Development of Glass-sealed Gold Nanoelectrodes for in vivo Detection of Dopamine in Rat Brain

In vivo monitoring of dopamine (DA) in cerebral nervous system with no traumatic brain injury is still a challenging work for reliably evaluating the role that DA plays in physical and cognitive functionality. In this work, to reduce the traumatic injury on the brain tissue, we develop a glass-sealed Au nanoelectrode (GSNE) with nanoscale physical dimention for cerebral DA detection. First, an Au microwire was sealed into the pre-thinned silica capillary. Then, the obtained Au/capillary assembly was pulled into two tips followed by polishing away the excess glass to expose the Au nanotip. The morphology of GSNE was characterized by scanning electron microscopy and transmission electron microscopy. The results showed that this nanoelectrode can be quickly fabricated with high reproducibility. By further electrodepositing cluster-like gold nanostructure on GSNE and modifying Nafion, amperometric detection of DA with high sensitivity and good selectivity were achieved on the Nafion-modified Au/GSNE. Moreover, the Nafion-modified Au/GSNE possessed advantages of easy tissue insertion and minimum tissue disturbance. Thus, the developed electrochemical nanosensor was successfully used for amperometrically monitoring DA level in the striatum of anesthetic rats.