Polyindole-Derived Nitrogen-Doped Graphene Quantum Dots-Based Electrochemical Sensor for Dopamine Detection

Abstract

The sensitive monitoring of dopamine levels in the human body is of utmost importance since its abnormal levels can cause a variety of medical and behavioral problems. In this regard, we report the synthesis of nitrogen-doped graphene quantum dots (N-GQDs) from polyindole (PIN) via a facile single-step hydrothermal synthetic strategy that can act as an efficient electrochemical catalyst for the detection of dopamine (DA). The average diameter of N-GQDs was ∼5.2 nm and showed a C/N atomic ratio of ∼2.75%. These N-GQDs exhibit a cyan fluorescence color under irradiation from a 365 nm lamp, while PIN has no characteristic PL. The presence of richly N-doped graphitic lattices in the N-GQDs possibly accounts for the improved catalytic activity of N-GQDs/GCE towards electrocatalytic DA detection. Under optimum conditions, this novel N-GQDs-modified electrode exhibits superior selectivity and sensitivity. Moreover, it could detect as low as 0.15 nM of DA with a linear range of 0.001–1000 µM. In addition, the outstanding sensing attributes of the detector were extended to the real samples as well. Overall, our findings evidence that N-GQDs-based DA electrochemical sensors can be synthesized from PIN precursor and could act as promising EC sensors in medical diagnostic applications.

Thiourea‐Modified Multiwalled Carbon Nanotubes as Electrochemical Biosensor for Ultra‐Precise Detection of Dopamine

“…Similarly, conjugated large pi bonds in TM‐CNT600 interact with dopamine through pi‐pi stacking. Furthermore, the positively charged dopamine might interact with conjugated large pi bonds in the TM‐CNT600 via cation‐pi interaction [67] . The higher levels of pyrrolic‐N and pyridinic‐N in TM‐CNT600, as deduced from the XPS characterization data (Figure 1), can efficiently increase its sensing ability.…”

“…Furthermore, the positively charged dopamine might interact with conjugated large pi bonds in the TM-CNT600 via cation-pi interaction. [67] The higher levels of pyrrolic-N and pyridinic-N in TM-CNT600, as deduced from the XPS characterization data (Figure 1), can efficiently increase its sensing ability. Because it increases electron density while preserving charge carrier mobility, pyridinic-N can improve the catalytic performance of TM-CNT600.…”

The Theoretical Description for Psilocin Electrochemical Determination over Cobalt Oxyhydroxide

“…Its toxic effects include hallucinogenic action [5][6][7], which is dose-related, reason why the development of an efficient electroanalytical process is really actual. Moreover, being an indolic compound, substituted by donor groups, it is interesting as a monomer for a conducting polymer, analogous to those yet synthetized from other indoles [8][9][10][11][12]. The indoles are generally electropolymerized via the positions 3 and 5.…”

“…Both phenolic hydroxyl and tertiary amine group lower the psilocin oxidation and polymerization potentials, leading to the enhanced electrochemical activity. It is even more expressed on chemically modified electrodes, which augment the electroanalytical activity and sensitivity and favors the composite material formation [11][12]. As for cobalt (III) oxyhydroxide, it is a suitable modifier candidate, due to its interesting properties.…”