Abstract: A reusable test unit is disclosed for testing the functionality of a portable blood analyzer, and particularly the interface between the high-impedance electrochemical sensors and the instrument. Signals are generated to simulate amperometric, conductimetric, and potentiometric sensors. Circuitry permits detection and discrimination between failures from damaged CMOS amplifiers and failures from leakage currents in contaminated connectors. The test unit may be configured to be insertable into the instrument to fit mechanically in the same fashion as a disposable sensor device. A scheme for three-dimensional routing of guard lines on a circuit board is disclosed for guarding against coupling between closely space traces and connector pads.

Abstract: A method of determining the concentration of a preselected analyte species present in a sample fluid is disclosed, which method comprises: (a) providing an external computational means, a reference electrode and at least one substantially dry-stored sensor capable of exhibiting a response to changes in the concentration of a preselected analyte species before the sensor attains full equilibrated wet-up; (b) establishing electrical contact between the sensor, reference electrode and external computational means; (c) contacting the sensor and reference electrode with a calibrant fluid; (d) performing a first signal measurement in a first time window in the presence of the calibrant fluid; (e) displacing the calibrant fluid after performing the first signal measurement; (f) contacting the sensor and reference electrode with a sample fluid; (g) performing a second signal measurement in a second time window in the presence of the sample fluid; and (h) relating the first and second signal measurements to determine

Abstract: A system comprising a disposable device and hand held reader can perform a variety of electrochemical measurements on blood or other fluids. In operation, a fluid sample is drawn into the disposable device through an orifice by capillary action. The orifice is sealed off and the disposable device is inserted into the reader. The reader which controls the test sequence and flow of fluid causes a calibrant pouch located inside the device to be pierced, releasing the calibrant fluid to flow across the sensor arrays to perform calibration. Next an air bladder located in the device is depressed, forcing the sample across the sensors where measurements are performed and read by the reader which performs the calibrations. Once the measurements are made, the device can be withdrawn from the reader and discarded.

Abstract: A plurality of uniform microfabricated sensing devices are produced by establishing a plurality of base sensors on a substrate wafer, forming over at least a portion of each base sensor a permselective layer, superimposing a photoformable proteinaceous photoresist layer over a substantial portion of the permselective layer, and forming a topmost layer of an immobilized ligand receptor. The ligand receptor and corresponding ligand may be immunoreactive species.

Abstract: An electrode for measuring the activity of ionic species. The electrode comprises a material which is chemically sensitive to at least one ionic species. The material comprises an insulating component and a conductive component of lower resistivity than the insulating component. The insulating component has a density of proton binding sites sufficiently large to be sensitive to the ionic species. The conductive component comprises particles, the size of which are sufficiently small to modify the bulk conductive properties such that the susceptibility of the particles to redox interference in the operation of the electrode is decreased, while maintaining sufficient conductivity to operate in Faradaic electrode configurations. Illustratively, the insulating component is tantalum oxide, zirconium oxide or aluminum oxide and the conductive component is iridium, platinum, ruthenium, palladium, rhodium or osmium oxide.

Abstract: A fluidics head to facilitate the automatic testing of chemical and ionic sensing electronic circuit devices is provided. The fluidics head comprises a fluid confining cell having an open orifice capable of containing a known test fluid while the orifice is in leakproof engagement with sensing electronic circuit devices, an inlet and outlet opening capable of filling and discharging test fluids, and electrical probes capable of contacting the sensing electronic circuit devices so as to test the electrical response of the devices with the test fluids.

Abstract: An improved connector for connection to and identification and testing of electric components such as integrated circuits is described which features a number of spring biased contact elements normally in contacting relation with a shorting bar. When a particular component is placed in a specified physical relation to the connector, a combination of exposed electrical contacts and nonconductive elements on the component to be tested displace specified ones of the contact members away from the shorting bars, providing a connection pattern which can be detected. At the same time, test signals can be applied to the electric component to be tested. The circuit may be identified and its specific parameters identified and characterized in a single operation according to the invention. Advantageously, the shorting bar is grounded so that any static charge on the component to be tested is grounded before the contact elements are displaced from the shorting bar.

Abstract: An improved reference electrode is disclosed for use in potentiometric measurements of the amount of ions in an aqueous solution. The reference electrode illustratively comprises a metal member on a substrate, and a layer of a salt reversible to the ion X overlying the metal member. The reference electrode is overlaid by a quantity of an electrolyte, which may be a polymer gel having a salt including the ion X dispersed therein. This structure is overlaid by a membrane permeable to water but not to the ion X that extends beyond the portion of the electrolyte overlying the electrode, but leaves a portion of the electrolyte exposed. This assembly may be shipped dry. In use, when the electrode is disposed in an aqueous solution containing an ionic species to be measured, water permeates the membrane and "wets up" the electrolyte relatively quickly.