Carbon-nanotube field-effect transistors for resolving single-molecule aptamer-ligand binding kinetics

Area of Science:

• Biochemistry
• Nanotechnology
• Molecular Biology

Background:

• Small molecules are vital for biological functions.
• Conventional detection methods lack portability and time-resolved capabilities for in situ measurements.
• Existing techniques require large molecular ensembles for signal detection.

Purpose of the Study:

• To demonstrate carbon-nanotube-based single-molecule field-effect transistors (smFETs) as a platform for small molecule recognition and assaying.
• To detect and quantify serotonin at the single-molecule level.
• To gain insights into the dynamics of aptamer-ligand interactions.

Main Methods:

• Fabrication of smFETs using carbon nanotubes and DNA aptamers.
• Monitoring electrical conductance changes in response to molecular binding.
• Analyzing the kinetics of aptamer conformational changes.

Main Results:

• smFETs successfully detected and quantified serotonin at the single-molecule level.
• Observed discrete changes in nanotube electrical conductance due to aptamer conformational changes.
• Identified the role of G-quadruplex formation and hairpin structure disruption in serotonin-aptamer complex dynamics.

Conclusions:

• smFETs provide a label-free platform for single-molecule analysis of molecular interactions.
• This technique offers high temporal resolution, yielding unique insights into complex biological processes.
• smFETs represent a promising advancement for studying biomolecular dynamics in situ.