Journal Article

High-Fidelity Tissue Engineering of Patient-Specific Auricles for Reconstruction of Pediatric Microtia and Other Auricular Deformities

Popa, Samantha, Perez, Justin L., Pramanik, Satadru, Spector, Jason A., Hernandez, Karina A., Zhou, Sherry, Kafka, Concepcion, Brown, Bryan N., Bonassar, Lawrence J., Reiffel, Alyssa J., Ryu, Won Seuk

2013

Overview

Autologous techniques for the reconstruction of pediatric microtia often result in suboptimal aesthetic outcomes and morbidity at the costal cartilage donor site. We therefore sought to combine digital photogrammetry with CAD/CAM techniques to develop collagen type I hydrogel scaffolds and their respective molds that would precisely mimic the normal anatomy of the patient-specific external ear as well as recapitulate the complex biomechanical properties of native auricular elastic cartilage while avoiding the morbidity of traditional autologous reconstructions. Three-dimensional structures of normal pediatric ears were digitized and converted to virtual solids for mold design. Image-based synthetic reconstructions of these ears were fabricated from collagen type I hydrogels. Half were seeded with bovine auricular chondrocytes. Cellular and acellular constructs were implanted subcutaneously in the dorsa of nude rats and harvested after 1 and 3 months. Gross inspection revealed that acellular implants had significantly decreased in size by 1 month. Cellular constructs retained their contour/projection from the animals' dorsa, even after 3 months. Post-harvest weight of cellular constructs was significantly greater than that of acellular constructs after 1 and 3 months. Safranin O-staining revealed that cellular constructs demonstrated evidence of a self-assembled perichondrial layer and copious neocartilage deposition. Verhoeff staining of 1 month cellular constructs revealed de novo elastic cartilage deposition, which was even more extensive and robust after 3 months. The equilibrium modulus and hydraulic permeability of cellular constructs were not significantly different from native bovine auricular cartilage after 3 months. We have developed high-fidelity, biocompatible, patient-specific tissue-engineered constructs for auricular reconstruction which largely mimic the native auricle both biomechanically and histologically, even after an extended period of implantation. This strategy holds immense potential for durable patient-specific tissue-engineered anatomically proper auricular reconstructions in the future.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Animals / Auricle / Biocompatibility / Biology / Biomechanics / Biomedical engineering / Biomedical materials / CAD software / CAD/CAM / Cartilage / Cattle / Child / Chondrocytes / Chondrocytes - cytology / Chondrocytes - metabolism / Collagen / Collagen (type I) / Collagen Type I - chemistry / Collagen Type I - physiology / Computer-Aided Design / Deformation / Deposition / Digitization / Ear / Ear Auricle - anatomy & histology / Ear Auricle - growth & development / Ear Cartilage - growth & development / Ear Cartilage - surgery / Ear, External - growth & development / Ear, External - surgery / Elastic properties / Engineering / Fidelity / Gene expression / Humans / Hydraulic permeability / Hydrogel, Polyethylene Glycol Dimethacrylate / Hydrogels / Implantation / Inspection / Ionizing radiation / Laboratories / Male / Materials Science / Mechanical properties / Medicine / Microtia / Morbidity / Pediatrics / Permeability / Photogrammetry / Polymers / Prostheses and Implants / Rats / Reconstruction / Reconstructive Surgical Procedures / Scaffolds / Staining / Surgical implants / Synthetic products / Tissue Engineering / Ultrasonic imaging