DNA Hybridization Measured with Graphene Transistor Arrays.

Area of Science:

• Nanotechnology
• Biotechnology
• Materials Science

Background:

• Graphene field-effect transistors (GFETs) offer potential for label-free biosensing.
• Existing methods for DNA detection often require complex labeling and can lack sensitivity.
• Developing robust and biocompatible graphene-based devices is crucial for practical applications.

Purpose of the Study:

• To fabricate high-quality graphene transistor arrays for sensitive DNA hybridization detection.
• To develop a process for large-area graphene sheet fabrication with protective and biocompatible coatings.
• To achieve label-free detection of DNA hybridization down to femtomolar concentrations.

Main Methods:

• Fabrication of graphene field-effect transistor (GFET) arrays using chemical vapor deposition (CVD) grown graphene.
• Development of protective Al2O3 and biocompatible SiOx capping layers for graphene sheets.
• Electrostatic immobilization of DNA probes onto a poly-l-lysine coated chip surface.
• Label-free detection of DNA hybridization using GFET arrays, including real-time in situ measurements.

Main Results:

• High-quality GFET arrays with stable, near-zero Dirac point voltages were fabricated.
• A detection limit of 10 femtomolar (fM) was achieved for 20-nucleotide DNA targets.
• Stable measurements with minimal voltage drift (<1 mV/hour) and significant signal changes (~100 mV) were observed.

Conclusions:

• The developed GFET fabrication process enables sensitive, label-free DNA hybridization detection.
• The protective and biocompatible coatings ensure device stability and performance in biological environments.
• This technology holds promise for advanced biosensing applications requiring high sensitivity and spatial resolution.