Electrochemical Biosensor Enhanced With Graphite Ink and Multiwalled Carbon Nanotube for High Sensitivity Detection of Serotonin

Serotonin plays a crucial role in regulating a broad range of physi-ological and psychological functions, and an imbalance in serotonin levels can trigger the pathogenesis of various diseases. Thus, monitoring serotonin levels is vital for the early detection of multiple diseases. We have developed a cost-effective and efficient wearable biosensor using graphite and carbon nanotube as working electrode materials for detecting low concentrations of serotonin solutions. The graphite electrode modified with multiwalled carbon nanotube (MWCNT) exhibited excellent electrochemical sensing performance in serotonin detection, compared with commonly used carbon paste electrodes coated with MWCNT. Quantitative detection of serotonin with the graphite sheet electrode/graphite ink/MWCNT is performed using differential pulse voltammetry, and a linear range of 100–900 nM with a minimum detection limit of 45 nM was achieved.