Reversing current rectification to improve DNA-sensing sensitivity in conical nanopores

Area of Science:

• Nanotechnology
• Biosensing
• Molecular Diagnostics

Background:

• Nanopore sensors offer high sensitivity for biomolecule detection.
• Ion current rectification in nanopores is sensitive to surface charge variations.
• Existing methods for DNA detection often require labels and lack ultrasensitivity.

Purpose of the Study:

• To develop an ultrasensitive, label-free DNA detection method.
• To engineer a nanopore biosensor capable of reversing current rectification direction for sensing.
• To leverage enzymatic reactions for modifying nanopore surface charge for DNA detection.

Main Methods:

• Fabrication of a glass conical nanopore with an asymmetric structure.
• Utilizing an enzymatic cleavage reaction to alter the nanopore's surface charge.
• Monitoring ion current rectification curves to quantify DNA concentration.

Main Results:

• The nanopore biosensor demonstrated ultrasensitive DNA detection down to 0.1 femtomolar (fM).
• The ion current rectification ratio shifted significantly with varying DNA concentrations, from -6.5 to +16.1.
• The sensor achieved a reversal in current rectification direction, enabling amplified signal response.

Conclusions:

• The developed nanopore biosensor provides a novel and ultrasensitive approach for label-free DNA detection.
• The direction reversal of current rectification amplification is a key innovation for enhanced sensing.
• This technology holds potential for advanced molecular diagnostics and biological analysis.