Tissue engineering of human ear pinna

Abstract

Auricular deformities (Microtia) can cause physical, social as well as psychological impacts on a patient's wellbeing. Biofabrication of a complex structure such as ear pinna is not precise with currently available techniques. These limitations can be overcome with the help of tissue engineering. In this article, the authors presented molding and three dimensional (3D) printing to generate a flexible, human size ear pinna. The decellularization of goat ear cartilage protocol and bioink alkaline digestion protocol was followed to yield complete removal of all cellular components without changing the properties of the Extra Cellular Matrix (ECM). Decellularized scaffold used in molding technology and 3D printing technology Computer-Aided Design /Stereolithography (CAD/STL) uses bioink to construct the patient-specific ear. In vivo biocompatibility of the both ear pinnae showed demonstrable recellularization. Histology and scanning electron microscopy analysis revealed the recellularization of cartilage-specific cells and the development of ECM in molded and 3D printed ear pinna after transplantation. Both the techniques provided ideal results for mechanical properties such as elasticity. Vascular Associated Protein expression revealed specific vasculogenic pattern (angiogenesis) in transplanted molded pinna. Chondrocyte specific progenitor cells express CD⁹⁰⁺ which highlighted newly developed chondrocytes in both the grafts which indicated that the xenograft was accepted by the rat. Transplantation of molded as well as 3D ear pinna was successful in an animal model and can be available for clinical treatments as a medical object to cure auricular deformities.

Keywords: 3D printing; Auricular deformities; Biofabrication; Bioink; Clinical treatments; Extracellular matrix; Scaffold; Tissue engineering.