Using Disulfide DNA to Enhance Control over DNA Self-Assembled Monolayer Surface Coverage and Reduce Impedance Signal...

Area of Science:

• Biomaterials Science
• Nanotechnology
• Electrochemistry

Background:

• Thiolated DNA probes form self-assembled monolayers (SAMs) on gold electrodes for biosensing.
• DNA SAMs are crucial for point-of-care (POC) diagnostics but suffer from structural instability and fabrication challenges.
• Electrochemical impedance spectroscopy (EIS) is sensitive to SAMs but prone to signal drift due to SAM disorganization.

Purpose of the Study:

• To investigate DNA SAM formation and quality using EIS and chronocoulometry (CC).
• To identify factors influencing SAM stability and background signal drift.
• To develop an improved protocol for fabricating stable and reproducible DNA SAMs.

Main Methods:

• Combined EIS and CC to analyze DNA SAM formation on gold electrodes.
• Investigated SAMs formed using different fabrication methods.
• Developed a novel protocol using disulfide-linked DNA probes.

Main Results:

• Maximizing upright DNA probe density is essential for SAM stability and suppressing background drift.
• The disulfide dimer delivery method enhances surface density and probe density control.
• This approach promotes stable, upright probe orientation, overcoming a key obstacle in DNA monolayer fabrication.

Conclusions:

• Delivering thiolated DNA probes as disulfide dimers significantly improves DNA SAM quality.
• This method enhances stability, reduces signal drift, and allows controllable probe density.
• The protocol offers a promising solution for reliable DNA-based bio-interfaces in diagnostics.