Bioengineering Full-scale auricles using 3D-printed external scaffolds and decellularized cartilage xenograft

Reconstruction of the human auricle remains a formidable challenge for plastic surgeons. Autologous costal cartilage grafts and alloplastic implants are technically challenging, and aesthetic and/or tactile outcomes are frequently suboptimal. Using a small animal "bioreactor", we have bioengineered full-scale ears utilizing decellularized cartilage xenograft placed within a 3D-printed external auricular scaffold that mimics the size, shape, and biomechanical properties of the native human auricle. The full-scale polylactic acid ear scaffolds were 3D-printed based upon data acquired from 3D photogrammetry of an adult ear. Ovine costal cartilage was processed either through mincing (1 mm3) or zesting (< 0.5 mm3), and then fully decellularized and sterilized. At explantation, both the minced and zested neoears maintained the size and contour complexities of the scaffold topography with steady tissue ingrowth through 6 months in vivo. A mild inflammatory infiltrate at 3 months was replaced by homogenous fibrovascular tissue ingrowth enveloping individual cartilage pieces at 6 months. All ear constructs were pliable, and the elasticity was confirmed by biomechanical analysis. Longer-term studies of the neoears with faster degrading biomaterials will be warranted for future clinical application. STATEMENT OF SIGNIFICANCE: Accurate reconstruction of the human auricle has always been a formidable challenge to plastic surgeons. In this article, we have bioengineered full-scale ears utilizing decellularized cartilage xenograft placed within a 3D-printed external auricular scaffold that mimic the size, shape, and biomechanical properties of the native human auricle. Longer-term studies of the neoears with faster degrading biomaterials will be warranted for future clinical application.