Micro-molded cannulae for intracochlear infusions in small rodents

Area of Science:

• Biomedical Engineering
• Materials Science
• Otolaryngology

Background:

• Accurate placement of inner ear devices is critical for therapeutic efficacy.
• Existing micro-cannulae may lack precise control over insertion depth and interface parameters.
• Development of micro-devices for cochlear implantation requires advanced fabrication methods.

Purpose of the Study:

• To design, fabricate, and test novel micro-cannulae with integrated insertion stops.
• To achieve precise control over insertion depth, interface contact area, and tubing geometry.
• To evaluate the histological accuracy of micro-cannula placement in the cochlea.

Main Methods:

• Silicon micro-molding fabricated via bulk-silicon micro-machining techniques.
• Microelectronic fabrication methods for precise parameter control.
• Histological evaluation of micro-cannula placement in the basal portion of scala tympani.

Main Results:

• Micro-cannulae with integrated insertion stops were successfully designed and fabricated.
• Precise control over insertion depth (±5 µm), interface contact area (±502 µm²), and tip out-of-roundness (±7%) was achieved.
• Histological analysis confirmed correct cannula positioning within the basal scala tympani.

Conclusions:

• The developed micro-cannulae offer precise insertion depth control, crucial for cochlear interventions.
• Micro-machining techniques enable reliable fabrication of micro-devices with defined geometric parameters.
• The validated placement accuracy supports the potential of these micro-cannulae in otological applications.