Electrode- and Label-Free Assessment of Electrophysiological Firing Rates through Cytochrome C Monitoring via Raman...

Area of Science:

• Neuroscience
• Toxicology
• Biophysics

Background:

• * In vitro neurotoxicology assesses chemical effects on the human brain.
• * Electrophysiological techniques like patch clamp offer high resolution but miss structural/metabolic changes.
• * Integrating electrical recordings with optical methods is crucial for comprehensive neurotoxicity assessment.

Purpose of the Study:

• * To develop an integrated platform for simultaneous electrophysiological and Raman spectroscopy measurements.
• * To establish a label-free, noninvasive method for assessing neuronal electrical activity and intracellular chemical content.
• * To correlate neuronal electrical activity with specific intracellular metabolic markers for improved neurotoxicity evaluation.

Main Methods:

• * Developed an integrated platform combining electrophysiology (e.g., multielectrode arrays) with Raman spectroscopy.
• * Optimized protocols to maximize signal-to-noise ratio, prevent crosstalk, and minimize phototoxicity.
• * Performed synchronous and sequential electrical-optical measurements on neuronal cultures.

Main Results:

• * A strong correlation was found between single-cell metabolic status and overall neuronal firing rate.
• * Raman spectroscopy monitoring of reduced cytochrome C can predict neuronal firing rates, especially with noisy electrodes.
• * Neuronal firing rate and cytochrome C levels were not correlated with lipids, proteins, or nucleic acids.

Conclusions:

• * Neuronal firing rate and reduced cytochrome C are linked metabolic activity indicators.
• * Raman spectroscopy provides additional insights into lipid, protein, and nucleic acid synthesis for acute/chronic neurotoxicity assessment.
• * The integrated platform enables a more accurate, label-free evaluation of neurotoxicity by combining electrical and metabolic data.