A method of using a graphite electrode to measure a concentration of glucose or methionine from a biological sample is described. A mechanical pencil lead may be used as the graphite electrode, and the biological sample may come from a patient's serum. The glucose or methionine may produce a peak current response within a range of 0.4-0.8 V when the sample is subjected to linear scan voltammetry.

To provide a potential measurement device capable of keeping a temperature of a cell and/or a culture solution (in particular, a temperature of a cell) constant. Provided is a potential measurement device including a semiconductor substrate; a wiring layer on the semiconductor substrate; a first electrode on the wiring layer; and a second electrode configured to detect an action potential of a cell on the wiring layer. A temperature measurement unit is formed on the semiconductor substrate. A heat conduction unit and a plurality of wirings connected to the second electrode are formed in the wiring layer.

To provide a potential measurement device capable of keeping a temperature of a cell and/or a culture solution (in particular, a temperature of a cell) constant. Provided is a potential measurement device including a semiconductor substrate; a wiring layer on the semiconductor substrate; a first electrode on the wiring layer; and a second electrode configured to detect an action potential of a cell on the wiring layer. A temperature measurement unit is formed on the semiconductor substrate. A heat conduction unit and a plurality of wirings connected to the second electrode are formed in the wiring layer.

A CuV.sub.2O.sub.6-based photoelectric sensor is prepared through the following steps: acquiring a CuV.sub.2O.sub.6 thin film through a direct-current reactive magnetron co-sputtering method; and loading an 8-hydroxyquinoline solution on the CuV.sub.2O.sub.6 thin film through a spin-coating method to acquire an 8-hydroxyquinoline-modified CuV.sub.2O.sub.6 photoelectric sensor. The 8-hydroxyquinoline-modified CuV.sub.2O.sub.6 photoelectric sensor has a good anti-interference capability in the detection of arginine; it is easy to realize the low-cost mass production of CuV.sub.2O.sub.6 photoelectrodes through a developed direct-current reactive magnetron sputtering coating method; and a sensor device is low in cost, simple, portable, and easy to use, and has an application value in food safety and health and hygiene detection.

The invention is directed to apparatus and methods for delivering multiple reagents to, and monitoring, a plurality of analytical reactions carried out on a large-scale array of electronic sensors under minimal noise conditions. In one aspect, the invention provides method of improving signal-to-noise ratios of output signals from the electronic sensors sensing analytes or reaction byproducts by subtracting an average of output signals measured from neighboring sensors where analyte or reaction byproducts are absent. In other aspects, the invention provides an array of electronic sensors integrated with a microwell array for confining analytes and/or particles for analytical reactions and a method for identifying microwells containing analytes and/or particles by passing a sensor-active reagent over the array and correlating sensor response times to the presence or absence of analytes or particles. Such detection of analyte- or particle-containing microwells may be used as a step in additional noise reduction methods.

A method of measuring signals from a surface. The method comprises: placing on the surface a flexible sensing device having an array of coated electrodes, wherein at least one electrode of the array is metallic and is at least partially coated by a polymer; and collecting signals from the sensing device.

Various cell analysis systems of the present teachings can measure the electrical and metabolic activity of single, living cells with subcellular addressability and simultaneous data acquisition for between about 10 cells to about 500,000 cells in a single analysis. Various sensor array devices of the present teachings can have sensor arrays with between 20 million to 660 million ChemFET sensors built into a massively paralleled array and can provide for simultaneous measurement of cells with data acquisition rates in the kilohertz (kHz) range. As various ChemFET sensor arrays of the present teachings can detect chemical analytes as well detect changes in cell membrane potential, various cell analysis systems of the present teachings also provide for the controlled chemical and electrical interrogation of cells.

Various cell analysis systems of the present teachings can measure the electrical and metabolic activity of single, living cells with subcellular addressability and simultaneous data acquisition for between about 10 cells to about 500,000 cells in a single analysis. Various sensor array devices of the present teachings can have sensor arrays with between 20 million to 660 million ChemFET sensors built into a massively paralleled array and can provide for simultaneous measurement of cells with data acquisition rates in the kilohertz (kHz) range. As various ChemFET sensor arrays of the present teachings can detect chemical analytes as well detect changes in cell membrane potential, various cell analysis systems of the present teachings also provide for the controlled chemical and electrical interrogation of cells.

A technique capable of appropriately detecting a timing for replacement of a liquid ejection head is to be provided. A liquid ejection head including: a first electrode configured to protect an electrothermal conversion element that ejects a liquid from an ejection port and to be capable of eluting into the liquid by an electrochemical reaction with the liquid; and a second electrode installed so as to be electrically connectable to the first electrode via the liquid, wherein a voltage is applied to cause the second electrode to generate the electrochemical reaction with the first electrode, so that the first electrode is eluted into the liquid, wherein polarities can be reversed between the first electrode and the second electrode for applying the voltage, and wherein wiring resistance in a circuit including a plurality of second electrodes as a part of wiring can be measured.

A technique capable of appropriately detecting a timing for replacement of a liquid ejection head is to be provided. A liquid ejection head including: a first electrode configured to protect an electrothermal conversion element that ejects a liquid from an ejection port and to be capable of eluting into the liquid by an electrochemical reaction with the liquid; and a second electrode installed so as to be electrically connectable to the first electrode via the liquid, wherein a voltage is applied to cause the second electrode to generate the electrochemical reaction with the first electrode, so that the first electrode is eluted into the liquid, wherein polarities can be reversed between the first electrode and the second electrode for applying the voltage, and wherein wiring resistance in a circuit including a plurality of second electrodes as a part of wiring can be measured.