Utilizing elastic decellularized plant tissues to model lung breathing mechanical stress
Despite the remarkable advancements made in tissue engineering (TE), there are still many challenges limiting the clinical applicability of TE solutions, which has prompted the search for new biomaterials. In this study, we propose exploring a recent approach utilizing decellularized plant materials to recapitulate the lung microenvironment. Specifically, spinach leaves were utilized as a biocompatible scaffold to model the mechanical stress caused by the lung during breathing. First, an engineered device was developed to stretch the scaffold and mimic physiological breath motions. The characterization data demonstrated that the device can apply a cyclic strain at a frequency of 18 cycles/min with an average strain amplitude of 13%. Lung epithelial A549 cells were then seeded on the decellularized scaffolds that were placed in the stretch device for 24 hours. After stretching, the cells were immunostained for YAP and F-Actin, and the expressed mRNA was measured using qRT-PCR. The results showed that (1) the cells aligned perpendicular to the direction of the stretch, (2) the cytoplasmic YAP protein localized to the nucleus and (3) collagen type I, IV and VI as well as interleukin-8 mRNA levels increased, indicating that the cells were able to sense and adapt to the mechanical strain. These preliminary results suggest that our lung-on-a-leaf model could potentially be used to further study other biological responses in the lung microenvironment.