Highly sensitive and rapid sequential cortisol detection using twin sensor QCM

Area of Science:

• Analytical Chemistry
• Biomedical Engineering
• Sensor Technology

Background:

• Cortisol monitoring is crucial for stress and disease diagnosis.
• Existing methods for cortisol detection can be time-consuming.
• Need for rapid, sensitive, and reliable cortisol detection systems.

Purpose of the Study:

• To develop a rapid, sequential analysis system for cortisol detection.
• To integrate flow injection analysis with a quartz crystal microbalance (QCM) sensor chip.
• To establish a sensitive and quantitative method for cortisol level measurement.

Main Methods:

• Utilized a twin sensor chip QCM system with one sensor for antigen-antibody interaction and another as a reference.
• Employed a competitive assay using cortisol-bovine serum albumin (Crt-BSA) tracer.
• Implemented a glycine-NaOH solution for antigen-antibody binding uncoupling to enable sequential analysis.

Main Results:

• Achieved a detection cycle time of under 10 minutes, including regeneration.
• Demonstrated quantitative detection of cortisol in the range of 5 pg mL⁻¹ to 100 pg mL⁻¹.
• The system effectively removed environmental influences using a reference sensor.

Conclusions:

• The developed sensor system offers a rapid and sensitive method for cortisol detection.
• Potential applications include active stress monitoring and disease diagnosis.
• The integration of flow injection analysis with QCM enhances sequential detection capabilities.