Electrostatic gating in carbon nanotube aptasensors

Area of Science:

• Nanotechnology
• Biosensors
• Molecular Biology

Background:

• Carbon nanotube (CNT)-based electronic biosensors offer promise for sensitive detection.
• Effective signal transduction mechanisms are crucial for developing robust CNT biosensors.
• Synthetic DNA aptamers can serve as specific recognition elements in biosensor design.

Purpose of the Study:

• To develop and characterize carbon nanotube (CNT) aptasensors for potassium ion detection.
• To elucidate the mechanism of aptamer-induced signal transduction in CNT electronic biosensors.
• To demonstrate the sensitivity and selectivity of the developed CNT aptasensor.

Main Methods:

• Fabrication of CNT network devices on flexible substrates using solution processing.
• Non-covalent functionalization of CNTs with potassium-binding DNA aptamers.
• Measurement of CNT conduction changes in response to varying potassium ion concentrations.

Main Results:

• Demonstrated monotonic increases in CNT conduction with increasing potassium ion concentration, achieving a 10 picomolar limit of detection.
• Identified aptamer-induced electrostatic gating via G-quadruplex stabilization and charge density modulation near the CNT channel.
• Confirmed sensitivity to potassium and selectivity against other ions in both resistive and transistor modes.

Conclusions:

• The study establishes aptamer-induced electrostatic gating as a viable signal transduction mechanism for CNT electronic biosensors.
• The developed CNT aptasensor architecture and response signatures provide a foundation for future aptasensor development.
• This work highlights the potential of integrating DNA aptamers with nanomaterials for advanced electronic biosensing applications.