High-Precision 3D Printing of Microporous Cochlear Implants for Personalized Local Drug Delivery.

Area of Science:

• Biomedical Engineering
• Materials Science
• Otolaryngology

Background:

• Hearing loss affects 20% globally, with current systemic treatments limited by the cochlea's anatomy and blood-labyrinth barrier.
• Local drug delivery systems are needed to achieve therapeutic concentrations in the cochlea and avoid systemic side effects.

Purpose of the Study:

• To design, fabricate, and characterize novel 3D-printed cochlear implants for localized drug delivery.
• To create implants with human ear-relevant dimensions and tunable internal microporosity for controlled drug release.

Main Methods:

• Utilized two-photon polymerization (2PP) with IP-Q photoresist to 3D print cochlear implants.
• Fabricated implants in two shapes (rectangular and cylindrical) with varying internal porous structures.
• Characterized implant dimensions, pore size accuracy, surface roughness, and water contact angle.

Main Results:

• Successfully printed cochlear implants with high reproducibility and shape fidelity (0.6 × 0.6 × 2.4 mm³).
• Achieved accurate pore sizes (17.88 ± 0.95 μm and 58.15 ± 1.62 μm) with tunable microporosity.
• Demonstrated high polymerization (~90%) and cytocompatibility of the printed IP-Q material with murine macrophages.

Conclusions:

• 3D-printed cochlear implants with human ear-relevant dimensions and tunable internal microporosity offer a novel approach for hearing loss treatment.
• This technology enables personalized local drug delivery, overcoming limitations of systemic administration.
• The developed implants show potential for effective and targeted therapy in the human cochlea.