Methods and devices for measuring the status of oxidative stress on the surface or in a biological matrix involve use of at least one compound selected from NADH, NADPH, Cyt C (Fe.sup.2+) or H.sub.2O.sub.2.

We describe a soil chemistry sensor for in-situ soil chemistry sensing, the sensor comprising a probe incorporating a first, ion-selective electrode and a second, reference electrode, wherein said ion-selective electrode comprises a first-electrode housing defining a first lumen having an ion-selective plug towards a distal end, said first-electrode including a first conductor in a first electrolyte, wherein said reference electrode comprises a second electrode housing defining a second lumen having a porous reference electrode plug towards a distal end, said second electrode including a second conductor in a second electrolyte, wherein said ion-selective plug and said porous reference electrode plug are within 10 mm of one another, and wherein said porous reference electrode plug and said ion-selective plug each comprise a polymer.

A a chip and a method for producing the chip with a plurality of measurement regions which are provided with electrodes for electrically detecting reactions in which, in order to reliably separate the individual measurement regions from one another, a monolayer of a fluorosilane is formed on the chip surface which has strongly hydrophobic properties. Therefore, during spotting with a liquid, the drops of liquid applied by spotting can be reliably prevented from coalescing, and thus, causing mixing of the substances in the drops of liquid which are supposed to be immobilized in the measurement regions.

A a chip and a method for producing the chip with a plurality of measurement regions which are provided with electrodes for electrically detecting reactions in which, in order to reliably separate the individual measurement regions from one another, a monolayer of a fluorosilane is formed on the chip surface which has strongly hydrophobic properties. Therefore, during spotting with a liquid, the drops of liquid applied by spotting can be reliably prevented from coalescing, and thus, causing mixing of the substances in the drops of liquid which are supposed to be immobilized in the measurement regions.

A potentiometric sensor that includes a housing and working electrode is provided. The housing includes a reference electrode, a first hydrogel that contains a reference solution, and a salt bridge. The sensor is wearable and can be used for continuous on-body sweat measurements.

Provided is an electrolyte sensor that uses conductive elastomer electrodes. Examples of the intended analytes for sensor use include those found in urine, saliva, blood, feces, and spinal fluid, although other analytes exist for electrolyte detection. Conductive elastomer trace electrodes are separated by a channel or gap which can be bridged by an electrolyte and thereby complete an electrical circuit to an alarm or other circuitry. Channel or gap distances vary the level of electrical resistance associated with detecting certain analytes.

Provided is an electrolyte sensor that uses conductive elastomer electrodes. Examples of the intended analytes for sensor use include those found in urine, saliva, blood, feces, and spinal fluid, although other analytes exist for electrolyte detection. Conductive elastomer trace electrodes are separated by a channel or gap which can be bridged by an electrolyte and thereby complete an electrical circuit to an alarm or other circuitry. Channel or gap distances vary the level of electrical resistance associated with detecting certain analytes.

A chemical sensor may include an electrode array for electrically interfacing with a fluid sample. The sensor can apply an electrical potential to the sample in order to effect a current flow within the sample. The sensor can measure the resulting current through the sample and determine characteristics about the fluid sample from the current measurement. In one mode of operation of the sensor, the applied electrical potential can be controlled to cause desired electrochemical reactions, such as oxidation or reduction, to occur within the sample to determine the concentration of the oxidized or reduced sample constituent. In another mode of operation, the applied electrical potential causes a current to flow simply due to the conductivity of the sample. In various embodiments, the sensor comprises a controller and a switch for switching between various modes of operation and applying appropriate electric potentials to the sample.

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.

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.