A medical device for blood enzyme monitoring based on an electronic board for biasing, conditioning, and A/D conversion of current signals from a graphene-based FET biosensor array

The increasing demand for portable and reliable point-of-care diagnostic systems has driven the development of advanced biosensing platforms capable of rapid and decentralized biomarker detection in biological fluids (blood, saliva, etc.). In this context, graphene field-effect transistor (gFET) biosensors represent a promising solution due to their high sensitivity, label-free operation, and compatibility with miniaturized diagnostic devices. This paper presents the design and realization of an electronic readout board for biasing, signal conditioning, and analog-to-digital (A/D) conversion of current signals from a gFET sensor array. The proposed board is designed to acquire signals from a 12-gFET biosensor array integrated with a microfluidic platform to detect biological analytes in blood samples. The developed architecture integrates power supply, energy harvesting, biasing, conditioning, and A/D conversion sections into a compact board. To reduce circuit complexity and board area, a shared-biasing architecture based on a multiplexer and a demultiplexer enables sequential selection and biasing of individual gFETs without duplicating the signal conditioning section. The designed board is powered by a Li-ion battery, recharged by a solar-harvesting section or a 12 VDC power supply. Finally, an Arduino Nano 33 BLE MCU board collects the digitized data, performs signal processing, and wirelessly sends the concentration data to a PC or tablet via BLE. Functional tests indicate the correct operation of all board sections. Future work will include characterization of gFET arrays with the proposed readout board.