Detection and size analysis of proteins with switchable DNA layers

Area of Science:

• Biotechnology
• Nanotechnology
• Molecular Biology

Background:

• Label-free protein detection is crucial for diagnostics.
• Existing methods often require complex sample preparation or are not easily miniaturized.
• Real-time monitoring of molecular interactions remains a challenge.

Purpose of the Study:

• To introduce a novel chip-compatible, label-free method for real-time protein detection and sizing.
• To demonstrate the sensitivity and specificity of the switchDNA approach for antibody detection.
• To explore the potential of monitoring molecular dynamics for protein identification.

Main Methods:

• Utilizing electrically driven conformation switching of DNA oligonucleotides on metal surfaces.
• Employing high-frequency response measurements to analyze switching dynamics.
• Correlating changes in switching dynamics to protein binding and size.

Main Results:

• Achieved label-free, real-time detection of proteins, including IgG antibodies and fragments.
• Demonstrated detection sensitivity below 10(-18) mol on the sensor surface.
• Successfully identified different antibody fragments based on their unique kinetic fingerprints, enabling simultaneous detection and sizing.

Conclusions:

• The switchDNA method offers a sensitive and specific platform for real-time protein analysis.
• Monitoring DNA switching dynamics provides a novel way to determine protein size.
• This generic approach enables simultaneous detection and sizing of target molecules on a single analytical platform.