HI-FI Auricular Engineering: Preventing Loss of Volume and Definition Using Custom Contour-Matched 3D-Printed Biodegradable External Scaffolds
Alexandra J. Lin, BA1, Jaime Bernstein, BS1, Benjamin Cohen, BS2, Justin Buro, BA1, Karel-Bart Celie, BA1, Yoshiko Toyoda, BA1, Andrew Miller, BS1, Alice Harper, BA1, Lawrence J. Bonassar, PhD2, John P. Morgan, PhD1, Jason A. Spector, MD FACS1.
1Laboratory of Bioregenerative Medicine & Surgery, Division of Plastic Surgery, Weill Cornell Medical College, New York, NY, USA, 2Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA.
PURPOSE: A major obstacle to clinical translation of tissue engineered auricles is the significant contraction and loss of topography that occurs during maturation of the soft collagen/chondrocyte matrix into elastic cartilage. Previously, we demonstrated that a 3D-printed biodegradable cage significantly mitigated contraction of simple disc-shaped collagen hydrogels seeded with human auricular chondrocytes (HAuCs) in vivo without impeding the development of elastic cartilage. Herein we fabricate cages to invest chondrocyte-collagen hydrogels with more intricate "anatomic" topographic features.
METHODS: Custom external cages were designed with a geometric element representative of the helical rim using SolidWorks (Dassault Systèmes, Vélizy-Villacoublay, France), then 3D-printed using polylactic acid (PLA). HAuCs were encapsulated into type I collagen hydrogels with high fidelity contour-matching to the cages. The hydrogels, either protected or unprotected by the PLA cages, were implanted into nude rats and explanted after 3 months.
RESULTS: All constructs developed a glossy white cartilaginous appearance, similar to native auricular cartilage. Cage-protected constructs contracted significantly less than unprotected constructs on base area comparison (14.33% vs. 56%, p = 0.0023), retained volume (213.4mm3 vs. 117.2mm3, p = 0.0290), and maintenance of the topographic "helical rim" feature compared to unprotected constructs.
CONCLUSION: Custom contour-matched 3D-printed biocompatible/biodegradable external cages significantly mitigate contraction and maintain the complex topography of HAuC constructs. This technique can be used to create custom cages that contour to any form, enabling the fabrication of engineered autologous cartilage tailored to individual patient anatomy, minimizing the contraction and loss of topography that has thus far impeded translation to the clinic.
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