Study of buffer ion concentration in fast-scan cyclic voltammetry method using nano-graphitic sensors

Point-of-Care diagnostic and implantable devices have been on the rise over the last twenty years due to their numerous benefits in healthcare delivery. In this context, nano-graphitic carbon sensors, along with other types of carbon-based sensors, have emerged as optimal candidates, because they can be assembled into densely packed arrays of microelectrochemical sensors with high performance in neurotransmitters detection. The fast-Scan cyclic voltammetry method is one of the best-known methods for measuring electrochemically active neurotransmitters. One of the important aspects of electrochemical measurements is the buffer solution used in the electrochemical sensing of neurotransmitters. However, the effect of the buffer solution has not yet been studied in FSCV measurements. The aim of this thesis is to investigate how buffer concentration can affect the characteristics of neurotransmitters such as sensitivity or impedance of the sensors. Several experiments were performed in which bioanalytes with different characteristics (dopamine, serotonin and melatonin) were dissolved in a buffer solution (phosphate-buffered saline), varying the concentration of the latter. These measurements were performed with the fast-scan cyclic voltammetry technique and using a custom-made experimental apparatus. The sensor was combined with an integrated readout circuit. The current signal was measured and then digitised using a data acquisition instrument. The results were extracted and analysed with custom-made programs. With this work, the understanding of the electrochemical behaviour of neurotransmitters during sensing experiments can be improved for future applications.