Biocompatible PEDOT:Nafion composite electrode coatings for selective detection of neurotransmitters in vivo.

ABSTRACT: A Nafion and poly(3,4-ethylenedioxythiophene) (PEDOT) containing composite polymer has been electropolymerized on carbon-fiber microelectrodes with the goal of creating a mechanically stable, robust, and controllable electrode coating that increases the selectivity and sensitivity of in vivo electrochemical measurements. The coating is deposited on carbon-fiber microelectrodes by applying a triangle waveform from +1.5 V to -0.8 V and back in a dilute solution of ethylenedioxythiophene (EDOT) and Nafion in acetonitrile. Scanning electron microscopy demonstrated that the coating is uniform and ?100 nm thick. Energy-dispersive X-ray spectroscopy demonstrated that both sulfur and fluorine are present in the coating, indicating the incorporation of PEDOT (poly(3,4-ethylenedioxythiophene) and Nafion. Two types of PEDOT:Nafion coated electrodes were then analyzed electrochemically. PEDOT:Nafion-coated electrodes made using 200 ?M EDOT exhibit a 10-90 response time of 0.46 ± 0.09 s versus 0.45 ± 0.11 s for an uncoated fiber in response to a 1.0 ?M bolus of dopamine. The electrodes coated using a higher EDOT concentration (400 ?M) are slower with a 10-90 response time of 0.84 ± 0.19 s, but display increased sensitivity to dopamine, at 46 ± 13 nA/?M, compared to 26 ± 6 nA/?M for the electrodes coated in 200 ?M EDOT and 13 ± 2 nA/?M for an uncoated fiber. PEDOT:Nafion-coated electrodes were lowered into the nucleus accumbens of a rat, and both spontaneous and electrically evoked dopamine release were measured. In addition to improvements in sensitivity and selectivity, the coating dramatically reduces acute in vivo biofouling.

SUBMITTER: Vreeland RF 

PROVIDER: S-EPMC4902006 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature