A team of bioengineers from the Indian Institute of Science Bangalore, India, has created a mucus-based bio-ink for 3D printing lung tissue — an advancement that could potentially be used to treat chronic lung conditions.

In a bid to better explore the production of lung tissue in the lab — either as a more accurate model to study human lungs or as a potential material to use in implants — the team sought to develop a suitable bio-ink as a means to 3D print structures mimicking human tissue.

Source: ACS Applied Bio Materials (2024). DOI: 10.1021/acsabm.4c00579

To develop the appropriate bio-ink, the team of bioengineers began with mucin, a mucus component. Because parts of this antibacterial polymer's molecular structure mimic epidermal growth factor — a protein that promotes cell attachment and growth — the team reacted mucin with methacrylic anhydride to create methacrylated mucin (MuMA), which they then combined with lung cells.

Further, the team added hyaluronic acid — a natural polymer in connective and other tissues — to the mix to increase the bioink's viscosity and to encourage cell growth as well as adhesion to MuMA. Once printed in test patterns, including round and square grids, the ink was subsequently exposed to blue light to crosslink the MuMA molecules. The bioengineers reported that the crosslink bonds stabilized the printed structure in a porous gel that absorbed water to support cell survival.

Meanwhile, the interconnected pores of the gel expedited the diffusion of nutrients and oxygen, which encouraged both cell growth and the formation of lung tissue.

The team concluded that because the printed structures were nontoxic and slowly biodegradable under physiological conditions, they are potentially useful as implants wherein the printed scaffold would gradually be replaced by newly grown lung tissue. Additionally, the bio-ink could also potentially be used to create 3D models of lungs to study lung disease processes and evaluate possible treatments.

An article detailing the team’s findings, “3D Bioprinting with Visible Light Cross-Linkable Mucin-Hyaluronic Acid Composite Bioink for Lung Tissue Engineering,” appears in the journal ACS Applied Bio Materials.