Bioprinted cell-instructive lung-dECM constructs for reconstructing an immuno-regenerative pulmonary microenvironment.

Pulmonary tissue engineering requires scaffolds that combine parenchymal mechanical compliance with extracellular matrix-bound instructive cues, yet soft materials often lack print fidelity. Here, we developed decellularized lung matrix (dLM) bioinks using an osmotic decellularization strategy designed to preserve sulfated glycosaminoglycans (sGAGs) and basement membrane proteins and benchmarked them against conventionally detergent-processed dLM. Rather than inferring printability from bulk viscosity without shear history, we standardized extrusion conditions by defining flow windows through print-matched thixotropy testing that incorporates nozzle residence time and wall shear stress to predict post-extrusion structural recovery. This framework revealed distinct structure-function tradeoffs, collagen-dominant dLM inks supported superior vertical layer stacking through higher viscosity and proportionate elastic and viscous recovery, whereas sGAG preserved polyelectrolyte rich matrices exhibited faster viscosity rebuild with rapid gelation after extrusion. Resultant dLM hydrogels maintained lung parenchymal viscoelasticity ranges and retained cytocompatibility through bioprinting. Printed dLM scaffolds directed mesenchymal stem cell fate in a spatially dependent manner; surface-seeding induced epithelial markers, including cytokeratin and tight junction proteins, and surfactant-associated transcripts, whereas encapsulated cells developed α-SMA expression, consistent with an interstitial myogenic phenotype. Macrophages cultured within sGAG-rich dLM scaffolds adopted anti-inflammatory polarization with elevated mannose receptor expression and regulatory cytokine production that persisted under inflammatory stimulation. Together these results show that strategic preservation of lung ECM components can yield printed scaffolds that reconcile pulmonary mechanics, high printing fidelity, regenerative niche-specific cell responses, and sustained in vitro immunomodulation, requirements that collectively establish a compositionally validated bioink platform for engineering lung tissue.