A gas-phase amplified quartz crystal microbalance immunosensor based on catalase modified immunoparticles

Area of Science:

• Biosensors and Bioanalytical Chemistry
• Nanotechnology and Materials Science

Background:

• Quartz crystal microbalance (QCM) is a sensitive mass-sensing platform.
• Ultrasensitive protein detection is crucial for diagnostics and research.
• Existing QCM immunosensors often lack sufficient sensitivity for low-concentration targets.

Purpose of the Study:

• To develop a novel signal amplification strategy for QCM-based immunosensors.
• To construct an ultrasensitive immunosensor for protein detection using catalytic gas generation.
• To improve the sensitivity and detection limit for immunoglobulin G (IgG) detection.

Main Methods:

• A sandwich-type immunocomplex was formed on a QCM sensor using immobilized anti-IgG antibodies and catalase-modified immunoparticles.
• Catalytic gas (oxygen) generation was induced by adding hydrogen peroxide (H2O2) to the immobilized catalase.
• The generated gas altered the sensor's surface properties, leading to a measurable QCM frequency shift.

Main Results:

• The gas-phase amplified QCM sensor demonstrated up to a 72-fold improvement in detection sensitivity compared to a label-free sensor.
• The detection limit for IgG was reduced from 236 ng mL(-1) to 51.0 ng mL(-1).
• Optimal conditions for flow cell structure, temperature, immunoparticle, and H2O2 concentrations were determined.

Conclusions:

• Catalytic gas generation provides an effective ultrasensitive signal amplification strategy for QCM immunosensors.
• The developed immunosensor shows significant potential for highly sensitive protein detection.
• This approach offers a promising advancement in bioanalytical sensing technologies.