Highly Sensitive Dopamine Detection Using a Bespoke Functionalised Carbon Nanotube Microelectrode Array

Understanding how the brain works requires developing advanced tools that allow measurement of bioelectrical and biochemical signals, including how they propagate between neurons. The introduction of nanomaterials as electrode materials has improved the impedance and sensitivity of microelectrode arrays (MEAs), allowing high quality recordings of single cells insitu using electrode diameters of <= 20 mu m. MEAs also have the potential to measure electroactive biological molecules insitu, such as dopamine, a neurotransmitter in the nervous system. Thus, this work focused on fabricating a functionalised carbon nanotube (CNT)-based MEA to demonstrate its potential for future measurement of small signals generated from excitable cells. To this end, the functionalised CNT MEA has recorded one of the lowest electrochemical interfacial impedances available in the literature, 2.8 +/- 0.2k Omega, for an electrode of its geometric surface area. Electrochemical detection of dopamine revealed again one of the best sensitivity values per area available in the literature, 9.48 mu A mu M(-1)mm(-2). Additionally, a limit of detection of 7nM was recorded for dopamine using the functionalised CNT MEA, with selectivity against common electrochemical interferents such as ascorbic acid. These results indicate improvement beyond currently available MEAs, along with the feasibility of using these devices for multi-site detection of physiologically relevant electroactive biomolecules