Auricular cartilage tissue engineering: from making cartilage to regenerating a shape-stable elastic organ.

Auricular cartilage tissue engineering has long been grouped under the broader category of craniofacial cartilage reconstruction, but this classification is becoming insufficient. Unlike articular cartilage repair, which mainly aims to restore load-bearing function and relieve pain, auricular reconstruction must reproduce a complex three-dimensional structure, preserve elastic recoil, resist long-term contraction, tolerate soft-tissue coverage, and remain surgically and aesthetically acceptable over time. These demands make auricular cartilage engineering fundamentally distinct from generic cartilage engineering. Over the past decade, the field has progressed from proof-of-concept ear-shaped constructs in small-animal models to more advanced strategies, including patient-specific scaffold design, expansion of autologous auricular chondrocytes, coculture systems, decellularized auricular extracellular matrices, and 3D printing or bioprinting. Together, these advances indicate that auricular cartilage tissue engineering has moved beyond simple proof-of-concept. However, routine clinical translation remains constrained by unresolved challenges, including long-term shape maintenance, soft-tissue coverage, inflammatory remodeling, scaffold degradation, reproducible manufacturing, regulatory approval, and integration into pediatric reconstructive workflows. At the same time, they reveal a key conceptual limitation: many studies still define success as the formation of "cartilage-like" tissue, even though auricular regeneration ultimately requires a stable elastic organ rather than a histologically acceptable cartilage mass. In this perspective, we argue that the field has reached a stage where conceptual refinement is as important as technical innovation. Future progress, we propose, depends on three related shifts: moving from a generic chondrogenic paradigm to one centered on elastic cartilage biology; redefining scaffolds as instructive microenvironments rather than mere shape-retaining supports; and evaluating translational success not only by feasibility, but also by reproducibility, manufacturability, and long-term clinical robustness. Rather than offering another technique-centered review of auricular reconstruction, this Perspective advances an auricular-specific framework for defining success in elastic organ regeneration. The next major advances, in our view, will come from approaches that integrate elastic cartilage biology, instructive scaffold design, and measurable translational criteria rather than optimizing these dimensions separately.