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Ultrasensitive detection of cortisol with enzyme fragment complementation technology using functionalized nanowire
Arun Kumar1, Shyam Aravamudhan, Milorad Gordic
1Department of Internal Medicine, Division of Allergy and Clinical Immunology, College of Medicine, University of South Florida, Tampa, FL 33612, USA.
Biosensors & Bioelectronics
|November 14, 2006
Summary
A new biosensor using functionalized gold nanowires offers sensitive detection of cortisol, a key metabolic regulator and stress biomarker. This advancement improves diagnostics for conditions like diabetes and obesity.
Area of Science:
- Nanomaterials Science
- Biomedical Engineering
- Analytical Chemistry
Background:
- Cortisol, a glucocorticoid hormone, is crucial for metabolism and serves as a stress biomarker.
- Elevated cortisol levels are linked to type 2 diabetes, obesity, and metabolic syndrome.
- Current methods for sensitive cortisol detection are limited, hindering timely diagnosis and management.
Purpose of the Study:
- To develop a highly sensitive and selective biosensor for cortisol detection.
- To leverage functionalized gold nanowires for enhanced electrochemical performance.
Main Methods:
- Fabrication of a biosensor utilizing aligned gold (Au) nanowires as the working electrode.
- Integration of platinum counter electrode and silver/silver chloride reference electrode.
- Functionalization of gold nanowires with cortisol antibodies and use of 3alpha-hydroxysteroid dehydrogenase for enzymatic conversion; micro-fluidic system fabricated using MEMS technology.
Main Results:
- The biosensor demonstrated a linear response curve in the 10-80 microM range for cortisol.
- Sensitive detection of hydrocortisone was achieved within the 5-30 microM range.
- Characterization confirmed the biosensor's performance using SEM, AFM, and FTIR techniques.
Conclusions:
- Functionalized gold nanowires integrated with a micro-fluidic device offer a sensitive and facile assay for cortisol detection.
- This technology holds promise for improved diagnostics in serum and other biological fluids.
- The enhanced surface-to-volume ratio and conductivity of gold nanowires significantly improve biosensor sensitivity and detection limits.