Late Breaking Abstract - 3D Bioprinting of Decellularised Porcine Lung ECM

Background: The concept of transplantable, bioengineered lungs has been proposed as a solution to meet growing transplantation needs. One of the ways to potentially build complex lung structure is 3D bioprinting. Decellularized extracellular matrix (dECM) based materials are considered as a potential novel source of material for bioinks because they have been shown in other contexts to provide a suitable microenvironment for regeneration. We hypothesized that using dECM porcine lung as bioink would recapitulate mechanical properties and microenvironment of the native lung. In this study, we evaluated the fluid properties of the dECM bioinks through examination of rheological properties of porcine lung-derived dECM solutions and gels. We also evaluated how respiratory cells interact with decellularized lung ECM gels. Material and Methods: Pepsin digested porcine dECM solutions were prepared. The gels were formed by setting the pH of the solutions to 7.2-7.4 and subsequently heating them to 37 ºC. Morphology of the gels was studied with scanning electron microscopy (SEM). Rheological properties of the solutions before and during gelation were measured with rheometry. A549 cells were seeded on dECM gels (2D) as well as embedded within dECM hydrogel (3D). Results and Discussion: Similar to native ECM, dECM gels exhibited fibrous structure. Rheometry measurements indicated shear-thinning behavior of dECM solutions, which is crucial for printability and protection of cells during the bioprinting. A549 cells exhibited high cell viability on and within dECM gels. SEM of A549 cells on dECM hydrogels (2D) showed that the cells were grown as monolayers.