Reviewed by Danielle Ellis, B.Sc.Sep 2 2024
An international team of researchers from China and the UK has developed a new and improved detector that can precisely monitor blood levels of cortisol, a stress biomarker. This study was published in the journal Talanta.
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Stress manifests itself in many ways in our daily lives, from the never-ending demands of jobs to the never-ending rush to get to school. However, neglecting elevated stress levels might result in grave health complications such as depression and Alzheimer's disease.
What if it were customary to monitor stress levels at home? Nanoparticles are making this prospect more likely.
A cost-effective, easily reproducible, and easy-to-use point-of-care testing device that accurately measures cortisol levels has long been sought. It could make a huge difference to an appropriate and speedy diagnosis of high cortisol levels, drastically improving people’s lives.
Tong Ji, Study First Author and Senior Technician, Xi’an Jiaotong-Liverpool University
Tong Ji is also a current part-time PhD Student at Xi’an Jiaotong-Liverpool University (XJTLU)
The electrodes in the devices that are now on the market are typically unstable under a variety of variable conditions, such as temperature and pH changes. Because of this, the gadgets have a limited shelf life and are challenging to manufacture on a commercial scale.
Current cortisol detectors have reference electrodes with a silver layer that is easily oxidized and unstable in electrochemical measurements. In this study, we used iridium oxide nanoparticles to cover the silver layer. This modification improves the stability, sensitivity, and reproducibility of cortisol detection in point-of-care devices.
Tong Ji, Study First Author and Senior Technician, Xi’an Jiaotong-Liverpool University
Dr. Qiuchen Dong, an Assistant Professor at XJTLU and Corresponding Author, added, “This is the first time iridium oxide has been used in this way. Our team has produced a simple, low-cost cortisol-measuring device that detects cortisol molecules at a concentration 3,000 times lower than the normal range of cortisol in our blood. This makes our device sensitive enough for commercial use.”
The selectivity of testing has also been enhanced by the electrodes modified with iridium oxide.
One problem with the current solutions is that there is much similarity between cortisol and other hormones such as progesterone, testosterone, and corticosterone. This means it is difficult for the detectors to tell them apart. Our iridium oxide-modified electrode is selective enough to distinguish the different hormones and helps to solve this issue.
Dr. Graham Dawson, Associate Professor and Study Co-Author, Xi’an Jiaotong-Liverpool University
Journal Reference:
Ji, T., et al. (2024) Iridium Oxide-modified Reference Screen-printed Electrodes for Point-of-Care Portable Electrochemical Cortisol Detection. Talanta. doi.org/10.1016/j.talanta.2024.126776.