A dual switched-capacitor integrator architecture for versatile, real-time amperometric biosensing

Abstract

In this paper, a versatile, re-programmable, current-input bioinstrumentation board is presented for electrochemical amperometric measurements. The proposed instrument has been fabricated on a six layer printed circuit board (PCB) and exploits dual switched-capacitor (SC) integration and sampleand-hold (SH) techniques. It comprises off-the-shelf switch and amplifier ICs and a commercially available FPGA-based DSP unit for digital signal control and synchronisation. It features eight amperometric channels, has a dynamic current range of 100dB, can be powered-up by a USB port or a 5V battery and is portable, with dimensions of 110×110 mm 2. An onboard digital-to-analog converter (DAC) combined with standard three-electrode potentiostats can provide precise, programmable biasing voltages to eight amperometric biosensors simultaneously. Validation of the robustness and accuracy of the proposed system is demonstrated by proof-of-concept amperometric measurements using a high-precision Keithley 6221 current source and NaCl solution on a PCB-based sensor.