Antibody functionalized interdigitated micro-electrode (IDmicroE) based impedimetric cortisol biosensor

Area of Science:

• Biosensor Technology
• Electrochemistry
• Biomedical Engineering

Background:

• Cortisol detection is crucial for diagnosing various endocrine disorders.
• Current methods for cortisol measurement can be complex and time-consuming.
• Development of rapid, sensitive, and point-of-care diagnostic tools is needed.

Purpose of the Study:

• To develop and validate an ultrasensitive, disposable, impedimetric biosensor for cortisol detection.
• To evaluate the sensor's performance in complex biological matrices like saliva.
• To establish the feasibility of using this biosensor for point-of-care cortisol monitoring.

Main Methods:

• Covalent immobilization of a cortisol-specific monoclonal antibody (C-Mab) on interdigitated micro-electrodes (IDmicroEs) using a dithiobis(succinimidyl propionate) (DTSP) self-assembled monolayer (SAM).
• Blocking of unreacted active groups with ethanolamine (EA) and glycine (Gly).
• Label-free electrochemical impedance spectroscopy (EIS) for quantifying cortisol concentration.

Main Results:

• The developed biosensor demonstrated high sensitivity (2.855 kohms M⁻¹).
• Accurate detection of cortisol in saliva across a wide concentration range (1 pM to 10 nM).
• The sensor performed reliably with complex bodily fluids, indicating robustness.

Conclusions:

• The impedimetric biosensor is a feasible and effective tool for disposable cortisol detection.
• The sensor's sensitivity and ability to work with saliva support its use in point-of-care settings.
• This technology offers a promising avenue for accessible cortisol diagnostics.