Experimentally validated vibro-acoustic modeling of 3D bio-printed grafts for potential use in human tympanic membrane regeneration

Three-dimensional (3D) bioprinting is a pioneering field of tissue engineering obtaining a special role in most medical engineering fields. Otology is a medicine branch that needs bioprinting technology to receive aids for the reconstruction of aesthetic necessities of the ear and treating hearing loss diseases due to several pathological reasons such as tympanic membrane (TM) perforation. In this work, computational dynamic simulations of 3D printed TM grafts are presented. The main purpose of numerical modeling of these experimentally validated composite scaffolds is to demonstrate the worth of simulation in shortening the design time and decreasing testing costs of biomedical engineering projects. The simulated 3D printed TM grafts were fabricated in two main architectural categories using three different polymeric materials of polydimethylsiloxanes (PDMS), flex polylactic acid (PLA), and polycaprolactone (PCL) with uniform infilling of fibrincollagen composite hydrogels. As a numerical and dynamic validation study, firstly, a finite element (FE) simulation of the artificial TM grafts is carried out for a vibro-acoustic analysis by the COMSOL Multiphysics software package. Then a comparative study of results obtained from the dynamic modeling is performed with a set of existing data taken from experimental validation test results from digital optoelectronic holography (DOEH) and laser Doppler vibrometry (LDV). Observations show a good correlation between the acoustic behaviors of in vitro tested 3D printed TM grafts and computational models in both frequency domain motion and normalized velocity patterns. Satisfying correlation between acoustic properties of simulated TM grafts and experimental test results shows potential applications of printed TM grafts in tympanoplasty.