Hydroxyl radicals (•OH) are well known as crucial chemicals for maintaining the normal activities of human cells; however, the excessive concentration of •OH disrupts their normal function, causing various diseases, including liver and heart diseases, cancers, and neurological disorders. The detection of •OH as a biomarker is thus essential for the early diagnosis of these serious conditions. Herein, a novel electrochemical sensor comprising a composite of cerium oxide nanoclusters, gold nanoparticles, and a highly conductive carbon was developed for detecting •OH. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to characterize the signals generated by the interaction of the composite with •OH radicals. The CV results revealed that the developed sensor could accurately and selectively detect •OH in the Fenton reaction. The sensor demonstrated a linear relationship between the current peak and •OH concentration in the range 0.05 - 0.5 mM and 0.5 - 5 mM with a limit of detection (LOD) of 58 µM. In addition, EIS studies indicated that this electrochemical sensor could distinguish between •OH and similar reactive oxygen species (ROS), like hydrogen peroxide (H2O2). It is also worth mentioning that additional merits, such as reproducibility, repeatability, and stability of the sensor were confirmed.
Supersensitive CeO x -based nanocomposite sensor for the electrochemical detection of hydroxyl free radicals
It is well known that an excess of hydroxyl radicals (˙OH) in the human body is responsible for oxidative stress-related diseases. An understanding of the relationship between the concentration of ˙OH and those diseases could contribute to better diagnosis and prevention. Here we present a supersensitive nanosensor integrated with an electrochemical method to measure the concentration of ˙OH in vitro. The electrochemical sensor consists of a composite comprised of ultrasmall cerium oxide nanoclusters (<2 nm) grafted to a highly conductive carbon deposited on a screen-printed carbon electrode (SPCE). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to analyze the interaction between cerium oxide nanoclusters and ˙OH. The CV results demonstrated that this electrochemical sensor had the capacity of detecting ˙OH with a high degree of accuracy and selectivity, achieving a consistent performance. Additionally, EIS results confirmed that our electrochemical sensor was able to differentiate ˙OH from hydrogen peroxide (H 2 O 2 ), which is another common reactive oxygen species (ROS) found in the human body. The limit of detection (LOD) observed with this electrochemical sensor was of 0.6 μM. Furthermore, this nanosized cerium oxide-based electrochemical sensor successfully detected in vitro the presence of ˙OH in preosteoblast cells from newborn mouse bone tissue. The supersensitive electrochemical sensor is expected to be beneficially used in multiple applications, including medical diagnosis, fuel–cell technology, and food and cosmetic industries.
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- Award ID(s):
- 1817294
- NSF-PAR ID:
- 10230829
- Date Published:
- Journal Name:
- Nanoscale
- Volume:
- 13
- Issue:
- 9
- ISSN:
- 2040-3364
- Page Range / eLocation ID:
- 5136 to 5144
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D1NR00015B
