Surface Immobilized Nucleic Acid-Transcription Factor Quantum Dots for Biosensing

Area of Science:

• Biotechnology
• Nanotechnology
• Analytical Chemistry

Background:

• Immobilizing biosensors on surfaces is crucial for practical applications.
• Conventional biosensors often rely on aptamers or antibodies for analyte detection.
• Allosteric transcription factors offer a potential alternative for molecular recognition.

Purpose of the Study:

• To prepare, characterize, and evaluate a surface-bound transcription factor-nucleic acid complex for analyte detection.
• To demonstrate a novel biosensor design using allosteric transcription factors.
• To establish a framework for future affinity-based biosensor development.

Main Methods:

• Fabrication of a gold surface modified with thiolated DNA and a quantum dot-linked transcription factor (TetR).
• Utilizing Förster resonance energy transfer (FRET) signal loss upon analyte binding.
• Real-time quantitative measurements of analyte concentration.

Main Results:

• The biosensor demonstrated a dose-dependent response to anhydrotetracycline (aTc) from 0-200 µm.
• A limit of detection of 80 nm for aTc was achieved.
• Analyte binding caused the release of TetR-quantum dots from the DNA, leading to signal loss.

Conclusions:

• A novel surface-bound biosensor utilizing allosteric transcription factors was successfully developed and characterized.
• This system provides a viable alternative to conventional biosensor components like aptamers and antibodies.
• The study lays the groundwork for designing future affinity-based biosensors with allosteric transcription factors for molecular recognition.