Electronic Cortisol Detection Using an Antibody-Embedded Polymer Coupled to a Field-Effect Transistor.

Area of Science:

• Biomedical Engineering
• Biosensor Technology
• Analytical Chemistry

Background:

• Cortisol detection is crucial for diagnosing various health conditions.
• Existing biosensors face challenges like the Debye length issue in physiological samples.
• Field-effect transistors (FETs) offer potential for sensitive biomolecule detection.

Purpose of the Study:

• To develop a FET-based cortisol sensor overcoming the Debye length limitation.
• To achieve sensitive and specific cortisol detection in physiological conditions.
• To validate the performance of the antibody-embedded polymer sensing membrane.

Main Methods:

• Fabrication of a FET with a remote gate functionalized with an antibody-embedded polymer.
• Synthesis of poly(styrene-co-methacrylic acid) (PSMA) linked with anticortisol antibodies.
• Characterization of sensor performance using varying cortisol concentrations in PBS and artificial sweat.
• Confirmation of antibody binding activity using a sandwich ELISA assay.

Main Results:

• The cortisol sensor demonstrated sensitivity ranging from 10 fg/mL to 10 ng/mL.
• A limit of detection (LOD) of 1 pg/mL was achieved in 1x PBS (λD = 0.2 nm).
• A LOD of 1 ng/mL was observed in lightly buffered artificial sweat.
• ELISA confirmed the specific binding activity of the antibody-embedded PSMA.

Conclusions:

• The developed FET-based cortisol sensor effectively overcomes the Debye length issue using an antibody-embedded polymer.
• The sensor exhibits high sensitivity and a low LOD for cortisol detection in physiological conditions.
• This technology holds promise for developing advanced cortisol monitoring devices.