Upconverted microrobots alleviate the idiopathic pulmonary fibrosis via improving the respiratory depression

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive pulmonary disorder characterized by fibrotic scarring, hypoxemia, and dyspnea. Although oxygen therapy is widely used to relieve acute dyspnea, it faces limitations such as oxygen toxicity and patient immobility. To address these challenges, this study developed upconversion-based microrobots capable of mitigating IPF through in situ oxygen generation. These microrobots consist of <em>Chlamydomonas reinhardtii</em> algae functionalized with upconversion nanoparticles. Upon inhalation and exposure to near-infrared light, the microrobots convert the incident light into red visible light, driving photosynthetic oxygen production at a rate of 0.298 ± 0.005 mg (L·min)^-1. Moreover, their autonomous mobility within the mucus enhances the uniformity of oxygen distribution and prolongs retention by evading pulmonary macrophage clearance. In a murine model of IPF, the microrobots effectively alleviated hypoxia, as evidenced by reduced HIF-1α expression in fibrotic lung tissues and elevated blood oxygen saturation. This platform presents an efficient and promising strategy for oxygen therapy in IPF and broader pulmonary oxygen-dependent applications.