Biofabrication of a shape-stable auricular structure for the reconstruction of ear deformities.

I.A Otto,M.W Grinstaff,P.E Capendale,J.P Garcia,C.C Breugem,R.F.M Van Doremalen,T Lawson,M Kon,M Castilho,M De Ruijter,R Levato,J Malda

doi:10.1016/j.mtbio.2021.100094

Abstract

Bioengineering of the human auricle remains a significant challenge, where the complex and unique shape, the generation of high-quality neocartilage, and shape preservation are key factors. Future regenerative medicine–based approaches for auricular cartilage reconstruction will benefit from a smart combination of various strategies. Our approach to fabrication of an ear-shaped construct uses hybrid bioprinting techniques, a recently identified progenitor cell population, previously validated biomaterials, and a smart scaffold design. Specifically, we generated a 3D-printed polycaprolactone (PCL) scaffold via fused deposition modeling, photocrosslinked a human auricular cartilage progenitor cell–laden gelatin methacryloyl (gelMA) hydrogel within the scaffold, and cultured the bioengineered structure in vitro in chondrogenic media for 30 days. Our results show that the fabrication process maintains the viability and chondrogenic phenotype of the cells, that the compressive properties of the combined PCL and gelMA hybrid auricular constructs are similar to native auricular cartilage, and that biofabricated hybrid auricular structures exhibit excellent shape fidelity compared with the 3D digital model along with deposition of cartilage-like matrix in both peripheral and central areas of the auricular structure. Our strategy affords an anatomically enhanced auricular structure with appropriate mechanical properties, ensures adequate preservation of the auricular shape during a dynamic in vitro culture period, and enables chondrogenically potent progenitor cells to produce abundant cartilage-like matrix throughout the auricular construct. The combination of smart scaffold design with 3D bioprinting and cartilage progenitor cells holds promise for the development of clinically translatable regenerative medicine strategies for auricular reconstruction.

Highlights

Regenerative medicine (RM) is a promising strategy for future treatment of auricular cartilage defects and congenital malformations [1,2,3]
Non-adherent cells were removed and the remaining attached cells were cultured in chondroprogenitor expansion medium, consisting of Dulbecco's modified Eagle Medium (DMEM) supplemented with 10% v/v fetal bovine serum (FBS; Lonza), 1% Non-Essential Amino Acids (NEAA; Gibco), 0.2 mM L-ascorbic acid 2-phosphate (Sigma-Aldrich, The Netherlands), 100 U/mL penicillin (Life Technologies, The Netherlands), 100 μg/mL streptomycin (Life Technologies) and 5 ng/mL basic fibroblast growth factor
LIVE/DEAD staining was performed on auricular cartilage progenitor cells (AuCPCs) in gelatin methacryloyl (gelMA) hydrogel at days 1, 3, and 10

Summary

Introduction

Regenerative medicine (RM) is a promising strategy for future treatment of auricular cartilage defects and congenital malformations [1,2,3]. It typically applies a combination of cells, materials and bioactive factors to engineer a new tissue or stimulate the regeneration of native tissue [4]. As current surgical strategies for auricular reconstruction use autologous costal cartilage for shaping the implant framework [5,6,7,8,9], the generation of neocartilage in the laboratory would obviate the need for a large harvest site and reduce associated morbidity [1,2,3,10,11]. The first clinical trial with tissue-engineered ear-shaped constructs implanted in five children presents encouraging preliminary outcomes [15]

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Results

Discussion

Conclusion