Tissue Engineering of Autologous Cartilage for Craniofacial Reconstruction by Injection Molding

Abstract

Each year, more than one million patients undergo some type of procedure involving cartilage reconstruction. Polymer hydrogels such as alginate have been demonstrated to be effective carriers of chondrocytes for subcutaneous cartilage formation. The goal of this study was to develop a simple method to create complex structures with good three-dimensional tolerance in order to form cartilage in specific shapes in an autologous animal model. Six alginate implants that had been seeded with autologous chondrocytes through an injection molding process were implanted subcutaneously in sheep, harvested after 6 months, and analyzed histologically, biochemically, and biomechanically, in comparison with original auricular cartilage. Molds of craniofacial implants were prepared with Silastic E RTV (Dow Corning, Midland, Mich.). Chondrocytes were harvested from sheep auricular cartilage and suspended in 2% alginate at a concentration of 50 x 10(6) cells/ml. The mixture of cells and gel was injected into the Silastic molds and removed after 20 minutes. Chondrocyte-alginate constructs were implanted subcutaneously in the necks of the sheep from which the cells had originally been harvested, and the constructs were removed after 30 weeks. Analyses of the implanted constructs indicated cartilage formation with three-dimensional shape retention. The proteoglycan and collagen contents of the constructs increased with time to approximately 80 percent of the values for native tissue. The equilibrium modulus and the hydraulic permeability were 74 and 105 percent of those of native sheep auricular cartilage, respectively.

Long-Term Morphological and Microarchitectural Stability of Tissue-Engineered, Patient-Specific AuriclesIn Vivo

“…28 Briefly, ears were obtained from freshly slaughtered 1-to 3-day-old calves (Gold Medal Packing, Oriskany, NY). Auricular cartilage was dissected from the surrounding skin and perichondrium under sterile conditions.…”

Reconstruction of human elastic cartilage by a CD44 + CD90 + stem cell in the ear perichondrium

“…stem cell identification | flow cytometry | cell transplantation | regenerative medicine | plastic surgery C raniofacial injuries and abnormalities affect millions of patients worldwide, highlighting the need for novel therapeutic strategies (1). Conventional approaches to treat these defects rely on reconstructive materials, such as autocartilage and bone grafts or synthetic compounds (2)(3)(4)(5)(6).…”

An Optical Method for Evaluation of Geometric Fidelity for Anatomically Shaped Tissue-Engineered Constructs

“…The feasibility of using medical imaging data to design tissue-engineered constructs has only been investigated very recently. 3,32 Similarly, over the past decade a number of efforts have demonstrated the utility of injection molding 3,11,30,33 and 3D tissue printing 17,20 in fabricating engineered tissues with complex geometry. Despite all this work there is limited information on the geometric accuracy of these techniques and how this geometric accuracy might compare between techniques.…”