Electrospun biomimetic tympanic membrane implants: Simulating the effect of fiber/filament arrangement on acousto-mechanical behavior

Myringoplasty is a routine surgery to restore the hearing of patients with a subacute and chronic tympanic membrane (TM) perforation. Electrospun scaffolds as a new art of synthetic TM replacement have a great potential to overcome the drawbacks of currently used autologous tissues due to the nano- and microfibers. Most recently with the development of tissue engineering, efforts have been made to mimic the radial and circular fiber arrangement of human TM to generate comparable acoustic vibration and mechanical stability. However, a convincing solution is still missing because of the lack of deep understanding the role of fiber arrangement in the oscillatory function. Therefore, the aim of this study is to systematically investigate the effect of fiber arrangement of TM implants on acousto-mechanical behavior based on finite element (FE) simulation. Electrospun 2D flat and 3D conical TM implants were designed in the FE model as nanofibrous composites with additional micro-filaments to mimic the radial and circular arrangement of collagen fibers as well as tailored fiber/filament structures. Not only harmonic acoustic vibration but also static mechanical deformation were simulated to get a systematic connection between the fiber arrangement in the native TM and its acousto-mechanical behavior. The results show that centering circular fibers at the umbo has a major contribution to improving acoustic vibration behavior while radial fibers entail a higher mechanical stability. The hybrid structure FFS3 that has the same fraction of radial and circular fibers shows promising results, since the implant design combines a higher acoustic compliance and a lower static deformation.