Ultrasensitive electrochemical detection of epinephrine using N-CDs/ MoS2QDs-engineered MWCNTs

초록

A highly selective, rapid, and sensitive electrochemical platform for epinephrine (EP) detection was developed by engineering the surface of multi-walled carbon nanotube (MWCNT) with nitrogen-doped carbon dots (N-CDs) and MoS2 quantum dots (MoS2QDs). The N-CDs and MoS2QDs were synthesized hydrothermally, with average sizes of 3.5 nm and 8 nm, respectively. These nanostructures were then anchored onto the surface of APTES functionalized MWCNT (f-MWCNT) through amine-mediated interactions, forming a conductive and catalytically active N-CDs/MoS2QDs@f-MWCNT hybrid. This composite was drop-cast onto a glassy carbon electrode (GCE) to fabricate the sensing interface, and the electrochemical sensing toward EP was investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). This sensor exhibited outstanding performance, achieving a broad detection range from 20 nM to 10 mu M with a lower limit of detection (LOD) of 6.8 nM in phosphate-buffered saline (PBS) and 11.5 nM in human serum. Electrochemical analysis on EP, including pH evaluation, scan rate analysis, and electrochemical impedance spectroscopy (EIS), confirmed efficient charge transfer and surface-controlled adsorption. In addition, the electrode exhibited strong stability, reproducibility over extended storage periods, and selectivity, demonstrating its suitability for practical EP sensing. Overall, this novel N-CDs/MoS2QDs@f-MWCNT sensor provides a robust and efficient platform for EP detection in clinical environments.

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