Sensors

eISSN: 1424-8220

2022, 22, 2699

SCIE

[논문]Impedance Technique-Based Label-Free Electrochemical Aptasensor for Thrombin Using Single-Walled Carbon Nanotubes-Casted Screen-Printed Carbon Electrode

Kyungsoon Park

박경순

An impedance technique-based aptasensor for the detection of thrombin was developed
using a single-walled carbon nanotube (SWCNT)-modified screen-printed carbon electrode (SPCE).
In this work, a thrombin-binding aptamer (TBA) as probe was used for the determination of thrombin,
and that was immobilized on SWCNT through π–π interaction. In the presence of thrombin, the TBA
on SWCNT binds with target thrombin, and the amount of TBA on the SWCNT surface decreases. The
detachment of TBA from SWCNT will be affected by the concentration of thrombin and the remaining
TBA on the SWCNT surface can be monitored by electrochemical methods. The TBA-modified
SWCNT/SPCE sensing layer was characterized by cyclic voltammetry (CV). For the measurement
of thrombin, the change in charge-transfer resistance (Rct) of the sensing interface was investigated
using electrochemical impedance spectroscopy (EIS) with a target thrombin and [Fe(CN)6]
3− as redox maker. Upon incubation with thrombin, a decrease of Rct change was observed due to the decrease in
the repulsive interaction between the redox marker and the electrode surface without any label. A
plot of Rct changes vs. the logarithm of thrombin concentration provides the linear detection ranges
from 0.1 nM to 1 µM, with a ~0.02 nM detection limit.

2022.3.31

https://doi.org/10.3390/s22072699