2015 4 th TERMIS World CongressBoston, MassachusettsSeptember 8–11, 2015

Abstract

Silk fibroin membranes have shown potential as an off-the-shelf alternative to existing graft materials to repair tympanic membrane (TM) perforations due to their excellent mechanical properties, transparency and biocompatibility. However, when developing such materials, acoustic properties must also be considered since the material used can have a significant impact on patient hearing out- comes. The two most commonly used graft materials for TM repair are temporalis fascia and cartilage, both harvested from the patient. Silk membranes over a range of thicknesses (5mm to 100mm) were tested alongside animal cartilage and fascia as well as with paper, another graft material used for TM repair. All silk membranes showed excellent acoustic properties, with a peak amplitude of at least 10 dB higher than that of cartilage or fascia. The resonance peak of the silk films increased from 2.5 kHz to 7.9 kHz as the film thickness increased from 5 mmto100mm while the peak amplitude decreased from 32.3 to 5.5 dB rel 1 mm/s/Pa. The paper showed similar properties to silk membranes of a similar thickness. The resonant frequency of silk membranes was much higher than thicker cartilage samples. This is presumably due to differences in stiffness, with the silk membranes showing a Young’s modulus up to 150 times greater than that of cartilage. Future work will focus on modifying the silk membranes to bring the mechanical properties and resonant frequency closer to that of the native tympanic membrane while maintaining the other superior properties of the material.