Lung organoids and organ-on-a-chip models in respiratory disease research: advances, applications, and challenges

Lung organoids are human-derived in vitro models that can form three-dimensional structures in culture. They provide useful systems for respiratory disease research. This review first outlines the main cell sources and construction methods for lung organoids. It then discusses how these models have been used to study pulmonary fibrosis, lung cancer, chronic obstructive pulmonary disease (COPD), and respiratory infections. The review also explains how organ-on-a-chip technology can add flow, stretch, and other physical cues to organoid models. These cues help researchers build more dynamic systems, but they do not remove the need for careful validation. Finally, this review summarizes key challenges in standardization, model complexity, and clinical translation. It also describes future directions for personalized and precision respiratory medicine.