Field-programmable gate array based controller for multi spot light-addressable potentiometric sensors with integrated signal correction mode

A light-addressable potentiometric sensor (LAPS) can measure the concentration of one or several analytes at the sensor surface simultaneously in a spatially resolved manner. A modulated light pointer stimulates the semiconductor structure at the area of interest and a responding photocurrent can be read out. By simultaneous stimulation of several areas with light pointers of different modulation frequencies, the read out can be performed at the same time. With the new proposed controller electronic based on a field-programmable gate array (FPGA), it is possible to control the modulation frequencies, phase shifts, and light brightness of multiple light pointers independently and simultaneously. Thus, it is possible to investigate the frequency response of the sensor, and to examine the analyte concentration by the determination of the surface potential with the help of current/voltage curves and phase/voltage curves. Additionally, the ability to individually change the light intensities of each light pointer is used to perform signal correction.

► Flexible up-scalable design of a light-addressable potentiometric sensor set-up.
► Utilisation of a field-programmable gate array to address LAPS measurement spots.
► Measurements in amplitude-mode and phase-mode for different pH solutions.
► Amplitude, phase & frequency behaviour of LAPS for single and multiple light stimulus.
► Signal calibration method by brightness control to compensated systematic errors.