Label-free SnO₂ nanowire FET biosensor for protein detection

Area of Science:

• Nanotechnology
• Materials Science
• Biomedical Engineering

Background:

• Field-effect transistors (FETs) are explored for biosensing applications.
• Tin oxide (SnO2) nanowires offer unique electronic properties for device fabrication.
• Developing sensitive and label-free biosensors is crucial for healthcare.

Purpose of the Study:

• To report novel tin oxide nanowire field-effect transistors (SnO2 NW-FETs) for pH and protein detection.
• To demonstrate the proof-of-concept for a bio-sensing device using carrier transport control.
• To enable label-free electronic readout for medical diagnosis.

Main Methods:

• Fabrication of SnO2 NW-FETs with an ultra-thin Al2O3 sensitive layer using atomic layer deposition (ALD).
• Demonstration of pH sensitivity across a range of 3 to 10.
• Functionalization of NW-FETs with streptavidin for specific biotinylated protein detection.
• Optimization of experimental procedures using Enzyme-Linked Immunosorbent Assay (ELISA).
• Integration into a microfluidic system for automated analysis.

Main Results:

• Successful demonstration of pH sensitivity from pH 3 to 10.
• Feasible detection of biotinylated protein using functionalized NW-FETs.
• Immediate, label-free electronic signal readout achieved.
• Integration into microfluidics enables automated analysis of small sample volumes (400 μl).

Conclusions:

• SnO2 NW-FETs are viable for sensitive pH and protein detection.
• The developed bio-sensing device offers label-free electronic readout.
• Integration into microfluidic systems paves the way for portable point-of-care (POC) diagnostic devices.