Evaluation Strategies for Tissue-engineered Tracheas: From In Vitro Characterization to In Vivo Assessment.

The trachea plays a critical role in maintaining airway patency, ventilation, and mucociliary clearance, supported by its unique anatomical and structural features. Tracheal defects resulting from congenital anomalies, malignancies, trauma, or prolonged intubation present significant clinical challenges. Traditional reconstruction methods, such as end-to-end anastomosis and patch grafts, are often limited by technical feasibility and suboptimal outcomes. Recently, tissue-engineered tracheal scaffolds (TETs), particularly those fabricated using 3D bioprinting technologies, have emerged as promising alternatives due to their ability to mimic natural structures and integrate functional components. However, despite technological progress, no long-term successful clinical applications have been established to date, highlighting the need for robust and standardized preclinical evaluation frameworks. This review systematically analyzes current in vitro and in vivo methodologies used to assess the safety, biocompatibility, mechanical integrity, and functional performance of 3D printing-based TETs. By introducing a variety of analysis methods to evaluate the mechanical, physicochemical, and biocompatibility properties of TETs, this study aims to propose essential components for the evaluation of 3D-printed TETs.