A Bidirectional-Current CMOS Potentiostat for Fast-Scan Cyclic Voltammetry Detector Arrays

Area of Science:

• Electrical Engineering
• Neuroscience
• Materials Science

Background:

• Microelectrode arrays are crucial for electrochemical sensing and neural recording.
• Existing potentiostat designs face limitations in handling bidirectional currents and parallel processing.
• Fast-scan cyclic voltammetry (FSCV) requires high-speed, sensitive detection systems.

Purpose of the Study:

• To present a novel potentiostat circuit capable of bipolar electrode voltages and bidirectional current detection.
• To enable parallel recording of quantal release events and electrode impedance characterization using microelectrode arrays.
• To facilitate high-throughput drug screening applications.

Main Methods:

• Development of a potentiostat circuit utilizing a regulated-cascode amplifier for positive currents and an active-input regulated-cascode mirror for negative currents.
• Fabrication of a 64-channel FSCV detector array using a 0.5-μm, 5-V CMOS process.
• Validation using prerecorded FSCV data from carbon-fiber microelectrodes.

Main Results:

• Demonstration of a compact 64-channel FSCV detector array (45 μm × 30 μm per detector) with minimal components (14 transistors, 50-fF capacitor).
• The potentiostat topology effectively handles both positive and negative input currents.
• Successful validation of the system's performance with real-world FSCV data.

Conclusions:

• The presented potentiostat circuit and CMOS detector array offer a powerful platform for advanced electrochemical analysis.
• This technology significantly enhances capabilities for parallel recording, impedance characterization, and drug screening.
• The system paves the way for more efficient and high-throughput studies in neuroscience and materials science.