09:30 〜 09:45
▼ [22a-A105-3] Facile Fabrication of Carbon Electrodes on Flexible Subtrate for In Vivo Sensing of Dopamine
キーワード：Dopamine Sensor, Carbonization, Fast-scan cyclic voltammtetry (FSCV)
Dopamine (DA) plays a vital role in the development of addiction. Addicting drugs such as nicotine increase the release of DA within the brain particularly in the nucleus accumbens shell (NAcSh). In our prior works, we used microdialysis to measure DA in the NAcSh during optogenetic or intraperitoneal stimulation. However, faster time resolution is required. Fast-scan cyclic voltammetry (FSCV) is cyclic voltammetry performed at scan rates a thousand times faster than traditional, typically at 400 V/s. Usually, carbon-fiber microelectrode (CFME) is used due to its biocompatibility and excellent electrochemical properties. However, CFME is hard to implant due to its brittleness, is unstable due to dissolution and, is difficult and expensive to fabricate.
In this work, we developed a facile method for fabricating carbon electrodes as an alternative to CFME adopted from Vomero (2018). Parylene C was vacuum-coated on gold electrodes and then photolyzed with a 266 nm laser. The power was set at 150 W and the duration was varied between 15 and 90 minutes. When photolyzed for only 30 minutes, the impedance was approximately the same with non-photolyzed electrodes indicating that parylene C remained coated on the electrode. The impedance decreased by 2 orders of magnitude after 45 minutes of photolysis and decreased further after 60 minutes. No more decreases were observed at 90 minutes. The X-ray photoelectron spectrum of electrodes photolyzed for 45 minutes revealed that approximately 30.3 of the carbon are bound to oxygen which helps increase sensitivity to dopamine.
We measured the sensitivity of photolyzed carbon electrodes to DA in vitro and in vivo. Wild-type mice were implanted with photolyzed electrodes at the position of the NAcSh. FSCV was conducted for 1 hour to establish baseline DA activity. The mice were then injected with nicotine and monitored for 1 hour. The results showed that our photolyzed carbon electrodes can measure DA activity.
In this work, we developed a facile method for fabricating carbon electrodes as an alternative to CFME adopted from Vomero (2018). Parylene C was vacuum-coated on gold electrodes and then photolyzed with a 266 nm laser. The power was set at 150 W and the duration was varied between 15 and 90 minutes. When photolyzed for only 30 minutes, the impedance was approximately the same with non-photolyzed electrodes indicating that parylene C remained coated on the electrode. The impedance decreased by 2 orders of magnitude after 45 minutes of photolysis and decreased further after 60 minutes. No more decreases were observed at 90 minutes. The X-ray photoelectron spectrum of electrodes photolyzed for 45 minutes revealed that approximately 30.3 of the carbon are bound to oxygen which helps increase sensitivity to dopamine.
We measured the sensitivity of photolyzed carbon electrodes to DA in vitro and in vivo. Wild-type mice were implanted with photolyzed electrodes at the position of the NAcSh. FSCV was conducted for 1 hour to establish baseline DA activity. The mice were then injected with nicotine and monitored for 1 hour. The results showed that our photolyzed carbon electrodes can measure DA activity.