Flexible Electrochemical Transducer Platform for Neurotransmitters

Abstract

We have designed a flexible electrochemical transducer film based on PEDOT-titania-poly(dimethylsiloxane) (PTS) for the simultaneous detection of neurotransmitters. PTS films were characterized using various techniques such as transmission electron microscopy, scanning electron microscopy, atomic force microscopy, four probe electrical conductivity, ac-impedance, and thermomechanical stability. The electrocatalytic behavior of the flexible PTS film toward the oxidation of neurotransmitters was investigated using cyclic voltammetry and differential pulse voltammetry. The fabricated transducer measured a limit of detection of 100 nm ± 5 with a response time of 15 s and a sensitivity of 63 μA mM^-1 cm^-2. The fabricated transducer film demonstrated for the simultaneous determination of epinephrine, dopamine, ascorbic acid, and uric acid with no interference between the analyte molecules. Further, transducer performance is validated by performing with real samples. The results suggested that the fabricated flexible PTS transducer with superior electrocatalytic activity, stability, and low response time can be explored for the sensing of neurotransmitters and hence can be exploited at in vitro and in vivo conditions for the early detection of the various diseases.

Scheme 1. Schematic Representation Illustrating the Preparation of Titania, PEDOT, PT, and poly(dimethylsiloxane) (PTS) Films

Figure 1

TEM (a,b), SEM (c), and AFM (d) images of titania; SAED pattern is shown in the inset of (b); TEM (e) and AFM (f) images of PEDOT, SEM (g), AFM (h), and TEM (i,j) images of PT3 nanocomposite; and inset of (j) SAED pattern of PT3. SEM (k) and 3D AFM (l) images of PTS3 inset of (l) shows the height profile of PTS3 film.

Figure 2

XRD profiles of (a) TiO₂, (b) PT3, (c) PTS3 film, and (d) PEDOT.

Figure 3

Electrochemical impedance profile [A] PT nanocomposites (a) PT1, (b) PT2, (c) PT3, and (d) PT4 and [B] PTS films (a) PTS1, (b) PTS2, and (c) PTS3.

Figure 4

(a) CV profile of PTS3 film for 50 successive scans (scan rate 50 mV/s, pH 7.4). (b) plot of I_pa vs square root of the scan rate of PTS3 film.

Figure 5

CV profile PT5 film in the presence of epinephrine solution in phosphate buffer solution (scan rate 50 mV/s, pH 7.4).

Figure 6

Cyclic voltammograms of (a) PTS5 film electrode at scan rate (range 10–100 mV/s) in pH 7.4 phosphate buffer solution containing 1 mL of 10^–6 M of EP. (b) Plot of peak current vs square root of scan rate plots of PTS5 film electrode, and (c) plot of E_p was plotted against log ν (phosphate buffer pH = 7.4).

Figure 7

(a) DPV profile PTS3 film in presence of epinephrine solution in phosphate buffer solution and (b) plot of EP concentration vs current (scan rate 50 mV/s), phosphate buffer pH = 7.4.

Figure 8

DPV profile of PTS5 film for simultaneous determination of AA, EP, DA, and UA (scan rate 50 mV/s).