| Summary: | 碩士 === 國立中興大學 === 精密工程學系所 === 106 === In this study, poly(ethylenedioxythiophene)/carbon nanotubes (PEDOT/CNTs) composite materials were used to modify acupuncture needles for the detection of serotonin (5-HT) and dopamine (DA), simultaneously. Firstly, the gold film was applied to the surface of the acupuncture by physical vapor deposition to increase its conductivity, and then the PEDOT/CNTs composite was deposited on the gold film by electrochemical deposition. The PEDOT layer has a high affinity for biomolecules while the oxygen functional groups of CNTs contains a porous interface layer, so that it can provide many active sites and improve the sensitivity of electrochemical detection of 5-HT and DA. Furthermore, detecting 5-HT and DA with Au/PEDOT/CNTs acupuncture biosensors by cyclic voltammetry and differential pulse voltammetry analysis. The result shows that PEDOT/CNTs modified acupuncture has greater current response than Au and PEDOT modified acupuncture. In the process of detecting neurotransmitters, the oxidation potential of 5-HT is 0.38 V and DA is 0.18 V. Both of them have a good linear relationship between the concentration range of 1 to 100 μM. The linear correlation coefficient of 5-HT is R² = 0.9712 with the detection limit of 0.81 μM (S/N=3), the linear correlation coefficient of DA is R² = 0.9915, with the detection limit of 0.49 μM (S/N=3). When the two coexisting concentrations differ by a factor of 10, the acupuncture needles can still distinguish two different substances clearly and also detect the signal in a well reproducibility (RSD is lower than 7%, RSD is lower than 10%, n = 5). The acupuncture sensor has the advantages of easy preparation, high reproducibility, smaller volume than traditional electrodes and successfully detecting 5-HT and DA with are a good prospect in future research on acupoint detection.
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