Publication
Sensorineural hearing loss is a profound form of deafness, arising from damage to cochlear hair cells, which can be treated by limited clinical options such as cochlear implants. However, the implantation procedure carries the inherent risk of electrode insertion trauma, which can potentially damage residual hearing. To date, several drug therapeutics have been proposed; however, most drug delivery systems administer single drugs over short durations with limited release, or they require additional surgery for removal. Here, we demonstrate the use of flexible biodegradable drug implants made by additive manufacturing, which could simultaneously deliver multiple anti-inflammatory drugs and growth factors over a prolonged period with a passively controlled release rate. Micro-drug reservoirs fabricated using poly(ethylene glycol) diacrylate through two-photon polymerization were filled with lipid-drug composites by drop-on-demand inkjet printing. The hydrophobic and water-impermeable characteristics of lipids, along with the one-way open reservoir design, allowed sustained release over 30 days. The biodegradable drug implants were integrated with a polyimide-Pt-based cochlear electrode array, which remained in place after implant degradation. In vitro and in vivo studies demonstrate the therapeutic efficacy of the implants for prolonged, multi-drug delivery, offering a promising solution for preserving hearing and improving the effectiveness of cochlear implants.