Biomolecular recognition with a sensitivity-enhanced nanowire transistor biosensor.

Area of Science:

• Nanotechnology
• Biosensors
• Field-Effect Transistors

Background:

• Conventional silicon nanowire field-effect transistors (SiNW-FETs) used as biosensors are all area modified (AAM), limiting sensitivity.
• Receptors in AAM SiNW-FETs cover both the nanowire and substrate, leading to inefficiencies.

Purpose of the Study:

• To fabricate and characterize selective surface modified (SSM) SiNW-FETs.
• To demonstrate the improved performance of SSM SiNW-FETs over AAM SiNW-FETs for biosensing applications.

Main Methods:

• Utilized a bottom-up technique to modify SiNWs with 3-aminopropyltrimethoxysilane (APTMS) prior to device fabrication.
• Verified the survival of APTMS linkers through harsh photolithographic processes.
• Evaluated electrical characteristics, including ohmic contact and transconductance.

Main Results:

• SSM SiNW-FETs exhibited desirable electrical properties.
• Demonstrated faster response times and reduced sample requirements compared to AAM SiNW-FETs using biotin-avidin binding.
• Achieved highly sensitive detection of dopamine released from PC12 cells using SSM boronic acid-modified SiNW-FETs.
• Determined dissociation constants (Kd) for biotin-avidin (15 ± 1 fM) and dopamine-boronic acid (33 ± 8 fM) complexes.

Conclusions:

• Selective surface modification significantly enhances the detection sensitivity of SiNW-FET biosensors.
• SSM SiNW-FETs offer a promising platform for highly sensitive biosensing in biomedical diagnosis.
• The developed fabrication method ensures linker stability through demanding manufacturing processes.