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Nanostructured Cyclodextrin-Mediated Surface for Capacitive Determination of Cortisol in Multiple Biofluids
ACS Applied Materials & Interfaces
|August 3, 2022
Summary
This study presents a reusable polypropylene glycol (PPG):β-cyclodextrin (βCD) biosensor for sensitive cortisol detection. The developed biosensor demonstrates excellent stability and reusability, crucial for accurate cortisol monitoring in various samples.
Area of Science:
- Electrochemistry
- Biosensor Development
- Analytical Chemistry
Background:
- Cortisol detection is vital for diagnosing various endocrine disorders.
- Existing biosensors often lack stability and reusability, limiting their practical application.
- Developing robust and sensitive cortisol detection methods remains a significant challenge.
Purpose of the Study:
- To develop a stable and reusable biosensor for cortisol detection using polypropylene glycol (PPG) and β-cyclodextrin (βCD).
- To compare two different surface modifications for immobilizing βCD onto PPG.
- To evaluate the performance of the developed biosensor in detecting cortisol in biological samples.
Main Methods:
- Fabrication of two PPG surfaces: one on gold (Au) with 3-mercaptopropionic acid (3MPA) self-assembled monolayer (SAM), and another on glassy carbon (GC) grafted with 4-carboxyphenyl diazonium salt.
- Surface characterization using electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR).
- Cortisol detection using a nonfaradaic electrochemical impedance capacitive model.
Main Results:
- The glassy carbon-based surface (GC-carboxyphenyl-PPG:βCD) exhibited superior stability, remaining functional for at least one month.
- The GC-carboxyphenyl-PPG:βCD biosensor demonstrated high reusability, with performance maintained up to 10 detection cycles.
- Sensitive detection of cortisol was achieved in PBS buffer (LOD 2.13 nM), urine (LOD 1.29 nM), and saliva (LOD 1.33 nM).
Conclusions:
- The developed GC-carboxyphenyl-PPG:βCD biosensor offers a stable and reusable platform for cortisol detection.
- The biosensor exhibits high sensitivity and applicability in complex biological matrices like urine and saliva.
- This work provides a promising tool for non-invasive cortisol monitoring in clinical diagnostics.
