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. 2025 Jan 20;15(2):146.
doi: 10.3390/nano15020146.

A Low-Cost Electrochemical Cell Sensor Based on MWCNT-COOH/α-Fe2O3 for Toxicity Detection of Drinking Water Disinfection Byproducts

Ying Liu  1 , Zhipeng Zhang  1 , Yuling Wu  1 , Huan Yang  1 , Jiao Qu  1 , Xiaolin Zhu  1
Affiliations

A Low-Cost Electrochemical Cell Sensor Based on MWCNT-COOH/α-Fe2O3 for Toxicity Detection of Drinking Water Disinfection Byproducts

Ying Liu et al. Nanomaterials (Basel). .

Abstract

The disinfection of drinking water is essential for eliminating pathogens and preventing waterborne diseases. However, this process generates various disinfection byproducts (DBPs), which toxicological research indicates can have detrimental effects on living organisms. Moreover, the safety of these DBPs has not been sufficiently assessed, underscoring the need for a comprehensive evaluation of their toxic effects and associated health risks. Compared to traditional methods for studying the toxicity of pollutants, emerging electrochemical sensing technologies offer advantages such as simplicity, speed, and sensitivity, presenting an effective means for toxicity research on pollutants. However, challenges remain in this field, including the need to improve electrode sensitivity and reduce electrode costs. In this study, a pencil graphite electrode (PGE) was modified with carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and nano-iron (III) oxide (α-Fe2O3) to fabricate a low-cost electrode with excellent electrocatalytic performance for cell-active substances. Subsequently, a novel cellular electrochemical sensor was constructed for the sensitive detection of the toxicity of three drinking water DBPs. The half inhibitory concentration (IC50) values of 2-chlorophenylacetonitrile (2-CPAN), 3-chlorophenylacetonitrile (3-CPAN), and 4-chlorophenylacetonitrile (4-CPAN) for HepG2 cells were 660.69, 831.76, and 812.83 µM, respectively. This study provides technical support and scientific evidence for the toxicity detection and safety assessment of emerging contaminants.

Keywords: biosensor; cytotoxicity; disinfection byproducts; multi-walled carbon nanotubes; nano-iron (III) oxide.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
SEM images of α-Fe2O3 (A), MWCNT-COOH (B), and MWCNT-COOH/α-Fe2O3 (C).
Figure 2
Figure 2
EDS spectrum of MWCNT-COOH/α-Fe2O3.
Figure 3
Figure 3
XRD (A) and FTIR spectra (B) of MWCNT-COOH, α-Fe2O3, and MWCNT-COOH/α-Fe2O3.
Figure 4
Figure 4
Differential pulse voltammetry of HepG2 cell lysate on (A) PGE, (B) MWCNT-COOH/PGE, and (C) MWCNT-COOH/α-Fe2O3/PGE and (D) baseline corrected differential pulse voltammetry of different electrodes in HepG2 cell lysate (Initial potential: 0 V; final potential: 0.8 V; voltage increment: 0.004 V; amplitude: 0.05 V pulse width: 0.05 s; sampling width: 0.0167 s; pulse period: 0.5 s; quiet time: 2 s).
Figure 5
Figure 5
(A) Effect of enrichment potential on electrochemical signals of HepG2 cells detected by MWCNT-COOH/α-Fe2O3/PGE. (B) Repeatability of MWCNT-COOH/α-Fe2O3/PGE (Cell density: 1 × 106 cells mL−1).
Figure 6
Figure 6
Cytotoxicity of 2-CPAN (A), 3-CPAN (B), and 4-CPAN (C) to HepG2 cells detected by the electrochemical sensor.
Figure 7
Figure 7
Cellular morphology of HepG2 cells (A) before and after treatment with (B) 125.89 µM, (C) 251.19 µM, (D) 501.19 µM, (E) 1000.00 µM, and (F) 1995.26 µM 2-CPAN for 36 h.
Figure 8
Figure 8
Cellular morphology of HepG2 cells (A) before and after treatment with (B) 125.89 µM, (C) 251.19 µM, (D) 501.19 µM, (E) 1000.00 µM, and (F) 1995.26 µM 3-CPAN for 36 h.
Figure 9
Figure 9
Cellular morphology of HepG2 cells (A) before and after treatment with (B) 125.89 µM, (C) 251.19 µM, (D) 501.19 µM, (E) 1000.00 µM, and (F) 1995.26 µM 4-CPAN for 36 h.
See this image and copyright information in PMC

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