Patent ID: 8855955
Filing Date: 2014-10-07
Classification: G01N,G01R

Abstract:
1. A process for reading electrical current of electrodes on a microarray of electrodes comprising the steps of: (a) providing a measurement system having a control system, an integration circuit, a microarray chamber, a plurality of voltage lines, an analog to digital converter connected to digital circuitry and analog circuitry, where the analog circuitry includes the integration circuit, where the digital circuitry is separate from the analog circuitry and includes the control system, where the control system, the integration circuit, and the microarray chamber are in circuit communication, where the microarray chamber contains a microarray having a plurality of electrodes in circuit communication with the control system and the integration circuit, where the voltage lines are switchably connectable to each electrode by the control system, where the integration circuit has a capacitance value, where the integration circuit has an integrating transimpedance amplifier having a positive input and a potentiometer circuit connected to the positive input via an operational amplifier; (b) initializing measurement by setting a measurement set of the electrodes to approximately ground, setting a counter electrode voltage of at least one counter electrode, and pausing for a steady state period, where the at least one counter electrode is in fluid communication with the measurement set of the electrodes; (c) measuring the current for each electrode of the measurement set of electrodes by (i) using a first voltage line to connect a measurement electrode to the integration circuit, the integration circuit having a reset switch, where the reset switch is in the closed position, (ii) pausing for an electrode settling period, (iii) opening the reset switch to measure and record a voltage response from the output of the integration circuit for a measurement time at a sampling rate, (iv) closing the reset switch, and (v) switching the measurement electrode back to a second voltage line; and (d) calculating the current of each of the electrodes of the measurement set.