Oriented Antibody-Assembled Metal-Organic Frameworks for Persistent Wearable Sweat Cortisol Detection

Area of Science:

• Biomedical Engineering
• Materials Science
• Analytical Chemistry

Background:

• Cortisol levels indicate psychological stress, aid in diagnosing adrenal diseases, and correlate with mental health conditions.
• Accurate and continuous monitoring of cortisol is crucial for various health applications.
• Existing methods for cortisol detection often lack the necessary sensitivity, stability, or wearability for real-time monitoring.

Purpose of the Study:

• To develop a wearable, label-free immunosensor for persistent sweat cortisol detection.
• To enhance antibody stability and antigen-binding capacity using a metal-organic framework (MOF).
• To validate the performance of the integrated system for on-body cortisol biosensing.

Main Methods:

• An antibody-oriented approach was used to modify an immunosensor with cortisol monoclonal antibodies (C_mab).
• The fragment crystallizable (Fc) region of antibodies was embedded within a MOF, exposing binding regions on the surface via selective growth and self-assembly.
• The integrated system was tested on volunteers for on-body sweat cortisol biosensing.

Main Results:

• The developed immunosensor demonstrated a good linear detection range for cortisol from 1 pg/mL to 1 μg/mL.
• A low limit of detection of 0.26 pg/mL was achieved.
• The wearable sensor exhibited excellent persistence, with only a 4.1% decay in performance after 9 days of storage.

Conclusions:

• The oriented antibody assembly within MOFs significantly improves antibody stability and antigen-binding capacity.
• This wearable sensor is suitable for practical, long-term continuous sweat biomarker detection.
• The study provides a robust method for enhancing antibody stability for biosensing applications.