Multimodal Layer-Crossing Interrogation of Brain Circuits Enabled by Microfluidic Axialtrodes.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Materials Science

Background:

• Conventional neural interfaces have limited spatial resolution due to distal-only tissue interaction.
• Developing advanced tools is crucial for understanding brain function and treating neurological disorders.

Purpose of the Study:

• To introduce a novel neural interface, the microfluidic axialtrode, for enhanced brain exploration.
• To demonstrate the axialtrode's capability for spatially distributed neural modulation and recording.

Main Methods:

• Fabrication of a flexible, multimaterial fiber with integrated electrodes and microfluidic channels via controlled angled cleaving.
• In vivo demonstration of optogenetics, electrophysiological recording, and drug delivery along the fiber's axis.
• Integration with a 3D-printed biocompatible scaffold for stability.

Main Results:

• The axialtrode enables simultaneous, spatially distributed optogenetics, multisite electrophysiological recording, and targeted drug delivery.
• The axial configuration enhances functional interface with neural tissue.
• The soft polymer construction and reduced footprint minimize inflammatory responses compared to silica fibers.

Conclusions:

• The microfluidic axialtrode offers a scalable and versatile platform for advanced neural interfacing.
• This technology facilitates simultaneous interaction with multiple neuronal layers.
• The design overcomes limitations of conventional neural probes for brain research and therapy development.