Enhanced dopamine detection sensitivity by PEDOT/graphene oxide coating on in vivo carbon fiber electrodes.
Dopamine (DA) is a monoamine neurotransmitter responsible for regulating a variety of vital life functions. In vivo detection of DA poses a challenge due to the low concentration and high speed of physiological signaling. Fast scan cyclic voltammetry at carbon fiber microelectrodes (CFEs) is an effective method to monitor real-time in vivo DA signaling, however the sensitivity is somewhat limited. Electrodeposition of poly(3,4-ethylene dioxythiophene) (PEDOT)/graphene oxide (GO) onto the CFE surface is shown to increase the sensitivity and lower the limit of detection for DA compared to bare CFEs. Thicker PEDOT/GO coatings demonstrate higher sensitivities for DA, but display the negative drawback of slow adsorption and electron transfer kinetics. The moderate thickness resulting from 25 s electrodeposition of PEDOT/GO produces the optimal electrode, exhibiting an 880% increase in sensitivity, a 50% decrease in limit of detection and minimally altered electrode kinetics. PEDOT/GO coated electrodes rapidly and robustly detect DA, both in solution and in the rat dorsal striatum. This increase in DA sensitivity is likely due to increasing the electrode surface area with a PEDOT/GO coating and improved adsorption of DA's oxidation product (DA-o-quinone). Increasing DA sensitivity without compromising electrode kinetics is expected to significantly improve our understanding of the DA function in vivo.
University of Pittsburgh, Department of Bioengineering, 3501 Fifth Ave., Pittsburgh, PA 15261, USA.
I Mitch
IM
Taylor
University of Pittsburgh, Department of Chemistry, 219 Parkman Ave., Pittsburgh, PA 15260, USA.
Elaine M
EM
Robbins
University of Pittsburgh, Department of Bioengineering, 3501 Fifth Ave., Pittsburgh, PA 15261, USA.
Kasey A
KA
Catt
University of Pittsburgh, Department of Bioengineering, 3501 Fifth Ave., Pittsburgh, PA 15261, USA.
Patrick A
PA
Cody
University of California, San Diego, Department of Bioengineering, 9500 Gilman Dr., La Jolla, CA 92093, USA.
Cassandra L
CL
Happe
University of Pittsburgh, Department of Bioengineering, 3501 Fifth Ave., Pittsburgh, PA 15261, USA. Electronic address: xic11@pitt.edu.
Xinyan Tracy
XT
Cui
D000818:Animals; D015374:Biosensing Techniques / Q000379:methods; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D003342:Corpus Striatum / Q000737:chemistry*; D004298:Dopamine / Q000032:analysis*; D055664:Electrochemical Techniques / Q000379:methods*; D004595:Electroplating; D006108:Graphite / Q000737:chemistry*; D057230:Limit of Detection; D008297:Male; D008839:Microelectrodes; D011108:Polymers / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley
D019086:Bridged Bicyclo Compounds, Heterocyclic; D011108:Polymers; C121383:poly(3,4-ethylene dioxythiophene); D006108:Graphite; D004298:Dopamine
Carbon fiber; Dopamine; FSCV; Graphene oxide; PEDOT