Microelectrode Arrays for Simultaneous Electrophysiology and Advanced Optical Microscopy

Area of Science:

• Neuroscience
• Biomedical Engineering
• Materials Science

Background:

• Advanced optical imaging is crucial for neuroscience, but conventional microscopes have resolution limits for structures like synapses.
• Microelectrode arrays (MEAs) are essential for understanding neural communication.
• Integrating electrophysiology with optical imaging presents challenges due to equipment interference.

Purpose of the Study:

• To develop transparent microelectrode arrays (MEAs) compatible with advanced optical microscopy.
• To enable simultaneous recording of neuronal electrical activity and optical imaging.
• To overcome limitations in studying neural circuits by combining high temporal and spatial resolution techniques.

Main Methods:

• Fabrication of transparent MEAs using conducting polymer poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) via optical lithography.
• Characterization of electrode transparency (>75% in visible spectrum) and impedance.
• Recording of action potentials from primary neuronal cells and performing calcium (Ca2+) imaging through the transparent electrodes.

Main Results:

• Demonstrated artifact-free recording of single neuronal units with a signal-to-noise ratio of 7.7 (17.7 dB) under laser illumination.
• Successfully performed calcium (Ca2+) imaging, a marker of neuronal activity, using the transparent MEAs.
• Showcased compatibility with conventional and super-resolution microscopy (SRM) without compromising image quality.

Conclusions:

• Transparent MEAs made from PEDOT:PSS offer a scalable solution for combined electrophysiology and advanced optical imaging.
• These devices facilitate the synergistic use of electrophysiology's temporal resolution and optical imaging's spatial resolution in neuroscience research.
• Pave the way for deeper insights into neural circuit function by integrating multimodal recording techniques.