Sensing Reversible Protein-Ligand Interactions with Single-Walled Carbon Nanotube Field-Effect Transistors

Area of Science:

• Nanotechnology
• Biochemistry
• Biosensors

Background:

• Avidin and its derivatives are crucial in biochemical assays.
• Single-walled carbon nanotube field-effect transistors (SWNT FETs) offer high sensitivity for biosensing applications.
• Noncovalent functionalization of SWNTs is key for preserving their electronic properties in biosensors.

Purpose of the Study:

• To develop and characterize a SWNT FET-based biosensor for the reversible detection of CaptAvidin.
• To investigate the sensor's performance under varying pH and ionic strength conditions.
• To obtain unique protein "fingerprints" for NeutrAvidin and streptavidin using the developed sensor.

Main Methods:

• Noncovalent functionalization of SWNT FETs with biotin using 1-pyrenebutyric acid.
• Detection of CaptAvidin binding through changes in FET characteristics.
• Analysis of binding affinities at different pH values and ionic strengths.
• Characterization of NeutrAvidin and streptavidin adsorption profiles.
• Fabrication of gold nanoparticle-decorated SWNT FETs for potential dual-mode sensing.

Main Results:

• Demonstrated reversible detection of CaptAvidin using biotin-functionalized SWNT FETs.
• Quantified binding affinities of CaptAvidin across a range of pH values.
• Analyzed sensor response to varying ionic strengths.
• Obtained distinct protein "fingerprints" for NeutrAvidin and streptavidin.
• Showcased reversible CaptAvidin binding on gold nanoparticle-decorated SWNT FETs.

Conclusions:

• SWNT FETs functionalized with biotin provide a sensitive platform for reversible CaptAvidin detection.
• The sensor exhibits tunable performance based on pH and ionic strength.
• Protein "fingerprinting" offers a method for differentiating related proteins.
• The developed biosensor holds potential for dual-mode sensing applications, integrating FETs with SERS.