Vibration properties of biomimetic tympanic membrane replacements made of polycaprolactone produced by the Melt Electro Writing

Introduction It was investigated whether it is possible to produce scaffolds from polycaprolactone (PCL) as a functional synthetic human tympanic membrane replacement for full defects using the new additive process Melt Electro Writing (MEW).

Methods Flat scaffolds with different structural parameters were created to functionally replicate the vibrational properties of human TM. They consisted of fiber arrays with fiber diameters of 10 μm and 15 μm, as well as 150 μm and 250 μm fiber spacing and were fabricated in several layers (4, 6 and 8) and different layer-to-layer orientations (45°, 90°). Thus total thicknesses in the range of human TMs, from 40 μm to 120 μm, could be achieved. The scaffolds with the desired vibrational properties were coated with collagen type I to form an airtight membrane. Vibration measurements were reproducibly performed in a test stand (n=5 per group) and compared with human TMs (n=4) in temporal bones and in the test stand.

Results and Discussion The structural properties influenced the stiffness and thus the vibration properties of the scaffolds. An increase in fiber layers or fiber thickness led to increased stiffness and a corresponding increase in resonant frequency. For certain structural parameters (4 layers, 45° orientation, 250 μm fiber spacing and 10 μm fiber diameter) the vibration characteristics of human TMs (first resonance frequency between 150 Hz and 470 Hz in the test stand, without malleus) could be achieved. The vibration magnitude of the flat scaffolds was generally larger than that of the human TM.

Conclusion The vibration characteristics of MEW PCL scaffolds can be controlled by changing the MEW fiber structure. Thus, they can be designed to be comparable in function and stability to those of human tympanic membranes.

Poster-PDF A-1474.pdf

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Publication History

Article published online:
13 May 2021