Abstract: An extracellular potential measuring device capable of simply and highly reliably detecting a change in a minute electrical signal emitted by a biological sample, and an extracellular potential measuring method using the device, and an apparatus comprising the device, are provided. The extracellular potential measuring device measures an extracellular potential with great precision and a high output. The device comprises at least one well comprising means for holding a cell provided on a substrate, a measuring electrode for detecting an electrical signal of each of the at least one well, and a reference electrode. The cell holding means comprises at least one depression provided within the well, and has a throughhole at a bottom surface thereof, the throughhole being linked to means for suctioning the cell.

Abstract: A device for detecting a physicochemical change in a biological sample comprising at least one measuring electrode provided by causing a conductive material to enter into a porous film, and a conductor connected to the measuring electrode.

Abstract: This relates to methods for the detection of psychoactive compounds in an in vitro neuronal tissue sample by detecting oscillations of extracellular voltage desirably before and after the introduction of a candidate sample onto an in vitro neuronal tissue sample and for devices useful in practicing the methods. Analysis of the extracellular voltage parameters leads to indication of the presence of psychoactive material in the candidate sample and information as to its pharmacological activity and/or composition. Further, it relates to a process of initiating and maintaining the presence of repetitive neuronal activity within the in vitro sample. Additionally, this includes a method for the stimulation of or initiation of repetitive neuronal activity, e.g.

Abstract: A method of observing a physical and chemical property of a tissue or cell by using an apparatus which comprises at least a cell culturing means, an environment conditioning means, an observing means and a comparing means, comprising the steps of (A) culturing the tissue or cell by the cell culturing means, (B) maintaining a first physical and chemical environment around the tissue or cell by the cell culturing means, (C) observing a first physical and chemical property of the tissue or cell in the first physical and chemical environment by the observing means, (D) changing the first physical and chemical environment to a second physical and chemical environment by the environment conditioning means, (E) observing a second physical and chemical property of the tissue or cell in the second physical and chemical environment by the observing means, and (F) comparing the first physical and chemical property of the tissue or cell with the second physical and chemical property of the tissue or cell by the comparing

Abstract: A two-dimensional sensor is described including a substrate having a Si layer, a SiO2 layer and a Si3N4 layer. On the surface of the Si back side, a thin film is formed by vapor deposition for making an effect electrode. On the surface of the Si3N4 front side, a fence is attached for containing a sample cell, culture medium and a reference electrode. This sensor is placed in an incubator and a bias voltage is applied between the effect and reference electrodes. When a high frequency modulated laser beam irradiates a spot on the back side of the sensor substrate, a signal of AC photocurrent is obtained from the effect electrode. This signal corresponds to a potential alteration due to the cell activity substantially at the spot. The signal is processed in a computer. Therefore, the beam spot size and location, corresponding to the size and the location of the measurement electrode, can be adjusted easily by focusing or moving the laser beam.

Abstract: A two-dimensional sensor includes a photoconductive layer whose conductivity increases at a light-irradiated spot, an insulating layer formed on the front surface of the photoconductive layer, an effect electrode formed on the back surface of the photoconductive layer, and a fence as a cell holder attached to the surface of the insulating layer for containing a cell, culture medium and a reference electrode. The sensor is placed in an incubator and a bias voltage is applied between the effect and reference electrodes. When a laser beam irradiates a spot of the back surface of the sensor, a signal is obtained from the effect electrode. This signal corresponds to a potential alteration due to the cell activity substantially at the laser-irradiated spot. The signal is processed in a computer. The beam spot size and location, corresponding to the size and the location of the measurement electrode, can be changed or adjusted easily by focusing or moving the laser beam.

Abstract: A planar electrode which enables multi-point simultaneous stimulation and recording of nerve cells over a long time is provided, which also has excellent response property. An ITO film is evaporated on the whole surface of an insulating substrate of the hard glass, and the ITO film is etched so that the central portion of each electrode is located on each intersection of 8.times.8 lattices, the center-to-center distances of nearest electrodes of each electrode are equal, and a lead wire is stretched radially. Then, for an insulating layer, negative photo-sensitive polyimide is spin-coated, and an insulating layer pattern is exposure-formed so that a 50 .mu.ms square hole is produced at the center of each electrode. Furthermore, to the exposed portion of each electrode (that is, the inside of the 50 .mu.ms square), Ni is evaporated in a film thickness of 500 nm, which is followed by evaporating gold (50 nm) and platinum black (about 1 .mu.m).

Abstract: This invention relates to a low impedance cell potential measuring electrode assembly typically having a number of microelectrodes on an insulating substrate and having a wall enclosing the region including the microelectrodes. The device is capable of measuring electrophysiological activities of a monitored sample using the microelectrodes while cultivating those cells or tissues in the in the region of the microelectrodes. The invention utilizes independent reference electrodes to lower the impedance of the overall system and to therefore lower the noise often inherent in the measured data. Optimally the microelectrodes are enclosed by a physical wall used for controlling the atmosphere around the monitored sample.

Abstract: A planar electrode which enables multi-point simultaneous stimulation and recording of nerve cells over a long time is provided, which also has excellent response property. An ITO film is evaporated on the whole surface of an insulating substrate of the hard glass, and the ITO film is etched so that the central portion of each electrode is located on each intersection of 8.times.8 lattices, the center-to-center distances of nearest electrodes of each electrode are equal, and a lead wire is stretched radially. Then, for an insulating layer, negative photo-sensitive polyimide is spin-coated, and an insulating layer pattern is exposure-formed so that a 50 .mu.ms square hole is produced at the center of each electrode. Furthermore, to the exposed portion of each electrode (that is, the inside of the 50 .mu.ms square), Ni is evaporated in a film thickness of 500 nm, which is followed by evaporating gold (50 nm) and platinum black (about 1 .mu.m ).

Abstract: A cell potential measurement apparatus, which uses a planar electrode enabling a multi-point simultaneous measurement of potential change arising from cell activities, is provided which can conduct measurements accurately and efficiently as well as can improve convenience of arranging measurement results.

Abstract: This invention relates to a low impedance cell potential measuring electrode assembly typically having a number of microelectrodes on an insulating substrate and having a wall enclosing the region including the microelectrodes. The device is capable of measuring electrophysiological activities of a monitored sample using the microelectrodes while cultivating those cells or tissues in the in the region of the microelectrodes. The invention utilizes independent reference electrodes to lower the impedance of the overall system and to therefore lower the noise often inherent in the measured data. Optimally the microelectrodes are enclosed by a physical wall used for controlling the atmosphere around the monitored sample.