Integration of Engineered Nano-Graphitic Carbon Sensors and Detection Circuitry for Enhanced Dopamine Sensing

In recent years, the rapid advancement of point-of-care (POC) and wearable/implantable devices has brought about significant transformations in healthcare delivery. These innovative technologies provide real-time monitoring, diagnosis, and treatment capabilities, thereby enhancing patient care, improving disease management, and reducing healthcare costs. Within this context, carbon sensors have emerged as promising tools due to their high electron mobility, excellent thermal conductivity, and large surface area. Among them, nano-graphitic (NG) carbon sensors have demonstrated success in constructing densely packed arrays of miniaturized electrochemical sensors at the micron-scale level, exhibiting exceptional performance in detecting low concentrations of bio-analytes. The aim of this work is divided in two. The first is to establish protocols for the fabrication of metal-induced NG sensors and execute proof-of-concept experiments to investigate the diverse effects of various parameters related to the production process on the structural and morphological characteristics of these sensors, which were analyzed through Raman and optical analysis during this phase. The second is to develop and implement the necessary detection circuitry for interfacing with the biosensors. The circuitry is responsible for signal amplification and digitization. Two potential analog front-end (AFE) circuits were considered, both of which were implemented on a printed circuit board (PCB) and subsequently compared and tested. Additionally, a second version of the AFE was designed to enable multichannel reading. Furthermore, concepts for the digitization component of the circuit (analog-to-digital converter, ADC) and its mechanisms will be explored to gain a deeper understanding of key project parameters. Finally some fast scan cyclic voltammetry (FSCV) measurements have been made in a microfluidic chamber in order to detect note concentrations of dopamine in a phosphate buffered saline solution (PBS) to confirm the capability of the produced biosensors. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images have been taken to check the morphology and roughness.