A precision bipolar digital-to-analog converter (DAC) that provides a bipolar current output having a substantially fixed zero center point is provided. The DAC includes digital-to-analog converter circuitry configured to provide, responsive to a reference signal indicative of the digital data, a first analog current signal having a first potential and a second analog current signal having a second potential, subtractor circuitry configured to provide a bipolar current signal by subtracting the second analog current signal from the first analog current signal, the bipolar current signal having a zero center point, and first control circuitry electrically coupled to the subtractor circuitry and to the digital-to-analog converter circuitry, and configured to modify the second potential so that the second potential equals the first potential.

Process for producing bands for biological measurements on the basis of flexible circuits on a carrier strip, provided with a flexible insulating substrate provided, on at least one of its faces, with conductive tracks, contact pads and electrodes, includes the application, to said face, of masking means leaving the contact pads and/or the electrodes of the band visible and the selective deposition of a layer of noble metal on said contact pads and electrodes through said masking means.

Devices for detecting a particle in a fluid sample are provided. The device includes a segmented microfluidic conduit configured to carry a flow of a fluid sample, where the conduit includes one or more nodes and two or more sections, and a node is positioned between adjacent sections of the conduit. The device also includes a detector configured to detect a change in current through the conduit. Also provided are methods of using the devices as well as systems and kits that include the devices. The devices, systems and methods find use in a variety of different applications, including diagnostic assays.

The invention includes compositions, devices, and methods for analyzing a polymer and/or polymer unit. The polymer may be a homo or hetero-polymer such as DNA, RNA, a polysaccharide, or a peptide. The device includes electrodes that form a tunnel gap through which the polymer can pass. The electrodes are functionalized with a reagent attached thereto, and the reagent is capable of forming a transient bond to a polymer unit. When the transient bond forms between the reagent and the unit, a detectable signal is generated and used to analyze the polymer.

An atomic level deposition for mass functionalization of a cavity filled with a pathogen sensitive antibody reagent to functionalize each Biosensor using atomic level vapor phase deposition enables high volume production of this sensor technology. A biosensor has a first substrate and a second substrate with a cavity formed in the first substrate to form a membrane. Holes is formed through the second substrate. An aluminum oxide layer is formed over the cavity and into the holes to form cores. The cavity is filled with a pathogen sensitive antibody reagent. A biofluid sample with the pathogen is deposited over the membrane. The biofluid is drawn through the cores to mix with the antibody reagent. The antibodies combine with the pathogen to change the impedance along the current path. The presence of the pathogen changes the ionic current flow through the biosensor for a positive detection of the pathogen.

Provided is a method for electrochemically detecting a catalytic reaction product that is generated by progress of a catalytic reaction in a first lump of liquid and dissolved in the first lump of liquid, the method including: containing the first lump of liquid and a second lump of liquid in a liquid bath, the second lump of liquid being in contact with the first lump of liquid to form a liquid-liquid interface and not dissolving the catalytic reaction product; arranging a working electrode in the first lump of liquid, and arranging a counter electrode and a reference electrode in the second lump of liquid; and detecting a current flowing through the working electrode by an oxidation or reduction reaction of the catalytic reaction product at the working electrode.

A working electrode for a subcutaneous sensor for use with a continuous biological monitor for a patient is disclosed. The working electrode includes a conductive substrate and a carbon-enzyme layer on the conductive substrate. The carbon-enzyme layer includes a polyurethane or silicone crosslinked with an acrylic polyol, and an enzyme fully entrapped by the polyurethane or silicone crosslinked with the acrylic polyol. The enzyme is selected according to a biological function to be monitored. The carbon-enzyme layer also includes a carbon material. The carbon-enzyme layer is electrically conductive and facilitates a generation of either peroxide or electrons within the carbon-enzyme layer responsive to reacting the enzyme with a target biologic from blood of the patient.

The invention encompasses novel methods of operating electrochemical sensors such as aptamer-based sensors to analyze complex samples, such as flowing whole blood both in vitro or in vivo. In such environments, electrochemical sensors are often subject to drift, which complicates the interpretation of sensor output in terms of target concentration. The method of the invention utilizes a dual-reporter recognition element that generates a first, sensing current that is responsive to target binding and to environmental factors and a second, reference current that is only affected by environmental factors. The reference current provides information about environmentally-induced drift, which allows the drift effect to be subtracted out. By removing drift artifacts, electrochemical sensors may be deployed to analyze complex samples, such as whole blood, in vivo.

The present disclosure relates to biosensors (10) having a receptor layer (5) and a mediator layer (6), the receptor layer including ethylene receptor molecules. The present disclosure also relates to sensor units (20) comprising one or more biosensors (10) and a controller (11). In some embodiments, one or more sensor units (20) may be in wireless communication with a receiver module or a network gateway.

The present disclosure relates to compositions, methods and test devices for determining the presence of active leukocyte cells, for example, by using novel LE and/or HNE substrates in an electrochemical assay.