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. 2019 Jul 9;4(7):11888-11892.
doi: 10.1021/acsomega.9b01152. eCollection 2019 Jul 31.

Label-Free Electrochemical Immunosensor Based on a Functionalized Ionic Liquid and Helical Carbon Nanotubes for the Determination of Cardiac Troponin I

Qihui Shen  1 , Man Liu  2 , Yang Lü  1 , Dawei Zhang  1 , Zhenyu Cheng  1 , Yan Liu  1 , Huajing Gao  1 , Zhaohui Jin  1
Affiliations

Label-Free Electrochemical Immunosensor Based on a Functionalized Ionic Liquid and Helical Carbon Nanotubes for the Determination of Cardiac Troponin I

Qihui Shen et al. ACS Omega. .

Abstract

A label-free electrochemical immunosensor for cardiac troponin I was prepared by using a helical carbon nanotube-supported aldehyde-functionalized ionic liquid. Because of the good conductivity of ionic liquid and helical carbon nanotubes, high sensitivity of the immunosensor was obtained. Functionalized ionic liquid provided binding sites for antibody, which simplified the process of sensor construction. Cardiac troponin I was detected by this immunosensor with a linear range of 0.05-30 ng/mL and a detection limit of 0.03 ng/mL. The electrochemical immunosensor had satisfactory reproducibility, high sensitivity, and acceptable specificity.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
SEM images of HCNTs (A) and DIL–HCNTs (B).
Figure 2
Figure 2
Cyclic voltammograms of bare Au (a), Nf/Au (b), DIL–HCNT–Nf/Au (c), anti-cTnI/DIL–HCNT–Nf/Au (d), BSA/anti-cTnI/DIL–HCNT–Nf/Au (e), and cTnI/BSA/anti-cTnI/DIL–HCNT–Nf/Au (f) in 5 mmol/L Fe(CN)63–/Fe(CN)64–. Scan rate was 100 mV/s.
Figure 3
Figure 3
Effect of the concentration of antibody (A), immobilization time (B), and immunoreaction time (C) on the peak current of immunosensor. The concentration of cTnI was 10 ng/mL.
Figure 4
Figure 4
DPV curves at different concentrations of cTnI. (Inset: calibration curve of the peak currents of DPV to different concentrations of cTnI. Error bars represent standard deviation, n = 3.) Experiment conditions: potential range: −0.4 to 0.6 V, pulse amplitude: 0.05 V, pulse width: 0.05 s, sample width: 0.02 s.
Figure 5
Figure 5
Specificity of the immunosensor.
Figure 6
Figure 6
Preparation of the nanocomposite of DIL–HCNT (A) and the electrochemical immunosensor (B).
See this image and copyright information in PMC

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