Ex vivo localization of wireless implantable microdevice using high-resolution 3D imaging techniques.

Area of Science:

• Biomedical Engineering
• Neuroscience
• Medical Imaging

Background:

• The CROSSBRAIN project aims to develop wireless implantable microbots (µBots) for localized neuromodulation.
• Accurate visualization and placement of µBots are critical for studying their functionality and therapeutic potential.
• Existing imaging and histological methods face limitations in preserving implant sites for MRI-incompatible µBots.

Purpose of the Study:

• To develop and validate an integrated imaging workflow for visualizing µBot dummies in ex vivo brain tissue.
• To establish an optimized strategy for precise localization of microscale implants incompatible with MRI.
• To provide a foundational methodology for future in vivo studies of functional µBots.

Main Methods:

• Utilized non-functional silicon µBot dummies (100 × 100 × 50 μm³) for ex vivo experiments.
• Developed an integrated workflow combining histological techniques with 3D X-ray tomography.
• Employed synchrotron radiation-based X-ray Phase Contrast Tomography (XPCT) for high-resolution imaging and conventional micro-Computed Tomography (micro-CT) for non-destructive guidance.

Main Results:

• Standard histological methods and tissue clearing failed to preserve dummy positions.
• The integrated approach combining histology with 3D X-ray tomography successfully visualized µBot dummies within brain tissue.
• XPCT provided detailed visualization of dummies amidst vascular and cellular structures; micro-CT enabled targeted sectioning.

Conclusions:

• The developed imaging workflow offers a robust strategy for visualizing MRI-incompatible µBots in brain tissue.
• This methodology is essential for ensuring optimal device placement and enabling future functional assessments.
• The approach supports the development of personalized neuromodulation therapies through precise device localization.