A Fully Biological Gas-Exchange Membrane toward a Biofabricated, Booster Lung

Area of Science:

• Biomaterials Engineering
• Regenerative Medicine
• Respiratory Physiology

Background:

• Chronic lung disease necessitates long-term respiratory support, but current extracorporeal membrane oxygenation (ECMO) is limited by clotting and bleeding complications.
• Permanent respiratory support requires biocompatible materials that prevent clot formation and bleeding, a challenge not yet met by artificial devices.
• Engineering a biofabricated tissue mimicking the alveolar-capillary barrier is crucial for developing long-term, implantable support lungs.

Purpose of the Study:

• To engineer a preliminary, fully biological tissue that replicates the alveolar-capillary barrier.
• To assess the potential of this tissue as a gas-exchange membrane for an implantable, biofabricated support lung.
• To evaluate the mechanical strength, permeability, and cellular viability of the engineered tissue.

Main Methods:

• Fabrication of high-concentration, type I collagen membranes (18.8 ± 3.6 μm-thick).
• Characterization of mechanical strength, water permeability, and oxygen transfer under static, air-liquid conditions.
• Coculture of membranes with human umbilical vein endothelial cells (HUVECs) and A549 lung epithelial cells, followed by assessment of tissue viability and permeability to 70 kDa-FITC dextran.

Main Results:

• The collagen I hydrogel membranes exhibited mechanical strength (≥120 mmHg) and significant oxygen transfer (75% of a silicone sheet).
• Cocultured cells remained viable in air-liquid conditions, demonstrating biocompatibility.
• Dextran permeability indicated the necessity of an alveolar epithelium for enhanced barrier function.

Conclusions:

• A biofabricated collagen I tissue shows promise as a gas-exchange membrane for implantable support lungs.
• Further optimization, including thinner membranes and advanced cell sourcing, is needed for a functional, intracorporeal support lung.
• This approach offers a potential solution for long-term respiratory support in chronic lung disease patients.