Electrolyte-free Amperometric Immunosensor using a Dendritic Nanotip

Area of Science:

• Nanotechnology
• Biosensing
• Amperometry

Background:

• Nanostructured sensors offer high sensitivity for amperometric biosensing.
• Fabrication and use of nanostructured sensors present challenges.
• Dendritic nanotips can enhance electric field generation for sensing.

Purpose of the Study:

• To describe a dendritic nanotip as an amperometric biosensor for sensitive bacterial detection.
• To investigate the fabrication and electrical characteristics of the nanotip.
• To evaluate the sensor's performance and sensitivity.

Main Methods:

• Fabrication of Si nanowires using UV lithography and etching.
• Coating Si nanowires with single-walled carbon nanotubes (SWCNTs).
• Electrical characterization using cyclic voltammetry and I-V measurements; bacterial capture and detection via fluorescence antibodies.

Main Results:

• Dendritic structure increased electric current density.
• Electrical current decreased when target bacteria were captured and bound with antibodies.
• Sensitivity achieved was 10 cfu/sample volume (10^3 cfu/mL), comparable to fluorescence methods.

Conclusions:

• The dendritic nanotip functions as a highly sensitive amperometric biosensor.
• The sensor design is simple and potentially electrolyte-free.
• This platform enables rapid and sensitive detection of target bacteria.