Field-Effect Transistor with a Plasmonic Fiber Optic Gate Electrode as a Multivariable Biosensor Device

Area of Science:

• Nanotechnology
• Spectroscopy
• Biosensing

Background:

• Surface plasmon resonance (SPR) is a powerful label-free optical sensing technique.
• Integrating SPR with transistor technology offers potential for enhanced sensitivity and multiplexed detection.
• Current SPR systems often lack the ability to differentiate between mass and charge binding events.

Purpose of the Study:

• To develop and characterize a novel multivariable sensor system combining transistor and fiber optic SPR.
• To enable simultaneous discrimination of mass and charge contributions in binding assays.
• To optimize sensor geometry for improved electronic and optical signal transduction.

Main Methods:

• Fabrication of a hybrid transistor-fiber optic SPR sensor where the gate electrode serves as the sensor surface.
• Systematic investigation of sensor geometry parameters, including fiber area to transistor channel area ratio and distance.
• Demonstration of dual-mode sensing capabilities and reversibility of optical signals via electric field application.
• Validation using layer-by-layer polyelectrolyte assembly and a thrombin binding assay with aptamer receptors.

Main Results:

• Successful integration of transistor and fiber optic SPR functionalities into a single sensor platform.
• Optimization of sensor geometry leading to improved electronic and optical signal detection.
• Demonstrated ability to discriminate between mass and charge binding events on the same sensor.
• Achieved reversible plasmon resonance wavelength shifts upon electric field application.
• Successful detection of medically relevant thrombin concentrations in a biosensing assay.

Conclusions:

• The developed dual-mode sensor offers a novel approach for multivariable analysis in biosensing.
• This platform provides simultaneous discrimination of mass and charge binding, enhancing assay capabilities.
• The optimized sensor geometry and demonstrated reversibility pave the way for advanced biosensing applications.