Model neural prostheses with integrated microfluidics: a potential intervention strategy for controlling reactive...

Area of Science:

• Biomedical Engineering
• Neuroscience
• Materials Science

Background:

• Chronic implantation of intracortical probes can trigger reactive tissue responses.
• Effective therapeutic strategies are needed to mitigate these adverse effects and improve device longevity.

Purpose of the Study:

• To fabricate and test silicon intracortical probes with microfluidic channels.
• To evaluate the feasibility of diffusion-mediated delivery of therapeutic agents to treat reactive tissue volumes around implanted devices.

Main Methods:

• Fabrication of 3D probes using surface micromachining and deep reactive ion etching (DRIE).
• In vitro release studies using Texas Red labeled transferrin and dextran in agarose gel.
• In vivo characterization in rat premotor cortex using confocal microscopy and immunohistochemistry for phosphorylated mitogen-activated protein kinases (MAPKs).

Main Results:

• Successful in vitro release of therapeutic agents from microchannels.
• Observed diffusion and cellular uptake of TR-transferrin up to 400 microm from the implantation site within 1 hour.
• Reactive tissue volume, indicated by MAPKs, extended 400-800 microm radially from the probe over 6 weeks.

Conclusions:

• Diffusion-mediated delivery via microfluidic probes is feasible for targeting reactive tissue around implants.
• This approach offers a potential strategy for managing inflammation and improving outcomes for chronically implanted intracortical devices.