Quantitative Evaluation of Mechanical Properties in Tissue-Engineered Auricular Cartilage

Abstract

Keywords:Auricular cartilage, elastic cartilage, auricle, pinna, outer ear, mechanical testing, elastin Conflict of interest:All authors have no conflict of interest. 3 AbstractTissue-engineering (TE) efforts for ear-reconstruction often fail due to mechanical incompetency. It is therefore key for successful auricular cartilage TE to ensure functional competency, i.e. to mimic the mechanical properties of the native ear tissue. A review of past attempts to engineer auricular cartilage shows unsatisfactory functional outcomes with various cell-seeded biodegradable polymeric scaffolds in immunocompetent animal models. However, promising improvements to construct stability were reported with either mechanically-reinforced scaffolds or novel two-stage implantation techniques. Nonetheless, quantitative mechanical evaluation of the constructs is usually overlooked, and such an evaluation of TE constructs alongside a benchmark of native auricular cartilage would allow real-time monitoring and improve functional outcomes of auricular TE strategies.Although quantitative mechanical evaluation techniques are readily available for cartilage, these techniques are designed to characterize the main functional components of hyaline and fibrous cartilage such as the collagen matrix or the glycosaminoglycan (GAG) network, but they overlook the functional role of elastin, which is a major constituent of auricular cartilage. Hence for monitoring auricular cartilage TE, novel evaluation techniques need to be designed. These should include a characterization of the specific composition and architecture of auricular cartilage, as well as mechanical evaluation of all functional components. Therefore, this paper reviews the existing literature on auricular cartilage TE as well as cartilage mechanical evaluation and proposes recommendations for designing a mechanical evaluation protocol specific for auricular cartilage, and establishing a benchmark for native auricular cartilage to be used for quantitative evaluation of TE auricular cartilage.15.02.13 4

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