A multichannel neural probe for selective chemical delivery at the cellular level

Area of Science:

• Neuroscience
• Bioengineering
• Materials Science

Background:

• Accurate chemical delivery and simultaneous neural recording/stimulation are crucial for in vivo neuroscience research.
• Existing microprobes often lack the capability for precise, localized chemical delivery.
• The development of integrated devices for multimodal neural interfacing is an ongoing challenge.

Purpose of the Study:

• To develop and characterize a novel bulk-micromachined multichannel silicon probe.
• To enable selective chemical delivery at the cellular level alongside electrical recording and stimulation of neurons in vivo.
• To assess the probe's performance for acute neural monitoring.

Main Methods:

• Fabrication of a hollow-core silicon probe using bulk micromachining with integrated microchannels.
• Theoretical and experimental analysis of fluid flow characteristics within the microchannels.
• Acute in vivo experiments involving chemical stimulation and neural response monitoring in guinea pig brains.

Main Results:

• The developed silicon probe successfully integrates multiple flow channels for selective chemical delivery.
• Microchannel formation is compatible with standard probe fabrication processes and on-chip circuitry.
• Experimental flow analysis demonstrated precise fluid delivery capabilities (e.g., 100 pl in 1 s at 11 torr).
• Intermixing of chemicals becomes significant for dwell times exceeding 30 minutes, suggesting the need for a shutter mechanism for chronic applications.

Conclusions:

• A novel multichannel silicon probe offers a versatile platform for combined chemical delivery and neural interfacing.
• The probe's design allows for precise, cellular-level manipulation of the neural environment.
• This technology has significant potential for advancing in vivo studies of neural function and pharmacology.