanopore. Devices and systems that are programmed to carry out the disclosed methods are also provided. Also provided herein are instruments that are programmed to operate a cartridge that includes an array of electrodes for actuating a droplet and further includes an electrochemical species sensing region. The instrument may be used to analyse a sample in a cartridge that includes an array of electrodes for actuating a droplet and further includes a nanopore layer for detecting translocation of a tag/second binding member through nanopore. An instrument configured to operate a first cartridge that includes an array of electrodes for actuating a droplet and further includes an electrochemical species sensing region and a second cartridge that includes an array of electrodes for actuating a droplet and further includes a nanopore layer for detecting translocation of a tag/second binding member through nanopore is disclosed. An instrument configured to operate a cartridge that includes an array of electrodes for actuating a droplet, an electrochemical species sensing region, and a nanopore layer for detecting translocation of a tag/second binding member through nanopore is disclosed.

The present invention is a device for detecting the presence of an analyte in a sample. The device comprises (i) at least one electrode, (ii) an oxidase enzyme, and (iii) first and second redox mediators.

A microneedle array device includes a substrate and an array of microneedles on the substrate. Each microneedle includes a redox enzyme and redox mediator and an electrically conductive layer on the substrate. The electrically conductive layer may extend partway up each microneedle exposing the tip thereof.

Provided is a novel mediator. The present invention relates to a novel mediator, and an electrode modifying agent and an electron transfer promoting agent comprising the mediator, an electrode, a battery, a composition, and an enzyme sensor comprising the electrode modifying agent or the electron transfer promoting agent, and a method using any of these.

A non-leaching mediator may include a polymer having a polymeric backbone, and a plurality of phenothiazine groups bonded to the polymeric backbone. The plurality of phenothiazine groups may include at least one of a phenothiazine group having the general formula (IV): ##STR00001##
and salts thereof, where n is about 9 and R represents the polymeric backbone to which the phenothiazine group is bonded, and a phenothiazine group having the general formula (V): ##STR00002##
and salts thereof, where n is about 9 and R represents the polymeric backbone to which the phenothiazine group is bonded.

Fluid collection devices, analysis instruments and methods for making and using same are disclosed. The fluid collection device is provided with a device and an electrochemical cell. The device has first and second walls defining a microfluidic channel, and a sample application port communicating with the microfluidic channel. The first wall and the second wall are spaced a distance less than 150 microns. The electrochemical cell is disposed on the first wall to contact a sample travelling through the microfluidic channel. The electrochemical cell comprising molecule receptors such that a physical property of the first electrochemical cell is effected upon one or more of the molecule receptors binding to an electroactive species within the sample.

Device and methods for use in a biosensor comprising a multisite array of test sites, the device and methods being useful for modulating the binding interactions between a (biomolecular) probe or detection agent and an analyte of interest by modulating the pH or ionic gradient near the electrodes in such biosensor. An electrochemically active agent that is suitable for use in biological buffers for changing the pH of the biological buffers. Method for changing the pH of biological buffers using the electrochemically active agents. The methods of modulating the binding interactions provided in a biosensor, analytic methods for more accurately controlling and measuring the pH or ionic gradient near the electrodes in such biosensor, and analytic methods for more accurately measuring an analyte of interest in a biological sample.

Provided is a biological substance detection sensor used in an electrochemical measurement method and allowing high-precision measurement by reducing a blank current. A biological substance detection sensor of the present invention for analyzing a component in a testing solution using a mediator includes at least: an insulating substrate; a conductive part formed on a surface of the insulating substrate and including at least one pair of a working electrode and a counter electrode; and a reagent part disposed in contact with or in a vicinity of the conductive part and including at least one of protein and the mediator. The reagent part further includes at least one additive selected from the group consisting of a halide and/or a pseudo halide.

A mutant cytochrome protein originated from a cytochrome protein having three heme-binding domains, which mutant cytochrome protein lacks the first heme-binding domain and the second heme-binding domain as counted from the N-terminus, is provided. The mutant cytochrome protein may lack a region(s) containing the first and second heme-binding domains.