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Updated: Feb 26, 2026
Development and Functionalization of Electrolyte-Gated Graphene Field-Effect Transistor for Biomarker Detection
Published on: February 1, 2022
Direct immune-detection of cortisol by chemiresistor graphene oxide sensor
Yo-Han Kim1, Kyungmin Lee1, Hunsang Jung1
1Department of Chemical Engineering, Myongji University, Yongin 17058, Republic of Korea.
Insights
This study presents a novel biosensor for detecting cortisol, a stress biomarker. The reduced graphene oxide chemiresistor offers high sensitivity and selectivity for cortisol detection in real samples, enabling point-of-care testing.
Area of Science:
- Electrochemistry
- Biosensor Technology
- Materials Science
Background:
- Cortisol is a key biomarker for stress and various physiological conditions.
- Accurate and rapid cortisol detection is crucial for medical diagnostics and research.
- Existing detection methods can be complex or lack point-of-care applicability.
Purpose of the Study:
- To develop a novel electrochemical biosensor for sensitive and selective cortisol detection.
- To utilize reduced graphene oxide (rGO) and cortisol monoclonal antibodies (c-Mab) for enhanced sensing capabilities.
- To validate the sensor's performance using real human saliva and biological samples.
Main Methods:
- Covalent immobilization of c-Mab onto an rGO channel to create a chemiresistor.
- Characterization of immune-recognition via resistance changes on the rGO channel.
- Direct measurement of cortisol concentrations in human saliva and rat adrenal gland slices.
Main Results:
- The biosensor demonstrated high specificity for cortisol detection.
- Achieved a limit of detection of 10 pg/mL (27.6 pM) for cortisol.
- Successfully measured cortisol levels in human saliva and biological samples, showing selectivity against other neuroendocrine factors.
Conclusions:
- The rGO-based chemiresistor biosensor provides a sensitive and selective platform for cortisol detection.
- This technology holds promise for point-of-care testing (POCT) of salivary cortisol.
- Potential applications include psychobiological studies and the development of implantable sensor chips.
Abstract:
In this study, a biosensor to detect a stress biomarker of cortisol using cortisol monoclonal antibody (c-Mab) covalently immobilized on reduced graphene oxide (rGO) channel as electrical sensing element was demonstrated. Highly specific immune-recognition between the c-Mab and the cortisol was identified and characterized on a basis of resistance change at the rGO channel based chemiresistor sensor achieving the limit of detection of 10pg/mL (27.6 pM). In addition, cortisol concentrations of real human salivary sample and buffer solution of rat adrenal gland acute slices, which could secret the cortisol induced by adrenocorticotropic hormone (ACTH), were directly measured by the chemiresistor corresponding to the specific sensing of the cortisol. The rGO chemiresistor could selectively measure the cortisol levels in spite of diverse neuroendocrine's existence. The potential perspective of this study can be a protocol of new cortisol sensor development, which will be applicable to point-of-care testing (POCT) targeted for salivary cortisol, in vitro psychobiological study on cortisol induction, and implantable sensor chip in the future.
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