Flexible, diamond-based microelectrodes fabricated using the diamond growth side for neural sensing

Area of Science:

• Materials Science
• Biomedical Engineering
• Neuroscience

Background:

• Diamond's properties (biocompatibility, inertness) are ideal for sensors.
• Diamond's hardness limits its use in neural implants due to mechanical mismatch with soft tissues.

Purpose of the Study:

• To develop a flexible, diamond-based microelectrode probe for neural implants.
• To optimize fabrication for using the diamond growth surface as the sensing area.

Main Methods:

• Fabrication of multichannel boron-doped diamond (BDD) microelectrodes on a Parylene C substrate.
• Comparison of BDD growth surface vs. nucleation surface for electrochemical properties and dopamine sensing.
• In vitro and in vivo validation of neural recording capabilities.
• In vitro biocompatibility assessment using rat cortical neuron cultures.

Main Results:

• The BDD growth surface showed a rougher morphology, higher sp3 content, wider potential window, and lower background current than the nucleation surface.
• BDD growth surface electrodes demonstrated superior sensitivity and stability for dopamine detection.
• Successful in vitro and in vivo neural recordings were achieved with the BDD growth side electrodes.
• The microcrystalline diamond film exhibited good biocompatibility in neuron cultures.

Conclusions:

• The BDD growth surface offers significant advantages for implantable microelectrodes, improving sensitivity, selectivity, and stability.
• Flexible diamond microelectrode probes are a promising technology for advanced neural implants.
• The developed fabrication method enables the use of diamond's beneficial properties in neural interfaces.