Improving serotonin fast-scan cyclic voltammetry detection: new waveforms to reduce electrode fouling.

Area of Science:

• Neuroscience
• Analytical Chemistry
• Biomedical Engineering

Background:

• Serotonin, a key neuromodulator in depression, is typically measured using fast-scan cyclic voltammetry (FSCV).
• Existing FSCV methods, like the Jackson waveform (JW), face limitations in sensitivity and electrode fouling, hindering real-time serotonin monitoring.

Purpose of the Study:

• To investigate the impact of extending FSCV switching potentials on serotonin detection sensitivity and electrode fouling.
• To develop and compare novel FSCV waveforms for improved real-time serotonin measurement.

Main Methods:

• Compared four FSCV waveforms: Jackson waveform (JW), dopamine waveform (DA), extended serotonin waveform (ESW), and extended hold serotonin waveform (EHSW).
• Evaluated waveform performance based on sensitivity (limit of detection, LOD), selectivity, and electrode fouling with serotonin and 5-hydroxyindoleacetic acid (5-HIAA).
• Assessed waveform utility in measuring serotonin via optogenetic stimulation in Drosophila larvae.

Main Results:

• The EHSW demonstrated the highest sensitivity (LOD = 0.6 nM), significantly outperforming the JW (LOD = 2.4 nM).
• Extended waveforms (ESW, EHSW) reduced electrode fouling by 50% compared to JW for both serotonin and 5-HIAA.
• The DA waveform eliminated electrode fouling due to its negative holding potential; JW and ESW showed high selectivity for serotonin over dopamine.

Conclusions:

• New FSCV waveforms, particularly EHSW and ESW, offer enhanced sensitivity and reduced fouling for serotonin detection.
• The DA waveform provides a fouling-free alternative, while JW and ESW excel in selectivity.
• These optimized waveforms provide versatile tools for real-time serotonin measurement, catering to diverse experimental needs in neuroscience research.