Label-free amplified bioaffinity detection using terahertz wave technology.

Area of Science:

• Biophysics
• Biosensing Technology
• Terahertz (THz) Spectroscopy

Background:

• Avidin-biotin binding is a high-affinity interaction crucial in molecular biology.
• Existing biosensing techniques face limitations in sensitivity and detection limits for thin films.
• Terahertz (THz) waves offer non-ionizing, label-free detection capabilities.

Purpose of the Study:

• To develop and validate a new affinity biosensor utilizing pulsed terahertz (THz) wave technology.
• To enhance the detection sensitivity of avidin-biotin binding using modified surfaces and amplification strategies.
• To evaluate the detection capability of the THz biosensor for sub-thin solid films.

Main Methods:

• Fabrication of a biosensor with a biotin-coated quartz surface modified with octadecanol.
• Conjugation of avidin to agarose particles.
• Application of avidin-conjugated agarose particles to the biotinylated surface for binding.
• Monitoring binding events using pulsed THz wave technology and measuring THz difference signals.

Main Results:

• Achieved an eight-fold enhancement in the THz difference signal upon avidin-biotin binding with agarose beads.
• Demonstrated a detection limit of less than 10.3 ng/cm² for avidin.
• The THz biosensor exhibited superior detection capabilities for sub-thin solid films compared to ellipsometry and reflectometry.

Conclusions:

• The developed THz affinity biosensor effectively amplifies and detects molecular binding events.
• This technology offers a highly sensitive platform for analyzing interactions at the nanoscale.
• Potential applications include DNA hybridization and ligand-analyte affinity binding detection.