Dopamine-Regulated Plasticity in MoO₃ Synaptic Transistors

Area of Science:

• Materials Science
• Neuroscience
• Electrical Engineering

Background:

• Field-effect transistor (FET) biosensors are crucial for biohybrid neural interfaces due to their sensitivity.
• Surface functionalization complexity hinders industrial adoption of FET biosensors.
• Developing simple, label-free biosensors is essential for advancing neural interface technology.

Purpose of the Study:

• To demonstrate a simple, label-free biosensor based on molybdenum oxide (MoO3) for detecting dopamine.
• To investigate dopamine-regulated plasticity in MoO3-based FETs for synaptic emulation.
• To optimize MoO3 channel properties for enhanced sensing performance and selectivity.

Main Methods:

• Fabrication of a MoO3-based FET biosensor.
• Utilizing dopamine oxidation at the channel surface to induce charge transfer.
• Modulating channel conductance by controlling oxygen levels and device dimensions.
• Testing sensor selectivity against common ions (K+, Na+, Ca2+).

Main Results:

• The MoO3 FET biosensor successfully emulates tunable synaptic weight through dopamine activity.
• Device performance shifts from metallic to semiconducting behavior based on oxygen levels.
• Optimized channel dimensions enable detection across a wide dopamine concentration range (100 nM to sub-mM).
• The biosensor exhibits excellent selectivity for dopamine over other tested ions.

Conclusions:

• A novel, simple, label-free MoO3 FET biosensor is developed for neurotransmitter detection.
• The device effectively mimics synaptic plasticity, offering a new platform for neural interfaces.
• Optimized MoO3 properties allow for sensitive and selective dopamine sensing, addressing key technological challenges.