Microelectrodes have shown outstanding performance in neural signal recording, neural stimulation and electrochemical sensing1,2. Compared with their micro-sized counterparts, microelectrodes normally exhibit improved signal-to-noise ratio, fast response time and can work with limited sample volumes. Microelectrodes are required to have good biocompatibility, low electrical impedance and long-term stability in many biomedical applications. Carbon fibres are manufactured from polymeric precursor fibres through carbonization, and high carbon content makes carbon fibres electrically conductive, corrosion resistant, biologically safe and inert3. Therefore, carbon fibre has been considered as an ideal candidate for making microelectrodes.
In this work, single carbon fibres were loaded into capillary tubes and fabricated into microelectrodes. The surface of the microelectrodes was functionalized with electrochemically reduced graphene oxide (rGO) sheets, decorated with carbon dots (CDs). It has been demonstrated that this surface modified microelectrode could achieve a high sensitivity and selectivity in detecting dopamine (DA), in the presence of ascorbic acid (AA) and uric acid (UA).